Comparison between moyamoya disease and moyamoya syndrome in Israel

BACKGROUND AND AIMS

Moyamoya is a chronic brain vasculopathy involving the distal intracranial internal carotid artery (ICA) or proximal middle cerebral artery (MCA). Moyamoya patients can be divided into those with primary moyamoya disease (MMD) and those with moyamoya secondary to other known causes such as intracranial atherosclerosis (moymoya syndrome [MMS]). Our aim was to compare the characteristics of MMD patients to those of MMS patients in a sample of Israeli patients seen over the course of 20 years at a tertiary referral center.

METHODS

Included patients were diagnosed with either MMD or MMS based on typical imaging findings and the presence or absence of known concomitant vascular risk factors or associated disorders and vascular disease. Patients with MMS were compared to those with MMD. Demographics, symptoms, signs, and radiological data were compared between the groups. Treatment options and long-term rates of recurrent stroke and functional outcome were also studied.

RESULTS

Overall, 64 patients were included (25 MMD, 39 MMS). Patients with MMD were significantly younger (median IQR 20 (7-32) vs. 40 (19-52); p=0.035). Patients with MMS more often had vascular risk factors but there were no significant differences in clinical presentations or long-term disability rates between the groups and a similar proportion of patients underwent surgical interventions to restore hemispheric perfusion in both groups (48% vs. 44% MMS vs. MMD; p=0.7). Almost one in four patient had a recurrent stroke after the initial diagnosis in both groups. Most recurrences occurred in the pre-surgery period in the MMS group and in the post-surgery period in the MMD group.

CONCLUSIONS

There were no statistically significant differences in clinical or radiological presentations between the MMS and MMD patients. The course is not benign with recurrent stroke occurring in as many as 25%. More data is needed in order to identify those at high risk for stroke occurrence and recurrence.

The impact of cusp overlap on permanent pacemaker requirement following self-expanding transcatheter aortic valve replacement

BACKGROUND/PURPOSE

The cusp overlap technique has standardized implantation for self-expanding valves with the goal of achieving more consistent implantation depths and lowering permanent pacemaker (PPM) implantation rates. We retrospectively compared short-term outcomes in patients undergoing transcatheter aortic valve replacement (TAVR) with a self-expanding valve implanted using the cusp overlap technique vs. the traditional coplanar technique in a large tertiary referral center.

METHODS

We conducted a retrospective study among PPM-naïve patients who underwent TAVR using the CoreValve Evolut PRO/PRO+. We compared in-hospital PPM rates in patients who underwent TAVR using the cusp overlap technique vs. the coplanar technique. Additional outcomes included in-hospital all-cause mortality, stroke, major vascular complications, annular rupture, and >mild paravalvular leak. Furthermore, we compared outcomes over time to see whether there was evidence of a learning curve.

RESULTS

Of the 528 patients included, 270 underwent TAVR using the coplanar technique and 258 underwent TAVR using the cusp overlap technique. The rate of new PPM implantation did not differ between cohorts (17.0 % vs. 16.7 %; p = 0.910). Additionally, rates of in-hospital all-cause mortality (0.0 % vs. 0.4 %; p = 0.328), stroke (3.7 % vs. 1.6 %; p = 0.124), major vascular complications (0.7 % vs. 1.2 %; p = 0.617), annular rupture (0.4 % vs. 0.0 %; p = 0.328) and >mild paravalvular leak (0.0 % vs. 0.4 %; p = 0.444) were similar. Our secondary analysis did not identify any evidence of a learning curve.

CONCLUSIONS

The cusp overlap technique may not yield a reduction in PPM rates when compared with the coplanar technique. Other confounders should be explored to further minimize in-hospital PPM rates.

Milestones in the natural course of the onset of e-cigarette dependence among adolescents and young adults: Retrospective study

INTRODUCTION

There is considerable controversy about the development of dependence among e-cigarette users. This study describes the average amount of time using e-cigarettes before dependence milestones emerge and the differences in developing dependence between e-cigarette users who smoke cigarettes compared to those who do not.

METHODS

Adolescents and young adults aged 16-25 living in Canada were recruited into an online survey in 2021. Current (past-month) e-cigarette users completed 15 items assessing dependence from the Penn-State Electronic Cigarette Dependence Index and the E-cigarette Dependence Scale for a total of 12 behavioural (e.g., difficulty refraining from vaping) and 3 frequency (e.g., using e-cigarette daily, weekly, or monthly) indicators of dependence milestones. Number of years after e-cigarette onset at which the cumulative probability of attaining each milestone was 25 % was computed.

RESULTS

Among 1205 participants, most (80.6 %) were female, 73.7 % were Caucasian, and 49.7 % resided in Ontario. Ten of the 12 e-cigarette use milestones were attained by 25 % of respondents 2 years after starting vaping except for daily cigarette use (2.5 years after onset) and waking at night to vape (5.6 years after onset). Within the entire study population, frequency milestones (weekly, monthly, daily e-cigarette use) were attained faster by ever-smokers (hazard ratio compared to attainment by never-smokers: 1.12, 1.21, and 1.28 respectively), whereas for at least monthly users, behavioural milestones were attained faster by never-smokers.

DISCUSSION

Many current e-cigarette users developed symptoms of e-cigarette dependence between two and five years since onset. Never smokers may be at higher risk of becoming e-cigarette dependent since they attained e-cigarette dependence milestones faster than smokers.

Effects of tumor type on outcomes in patients with large vessel occlusion stroke and cancer

BACKGROUND

Large vessel occlusions (LVO) stroke is associated with cancer. Whether this association differs among patients with LVO that undergo endovascular thrombectomy (EVT) according to cancer type remains unknown.

PATIENTS AND METHODS

Data from consecutive patients that underwent EVT for LVO at three academic centers were pulled and analyzed retrospectively. Patients with LVO and solid tumors were compared to those with hematological tumors. Associations of cancer type with 90-day functional outcome and mortality were calculated in multivariable analyses.

RESULTS

Of the 154 patients with cancer and LVO that underwent EVT (mean age 74±11, 43% men, median NIHSS 15), 137 had solid tumors (89%) and 17 (11%) had hematologic tumors. Patients with solid cancer did not significantly differ from those with hematological malignancy in demographics, risk factor profile, stroke severity and subtype, and procedural variables. Outcome parameters including rates of favorable target recanalization and favorable outcome or mortality at discharge and 90 days post stroke were similar. Safety parameters including rates of symptomatic intracranial hemorrhage also did not differ between the groups. On regression analyses, controlling for various prognostic variables cancer type was not associated with mortality or favorable outcomes.

CONCLUSIONS

Our study suggests that the safety and efficacy of EVT in patients with malignancy does not depend on cancer type. Patients with malignancy should be considered for EVT regardless of cancer type.

