Optimization of Mesenchymal Stem Cells to Increase Their Therapeutic Potential

The heart which has limited renewal and regenerative capacity is a prime target for cellular therapy. Stem cell transplantation has emerged as a promising therapeutic strategy to improve healing of the ischemic heart, repopulate the injured myocardium, and restore cardiac function. However, clinical usefulness is impacted by the quality and quantity of delivered cells, the suboptimal manipulations prior to transplantation, and the general poor viability of the cells transferred particularly to an ischemic microenvironment. Focus is now on developing new ways to enhance stem cell renewal and survival capacity before transplant. This can be done by physical, chemical, pharmacological, or genetic manipulation of cells followed by accurate evaluation of conditioning methods by validated tests.This chapter covers the proper handling of mesenchymal stem cells (human and rat lines) and methodologies to evaluate efficacy and the translational potential of conditioning methods. Specifically, we will cover stem cell culture methods, preconditioning protocols, viability assessment in hypoxic and oxidative challenges as encountered in an ischemic microenvironment, and the proliferative capacity of cells.

Molecular mechanisms underlying oxytocin-induced cardiomyocyte protection from simulated ischemia-reperfusion

Oxytocin (OT) stimulates cardioprotection. Here we investigated heart-derived H9c2 cells in simulated ischemia-reperfusion (I-R) experiments in order to examine the mechanism of OT protection. I-R was induced in an anoxic chamber for 2 hours and followed by 2 h of reperfusion. In comparison to normoxia, I-R resulted in decrease of formazan production by H9c2 cells to 63.5 ± 1.7% (MTT assay) and in enhanced apoptosis from 1.7 ± 0.3% to 2.8 ± 0.4% (Tunel test). Using these assays it was observed that treatment with OT (1-500 nM) exerted significant protection during I-R, especially when OT was added at the time of ischemia or reperfusion. Using the CM-H2DCFDA probe we found that OT triggers a short-lived burst in reactive oxygen species (ROS) production in cells but reduces ROS production evoked by I-R. In cells treated with OT, Western-blot revealed the phosphorylation of Akt (Thr 308, p-Akt), eNOS and ERK 1/2. Microscopy showed translocation of p-Akt and eNOS into the nuclear and perinuclear area and NO production in cells treated with OT. The OT-induced protection against I-R was abrogated by an OT antagonist, the Pi3K inhibitor Wortmannin, the cGMP-dependent protein kinase (PKG) inhibitor, KT5823, as well as soluble guanylate cyclase (GC) inhibitor, ODQ, and particulate GC antagonist, A71915. In conditions of I-R, the cells with siRNA-mediated reduction in OT receptor (OTR) expression responded to OT treatment by enhanced apoptosis. In conclusion, the OTR protected H9c2 cells against I-R, especially if activated at the onset of ischemia or reperfusion. The OTR-transduced signals include pro-survival kinases, such as Akt and PKG.

The Effect of Advancing Age on Total Joint Replacement Outcomes

OBJECTIVE

To describe age-related differences in outcomes among older adults undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA).

DESIGN

Retrospective study.

PARTICIPANTS

A total of 1792 patients who underwent primary THA or TKA at the University of Iowa Hospitals and Clinics between 2010 and 2013 were identified in the University HealthSystem Consortium Database and University of Iowa Orthopedics Joint Replacement Registry.

MAIN OUTCOME MEASURES

Hospital length of stay (LOS), 30-day readmission rate, in-hospital mortality, number of days admitted to intensive care unit (ICU discharge disposition), in-hospital complications (pulmonary embolism, deep vein thrombosis, wound infection, hemorrhage, sepsis, or myocardial infarction), quality of life (measured using Short-Form 36 [SF-36]), discharge disposition (home, home with home health, nursing home, inpatient rehabilitation, transfer to another acute care hospital, and dead), and total patient level observed hospital cost (based on hospital charge information from each revenue code and estimated labor costs). Outcomes were compared in patients stratified by age and categorized by decade (ie, ≤50, 51-60, 61-70, 71-80, and ≥81).

RESULTS

A total of 871 THAs and 921 TKAs were performed. The mean age of our cohort was 60.5 years and 56.1% were women. In-hospital complication rates and ICU utilization progressively increased with increasing age. There was also a higher likelihood of skilled nursing facility placement and longer LOS. There was no increase in 30-day readmissions, mortality, or total cost. Improvements in patient reported outcomes (SF-36) scores were similar for all age-groups.

