Publisher Correction: Extensive signal integration by the phytohormone protein network.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Extensive signal integration by the phytohormone protein network.

Plant hormones coordinate responses to environmental cues with developmental programs1, and are fundamental for stress resilience and agronomic yield2. The core signalling pathways underlying the effects of phytohormones have been elucidated by genetic screens and hypothesis-driven approaches, and extended by interactome studies of select pathways3. However, fundamental questions remain about how information from different pathways is integrated. Genetically, most phenotypes seem to be regulated by several hormones, but transcriptional profiling suggests that hormones trigger largely exclusive transcriptional programs4. We hypothesized that protein-protein interactions have an important role in phytohormone signal integration. Here, we experimentally generated a systems-level map of the Arabidopsis phytohormone signalling network, consisting of more than 2,000 binary protein-protein interactions. In the highly interconnected network, we identify pathway communities and hundreds of previously unknown pathway contacts that represent potential points of crosstalk. Functional validation of candidates in seven hormone pathways reveals new functions for 74% of tested proteins in 84% of candidate interactions, and indicates that a large majority of signalling proteins function pleiotropically in several pathways. Moreover, we identify several hundred largely small-molecule-dependent interactions of hormone receptors. Comparison with previous reports suggests that noncanonical and nontranscription-mediated receptor signalling is more common than hitherto appreciated.

Platelet reactivity and clinical outcomes in acute coronary syndrome patients treated with prasugrel and clopidogrel: a pre-specified exploratory analysis from the TROPICAL-ACS trial.

AIMS: The value of platelet function testing (PFT) in predicting clinical outcomes and guiding P2Y12-inhibitor treatment is uncertain. In a pre-specified sub-study of the TROPICAL-ACS trial, we assessed ischaemic and bleeding risks according to high platelet reactivity (HPR) and low platelet reactivity (LPR) to ADP in patients receiving uniform prasugrel vs. PFT-guided clopidogrel or prasugrel. METHODS AND RESULTS: Acute coronary syndrome patients with PFT done 14 days after hospital discharge were included with prior randomization to uniform prasugrel for 12 months (control group, no treatment modification) vs. early de-escalation from prasugrel to clopidogrel and PFT-guided maintenance treatment (HPR: switch-back to prasugrel, non-HPR: clopidogrel). The composite ischaemic endpoint included cardiovascular death, myocardial infarction, or stroke, while key safety outcome was Bleeding Academic Research Consortium (BARC) 2-5 bleeding, from PFT until 12 months. We identified 2527 patients with PFT results available: 1266 were randomized to the guided and 1261 to the control group. Before treatment adjustment, HPR was more prevalent in the guided group (40% vs. 15%), while LPR was more common in control patients (27% vs. 11%). Compared to control patients without HPR on prasugrel (n = 1073), similar outcomes were observed in guided patients kept on clopidogrel [n = 755, hazard ratio (HR): 1.06 (0.57-1.95), P = 0.86] and also in patients with HPR on clopidogrel switched to prasugrel [n = 511, HR: 0.96 (0.47-1.96), P = 0.91]. In contrast, HPR on prasugrel was associated with a higher risk for ischaemic events in control patients [n = 188, HR: 2.16 (1.01-4.65), P = 0.049]. Low platelet reactivity was an independent predictor of bleeding [HR: 1.74 (1.18-2.56), P = 0.005], without interaction (Pint = 0.76) between study groups. CONCLUSION: Based on this substudy of a randomized trial, selecting prasugrel or clopidogrel based on PFT resulted in similar ischaemic outcomes as uniform prasugrel therapy without HPR. Although infrequent, HPR on prasugrel was associated with increased risk of ischaemic events. Low platelet reactivity was a strong and independent predictor of bleeding both on prasugrel and clopidogrel.

Guided de-escalation of DAPT in acute coronary syndrome patients undergoing percutaneous coronary intervention with BVS implantation: a post-hoc analysis from the randomized TROPICAL-ACS trial.