Management of Mechanical Prosthetic Heart Valve Thrombosis: JACC Review Topic of the Week

Mechanical prosthetic heart valves, though more durable than bioprostheses, are more thrombogenic and require lifelong anticoagulation. Mechanical valve dysfunction can be caused by 4 main phenomena: 1) thrombosis; 2) fibrotic pannus ingrowth; 3) degeneration; and 4) endocarditis. Mechanical valve thrombosis (MVT) is a known complication with clinical presentation ranging from incidental imaging finding to cardiogenic shock. Thus, a high index of suspicion and expedited evaluation are essential. Multimodality imaging, including echocardiography, cine-fluoroscopy, and computed tomography, is commonly used to diagnose MVT and follow treatment response. Although surgery is oftentimes required for obstructive MVT, other guideline-recommended therapies include parenteral anticoagulation and thrombolysis. Transcatheter manipulation of stuck mechanical valve leaflet is another treatment option for those with contraindications to thrombolytic therapy or prohibitive surgical risk or as a bridge to surgery. The optimal strategy depends on degree of valve obstruction and the patient's comorbidities and hemodynamic status on presentation.

Rare case of infective endocarditis from invasive aspergillosis encasing the pulmonary valve: a case report

Background

Aspergillus endocarditis is a rare cause of infective endocarditis and requires high index of suspicion for diagnosis.

Case summary

We describe a case of a 50-year-old man with history of metastatic thymoma on immunosuppression (gemcitabine and capecitabine) who presented with progressive dyspnoea. Echocardiography and computed tomography (CT) of chest showed filling defect in the pulmonary artery. The initial differential diagnosis was of pulmonary embolism and metastatic disease. The mass was subsequently excised, which revealed a diagnosis of Aspergillus endocarditis of the pulmonary valve. Unfortunately, he passed away despite medical treatment with antifungal therapy after surgery.

Discussion

Aspergillus endocarditis should be suspected in immunosuppressed hosts with negative blood cultures and large vegetations on echocardiography. Diagnosis is made by tissue histology but may be difficult or delayed. Optimal treatment involves aggressive surgical debridement and prolonged antifungal therapy; prognosis is poor with high mortality.

TAVR in 2023: Who Should Not Get It?

Since the first transcatheter delivery of an aortic valve prosthesis was performed by Cribier et al in 2002, the picture of aortic stenosis (AS) therapeutics has changed dramatically. Initiated from an indication of inoperable to high surgical risk, extending to intermediate and low risk, transcatheter aortic valve replacement (TAVR) is now an approved treatment for patients with severe, symptomatic AS across all the risk categories. The current evidence supports TAVR as a frontline therapy for treating severe AS. The crucial question remains concerning the subset of patients who still are not ideal candidates for TAVR because of certain inherent anatomic, nonmodifiable, and procedure-specific factors. Therefore, in this study, we focus on these scenarios and reasons for referring selected patients for surgical aortic valve replacement in 2023.

Covid-19 associated free hanging clots in acute symptomatic carotid stenosis

BACKGROUND

Thrombotic complications including stroke were previously described following Covid-19. We aim to describe the clinical and radiological characteristics of Covid-19 related with acutely symptomatic carotid stenosis (aSCS).

METHOD

All patients presenting with an aSCS were prospectively enrolled in an ongoing institutional database. Inclusion criteria for the Covid-19-aSCS group were a combination of both antigen test and a positive reverse-transcriptase (PCR) test for Covid-19 upon admission. Patients with additional potential etiologies for stroke including cardioembolism, carotid dissection or patients with stenosis of <50% on CTA were excluded. A cohort of non-Covid-19 related aSCS patients admitted to the same institution before the pandemic during 2019 served as controls.

RESULTS

Compared to controls (n = 31), Covid-19-aSCS (n = 8), were younger (64.2 ± 10.7 vs 73.5 ± 10, p = 0.027), and less frequently had hypertension (50% vs 90%, p = 0.008) or hyperlipidemia (38% vs 77%, p = 0.029) before admission. Covid-19-aSCS patients had a higher admission NIHSS score (mean 9 ± 7 vs 3 ± 4, p = 0.004) and tended to present more often with stroke (88% vs 55%, p = 0.09) rather than a TIA. Covid-19-aSCS patients had higher rates of free-floating thrombus and clot burden on CTA (88% vs 6.5%, p = 0.002). Covid-19 patients also less often achieved excellent outcomes, with lower percentage of mRS score of 0 after 90-days (13% vs 58%, p = 0.022).

CONCLUSION

Covid-19- aSCS may occur in a younger and healthier subpopulation. Covid-19- aSCS patients may have higher tendencies for developing complex clots and less often achieve excellent outcomes.

Impact of left ventricular outflow tract calcium on valve geometry in self-expanding transcatheter aortic-valve replacement

OBJECTIVES

Evaluate transcatheter heart valve (THV) geometry according to left ventricular outflow tract (LVOT) calcium degree and its impact on hemodynamics and outcomes in patients undergoing transcatheter aortic valve replacement (TAVR) with a contemporary self-expanding THV.

BACKGROUND

LVOT calcium remains challenging for contemporary THVs. LVOT calcium location and degree may affect THV deployment and impact flow patterns and shear stress, accelerating THV degeneration.

METHODS

EPROMPT (CoreValve Evolut Pro Prospective Registry; NCT03423459) is a prospective, investigator-initiated, multicenter registry of patients undergoing TAVR using CoreValve Evolut PRO/PRO + THVs. A total of 107 patients were enrolled in EPROMPT's computed tomography (CT) cohort between January 2018 and October 2021. These patients underwent follow-up CT scan 30 days post-TAVR. We analyzed THV geometry and its interaction with the aortic root following deployment using 30-day post-TAVR CT in patients with none/mild versus moderate/severe LVOT calcium.

RESULTS

Thirty-day THV inflows were less eccentric in the short axis in patients with none/mild versus moderate/severe LVOT calcium (1.16 ± 0.09 vs. 1.21 ± 0.12; p = 0.007). THV became more circular and was similar between both cohorts at the THV waist (1.08 ± 0.06 vs. 1.09 ± 0.11; p = 0.551), leaflet tips (1.03 ± 0.04 vs. 1.05 ± 0.09; p = 0.299), and THV outflow (1.04 ± 2.2 vs. 1.03 ± 2.7; p = 0.143). Thirty-day > mild paravalvular leak was low in both cohorts (1.5% vs. 2.4%; p = 0.724); mean gradients were similar (7.7 ± 3.6 vs. 7.7 ± 3.4 mmHg; p = 0.955).

CONCLUSIONS

Despite inflow deformities observed in patients with moderate/severe LVOT calcium, Evolut PRO/PRO + conforms to elliptical aortic annuli, maintaining circularity and proper function at the leaflets and outflow, even in patients with moderate/severe LVOT calcium.

Predictors and Prognostic Implications of Hemorrhagic Transformation Following Cerebral Endovascular Thrombectomy in Acute Ischemic Stroke: A Multicenter Analysis

PURPOSE

Hemorrhagic transformation (HT) following cerebral endovascular thrombectomy (EVT) for large vessel occlusion (LVO) in acute ischemic stroke is associated with poor outcome. Recent studies have shown that EVT can be efficacious in imaging-selected patients as late as 6-24 h from onset (late time window; LTW). We sought to determine predictors and prognostic implications of HT following EVT in LTW.