CONCLUSIONS

Compared to younger patients, older THA and TKA recipients were more likely to experience postoperative complications, admission to the ICU, discharge to a skilled care facility, and had longer hospital LOS. Improvements in patient-related outcomes were similar across all age-groups. These findings may be helpful when counseling older patients regarding elective total joint arthroplasty.

Outcome Reporting in Cardiac Surgery Trials: Systematic Review and Critical Appraisal

Background

There is currently no accepted standard for reporting outcomes following cardiac surgery. The objective of this paper was to systematically review the literature to evaluate the current use and definition of perioperative outcomes reported in cardiac surgery trials.

Methods and Results

We reviewed 5 prominent medical and surgical journals on Medline from January 1, 2010, to June 30, 2014, for randomized controlled trials involving coronary artery bypass grafting and/or valve surgery. We identified 34 trials meeting inclusion criteria. Sample sizes ranged from 57 to 4752 participants (median 351). Composite end points were used as a primary outcome in 56% (n=19) of the randomized controlled trials and as a secondary outcome in 12% (n=4). There were 14 different composite end points. Mortality at any time (all-cause and/or cardiovascular) was reported as an individual end point or as part of a combined end point in 82% (n=28), myocardial infarction was reported in 68% (n=23), and bleeding was reported in 24% (n=8). Patient-centered outcomes, such as quality of life and functional classification, were reported in 29% (n=10). Definition of clinical events such as myocardial infarction, stroke, renal failure, and bleeding varied considerably among trials, particularly for postoperative myocardial infarction and bleeding, for which 8 different definitions were used for each.

Conclusions

Outcome reporting in the cardiac surgery literature is heterogeneous, and efforts should be made to standardize the outcomes reported and the definitions used to ascertain them. The development of standardizing outcome reporting is an essential step toward strengthening the process of evidence-based care in cardiac surgery.

Celastrol protects ischaemic myocardium through a heat shock response with up-regulation of haeme oxygenase-1

BACKGROUND AND PURPOSE

Celastrol, a triterpene from plants, has been used in traditional oriental medicine to treat various diseases. Here, we investigated the cardioprotective effects of celastrol against ischaemia.

EXPERIMENTAL APPROACH

Protective pathways induced by celastrol were investigated in hypoxic cultures of H9c2 rat cardiomyoblasts and in a rat model of myocardial infarction, assessed with echocardiographic and histological analysis.

KEY RESULTS

In H9c2 cells, celastrol triggered reactive oxygen species (ROS) formation within minutes, induced nuclear translocation of the transcription factor heat shock factor 1 (HSF1) resulting in a heat shock response (HSR) leading to increased expression of heat shock proteins (HSPs). ROS scavenger N-acetylcysteine reduced expression of HSP70 and HSP32 (haeme oxygenase-1, HO-1). Celastrol improved H9c2 survival under hypoxic stress, and functional analysis revealed HSF1 and HO-1 as key effectors of the HSR, induced by celastrol, in promoting cytoprotection. In the rat ischaemic myocardium, celastrol treatment improved cardiac function and reduced adverse left ventricular remodelling at 14 days. Celastrol triggered expression of cardioprotective HO-1 and inhibited fibrosis and infarct size. In the peri-infarct area, celastrol reduced myofibroblast and macrophage infiltration, while attenuating up-regulation of TGF-β and collagen genes.

CONCLUSIONS AND IMPLICATIONS

Celastrol treatment induced an HSR through activation of HSF1 with up-regulation of HO-1 as the key effector, promoting cardiomyocyte survival, reduction of injury and adverse remodelling with preservation of cardiac function. Celastrol may represent a novel potent pharmacological cardioprotective agent mimicking ischaemic conditioning that could have a valuable impact in the treatment of myocardial infarction.

A morphometric 3D model of coronary artery bypass graft dysfunction with multidetector computed tomography

OBJECTIVE

The objective was to assess, with computed tomography (CT) angiography, quantitative morphological parameters of a composite coronary artery bypass grafting (CABG) strategy and to correlate these with graft dysfunction.

FINDINGS

Forty patients [median postoperative time, 32 (14-51) months] underwent CT angiography. Graft patency was assessed, and specific quantitative morphological parameters of the graft were collected. Graft segments had an overall patency rate of 93% (78/84). Two specific morphological parameters were found to be associated with graft dysfunction.

CONCLUSION

A CT morphometric model can be used to identify quantitative 3D parameters associated with graft dysfunction. Such an approach could help in developing and improving CABG designs.