To investigate the safety and efficacy of an early platelet function testing (PFT)-guided de-escalation of dual antiplatelet treatment (DAPT) in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) with bioresorbable vascular scaffolds (BVS). Early DAPT de-escalation is a new non-inferior alternative to 12-months DAPT in patients with biomarker positive ACS treated with stent implantation. In this post-hoc analysis of the TROPICAL-ACS trial, which randomized 2610 ACS patients to a PFT-guided DAPT de-escalation (switch from prasugrel to clopidogrel) or to control group (uniform prasugrel), we compared clinical outcomes of patients (n = 151) who received a BVS during the index PCI. The frequency of the primary endpoint (cardiovascular death, myocardial infarction, stroke or BARC ≥ 2 bleeding) was 8.8% (n = 6) in the de-escalation group vs. 12.0% (n = 10) in the control group (HR 0.72, 95% CI 0.26-1.98, p = 0.52) at 12 months. One early definite stent thrombosis (ST) occurred in the control group (day 19) and 1 possible ST (sudden cardiovascular death) in the de-escalation group (day 86), both despite prasugrel treatment and in a background of high on-treatment platelet reactivity assessed at day 14 after randomization (ADP-induced platelet aggregation values of 108 U and 59 U, respectively). A PFT-guided DAPT de-escalation strategy could potentially be a safe and effective strategy in ACS patients with BVS implantation but the level of platelet inhibition may be of particular importance. This hypothesis-generating post-hoc analysis requires verification in larger studies with upcoming BVS platforms.

Age and outcomes following guided de-escalation of antiplatelet treatment in acute coronary syndrome patients undergoing percutaneous coronary intervention: results from the randomized TROPICAL-ACS trial.

Aims: Guided de-escalation of P2Y12-inhibitor treatment was recently identified as an effective alternative treatment strategy in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention. Safety and efficacy of this strategy may differ in relation to patient's age. This pre-specified analysis of the TROPICAL-ACS trial aimed to assess the impact of age on clinical outcomes following guided de-escalation of antiplatelet treatment in ACS patients. Methods and results: Patients were randomly assigned in a 1:1 fashion to either standard treatment with prasugrel for 12 months (control group) or to a guided de-escalation regimen (1 week prasugrel followed by 1 week clopidogrel and platelet function testing guided maintenance therapy with clopidogrel or prasugrel from day 14 after hospital discharge; guided de-escalation group). We used Cox regression models to assess the associations of age on clinical endpoints and interactions. In younger patients (age ≤70, n = 2240), the 1 year incidence of the primary endpoint (cardiovascular death, myocardial infarction, stroke, or bleeding ≥ grade 2 according to Bleeding Academic Research Consortium criteria) was significantly lower in guided de-escalation vs. control group [5.9% vs. 8.3%; hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.51-0.96; P = 0.03, number needed to treat = 42]. In elderly patients (age >70, n = 370), the absolute risk of events was higher without significant differences between guided de-escalation vs. control group (15.5% vs. 13.6%; HR 1.17, 95% CI 0.69-2.01; P = 0.56). When the impact of age, as a continuous variable, was analysed on outcomes after guided de-escalation vs. control treatment, an increasing relative risk reduction was observed in the primary endpoint by decreasing age (Pint = 0.02), due to significant reductions in bleeding. Conclusion: Treatment effects of guided de-escalation for P2Y12 inhibitors depend on patient's age with younger patients deriving a significant net clinical benefit. Although the safety and efficacy of guided de-escalation in the elderly was similar to uniform prasugrel therapy, this should be further investigated due to the limited sample size of this group.

Guided de-escalation of antiplatelet treatment in patients with acute coronary syndrome undergoing percutaneous coronary intervention (TROPICAL-ACS): a randomised, open-label, multicentre trial.