METHODS

Consecutive patients undergoing EVT for LVO were recruited into a prospective multicenter database. HT was divided into petechial hemorrhagic-infarction and parenchymal hematoma (PH) type 1 or 2 defined as confluent hemorrhage covering < or > than 1/3 of the infarct volume, respectively. Multivariate analyses were performed to determine variables associated with HT subtypes.

RESULTS

Among 611 patients included (mean age 70.5 ± 12.5 years; median NIHSS 16), 115 (18.8%) had HT and 33 of them (5.4%) had PH2. Independent PH2 predictors included failed recanalization (OR 7.0, 95% CI 2.3-21.6), longer time from symptom onset to admission (OR 1.002 per minute 95% CI 1.001-1.003) and hyperlipidemia (OR 3.12; 95%CI 1.12-8.7). HT was not associated with outcome. In contrast, PH2 patients had lower favorable outcome rates (14.3 vs 41.6%, p = 0.004) and higher mortality rates (39 vs 17%, p = 0.001). Patients who underwent EVT in the late versus early window had similar PH2 rates (4.5 vs 6.7%, p = 0.27). In multivariate models, PH2 tripled the odds of both 90-day poor outcome (OR 3.1, 95% CI 1.01-9.5) and 90-day mortality (OR 3.2, 95% CI 1.4-7.3).

CONCLUSIONS

PH2 following EVT is associated with increased mortality and unfavorable outcome rates. Rates of PH2 are not different between LTW patients and those treated < 6 h from symptom onset.

Outcomes after reperfusion therapies in patients with ACA stroke: A multicenter cohort study from the EVATRISP collaboration

BACKGROUND

Patients with stroke secondary to occlusions of the anterior cerebral artery (ACA) often have poor outcomes. The optimal acute therapeutic intervention for these patients remains unknown.

METHODS

Patients with isolated ACA-stroke were identified from 10 centers participating in the EndoVascular treatment And ThRombolysis in Ischemic Stroke Patients (EVATRISP) prospective registry. Patients treated with endovascular thrombectomy (EVT) were compared to those treated with intravenous thrombolysis (IVT). Odds ratios with 95% confidence intervals (OR; 95%CI) were calculated using multivariate regression analysis.

RESULTS

Included were 92 patients with ACA-stroke. Of the 92 ACA patients, 55 (60%) were treated with IVT only and 37 (40%) with EVT (±bridging IVT). ACA patients treated with EVT had more often wake-up stroke (24% vs. 6%, p = 0.044) and proximal ACA occlusions (43% vs. 24%, p = 0.047) and tended to have higher stroke severity on admission [NIHSS: 10.0 vs 7.0, p = 0.054). However, odds for favorable outcome, mortality or symptomatic intracranial hemorrhage did not differ significantly between both groups. Exploration of the effect of clot location inside the ACA showed that in patients with A1 or A2/A3 ACA occlusions the chances of favorable outcome were not influenced by treatment allocation to IVT or EVT.

DISCUSSION

Treatment with either IVT or EVT could be safe with similar effect in patients with ACA-strokes and these effects may be independent of clot location within the occluded ACA.

Transcatheter Versus Surgical Aortic Valve Replacement in Young, Low-Risk Patients With Severe Aortic Stenosis

Transcatheter aortic valve replacement (TAVR) is approved for all patient risk profiles and is an option for all patients irrespective of age. However, patients enrolled in the low- and intermediate-risk trials were in their 70s, and those in the high-risk trials were in their 80s. TAVR has never been systematically tested in young (<65 years), low-risk patients. Unanswered questions remain, including the safety and effectiveness of TAVR in patients with bicuspid aortic valves; future coronary access; durability of transcatheter heart valves; technical considerations for surgical transcatheter heart valve explantation; management of concomitant conditions such as aortopathy, mitral valve disease, and coronary artery disease; and the safety and feasibility of future TAVR-in-TAVR. The authors predict that balancing these questions with patients' clear preference for less invasive treatment will become common. In this paper, the authors consider each of these questions and discuss risks and benefits of theoretical treatment strategies in the lifetime management of young patients with severe aortic stenosis.

Single-Center Experience With the LOTUS Edge Transcatheter Heart Valve

BACKGROUND

Before its voluntary recall, the mechanically expandable LOTUS Edge transcatheter heart valve (THV) offered a number of unique features, notably sealing against paravalvular leak (PVL) and the ability to be fully deployed, re-captured, and re-deployed.

METHODS

We performed a detailed review of all patients at our institution who underwent transcatheter aortic valve replacement (TAVR) using the LOTUS Edge THV from 2019 to 2020. We describe procedural and in-hospital outcomes.

RESULTS

In brief, 59 patients underwent TAVR using the LOTUS Edge, of whom 18 were high-risk (most of whom had moderate or severe left ventricular outflow tract [LVOT] calcium), 36 were intermediate-risk enrolled in the REPRISE IV trial (one of whom had a bicuspid valve), and 5 were low-risk bicuspid patients enrolled in the LRT trial. Conduction disturbances were common (new left bundle branch block in 64.4%), with high rates of new permanent pacemaker (PPM) implantation across all risk groups (16.9%). Overall, stroke occurred in 11.9% of patients, and in 3/5 low-risk bicuspid patients, but occurred less frequently in patients with cerebral embolic protection.

CONCLUSIONS

In our experience, in patients with heavy LVOT calcium burden and/or bicuspid valves, the LOTUS Edge THV offered excellent seal against PVL. However, the high rates of periprocedural stroke and new PPM implantation were a concern.

Clopidogrel underactivity is a common in patients with acute symptomatic severe carotid stenosis

BACKGROUND

Clopidogrel is commonly used for secondary stroke prevention in patients with large vessel stenosis. Reduced Clopidogrel high on treatment platelet reactivity (CR) can lead to Clopidogrel underactivity (CU) causing acute thrombosis. However, the prevalence of CU among patients with acute symptomatic carotid disease remains unknown. Therefore, we aimed to find the prevalence and identify the predictors for CU among patients with acutely symptomatic carotid stenosis.

PATIENTS AND METHODS

Over the span of 14 months, CR was measured at the time of endovascular procedure in all patients undergoing angiography and stenting because of acute symptomatic carotid stenosis. Only patients treated per institutional protocol with a combination of Clopidogrel and Aspirin were included. CR was measured with VerifyNowP2Y12 reaction units (PRU) and CU was defined as PRU > 208. Patients with CU were compared to those without CU.

RESULTS

Thirty-five patients were included (mean age 71.3 ± 10, 76% men) and twelve (34.3%, mean age 71.8 ± 8.4, 58% men) had CU at the time of endovascular intervention. On univariate analysis more severe carotid stenosis was seen in CU patients (92.6 ± 6.5% vs 81.6 ± 13.6%, p = 0.013) and percent stenosis was independently associated with CU on multivariate analysis (p = 0.023).

CONCLUSIONS

CU is present in 1 of every 3 patients with acutely symptomatic carotid disease. The current results suggest that CR testing should become part of routine care in patients with acutely symptomatic carotid disease.

