Celastrol-type HSP90 modulators allow for potent cardioprotective effects

AIMS

Cardiac ischemic conditioning has been shown to decrease ischemic injury in experimental models and clinically. Activation of survival pathways leading to heat shock proteins (HSP) modulation is an important contributor to this effect. We have previously shown that celastrol, an HSP90 modulator, achieves cardioprotection through activation of cytoprotective HSP's and heme-oxygenase-1 (HO-1). This is the first comparative evaluation of several modulators of HSP90 activity for cardioprotection. Furthermore, basic celastrol structure-activity relationship was characterized in order to develop novel potent infarct sparing agents suitable for clinical development.

MAIN METHODS

Combining in vitro cell culture using rat myocardial cell line exposed to ischemic and ischemia/reperfusion (I/R) stresses, and ex vivo Langendorff rat heart perfusion I/R model, we evaluated cardioprotective effects of various compounds. Selected signalling pathways were evaluated by western blot and reporter gene activation.

KEY FINDINGS

From a variety of HSP90 modulator chemotypes, the celastrol family was most efficient in inducing cytoprotective HSP70 and HO-1 protein overexpression and cell survival in vitro. Celastrol and two synthetic analogs were protective against ischemia and prevented ischemia/reperfusion (I/R) injury when given as pre-treatment or at time of reperfusion, increasing viability and reducing mitochondrial permeability transition pore opening. Ex vivo experiments demonstrated that the two synthetic analogs show cardioprotective activity at lower concentrations compared to celastrol, with activation of multiple survival pathways.

SIGNIFICANCE

Celastrol backbone is essential for cardioprotection through HSP90 activity modulation. These compounds hold promise as novel adjunct treatment to improve outcome in the clinical management of I/R injury.

Effect of methylprednisolone on acute kidney injury in patients undergoing cardiac surgery with a cardiopulmonary bypass pump: a randomized controlled trial

BACKGROUND

Perioperative corticosteroid use may reduce acute kidney injury. We sought to test whether methylprednisolone reduces the risk of acute kidney injury after cardiac surgery.

METHODS

We conducted a prespecified substudy of a randomized controlled trial involving patients undergoing cardiac surgery with cardiopulmonary bypass (2007-2014); patients were recruited from 79 centres in 18 countries. Eligibility criteria included a moderate-to-high risk of perioperative death based on a preoperative score of 6 or greater on the European System for Cardiac Operative Risk Evaluation I. Patients (n = 7286) were randomly assigned (1:1) to receive intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients, caregivers, data collectors and outcome adjudicators were unaware of the assigned intervention. The primary outcome was postoperative acute kidney injury, defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 μmol/L) or 50% or greater in the 14-day period after surgery, or use of dialysis within 30 days after surgery.

RESULTS

Acute kidney injury occurred in 1479/3647 patients (40.6%) in the methylprednisolone group and in 1426/3639 patients (39.2%) in the placebo group (adjusted relative risk 1.04, 95% confidence interval 0.96 to 1.11). Results were consistent across several definitions of acute kidney injury and in patients with preoperative chronic kidney disease.

INTERPRETATION

Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery. Trial registration: ClinicalTrials.gov, no. NCT00427388.

2124. A Bundled Intervention Was Associated with Decreased Risk of Complex Staphylococcus aureus Surgical Site Infections among Patients Undergoing Clean Operative Procedures

Background

Our previous multicenter study suggested that a bundled intervention was associated with lower rates of complex S. aureus surgical site infections (SA SSIs) among patients undergoing cardiac or orthopedic operations in community hospitals. We aimed to evaluate the effect of this bundle in patients undergoing neurosurgical (NSG) operation, cardiac operation, or hip/knee arthroplasty at an academic health center.

Methods

This pragmatic quasi-experimental study included adult patients who underwent one of the procedures between June 1, 2012 and September 30, 2015 except those whose operations were done to treat infection. The bundle involved screening patients for SA nasal carriage, decolonizing carriers with intranasal mupirocin and chlorhexidine-gluconate bathing, and perioperative prophylaxis with vancomycin and cefazolin for patients who carried MRSA. The primary outcome was complex SA SSIs. To analyze changes in SSI rates, we used Poisson regression in time-series analysis. We used breast operations as a non-equivalent control group.

Results

One hundred forty-one complex SA SSIs occurred after 23,920 operations during the pre-intervention period (July 2004 to June 2012) and 28 occurred after 11,588 operations during intervention period (July 2012 to September 2015) (rate ratio [RR] 0.41; 95% confidence interval [CI] 0.27–0.61; Figure 1). During the same period, the complex SA SSI rate after breast operations did not decrease (RR 1.96; 0.82–4.65). Neurosurgeons implemented other interventions before implementing the full bundle in period 4 (Figure 2). The rate of complex SA SSIs after NSG operations decreased significantly only after the bundle was implemented (period 1 vs. 4, RR 0.22; 0.11–0.46). During the intervention period, 53% of patients received all bundle elements appropriate for their carriage status and 39% received some bundle elements. The complex SA SSI rate decreased significantly among patients who fully adhered (RR 0.23; 0.09–0.57) and among patients who partially adhered or not adhered (RR 0.56; 0.39–0.81).