BACKGROUND: Current guidelines recommend potent platelet inhibition with prasugrel or ticagrelor for 12 months after an acute coronary syndrome managed with percutaneous coronary intervention (PCI). However, the greatest anti-ischaemic benefit of potent antiplatelet drugs over the less potent clopidogrel occurs early, while most excess bleeding events arise during chronic treatment. Hence, a stage-adapted treatment with potent platelet inhibition in the acute phase and de-escalation to clopidogrel in the maintenance phase could be an alternative approach. We aimed to investigate the safety and efficacy of early de-escalation of antiplatelet treatment from prasugrel to clopidogrel guided by platelet function testing (PFT). METHODS: In this investigator-initiated, randomised, open-label, assessor-blinded, multicentre trial (TROPICAL-ACS) done at 33 sites in Europe, patients were enrolled if they had biomarker-positive acute coronary syndrome with successful PCI and a planned duration of dual antiplatelet treatment of 12 months. Enrolled patients were randomly assigned (1:1) using an internet-based randomisation procedure with a computer-generated block randomisation with stratification across study sites to either standard treatment with prasugrel for 12 months (control group) or a step-down regimen (1 week prasugrel followed by 1 week clopidogrel and PFT-guided maintenance therapy with clopidogrel or prasugrel from day 14 after hospital discharge; guided de-escalation group). The assessors were masked to the treatment allocation. The primary endpoint was net clinical benefit (cardiovascular death, myocardial infarction, stroke or bleeding grade 2 or higher according to Bleeding Academic Research Consortium [BARC]) criteria) 1 year after randomisation (non-inferiority hypothesis; margin of 30%). Analysis was intention to treat. This study is registered with ClinicalTrials.gov, number NCT01959451, and EudraCT, 2013-001636-22. FINDINGS: Between Dec 2, 2013, and May 20, 2016, 2610 patients were assigned to study groups; 1304 to the guided de-escalation group and 1306 to the control group. The primary endpoint occurred in 95 patients (7%) in the guided de-escalation group and in 118 patients (9%) in the control group (pnon-inferiority=0·0004; hazard ratio [HR] 0·81 [95% CI 0·62-1·06], psuperiority=0·12). Despite early de-escalation, there was no increase in the combined risk of cardiovascular death, myocardial infarction, or stroke in the de-escalation group (32 patients [3%]) versus in the control group (42 patients [3%]; pnon-inferiority=0·0115). There were 64 BARC 2 or higher bleeding events (5%) in the de-escalation group versus 79 events (6%) in the control group (HR 0·82 [95% CI 0·59-1·13]; p=0·23). INTERPRETATION: Guided de-escalation of antiplatelet treatment was non-inferior to standard treatment with prasugrel at 1 year after PCI in terms of net clinical benefit. Our trial shows that early de-escalation of antiplatelet treatment can be considered as an alternative approach in patients with acute coronary syndrome managed with PCI. FUNDING: Klinikum der Universität München, Roche Diagnostics, Eli Lilly, and Daiichi Sankyo.

Platelet Function Testing in Patients on Antiplatelet Medications.

Guidelines provide a Class IA recommendation for the use of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention (PCI). However, there is interindividual variability in the pharmacodynamic response to antiplatelet medications. Some patients present with a status of high on-treatment platelet reactivity (HPR) during platelet function testing after standard doses of antiplatelet drugs, reflecting a failure to achieve adequate platelet inhibition. As an example, patients with HPR on clopidogrel are at increased risk for thrombotic events, particularly for stent thrombosis and myocardial infarction, but cardiovascular mortality is also elevated. On the contrary, low on-treatment platelet reactivity or an enhanced response to antiplatelet medications has been linked to a higher risk for bleeding. Although both thrombotic and bleeding events are multifactorial in origin, there is supportive evidence for the prognostic value of platelet function testing for risk prediction of both sides of the coin. However, although small studies have provided evidence that treatment adjustments based on platelet function testing results may improve clinical outcomes, the available randomized controlled trials showed no benefit of modifying antiplatelet treatment based on platelet function testing. This review presents the current evidence regarding platelet function testing in patients undergoing PCI. The prognostic value of platelet function testing regarding ischemic and bleeding events is highlighted. Furthermore, the value of platelet function testing for guiding treatment and possible explanations for the so-far negative trial results are presented. The possible future role of platelet function testing for individualized antiplatelet treatment regimens in high-risk patients will be also discussed.

Ticagrelor versus prasugrel in patients with high on-clopidogrel treatment platelet reactivity after PCI: The ISAR-ADAPT-PF study.