Preventing Coronary Obstruction During Transcatheter Aortic Valve Replacement: Results From the Multicenter International BASILICA Registry

OBJECTIVES

This study sought to determine the safety of the BASILICA (bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction) procedure.

BACKGROUND

Transcatheter aortic valve replacement causes coronary artery obstruction in 0.7% of cases, with 40% to 50% mortality. BASILICA is a procedure to prevent coronary obstruction. Safety and feasibility in a large patient cohort is lacking.

METHODS

The international BASILICA registry was a retrospective, multicenter, real-world registry of patients at risk of coronary artery obstruction undergoing BASILICA and transcatheter aortic valve replacement. Valve Academic Research Consortium-2 definitions were used to adjudicate events.

RESULTS

Between June 2017 and December 2020, 214 patients were included from 25 centers in North America and Europe; 72.8% had bioprosthetic aortic valves and 78.5% underwent solo BASILICA. Leaflet traversal was successful in 94.9% and leaflet laceration in 94.4%. Partial or complete coronary artery obstruction was seen in 4.7%. Procedure success, defined as successful BASILICA traversal and laceration without mortality, coronary obstruction, or emergency intervention, was achieved in 86.9%. Thirty-day mortality was 2.8% and stroke was 2.8%, with 0.5% disabling stroke. Thirty-day death and disabling stroke were seen in 3.4%. Valve Academic Research Consortium-2 composite safety was achieved in 82.8%. One-year survival was 83.9%. Outcomes were similar between solo and doppio BASILICA, between native and bioprosthetic valves, and with the use of cerebral embolic protection.

CONCLUSIONS

BASILICA is safe, with low reported rates of stroke and death. BASILICA is feasible in the real-world setting, with a high procedure success rate and low rates of coronary artery obstruction.

A Bioengineered Neuregulin-Hydrogel Therapy Reduces Scar Size and Enhances Post-Infarct Ventricular Contractility in an Ovine Large Animal Model

The clinical efficacy of neuregulin (NRG) in the treatment of heart failure is hindered by off-target exposure due to systemic delivery. We previously encapsulated neuregulin in a hydrogel (HG) for targeted and sustained myocardial delivery, demonstrating significant induction of cardiomyocyte proliferation and preservation of post-infarct cardiac function in a murine myocardial infarction (MI) model. Here, we performed a focused evaluation of our hydrogel-encapsulated neuregulin (NRG-HG) therapy’s potential to enhance cardiac function in an ovine large animal MI model. Adult male Dorset sheep (n = 21) underwent surgical induction of MI by coronary artery ligation. The sheep were randomized to receive an intramyocardial injection of saline, HG only, NRG only, or NRG-HG circumferentially around the infarct borderzone. Eight weeks after MI, closed-chest intracardiac pressure–volume hemodynamics were assessed, followed by heart explant for infarct size analysis. Compared to each of the control groups, NRG-HG significantly augmented left ventricular ejection fraction (p = 0.006) and contractility based on the slope of the end-systolic pressure–volume relationship (p = 0.006). NRG-HG also significantly reduced infarct scar size (p = 0.002). Overall, using a bioengineered hydrogel delivery system, a one-time dose of NRG delivered intramyocardially to the infarct borderzone at the time of MI in adult sheep significantly reduces scar size and enhances ventricular contractility at 8 weeks after MI.

Safety of photosynthetic Synechococcus elongatus for in vivo cyanobacteria-mammalian symbiotic therapeutics

The cyanobacterium Synechococcus elongatus (SE) has been shown to rescue ischaemic heart muscle after myocardial infarction by photosynthetic oxygen production. Here, we investigated SE toxicity and hypothesized that systemic SE exposure does not elicit a significant immune response in rats. Wistar rats intravenously received SE (n = 12), sterile saline (n = 12) or E. coli lipopolysaccharide (LPS, n = 4), and a subset (8 SE, 8 saline) received a repeat injection 4 weeks later. At baseline, 4 h, 24 h, 48 h, 8 days and 4 weeks after injection, clinical assessments, blood cultures, blood counts, lymphocyte phenotypes, liver function tests, proinflammatory cytokines and immunoglobulins were assessed. Across all metrics, SE rats responded comparably to saline controls, displaying no clinically significant immune response. As expected, LPS rats exhibited severe immunological responses. Systemic SE administration does not induce sepsis or toxicity in rats, thereby supporting the safety of cyanobacteria-mammalian symbiotic therapeutics using this organism.

Atrial Fibrillation Treatment Adequacy and Outcome after Endovascular Thrombectomy

BACKGROUND

Atrial fibrillation (AF) often leads to large vessel occlusions (LVO) which may necessitate endovascular thrombectomy (EVT). Whether the adequacy of treatment with oral anticoagulants (OAC) prior to LVO modifies outcomes remains unknown.

PATIENTS AND METHODS

Consecutive EVT-treated LVO patients were recruited and the data was analyzed retrospectively. We combined patients with known AF that were untreated with OAC or inadequately treated with those with new-onset AF to form a group of undertreated-AF patients and compared them to adequately treated AF patients.

RESULTS

Of the 230 patients included, 109 (47%) had AF (86 known AF, 23 new-onset AF). AF patients were significantly older and more often reached favorable recanalization but less often had favorable outcomes compared to those without AF. Most patients with known AF (76%) were inadequately treated at stroke onset. Patients with undertreated-AF more often received tPA prior to EVT (26% vs. 4% p=0.009), more often had favorable collaterals (65% vs. 33% p<0.001) and more often reached favorable outcomes (28% vs. 9%, p=0.047) compared to adequately treated AF patients. On multivariate analyses adequately treated AF did not impact survival (Odds Ration [OR] 0.89 95% Confidence Interval [CI] 0.23-3.43), chances for favorable recanalization (OR 0.57 95%CI 0.15-2.13) or favorable outcome (OR 5.95 95%CI 0.62-57.39).

CONCLUSIONS

Treatment adequacy does not affect the rates of favorable functional outcome or survival in AF patients with LVO.

Intravenous thrombolysis for large vessel or distal occlusions presenting with mild stroke severity

BACKGROUND AND PURPOSE

We investigated the effectiveness of intravenous thrombolysis (IVT) in acute ischaemic stroke (AIS) patients with large vessel or distal occlusions and mild neurological deficits, defined as National Institutes of Health Stroke Scale scores < 6 points.

METHODS

The primary efficacy outcome was 3-month functional independence (FI) [modified Rankin Scale (mRS) scores 0-2] that was compared between patients with and without IVT treatment. Other efficacy outcomes of interest included 3-month favorable functional outcome (mRS scores 0-1) and mRS score distribution at discharge and at 3 months. The safety outcomes comprised all-cause 3-month mortality, symptomatic intracranial hemorrhage (ICH), asymptomatic ICH and severe systemic bleeding.

