Intrapericardial drug delivery: pharmacologic properties and long-term safety in swine

A nanosized anionic MOF with rich thiadiazole groups for controlled oral drug delivery

Controlling the crystal size and surface chemistry of MOF materials, and understanding their multifunctional effect are of great significance for the biomedical applications of MOF systems. Herein, we designed and synthesized a new anionic MOF, ZJU-64-NSN, which features 1D channels decorated with highly polarized thiadiazole groups, and its crystal size could be systematically tuned from 200 ​μm to 300 ​nm through a green and simple approach. As a result, the optimal nanosized ZJU-64-NSN is found to enable an ultrafast loading of cationic drug procainamide (PA) (21.2 ​wt% within 1 ​min). Moreover, the undesirable chemical stability of PA@ZJU-64-NSN is greatly improved by the surface coating of polyethylene glycol (PEG) biopolymer. The final drug delivery system PEG/PA@ZJU-64-NSN is found to effectively prevent PA from premature release under the harsh stomach environments due to the intense host-guest interaction, and mainly release PA to the targeted intestinal surroundings. Such controlled drug delivery is proved to be triggered by endogenic Na⁺ ions instead of H⁺ ions, well revealed by the study on the dynamics behavior of drug release and UV–Vis absorption spectrum. Good biocompatibility of ZJU-64-NSN and PEG-coated ZJU-64-NSN has been fully demonstrated by MTT assay as well as confocal microscopy imaging.

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A new anionic MOF enables an ultrafast drug loading.

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The crystal size of such MOF could be well size-controlled.

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The surface coating of PEG improves the chemical stability of drug carrier.

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The drug delivery system reveals an endogenic Na ​⁺ ​-triggered procainamide release.

The epicardial delivery of cardiosphere derived cells or their extracellular vesicles is safe but of limited value in experimental infarction

The epicardial administration of therapeutics via the pericardial sac offers an attractive route, since it is minimally invasive and carries no risks of coronary embolization. The aim of this study was to assess viability, safety and effectiveness of cardiosphere-derived cells (CDCs), their extracellular vesicles (EVs) or placebo administered via a mini-thoracotomy 72 h after experimental infarction in swine. The epicardial administration was completed successfully in all cases in a surgery time (knife-to-skin) below 30 min. No significant differences between groups were found in cardiac function parameters evaluated using magnetic resonance imaging before therapy and at the end of the study, despite a trend towards improved function in CDC-treated animals. Moreover, infarct size at 10 weeks was smaller in treated animals, albeit not significantly. Arrhythmia inducibility did not differ between groups. Pathological examination showed no differences, nor were there any pericardial adhesions evidenced in any case 10 weeks after surgery. These results show that the epicardial delivery of CDCs or their EVs is safe and technically easy 3 days after experimental myocardial infarction in swine, but it does not appear to have any beneficial effect on cardiac function. Our results do not support clinical translation of these therapies as implemented in this work.

Access routes, devices and guidance methods for intrapericardial delivery in cardiac conditions

Drug deposition into the intrapericardial space is favourable for achieving localised effects and targeted cardiac delivery owing to its proximity to the myocardium as well as facilitating optimised pharmacokinetic profiles and a reduction in systemic side effects. Access to the pericardium requires invasive procedures but the risks associated with this have been reduced with technological advances, such as combining transatrial and subxiphoid access with different guidance methods. A variety of introducer devices, ranging from needles to loop-catheters, have also been developed and validated in pre-clinical studies investigating intrapericardial delivery of therapeutic agents. Access techniques are generally well-tolerated, self-limiting and safe, although some rare complications associated with certain approaches have been reported. This review covers these access techniques and how they have been applied to the delivery of drugs, cells, and biologicals, demonstrating the potential of intrapericardial delivery for treatments in cardiac arrhythmia, vascular damage, and myocardial infarction.