Patients with high on-treatment platelet reactivity (HTPR) on clopidogrel are at high risk for adverse cardiovascular events after percutaneous coronary intervention (PCI). The aim of the ISAR-ADAPT-PF study was to assess the antiplatelet efficacy of ticagrelor versus prasugrel in patients with HTPR on clopidogrel. In a prospective and randomized clinical study, 70 patients with HTPR on clopidogrel loading dose (LD) within 24 h post PCI were assigned to receive either ticagrelor [180 mg LD followed by 90 mg maintenance dose (MD) twice daily] or prasugrel (60 mg LD followed by 10 mg MD once daily). The adenosine diphosphate-induced platelet aggregation assessed on the Multiplate analyzer on day 2 after randomization (primary end point) was as follows: the mean difference between the two treatment groups was 6 aggregation units (AU) × min with an upper 95% confidence interval (CI) of 41 AU × min, which was greater than the predefined noninferiority margin of 18 AU × min (P for noninferiority = 0.29). However, no significant differences in absolute platelet reactivity levels between ticagrelor- versus prasugrel-treated patients at that time point were observed (138 ± 100 AU × min vs. 132 ± 64 AU × min, P for superiority = 0.77). In conclusion, neither drug was statistically more effective for inhibition of platelet aggregation in patients with HTPR on clopidogrel post PCI, although the study could not formally demonstrate the assumed noninferiority of ticagrelor versus prasugrel.

Impact of the bioresorbable vascular scaffold surface area on on-treatment platelet reactivity.

While promising data with the novel bioresorbable vascular scaffold (BVS) are accumulating, signals of scaffold thrombosis (ST) were noted in recent reports. We aimed to assess the relationship between the total surface area (TSA) of implanted everolimus-eluting BVSs and the on-treatment adenosine diphosphate (ADP)-induced platelet reactivity in patients undergoing percutaneous coronary intervention (PCI). 202 consecutive patients undergoing BVS implantation and platelet function testing were included. For investigating the impact of the scaffold surface on platelet reactivity, patients were stratified into two groups regarding the median BVS TSA. The on-treatment ADP-induced platelet reactivity was determined with the Multiplate analyzer and 30-day follow-up was available in 98% of patients. ADP-induced platelet aggregation values (median, [IQR]) did not differ between the two study groups (12.0 [9.0-19.0] U for patients with TSA > 1.39 cm(2) and 13.0 [9.0-19.5] U for patients with TSA ≤ 1.39 cm(2); p = 0.69). No correlation was observed between the BVS TSA and levels of platelet reactivity (Spearman rank correlation = -0.10, p = 0.16). At 30 days after PCI, two early STs (1%) were documented. Thus, in patients on a dual antiplatelet treatment regimen following BVS implantation, the extent of blood-to-BVS contact surface does not negatively affect levels of on-treatment platelet reactivity.

Predictors of antiplatelet response to prasugrel during maintenance treatment.

Insufficient P2Y12 receptor inhibition is associated with a higher risk of thrombotic events after percutaneous coronary intervention (PCI). The third generation thienopyridine prasugrel achieves stronger platelet inhibition as compared to its predecessor clopidogrel. Little is known about predictors of prasugrel drug responsiveness. The aim of this study was to explore predictors of prasugrel responsiveness in patients with a recent PCI on prasugrel maintenance dose (MD) treatment. In a registry of PCI-treated patients (n = 163, recruited between August 2009 and March 2012) on prasugrel MD treatment, the ADP-induced platelet aggregation (PA) was assessed on a Multiplate analyzer. The mean (interquartile range (IQR)) ADP-induced PA on prasugrel MD treatment was 206 (138-331) AU × min. Obese (defined by a body mass index (BMI) ≥ 30) patients (n = 42) (303 [192-467] vs. 187 [117-305] AU × min, p = 0.0001), patients (n = 70) with a history of clopidogrel low responsiveness (278 [161-409] vs. 192 [126-282] AU × min, p = 0.002) and patients (n = 18) on a low (5 mg) prasugrel MD (483 [252-798] vs. 198 [133-313] AU × min; p = 0.0001) showed higher PA values on prasugrel MD as compared to the remaining patients. In a multivariable linear regression model, the latter three variables were independently associated with higher PA values on prasugrel MD treatment. In summary response variability is observed in patients on prasugrel MD treatment. Obesity, a history of clopidogrel low responsiveness and a reduced prasugrel MD of 5 mg are independent predictors of an attenuated response to prasugrel treatment. Further studies are needed to explore clinical implications of this observation.