RESULTS

We evaluated 336 AIS patients with large vessel or distal occlusions and mild stroke severity (mean age 63 ± 15 years, 45% women). Patients treated with IVT (n = 162) had higher FI (85.6% vs. 74.8%, P = 0.027) with lower mRS scores at hospital discharge (P = 0.034) compared with the remaining patients. No differences were detected in any of the safety outcomes including symptomatic ICH, asymptomatic ICH, severe systemic bleeding and 3-month mortality. IVT was associated with higher likelihood of 3-month FI [odds ratio (OR), 2.19; 95% confidence intervals (CI), 1.09-4.42], 3-month favorable functional outcome (OR, 1.99; 95% CI, 1.10-3.57), functional improvement at discharge [common OR (per 1-point decrease in mRS score), 2.94; 95% CI, 1.67-5.26)] and at 3 months (common OR, 1.72; 95% CI, 1.06-2.86) on multivariable logistic regression models adjusting for potential confounders, including mechanical thrombectomy.

CONCLUSIONS

Intravenous thrombolysis is independently associated with higher odds of improved discharge and 3-month functional outcomes in AIS patients with large vessel or distal occlusions and mild stroke severity. IVT appears not to increase the risk of systemic or symptomatic intracranial bleeding.

Impact of Donor Obesity on Outcomes After Orthotopic Heart Transplantation

Background

The impact of donor obesity on the outcome of orthotopic heart transplantation has not been studied. The aim of this study was to investigate the impact of donor obesity on the outcomes of adult orthotopic heart transplantation recipients.

Methods and Results

Data were obtained from the United Network for Organ Sharing database. All adult (age ≥18 years) patients undergoing orthotopic heart transplantation from 2000 through 2016 were included (n=31 920). We stratified the cohort by donor body mass index (BMI); 13 015 patients (40.8%) received a heart from a normal‐weight donor (BMI 18.5–24.9), 11 271 patients (35.3%) received a heart from an overweight donor (BMI 25.0–29.9), 4910 patients (15.4%) received a heart from an obese donor (BMI 30.0–34.9), and 2724 patients (8.5%) received a heart from an extremely obese donor (BMI ≥35). The cohort of obese donors was older, included a higher incidence of diabetes mellitus, and had a higher creatinine. Our data also showed that the recipients of obese donor grafts were older, had a higher BMI, creatinine, percentage of diabetes mellitus, and longer total waiting period. There was no significant difference detected in the survival likelihood (P=0.08) of patients based on a donor's BMI‐based categorized cohort. There were no significant differences found in the overall survival probability among 4 groups in the adjusted survival analyses (P=0.25).

Conclusions

This study demonstrated that patients receiving higher BMI donor hearts might not be subjected to an increased risk of death, at least during the short term after transplant, compared with those using the normal‐weight donors.

Smoking among female daily smokers in Surabaya, Indonesia

OBJECTIVES

Nationally representative studies suggest 1-2% of Indonesian women (2.3 million) smoke various tobacco products daily; however, in recent years, there has been concern that the tobacco industry has successfully increased female smoking. Our objective was to describe current cigarette smoking behaviors, past quit attempts, and intention to quit of female daily smokers in Surabaya, Indonesia.

STUDY DESIGN

Survey.

METHODS

Female daily smokers (n = 112) in Surabaya, Indonesia, the country's second largest city, were recruited to participate in a survey during 2018. Convenience sampling was utilized in two malls. Potential participants were intercepted in or near designated smoking areas and invited to the nearby data collection site. Survey items from Global Adult Tobacco Survey and the International Tobacco Control Policy Evaluation Project were utilized.

RESULTS

Participants self-reported smoking 13.8 cigarettes per day (7.3 white machine-rolled cigarettes per day, 4.2 kreteks per day, and 2.4 roll-your-own cigarettes per day). Over 75% smoked their first cigarette within 30 min of waking. Over 53% had a heaviness of smoking index score suggesting moderate or high addiction. Approximately half (51%) did not attempt to quit smoking in the previous 12 months, and 55% planned to quit beyond 6 months or not at all.

CONCLUSIONS

Our sample smoked five to six more cigarettes per day than female daily smokers in previous national surveys. Relative to previous studies, our data suggest an unexpected preference for white machine-rolled cigarettes and that there could be, at a minimum, pockets of increased smoking and addiction among female daily smokers in Indonesia.

Redo Valve-Sparing Root Replacement for Delayed Cusp Derangement From Ventricular Septal Defect

A 28-year-old man with ventricular septal defect, double-chambered right ventricle with associated right ventricular outflow tract obstruction, and anomalous right coronary artery underwent resection of the double-chambered right ventricle, transaortic ventricular septal defect repair, and unroofing of anomalous right coronary artery. Two years later, he returned with delayed presentation of ventricular septal defect flow funnel-related aortic cusp prolapse and symptomatic severe aortic regurgitation. He underwent reoperative valve-sparing aortic root replacement and aortic cusp repair with an excellent outcome.

Impact of "increased-risk" donor hearts on transplant outcomes: A propensity-matched analysis

OBJECTIVES

Orthotopic heart transplantation (OHT) remains the gold standard for advanced heart failure. Increased risk (IR) donors were categorized by the United Network for Organ Sharing Database (UNOS) according to the Centers for Disease Control and Prevention (CDC) criteria. However, the impact of CDC IR donor hearts on the outcome of adult OHT recipients remains unclear. The aim of this study was to compare the outcome of adult OHT recipients between CDC IR and non-CDC IR donor grafts.

METHODS

Data were obtained from the United Network for Organ Sharing Databas. All adult patients (age ≥18 years) undergoing OHT from 2004 through 2016 were included (n = 24,751). Propensity scores for CDC IR donors were calculated by estimating probabilities of CDC IR donor graft use using a nonparsimonious multivariable logistic regression model. Patients were matched 1:1 using a greedy matching algorithm based on the propensity score of each patient. The impact of CDC IR donors on the post-transplant outcomes, such as 30-day and overall mortalities, was investigated using Cox-proportional hazards. Overall survival probability analyses were performed.

RESULTS

Of 24,751 primary heart transplants from 2004 to 2016 with 3584 (14.5%) as IR donors, 6304 transplants were successfully matched (n = 3152 in CDC IR group and non-IR group). There were no significant differences in baseline characteristics in recipients and donors. In the Cox-proportional hazards model for matched subjects, the use of CDC IR grafts was not associated with 30-day (hazard ratio of IR group vs non-IR group 0.97; 95% confidence interval, 0.87-1.08; P = .57) and overall mortalities (hazard ratio, 0.94; 95% confidence interval, 0.73-1.21; P = .62). Interestingly, post-transplant acute myocardial rejection episodes during hospital stays were found more often in the CDC-IR group, compared with the non-CDC IR group (CDC IR, n = 358 [11.4%]; non-CDC IR, n = 304 [9.6%] P = .03), whereas post-transplant pacemaker placements were performed less frequently in the CDC IR group (CDC IR, n = 80 [2.6%]; non-CDC IR, n = 111 [3.5%] P = .020). Importantly, there was no significant difference in the overall survival probability between CDC IR and non-IR groups in both unadjusted and adjusted survival analyses.

CONCLUSIONS

CDC IR status does not have a significant impact on adult OHT recipient survival probability. Increased use of CDC IR donor grafts can potentially alleviate the persistent and worsening shortage of available donor organs and shorten the waitlist time for heart transplantation.