All Roads Lead to Rome (the Heart): Cell Retention and Outcomes From Various Delivery Routes of Cell Therapy Products to the Heart

In the past decades, numerous preclinical studies and several clinical trials have evidenced the feasibility of cell transplantation in treating heart diseases. Over the years, different delivery routes of cell therapy have emerged and broadened the width of the field. However, a common hurdle is shared by all current delivery routes: low cell retention. A myriad of studies confirm that cell retention plays a crucial role in the success of cell-mediated cardiac repair. It is important for any delivery route to maintain donor cells in the recipient heart for enough time to not only proliferate by themselves, but also to send paracrine signals to surrounding damaged heart cells and repair them. In this review, we first undertake an in-depth study of primary theories of cell loss, including low efficiency in cell injection, "washout" effects, and cell death, and then organize the literature from the past decade that focuses on cell transplantation to the heart using various cell delivery routes, including intracoronary injection, systemic intravenous injection, retrograde coronary venous injection, and intramyocardial injection. In addition to a recapitulation of these approaches, we also clearly evaluate their strengths and weaknesses. Furthermore, we conduct comparative research on the cell retention rate and functional outcomes of these delivery routes. Finally, we extend our discussion to state-of-the-art bioengineering techniques that enhance cell retention, as well as alternative delivery routes, such as intrapericardial delivery. A combination of these novel strategies and more accurate assessment methods will help to address the hurdle of low cell retention and boost the efficacy of cell transplantation to the heart.

Therapeutic advances in cardiac targeted drug delivery: from theory to practice

The most commonly used administration methods in clinics and life are oral administration, intravenous injection, and other systemic administration methods. Targeted administration must be an essential long-term development direction due to the limited availability and a high incidence of systemic side effects. Cardiovascular diseases (CVD) are the leading cause of death all over the world. Targeted drug delivery (TDD) methods with the heart as the target organ have developed rapidly and are diversified. This article reviews the research progress of various TDD methods around the world with a heart as the target organ. It is mainly divided into two parts: the targeting vector represented by nanoparticles and various TDD methods such as intracoronary injection, ventricular wall injection, pericardial injection, and implantable medical device therapy and put forward some suggestions on the development of targeting. Different TDD methods described in this paper have not been widely used in clinical practice, and some have not even completed preclinical studies. Targeted drug delivery still requires long-term efforts by many researchers to realize the true meaning of the heart. HIGHLIGHTS Targeted administration can achieve a better therapeutic effect and effectively reduce the occurrence of adverse reactions. Parenteral administration or medical device implantation can be used for targeted drug delivery. Combined with new dosage forms or new technologies, better-targeted therapy can be achieved. Clinical trials have confirmed the safety and effectiveness of several administration methods.

Nanoparticles administered intrapericardially enhance payload myocardial distribution and retention

Pharmacological therapies for cardiovascular diseases are limited by short-term pharmacokinetics and extra-cardiac adverse effects. Improving delivery selectivity specifically to the heart, wherein therapeutic drug levels can be maintained over time, is highly desirable. Nanoparticle (NP)-based pericardial drug delivery could provide a strategy to concentrate therapeutics within a unique, cardiac-restricted compartment to allow sustained drug penetration into the myocardium. Our objective was to explore the kinetics of myocardial penetration and retention after pericardial NP drug delivery. Fluorescently-tagged poly(lactic-co-glycolic acid) (PLGA) NPs were loaded with BODIPY, a fluorophore, and percutaneously administered into the pericardium via subxiphoid puncture in rabbits. At distinct timepoints hearts were examined for presence of NPs and BODIPY. PLGA NPs were found non-uniformly distributed on the epicardium following pericardial administration, displaying a half-life of ~2.5days in the heart. While NPs were mostly confined to epicardial layers, BODIPY was capable of penetrating into the myocardium, resulting in a transmural gradient. The distinct architecture and physiology of the different regions of the heart influenced BODIPY distribution, with fluorophore penetrating more readily into atria than ventricles. BODIPY proved to have a long-term presence within the heart, with a half-life of ~7days. Our findings demonstrate the potential of utilizing the pericardial space as a sustained drug-eluting reservoir through the application of nanoparticle-based drug delivery, opening several exciting avenues for selective and prolonged cardiac therapeutics.