[Resource activation and therapeutic success in in-patient and day-care psychosomatic treatment]. / Ressourcenaktivierung und Therapieerfolg in der (teil)stationären Psychosomatik.

OBJECTIVE: The aim of the study was to examine the association between resource activation and treatment success in in-patient and day-care psychosomatic treatment. METHODS: 130 patients were examined at the beginning and at the end of their in-patient or day-care psychosomatic treatment. The change of resource realization (RES[1]) and different measures of therapeutic success (SCL-90-R[2], BDI-II[3], WHO-5-Q[4], GAS[5], retrospective success evaluation [6]) were assessed using standardized questionnaires. RESULTS: The results demonstrated a significant trans-diagnostic change in patients' resource realization, which correlated with different measures of mental health (SCL-90-R, BDI-II, WHO-5-Q). Resource realization at the beginning of the treatment and the process of resource activation (pre-post measure of resource realization) turned out to be relevant for predicting treatment success. Furthermore, mediation analysis shows that initiation of experiences of mastery (BSPR-P[7]) seems to be effective as a mediation process. CONCLUSION: The results show that resource realization improves during psychosomatic treatment and is associated with treatment success.

Impact of body mass on P2Y12-inhibitor de-escalation in acute coronary syndromes-a substudy of the TROPICAL-ACS trial.

AIMS: Clinical guidelines recommend de-escalation antiplatelet strategies to reduce bleeding risk in acute coronary syndrome (ACS) patients, albeit with a weak recommendation. This substudy of the TROPICAL-ACS trial aimed to determine the impact of body mass on the efficacy of a platelet function testing-guided de-escalation regimen in ACS patients after percutaneous coronary intervention. METHODS AND RESULTS: Patients were randomized to prasugrel (control group) or a platelet function testing-guided regimen with clopidogrel or prasugrel defined after 1-week clopidogrel. The primary endpoint was the net clinical benefit [cardiovascular death, myocardial infarction, stroke, or Bleeding Academic Research Consortium (BARC) 2-5 bleeding] for 12 months. Overweight was defined as a body mass index >25 kg/m2.Patients without overweight showed a significant net clinical benefit from the de-escalation strategy, while in overweight cases de-escalation was comparable to prasugrel treatment [hazard ratio (HR): 0.52; 95% confidence interval (CI): 0.31-0.88; P = 0.013 and HR: 0.95; 95% CI: 0.69-1.31, P = 0.717, P-non-inferiority = 0.03, respectively, P-interaction = 0.053]. The benefit of de-escalation in terms of the risk of bleeding or of the ischaemic events did not reach statistical significance. Bleeding events with de-escalation were less frequent in non-overweight patients but comparable in overweight patients (HR: 0.55; 95% CI: 0.30-1.03; P = 0.057 and HR: 0.95; 95% CI: 0.64-1.41, respectively, P-interaction = 0.147). Non-overweight patients had lower ischaemic event rates with de-escalation, while overweight cases had slightly less (HR: 0.47; 95% CI: 0.18-1.25; P = 0.128 and HR: 0.89; 95% CI: 0.53-1.50, respectively, P-interaction = 0.261). CONCLUSION: The strategy of guided dual antiplatelet therapy de-escalation was associated with a significant net clinical benefit in non-overweight patients, while the two strategies were equivalent in overweight patients.

Kinetic approach to pathway attenuation using XOMA 052, a regulatory therapeutic antibody that modulates interleukin-1beta activity.

Many therapeutic antibodies act as antagonists to competitively block cellular signaling pathways. We describe here an approach for the therapeutic use of monoclonal antibodies based on context-dependent attenuation to reduce pathologically high activity while allowing homeostatic signaling in biologically important pathways. Such attenuation is achieved by modulating the kinetics of a ligand binding to its various receptors and regulatory proteins rather than by complete blockade of signaling pathways. The anti-interleukin-1beta (IL-1beta) antibody XOMA 052 is a potent inhibitor of IL-1beta activity that reduces the affinity of IL-1beta for its signaling receptor and co-receptor but not for its decoy and soluble inhibitory receptors. This mechanism shifts the effective dose response of the cytokine so that the potency of IL-1beta bound by XOMA 052 is 20-100-fold lower than that of IL-1beta in the absence of antibody in a variety of in vitro cell-based assays. We propose that by decreasing potency of IL-1beta while allowing binding to its clearance and inhibitory receptors, XOMA 052 treatment will attenuate IL-1beta activity in concert with endogenous regulatory mechanisms. Furthermore, the ability to bind the decoy receptor may reduce the potential for accumulation of antibody.target complexes. Regulatory antibodies like XOMA 052, which selectively modulate signaling pathways, may represent a new mechanistic class of therapeutic antibodies.