An innovative biologic system for photon-powered myocardium in the ischemic heart

Coronary artery disease is one of the most common causes of death and disability, afflicting more than 15 million Americans. Although pharmacological advances and revascularization techniques have decreased mortality, many survivors will eventually succumb to heart failure secondary to the residual microvascular perfusion deficit that remains after revascularization. We present a novel system that rescues the myocardium from acute ischemia, using photosynthesis through intramyocardial delivery of the cyanobacterium Synechococcus elongatus. By using light rather than blood flow as a source of energy, photosynthetic therapy increases tissue oxygenation, maintains myocardial metabolism, and yields durable improvements in cardiac function during and after induction of ischemia. By circumventing blood flow entirely to provide tissue with oxygen and nutrients, this system has the potential to create a paradigm shift in the way ischemic heart disease is treated.

Layered smooth muscle cell-endothelial progenitor cell sheets derived from the bone marrow augment postinfarction ventricular function

OBJECTIVE

The angiogenic potential of endothelial progenitor cells (EPCs) may be limited by the absence of their natural biologic foundation, namely smooth muscle pericytes. We hypothesized that joint delivery of EPCs and smooth muscle cells (SMCs) in a novel, totally bone marrow-derived cell sheet will mimic the native architecture of a mature blood vessel and act as an angiogenic construct to limit post infarction ventricular remodeling.

METHODS

Primary EPCs and mesenchymal stem cells were isolated from bone marrow of Wistar rats. Mesenchymal stem cells were transdifferentiated into SMCs by culture on fibronectin-coated culture dishes. Confluent SMCs topped with confluent EPCs were detached from an Upcell dish to create a SMC-EPC bi-level cell sheet. A rodent model of ischemic cardiomyopathy was then created by ligating the left anterior descending artery. Rats were randomized into 3 groups: cell sheet transplantation (n = 9), no treatment (n = 12), or sham surgery control (n = 7).

RESULTS

Four weeks postinfarction, mature vessel density tended to increase in cell sheet-treated animals compared with controls. Cell sheet therapy significantly attenuated the extent of cardiac fibrosis compared with that of the untreated group (untreated vs cell sheet, 198 degrees [interquartile range (IQR), 151-246 degrees] vs 103 degrees [IQR, 92-113 degrees], P = .04). Furthermore, EPC-SMC cell sheet transplantation attenuated myocardial dysfunction, as evidenced by an increase in left ventricular ejection fraction (untreated vs cell sheet vs sham, 33.5% [IQR, 27.8%-35.7%] vs 45.9% [IQR, 43.6%-48.4%] vs 59.3% [IQR, 58.8%-63.5%], P = .001) and decreases in left ventricular dimensions.

CONCLUSIONS

The bone marrow-derived, spatially arranged SMC-EPC bi-level cell sheet is a novel, multilineage cellular therapy obtained from a translationally practical source. Interactions between SMCs and EPCs augment mature neovascularization, limit adverse remodeling, and improve ventricular function after myocardial infarction.

Injectable Bioengineered Hydrogel Therapy in the Treatment of Ischemic Cardiomyopathy

OPINION STATEMENT

Over the past two decades, the field of cardiovascular medicine has seen the rapid development of multiple different modalities for the treatment of ischemic myocardial disease. Most research efforts have focused on strategies aimed at coronary revascularization, with significant technological advances made in percutaneous coronary interventions as well as coronary artery bypass graft surgery. However, recent research efforts have shifted towards ways to address the downstream effects of myocardial infarction on both cellular and molecular levels. To this end, the broad application of injectable hydrogel therapy after myocardial infarction has stimulated tremendous interest. In this article, we will review what hydrogels are, how they can be bioengineered in unique ways to optimize therapeutic potential, and how they can be used as part of a treatment strategy after myocardial infarction.

Using the theory of normative social behavior to understand compliance with a smoke-free law in a middle-income country

Smoke-free laws, which ban smoking in public venues, can be effective in protecting public health, but it has been difficult to achieve compliance with these laws in low- and middle-income countries. This study was conducted to understand the social norms around public smoking and learn how to improve compliance in Bogor, the first Indonesian city to pass a comprehensive smoke-free law. Eleven stratified focus groups were conducted (n = 89). Data were analyzed using the theory of normative social behavior, which posits that the influence of descriptive norms (perceptions about what other people do) on behavior is moderated by injunctive norms (perceptions about what one is expected to do), outcome expectations and group identity. The findings showed that participants perceived smoking in public to be common for men (descriptive norm). Public smoking is acceptable except in places with air conditioning and around children or pregnant women (injunctive norms). Men smoke without penalty of social or legal sanctions (outcome expectations) and may feel affiliation with other smokers (group identity). Together, these factors support public smoking and inhibit compliance with the smoke-free law. Theory-based communication and policy remedies are suggested that may bolster compliance with Bogor's smoke-free law given the current pro-smoking norms.

Isolation and trans-differentiation of mesenchymal stromal cells into smooth muscle cells: Utility and applicability for cell-sheet engineering

BACKGROUND

Bone marrow (BM)-derived mesenchymal stromal cells (MSCs) have shown potential to differentiate into various cell types, including smooth muscle cells (SMCs). The extracellular matrix (ECM) represents an appealing and readily available source of SMCs for use in tissue engineering. In this study, we hypothesized that the ECM could be used to induce MSC differentiation to SMCs for engineered cell-sheet construction.

METHODS

Primary MSCs were isolated from the BM of Wistar rats, transferred and cultured on dishes coated with 3 different types of ECM: collagen type IV (Col IV), fibronectin (FN), and laminin (LM). Primary MSCs were also included as a control. The proportions of SMC (a smooth muscle actin [aSMA] and SM22a) and MSC markers were examined with flow cytometry and Western blotting, and cell proliferation rates were also quantified.

RESULTS

Both FN and LM groups were able to induce differentiation of MSCs toward smooth muscle-like cell types, as evidenced by an increase in the proportion of SMC markers (aSMA; Col IV 42.3 ± 6.9%, FN 65.1 ± 6.5%, LM 59.3 ± 7.0%, Control 39.9 ± 3.1%; P = 0.02, SM22; Col IV 56.0 ± 7.7%, FN 74.2 ± 6.7%, LM 60.4 ± 8.7%, Control 44.9 ± 3.6%) and a decrease in that of MSC markers (CD105: Col IV 64.0 ± 5.2%, FN 57.6 ± 4.0%, LM 60.3 ± 7.0%, Control 85.3 ± 4.2%; P = 0.03). The LM group showed a decrease in overall cell proliferation, whereas FN and Col IV groups remained similar to control MSCs (Col IV, 9.0 ± 2.3%; FN, 9.8 ± 2.5%; LM, 4.3 ± 1.3%; Control, 9.8 ± 2.8%).

CONCLUSIONS

Our findings indicate that ECM selection can guide differentiation of MSCs into the SMC lineage. Fibronectin preserved cellular proliferative capacity while yielding the highest proportion of differentiated SMCs, suggesting that FN-coated materials may be facilitate smooth muscle tissue engineering.