Microcirculatory response during on-pump versus off-pump coronary artery bypass graft surgery

OBJECTIVES

The use of cardiopulmonary bypass (CPB) during coronary artery bypass graft surgery (CABG) is associated with a systemic inflammatory response, resulting in altered microcirculation. The aim of this study was to evaluate whether beating heart surgery can preserve the microcirculation.

METHODS

Sublingual microcirculation was characterized by a Sidestream Darkfield Imaging Microscope during off-pump (OPCABG) and on-pump (ONCABG) surgery. Microcirculatory parameters were evaluated during eight precise perioperative time points.

RESULTS

The quality of the microcirculation decreased during early ONCABG. OPCABG resulted in a significantly better microcirculation compared to ONCABG for three of six parameters during surgery. However, by the end of surgery and postoperatively, the microcirculatory parameters were no different between the groups.

CONCLUSIONS

While the results do not show a marked preservation of the microcirculation during and after OPCABG compared to ONCABG, they coincide with the body temperature fluctuations of each group during and after surgery. Our work suggests that active warming could impact the microcirculation parameters.

Abstract 360: How Should We Measure Quality of Care for Transcatheter Aortic Valve Implantation (TAVI)? Results for 6 Quebec TAVI Programs Compared with International Registries

Background: Our publicly funded cardiology evaluation unit examined quality indicators relating to the use and outcomes of transcatheter aortic valve implantation (TAVI). We compared results in Québec hospitals with registries around the world.

Methods: We abstracted data on all TAVI cases (n=294) in 6 hospitals in 2013-14. Variables, outcomes and definitions were chosen to facilitate comparisons with registries. Results were presented to TAVI teams with the goal of choosing quality indicators and improving performance.

Results: Annual TAVI center volume ranged from 30 to 115 and rate of TAVI varied widely across Quebec’s 16 health regions, as did rates around the world. Median patient age was 83 years (interquartile range [IQR]: 78-86) with little variation across centers and international registries. Documented proportion of patients with NYHA class III/IV was 64% (188/294) for Quebec and varied from 75 to 86% across registries. A surgical risk score (STS) was recorded in only 53% (156/294) of Quebec patients but was often obligatory in registries. The median STS score for Quebec was very similar to that reported in the USA [6% (IQR: 4-10) vs 7% (IQR: 5-11), respectively] but was much lower than in France, Austria and Brazil. Frequency of in-hospital adverse events varied widely across Québec centers: stroke (0-7.5%), bleeding (16.7-26.7%) and transfusion (16.7-43.3%). Overall incidence of in-hospital stroke was 2.3% (7/294) and varied from 1.8 to 5.3% across registries. Bleeding and transfusion were rarely reported in registries. Conversion to surgery was 3% (9/294) in Quebec, and 0.4-4.3% in registries. In Quebec, 15% of patients required a new pacemaker, with wide variation across centers (0-21%) and registries (6.6-25%). Rates of procedural success varied widely across Quebec, largely due to non-standardized classification of post-TAVI aortic regurgitation. Such classification also varied across registries. Overall procedural success for Quebec (73%; 215/294) was lower than in registries but in the latter, the definition of success was often unclear. In-hospital mortality in Quebec was 6.5% (19/294) versus 5.5% in USA and a reported 5.1% for transvascular and 7.7% for transapical TAVI in Germany. Other registries only reported 30-day mortality, varying from 4.1 to 9.1%. Discharge home was more likely in Quebec (80%) than the USA (63%); this outcome was not reported elsewhere.

Conclusions: Practice and outcomes in TAVI vary widely across Quebec hospitals and internationally. Despite publication of recommended endpoints (VARC and BARC), there is a lack of standardized reported outcomes and patient populations. While quality benchmarks for patient selection and outcomes remain unclear, continued monitoring with timely feedback to TAVI teams and decision-makers is essential for this new and costly intervention that is predominantly being performed in the very elderly.

Measuring rapid recovery program outcomes: are all patients candidates for rapid recovery

Total joint arthroplasty procedures have been demonstrated to be effective in the treatment of end stage hip and knee arthritis. The purpose of this paper is to outline various processes utilized to assess the outcomes of rapid recovery programs and to outline areas where future research and metrics will be beneficial in demonstrating the effectiveness of these programs. We have highlighted the use of large databases [NIS (National Inpatient Sample) and NSQIP (National Surgical Quality Improvement Program)] to help identify patients who are candidates for the rapid recovery approach. Continued thorough investigation should not only justify rapid recovery, but also move traditional joint arthroplasty programs to more efficient cost effective care once appropriate metrics are identified that support the need for resources for rapid recovery programs.