Bacteremia and antimicrobial drug resistance over time, Ghana.

Bacterial distribution and antimicrobial drug resistance were monitored in patients with bacterial bloodstream infections in rural hospitals in Ghana. In 2001-2002 and in 2009, Salmonella enterica serovar Typhi was the most prevalent pathogen. Although most S. enterica serovar Typhi isolates were chloramphenicol resistant, all isolates tested were susceptible to ciprofloxacin.

Smoking and outcomes following guided de-escalation of antiplatelet treatment in acute coronary syndrome patients: a substudy from the randomized TROPICAL-ACS trial.

AIMS: Prior analyses disclosed variations in antiplatelet drug response and clinical outcomes between smokers and non-smokers, thus the safety and efficacy of any dual antiplatelet therapy (DAPT) de-escalation strategy may differ in relation to smoking status. Hence, we assessed the impact of smoking on clinical outcomes and adenosine diphosphate-induced platelet aggregation following guided de-escalation of DAPT in invasively managed acute coronary syndrome (ACS) patients. METHODS AND RESULTS: The multicentre TROPICAL-ACS trial randomized 2610 biomarker-positive ACS patients 1:1 to standard treatment with prasugrel for 12 months (control group) or a platelet function testing guided de-escalation of DAPT. Current smokers (n = 1182) showed comparable event rates between study groups [6.6% vs. 6.6%; hazard ratio (HR) 1.0, 95% confidence interval (CI) 0.64-1.56, P > 0.99]. In non-smokers (n = 1428), a guided DAPT de-escalation was associated with a lower 1-year incidence of the primary endpoint [cardiovascular death, myocardial infarction, stroke, or bleeding ≥ Grade 2 according to Bleeding Academic Research Consortium (BARC) criteria] compared with control group patients (7.9% vs. 11.0%; HR 0.71, 95% CI 0.50-0.99, P = 0.048). This reduction was mainly driven by a lower rate of BARC ≥ Grade 2 bleedings (5.2% vs. 7.7%; HR 0.68, 95% CI 0.45-1.03, P = 0.066). There was no significant interaction of smoking status with treatment effects of guided DAPT de-escalation (Pint = 0.23). Adenosine diphosphate-induced platelet aggregation values were higher in current smokers [median 28 U, interquartile range (IQR: 20-40)] vs. non-smoker [median 24 U (16-25), P < 0.0001] in the control group and in current smokers [median 42 U, IQR (27-68)] vs. non-smoker [median 37 U, IQR (25-55), P < 0.001] in the monitoring group. CONCLUSION: Guided DAPT de-escalation appears to be equally safe and effective in smokers and non-smokers. Regardless of smoking status and especially for those patients deemed unsuitable for 1 year of potent platelet inhibition this DAPT strategy might be used as an alternative antiplatelet treatment regimen.

Shiga toxin 2 targets the murine renal collecting duct epithelium.

Hemolytic-uremic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli infection is a leading cause of pediatric acute renal failure. Bacterial toxins produced in the gut enter the circulation and cause a systemic toxemia and targeted cell damage. It had been previously shown that injection of Shiga toxin 2 (Stx2) and lipopolysaccharide (LPS) caused signs and symptoms of HUS in mice, but the mechanism leading to renal failure remained uncharacterized. The current study elucidated that murine cells of the glomerular filtration barrier were unresponsive to Stx2 because they lacked the receptor glycosphingolipid globotriaosylceramide (Gb(3)) in vitro and in vivo. In contrast to the analogous human cells, Stx2 did not alter inflammatory kinase activity, cytokine release, or cell viability of the murine glomerular cells. However, murine renal cortical and medullary tubular cells expressed Gb(3) and responded to Stx2 by undergoing apoptosis. Stx2-induced loss of functioning collecting ducts in vivo caused production of increased dilute urine, resulted in dehydration, and contributed to renal failure. Stx2-mediated renal dysfunction was ameliorated by administration of the nonselective caspase inhibitor Q-VD-OPH in vivo. Stx2 therefore targets the murine collecting duct, and this Stx2-induced injury can be blocked by inhibitors of apoptosis in vivo.