Regulating Stem Cell Secretome Using Injectable Hydrogels with In Situ Network Formation

A family of shear-thinning hydrogels for injectable encapsulation and long-term delivery (SHIELD) has been designed and synthesized with controlled in situ stiffening properties to regulate the stem cell secretome. The authors demonstrate that SHIELD with an intermediate stiffness (200-400 Pa) could significantly promote the angiogenic potential of human adipose-derived stem cells.

A Tissue-Engineered Chondrocyte Cell Sheet Induces Extracellular Matrix Modification to Enhance Ventricular Biomechanics and Attenuate Myocardial Stiffness in Ischemic Cardiomyopathy

There exists a substantial body of work describing cardiac support devices to mechanically support the left ventricle (LV); however, these devices lack biological effects. To remedy this, we implemented a cell sheet engineering approach utilizing chondrocytes, which in their natural environment produce a relatively elastic extracellular matrix (ECM) for a cushioning effect. Therefore, we hypothesized that a chondrocyte cell sheet applied to infarcted and borderzone myocardium will biologically enhance the ventricular ECM and increase elasticity to augment cardiac function in a model of ischemic cardiomyopathy (ICM). Primary articular cartilage chondrocytes of Wistar rats were isolated and cultured on temperature-responsive culture dishes to generate cell sheets. A rodent ICM model was created by ligating the left anterior descending coronary artery. Rats were divided into two groups: cell sheet transplantation (1.0 × 10(7) cells/dish) and no treatment. The cell sheet was placed onto the surface of the heart covering the infarct and borderzone areas. At 4 weeks following treatment, the decreased fibrotic extension and increased elastic microfiber networks in the infarct and borderzone areas correlated with this technology's potential to stimulate ECM formation. The enhanced ventricular elasticity was further confirmed by the axial stretch test, which revealed that the cell sheet tended to attenuate tensile modulus, a parameter of stiffness. This translated to increased wall thickness in the infarct area, decreased LV volume, wall stress, mass, and improvement of LV function. Thus, the chondrocyte cell sheet strengthens the ventricular biomechanical properties by inducing the formation of elastic microfiber networks in ICM, resulting in attenuated myocardial stiffness and improved myocardial function.

Early surgical intervention or watchful waiting for the management of asymptomatic mitral regurgitation: a systematic review and meta-analysis

BACKGROUND

Discordance between studies drives continued debate regarding the best management of asymptomatic severe mitral regurgitation (MR). The aim of the present study was to conduct a systematic review and meta-analysis of management plans for asymptomatic severe MR, and compare the effectiveness of a strategy of early surgery to watchful waiting.

METHODS

A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies were excluded if they: (I) lacked a watchful waiting cohort; (II) included symptomatic patients; or (III) included etiologies other than degenerative mitral valve disease. The primary outcome of the study was all-cause mortality at 10 years. Secondary outcomes included operative mortality, repair rate, repeat mitral valve surgery, and development of new atrial fibrillation.

RESULTS

Five observational studies were eligible for review and three were included in the pooled analysis. In asymptomatic patients without class I triggers (symptoms or ventricular dysfunction), pooled analysis revealed a significant reduction in long-term mortality with an early surgery approach [hazard ratio (HR) =0.38; 95% confidence interval (CI): 0.21-0.71]. This survival benefit persisted in a sub-group analysis limited to patients without class II triggers (atrial fibrillation or pulmonary hypertension) [relative risk (RR) =0.85; 95% CI: 0.75-0.98]. Aggregate rates of operative mortality did not differ between treatment arms (0.7% vs. 0.7% for early surgery vs. watchful waiting). However, significantly higher repair rates were achieved in the early surgery cohorts (RR =1.10; 95% CI: 1.02-1.18).

CONCLUSIONS

Despite disagreement between individual studies, the present meta-analysis demonstrates that a strategy of early surgery may improve survival and increase the likelihood of mitral valve repair compared with watchful waiting. Early surgery may also benefit patients when instituted prior to the development of class II triggers.

Protein Corona Influences Cell-Biomaterial Interactions in Nanostructured Tissue Engineering Scaffolds

Biomaterials are extensively used to restore damaged tissues, in the forms of implants (e.g. tissue engineered scaffolds) or biomedical devices (e.g. pacemakers). Once in contact with the physiological environment, nanostructured biomaterials undergo modifications as a result of endogenous proteins binding to their surface. The formation of this macromolecular coating complex, known as 'protein corona', onto the surface of nanoparticles and its effect on cell-particle interactions are currently under intense investigation. In striking contrast, protein corona constructs within nanostructured porous tissue engineering scaffolds remain poorly characterized. As organismal systems are highly dynamic, it is conceivable that the formation of distinct protein corona on implanted scaffolds might itself modulate cell-extracellular matrix interactions. Here, we report that corona complexes formed onto the fibrils of engineered collagen scaffolds display specific, distinct, and reproducible compositions that are a signature of the tissue microenvironment as well as being indicative of the subject's health condition. Protein corona formed on collagen matrices modulated cellular secretome in a context-specific manner ex-vivo, demonstrating their role in regulating scaffold-cellular interactions. Together, these findings underscore the importance of custom-designing personalized nanostructured biomaterials, according to the biological milieu and disease state. We propose the use of protein corona as in situ biosensor of temporal and local biomarkers.

Bioengineered stromal cell-derived factor-1α analogue delivered as an angiogenic therapy significantly restores viscoelastic material properties of infarcted cardiac muscle

Ischemic heart disease is a major health problem worldwide, and current therapies fail to address microrevascularization. Previously, our group demonstrated that the sustained release of novel engineered stromal cell-derived factor 1-a analogue (ESA) limits infarct spreading, collagen deposition, improves cardiac function by promoting angiogenesis in the region surrounding the infarct, and restores the tensile properties of infarcted myocardium. In this study, using a well-established rat model of ischemic cardiomyopathy, we describe a novel and innovative method for analyzing the viscoelastic properties of infarcted myocardium. Our results demonstrate that, compared with a saline control group, animals treated with ESA have significantly improved myocardial relaxation rates, while reducing the transition strain, leading to restoration of left ventricular mechanics.

Tissue-engineered, hydrogel-based endothelial progenitor cell therapy robustly revascularizes ischemic myocardium and preserves ventricular function

OBJECTIVES

Cell-based angiogenic therapy for ischemic heart failure has had limited clinical impact, likely related to low cell retention (<1%) and dispersion. We developed a novel, tissue-engineered, hydrogel-based cell-delivery strategy to overcome these limitations and provide prolonged regional retention of myocardial endothelial progenitor cells at high cell dosage.

METHODS

Endothelial progenitor cells were isolated from Wistar rats and encapsulated in fibrin gels. In vitro viability was quantified using a fluorescent live-dead stain of transgenic enhanced green fluorescent protein(+) endothelial progenitor cells. Endothelial progenitor cell-laden constructs were implanted onto ischemic rat myocardium in a model of acute myocardial infarction (left anterior descending ligation) for 4 weeks. Intramyocardial cell injection (2 × 10(6) endothelial progenitor cells), empty fibrin, and isolated left anterior descending ligation groups served as controls. Hemodynamics were quantified using echocardiography, Doppler flow analysis, and intraventricular pressure-volume analysis. Vasculogenesis and ventricular geometry were quantified. Endothelial progenitor cell migration was analyzed by using endothelial progenitor cells from transgenic enhanced green fluorescent protein(+) rodents.