Conclusion

Despite suboptimal adherence, the complex SA SSI rate decreased after implementing the evidence-based bundle but did not decrease in the non-equivalent control. Implementation science could help improve bundle adherence.

Disclosures

All authors: No reported disclosures.

DuraGraft vascular conduit preservation solution in patients undergoing coronary artery bypass grafting: rationale and design of a within-patient randomised multicentre trial

Introduction

Saphenous vein grafts (SVGs) remain the most often used conduits in coronary artery bypass grafting (CABG). However, they are prone to vein graft disease (VGD) during follow-up, which may compromise clinical outcomes. Injury to the SVG endothelium during harvesting and storage promotes neointimal hyperplasia that can advance to atherosclerosis characterised by SVG failure. This trial investigates the potential benefit of DuraGraft, a novel, one-time intraoperative graft treatment developed to efficiently protect the structural and functional integrity of the vascular endothelium, on the development and progression of VGD in CABG patients.

Methods and analysis

This ongoing prospective randomised, double-blinded multicentre trial (NCT02272582/NCT02774824) includes patients undergoing isolated CABG requiring at least two SVGs. It compares the impact of DuraGraft, a novel treatment against VGD versus the standard-of-care (SOC; heparinised saline) using a within-patient randomisation (with one SVG treated with DuraGraft and the other treated with SOC). Besides clinical assessments, patients undergo longitudinal 64-slice or better multidetector CT (MDCT) angiography of paired grafts (within each patient) at 4–6 weeks, 3 months and 12 months. Primary endpoints will be the magnitude of change in mean wall thickness and lumen diameter (stenosis) of paired grafts, at 3 and 12 months, respectively. Besides the evaluation of overall safety, longitudinal assessment of each graft (secondary endpoint) is performed in order to obtain insight into graft behaviour after CABG. Enrolment of 119 patients was successfully completed, and analysis of MDCT angiography follow-up is ongoing with the completed analysis becoming available by end of first quarter of 2018.

Ethics and dissemination

The regional ethics committees have approved the trial. Results will be submitted for publication.

Clinical trial identifier

NCT02272582 and NCT02774824.

Incidental findings in CT imaging of coronary artery bypass grafts: results from a Canadian multicenter prospective cohort

Objective

To assess the prevalence and clinical significance of incidental findings identified during computed tomography imaging of coronary artery bypass grafts.

Results

This prospective study includes 144 patients undergoing coronary graft patency assessment using computed tomography. Incidental findings were classified as significant if they were considered to need an immediate action or treatment, short-term work-up or follow-up, or minor. A total of 211 incidental findings were present in 109 (75.7%) patients. Seventy-one incidental findings (33.6%) were cardiac and 140 (66.4%) were extracardiac. Most common cardiac incidental findings were atrial dilatation [39 patients, 48 incidental findings (67.6%)] and aortic valve calcifications (7 patients, 9.9%). Among the 140 extracardiac incidental findings, the most common were lung nodules (51 patients, 54 nodules, 38.6%), and emphysema (21 patients, 15%). Thirty-six (25.7%) extracardiac incidental findings were significant and notably, 23 (63.9%) were lung nodules. Follow-up was recommended in 37 cases, among which all patients with significant lung nodules (23 patients, 62.2%). In conclusion, most common computed tomography incidental findings in patients with coronary grafts were lung nodules and emphysema.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3168-1) contains supplementary material, which is available to authorized users.

Conversion after off-pump coronary artery bypass grafting: the CORONARY trial experience

Objectives

Emergent and late conversions form OFF-to-ON pump coronary artery bypass grafting (CABG) have been associated with worse outcomes, however, it remains unclear as to which risk factors are associated with conversion and how to prevent them.

Methods

Among 4718 patients who randomly underwent off- or on-pump CABG, the incidence of off-pump to on-pump cross-over, or 'OFF-to-ON conversion', was 7.9% (186/2356). The primary outcome was a composite of death, stroke, myocardial infarction, or new renal failure requiring dialysis. We assessed the risk factors and outcomes of converted patients.

Results

Emergent OFF-to-ON conversions, defined as conversions for hypotension or ischaemia, were required for 3.2% of patients ( n  = 75), while most elective conversions were due to small or intramuscular coronaries ( n  = 83). OFF-to-ON converted patients required increased surgery time, blood transfusions, intensive care unit stay, and presented a higher incidence at 1 year of the composite outcome compared with non-converted off-pump patients (all P < 0.01), especially if the conversion was emergent. Conversely, elective conversions outcomes were no different compared with non-converted off-pump patients ( P  = 0.35). Independent predictors of emergent conversions included higher heart rate or chronic atrial fibrillation, urgent surgery, more grafts planned and surgeon experience with off-pump CABG.

Conclusions

Emergent OFF-to-ON conversion is associated with worse outcomes compared with elective conversion or no conversion. In the presence of risk factors for emergent conversion, an early and elective conversion approach is a judicious strategy.