Effect of insulin and glucose infusion on myocardial infarction size in uraemic rats.

The post myocardial infarction (MI) mortality rate is high in renal patients. One possible explanation is the reduced ischemia tolerance caused by uraemia. Previous investigations showed larger MI size in uraemic rats when compared with sham-operated controls. To explore a possible link between uraemic insulin resistance syndrome and MI size in uraemia, we studied an intervention model with administration of insulin and glucose during acute MI in subtotally nephrectomized (SNX) rats and sham-operated controls. In 16 SNX rats and 16 sham-operated controls, the left coronary artery was ligated for 60 min, followed by reperfusion for 90 min. To visualize the perfused myocardium, lissamine-green ink was injected. The nonperfused area (lissamine exclusion) and the area of total infarction (TTC stain) were assessed in sections of the left ventricle (LV) using image analysis. While eight SNX rats and eight sham-operated controls were treated with a placebo during the procedure, the other animals received an insulin bolus of 85 mU/kg and then a continuous insulin infusion of 8 mU/kg per minute. Blood glucose levels were clamped to baseline levels with an infusion of 25% glucose. Insulin receptor substrates (IRS-1 and IRS-2) and glucose transporter (GLUT 4) were studied by western blot in another seven SNX and seven sham-operated controls without further intervention. The infarcted area, given as a proportion of the nonperfused risk area, was not different in sham-operated controls treated with a hyperinsulinaemic clamp versus untreated (0.55 +/- 0.07 vs. 0.51 +/- 0.13, p = 0.477). The eight SNX animals treated with the hyperinsulinaemic clamp utilized significantly less glucose to stabilize baseline glucose levels when compared with the sham-operated controls (5,637 vs. 3,207 microl Glc 25%, p = 0.007). The infarcted area was significantly lower in SNX rats treated with the hyperinsulinaemic clamp compared to non-treated SNX animals (0.56 +/- 0.06 vs. 0.79 +/- 0.09, p < 0.001). SNX rats with the insulin clamp had the same infarcted area size as sham-operated controls (0.56 +/- 0.06 vs. 0.51 +/- 0.13, p = 0.357). Western blotting did not show any change in the expression of GLUT 4 and IRS-1/IRS-2 in SNX animals when compared with sham-operated controls. The size of MI in uraemic rats is significantly reduced by a glucose/insulin infusion. The results suggest an insulin resistance in uraemic rats with similar benefits of glucose/insulin application during acute MI, as found in diabetic individuals. Further analysis did not reveal a down regulation in GLUT 4 and IRS-1/IRS-2.

Regenerative capacity of intravenous autologous, allogeneic and human mesenchymal stem cells in the infarcted pig myocardium-complicated by myocardial tumor formation.

OBJECTIVES: Intravenous delivery of mesenchymal stem cells (MSCs) is an attractive approach for regeneration of infarcted myocardium. However, its efficacy is not well-defined in large animals. METHODS: Pigs (n =8) received intravenously autologous, allogeneic porcine or human MSCs (1 x 10(6) per kg bodyweight) labeled with fluorescent dye 48 hours post proximal LAD occlusion. Infarct size, histology and myocardial function were assessed 4 weeks later. RESULTS: Labeled MSCs migrated in the peri-infarct region resulting in improved myocardial function. Infarct size was larger in the control group (32+/-7%) compared to autologous (19+/-7%, p =0.008), allogeneic (24+/-4%, p =0.01) and human MSCs (26+/-5%, p =0.03). Fractional area shortening significantly increased after 4 weeks in pigs receiving autologous MSCs (34+/-7%, p =0.001), allogeneic MSCs (28+/-2%, p =0.004) and human MSCs (24+/-5%, p =0.027), but was lower in the control group (23+/-3%, n.s.). However, substantial callus formation and a non-malignant cardiac "tumor" containing mesenchymal tissue was observed in one animal treated with human MSCs. CONCLUSIONS: Intravenously administered MSCs prevent pathologic remodeling and scar formation but bare potential risks from inflammatory-related products.