RESULTS

Endothelial progenitor cells demonstrated an overall 88.7% viability for all matrix and cell conditions investigated after 48 hours. Histologic assessment of 1-week implants demonstrated significant migration of transgenic enhanced green fluorescent protein(+) endothelial progenitor cells from the fibrin matrix to the infarcted myocardium compared with intramyocardial cell injection (28 ± 12.3 cells/high power field vs 2.4 ± 2.1 cells/high power field, P = .0001). We also observed a marked increase in vasculogenesis at the implant site. Significant improvements in ventricular hemodynamics and geometry were present after endothelial progenitor cell-hydrogel therapy compared with control.

CONCLUSIONS

We present a tissue-engineered, hydrogel-based endothelial progenitor cell-mediated therapy to enhance cell delivery, cell retention, vasculogenesis, and preservation of myocardial structure and function.

A bioengineered hydrogel system enables targeted and sustained intramyocardial delivery of neuregulin, activating the cardiomyocyte cell cycle and enhancing ventricular function in a murine model of ischemic cardiomyopathy

BACKGROUND

Neuregulin-1β (NRG) is a member of the epidermal growth factor family possessing a critical role in cardiomyocyte development and proliferation. Systemic administration of NRG demonstrated efficacy in cardiomyopathy animal models, leading to clinical trials using daily NRG infusions. This approach is hindered by requiring daily infusions and off-target exposure. Therefore, this study aimed to encapsulate NRG in a hydrogel to be directly delivered to the myocardium, accomplishing sustained localized NRG delivery.

METHODS AND RESULTS

NRG was encapsulated in hydrogel, and release over 14 days was confirmed by ELISA in vitro. Sprague-Dawley rats were used for cardiomyocyte isolation. Cells were stimulated by PBS, NRG, hydrogel, or NRG-hydrogel (NRG-HG) and evaluated for proliferation. Cardiomyocytes demonstrated EdU (5-ethynyl-2'-deoxyuridine) and phosphorylated histone H3 positivity in the NRG-HG group only. For in vivo studies, 2-month-old mice (n=60) underwent left anterior descending coronary artery ligation and were randomized to the 4 treatment groups mentioned. Only NRG-HG-treated mice demonstrated phosphorylated histone H3 and Ki67 positivity along with decreased caspase-3 activity compared with all controls. NRG was detected in myocardium 6 days after injection without evidence of off-target exposure in NRG-HG animals. At 2 weeks, the NRG-HG group exhibited enhanced left ventricular ejection fraction, decreased left ventricular area, and augmented borderzone thickness.

CONCLUSIONS

Targeted and sustained delivery of NRG directly to the myocardial borderzone augments cardiomyocyte mitotic activity, decreases apoptosis, and greatly enhances left ventricular function in a model of ischemic cardiomyopathy. This novel approach to NRG administration avoids off-target exposure and represents a clinically translatable strategy in myocardial regenerative therapeutics.

Preclinical evaluation of the engineered stem cell chemokine stromal cell-derived factor 1α analog in a translational ovine myocardial infarction model

RATIONALE

After myocardial infarction, there is an inadequate blood supply to the myocardium, and the surrounding borderzone becomes hypocontractile.

OBJECTIVE

To develop a clinically translatable therapy, we hypothesized that in a preclinical ovine model of myocardial infarction, the modified endothelial progenitor stem cell chemokine, engineered stromal cell-derived factor 1α analog (ESA), would induce endothelial progenitor stem cell chemotaxis, limit adverse ventricular remodeling, and preserve borderzone contractility.

METHODS AND RESULTS

Thirty-six adult male Dorset sheep underwent permanent ligation of the left anterior descending coronary artery, inducing an anteroapical infarction, and were randomized to borderzone injection of saline (n=18) or ESA (n=18). Ventricular function, geometry, and regional strain were assessed using cardiac MRI and pressure-volume catheter transduction. Bone marrow was harvested for in vitro analysis, and myocardial biopsies were taken for mRNA, protein, and immunohistochemical analysis. ESA induced greater chemotaxis of endothelial progenitor stem cells compared with saline (P<0.01) and was equivalent to recombinant stromal cell-derived factor 1α (P=0.27). Analysis of mRNA expression and protein levels in ESA-treated animals revealed reduced matrix metalloproteinase 2 in the borderzone (P<0.05), with elevated levels of tissue inhibitor of matrix metalloproteinase 1 and elastin in the infarct (P<0.05), whereas immunohistochemical analysis of borderzone myocardium showed increased capillary and arteriolar density in the ESA group (P<0.01). Animals in the ESA treatment group also had significant reductions in infarct size (P<0.01), increased maximal principle strain in the borderzone (P<0.01), and a steeper slope of the end-systolic pressure-volume relationship (P=0.01).

CONCLUSIONS

The novel, biomolecularly designed peptide ESA induces chemotaxis of endothelial progenitor stem cells, stimulates neovasculogenesis, limits infarct expansion, and preserves contractility in an ovine model of myocardial infarction.

Spatially oriented, temporally sequential smooth muscle cell-endothelial progenitor cell bi-level cell sheet neovascularizes ischemic myocardium

BACKGROUND

Endothelial progenitor cells (EPCs) possess robust therapeutic angiogenic potential, yet may be limited in the capacity to develop into fully mature vasculature. This problem might be exacerbated by the absence of a neovascular foundation, namely pericytes, with simple EPC injection. We hypothesized that coculturing EPCs with smooth muscle cells (SMCs), components of the surrounding vascular wall, in a cell sheet will mimic the native spatial orientation and interaction between EPCs and SMCs to create a supratherapeutic angiogenic construct in a model of ischemic cardiomyopathy.

METHODS AND RESULTS

Primary EPCs and SMCs were isolated from Wistar rats. Confluent SMCs topped with confluent EPCs were spontaneously detached from the Upcell dish to create an SMC-EPC bi-level cell sheet. A rodent ischemic cardiomyopathy model was created by ligating the left anterior descending coronary artery. Rats were then immediately divided into 3 groups: cell-sheet transplantation (n=14), cell injection (n=12), and no treatment (n=13). Cocultured EPCs and SMCs stimulated an abundant release of multiple cytokines in vitro. Increased capillary density and improved blood perfusion in the borderzone elucidated the significant in vivo angiogenic potential of this technology. Most interestingly, however, cell fate-tracking experiments demonstrated that the cell-sheet EPCs and SMCs directly migrated into the myocardium and differentiated into elements of newly formed functional vasculature. The robust angiogenic effect of this cell sheet translated to enhanced ventricular function as demonstrated by echocardiography.

CONCLUSIONS

Spatially arranged EPC-SMC bi-level cell-sheet technology facilitated the natural interaction between EPCs and SMCs, thereby creating structurally mature, functional microvasculature in a rodent ischemic cardiomyopathy model, leading to improved myocardial function.