Diabetes and outcomes following guided de-escalation of antiplatelet treatment in acute coronary syndrome patients undergoing percutaneous coronary intervention: a pre-specified analysis from the randomised TROPICAL-ACS trial.

AIMS: A guided de-escalation of P2Y12 inhibitor treatment is considered an alternative treatment strategy in ACS patients undergoing PCI. However, the safety and efficacy of this strategy may differ in diabetic vs non-diabetic patients. The aim of this study was to compare the outcomes of platelet function testing (PFT)-guided de-escalation of dual antiplatelet therapy (DAPT) in ACS patients with and without diabetes mellitus. METHODS AND RESULTS: The TROPICAL-ACS trial randomised 2,610 biomarker-positive ACS patients 1:1 to either standard treatment with prasugrel for 12 months (control group) or PFT-guided DAPT de-escalation. The association and interaction of diabetes on clinical endpoints across treatment groups and on platelet reactivity was investigated. In diabetic patients (n=527, 20.2%), the overall event rates were high and the one-year incidence of the primary endpoint (cardiovascular death, myocardial infarction, stroke or bleeding ≥grade 2) did not differ between guided de-escalation and control group patients (12.5% vs 10.8%; HR 1.17, 95% CI: 0.71-1.93, p=0.55). In non-diabetic patients (n=2,083, 79.8%), the one-year incidence of the primary endpoint was lower in the guided de-escalation vs control group (6.1% vs 8.5%; HR 0.71, 95% CI: 0.52-0.99, p=0.04, pint=0.10). Diabetic patients showed higher platelet reactivity levels in both control (=on prasugrel, p=0.01) and guided de-escalation group (=on clopidogrel, p=0.005) patients. CONCLUSIONS: Although diabetic status did not significantly interfere with the treatment effects of guided DAPT de-escalation, our results suggest that this approach might be safe and effective in non-diabetic patients. Further investigation is definitely warranted in diabetic patients.

Diurnal Variability of On-Treatment Platelet Reactivity in Clopidogrel versus Prasugrel Treated Acute Coronary Syndrome Patients: A Pre-Specified TROPICAL-ACS Sub-Study.

Long-term evidence supports a clustering of cardiovascular events in the early morning and smaller mechanistic studies in aspirin-treated patients have shown increased platelet reactivity at the end of the dosing interval. Comparative pharmacodynamic analyses for different adenosine diphosphate (ADP) receptor inhibitors in percutaneous coronary intervention-treated acute coronary syndrome (ACS) patients are lacking and this pre-specified analysis from the randomized Testing Responsiveness To Platelet Inhibition On Chronic Antiplatelet Treatment For Acute Coronary Syndromes (TROPICAL-ACS) trial aimed for the first time at investigating diurnal variability of on-treatment platelet reactivity in clopidogrel versus prasugrel treated patients. TROPICAL-ACS randomized 2,610 ACS patients to either treatment with prasugrel (control group) or to a platelet function testing-guided de-escalation of anti-platelet treatment with a switch to clopidogrel (guided de-escalation group). This study design enabled a diurnal comparison of on-prasugrel versus on-clopidogrel treatment platelet reactivity under steady-state conditions. For 2,526 patients (97%), both the exact time of blood sampling and the ADP-induced platelet aggregation value (in units, Multiplate analyser) were available. Platelet reactivity in patients on clopidogrel (n = 1,265) was higher and subject to significant diurnal variability (p = 0.019) with a peaking of platelet reactivity in the early morning (5-10 a.m.). In prasugrel-treated patients (n = 1,261), there was no sign for diurnal variability (p = 0.174) or a peaking of platelet reactivity in the morning. The potent ADP receptor inhibitor prasugrel is not subject to diurnal variability while we observed a significant diurnal variability of on-clopidogrel platelet reactivity. The clinical impact of this observation may differ for patients with and without an adequate response to clopidogrel treatment and the issue of diurnal variability of platelet reactivity in ACS patients warrants further investigation.