Effectiveness of biatrial epicardial application of amiodarone-releasing adhesive hydrogel to prevent postoperative atrial fibrillation

OBJECTIVE

Postoperative atrial fibrillation (POAF) is the most frequent complication arising after cardiac surgery, occurring in 30% of cases. Amiodarone is the most effective drug for prophylaxis and treatment. However, because of significant extracardiac side effects, only high-risk patients are eligible for prophylactic amiodarone therapy. We performed a randomized prospective study of 100 patients undergoing cardiac surgery with epicardial application of amiodarone-releasing hydrogel to determine the effectiveness of preventing POAF.

METHODS

After institutional review board approval, 100 patients, from January 2012 to July 2013, who had undergone cardiac surgery, were randomized to 2 equal groups. The study group received poly-based hydrogel with amiodarone sprayed diffusely over the epicardium. The control group underwent the procedure without the spray. Continuous telemetry monitored for POAF, and amiodarone levels in the atria, plasma, and tissue were measured postoperatively. Daily electrocardiographic parameters were measured until postoperative day 14.

RESULTS

The incidence of POAF was significantly less in the study group, with 4 of 50 patients (8%) incurring atrial fibrillation compared with 13 of 50 patients (26%) in the control group (P < .01). The mean amiodarone concentrations in the atria (12.06 ± 3.1) were significantly greater than those in the extracardiac tissues (1.32 ± 0.9; P < .01). The plasma amiodarone levels remained below the detection limit (<8 μg/mL) during the 14 days of follow-up. Bradycardia was observed less in the study group (76 ± 29) than in the control group (93 ± 18; P < .01).

CONCLUSIONS

Epicardial application of amiodarone-releasing adhesive hydrogel is a less invasive, well-tolerated, quick, and effective therapeutic option for preventing POAF at minimal risk of extracardiac adverse side effects.

A Novel Amiodarone-Eluting Biological Glue for Reducing Postoperative Atrial Fibrillation

Objective:

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery, leading to increased morbidity and mortality. The aim of this preliminary study was to evaluate a novel drug delivery system for local release of amiodarone.

Methods:

In the current prospective study, 9 goats underwent attachment of right atrial (RA) epicardial electrodes. Alginate-based glue with amiodarone was applied to the RA of the treatment groups. Rapid atrial response (RAR) to burst pacing was assessed before application and in the third postoperative day (POD3). Average RAR frequency was defined as the average percentage of inductions resulting in RAR per animal. Myocardial and extracardiac tissue amiodarone concentrations were analyzed.

Results:

Differences in RAR proportions between baseline and POD3 were greater in the treatment group versus the control group ( P = .034). Average RAR frequency was reduced by 34% in the treatment group (baseline: 65%; POD3: 31%), while it was increased by 11.3% in the control (baseline:43.8%; POD3: 55%). The treatment group demonstrated a greater proportion of animals meeting the success criterion of net percentage reduction in RAR frequency greater than 25% ( P = .047). The average amount of total amiodarone detected in the RA was 104.4 ± 28.9 µg; the transmural concentration was linearly distributed ( P < .0001). Extracardiac tissue concentrations were below the detection level.

Conclusions:

Local alginate-based amiodarone delivery demonstrated an RAR frequency reduction of clinical importance in response to burst pacing. The electrophysiological response was achieved while maintaining below-detection systemic drug levels. Current findings may point to the system’s future applicability in reducing POAF risk in humans.

Local administration of tranexamic acid in off-pump coronary artery bypass

PURPOSE

We administered tranexamic acid locally to patients undergoing off-pump coronary artery bypass, to investigate the hemostatic effects and safety.

PATIENTS AND METHODS

The subjects were 100 consecutive patients who underwent off-pump coronary artery bypass between July 2009 and January 2011. We assigned 50 patients in the early phase, in which tranexamic acid was not employed, to group N, and 50 in the late phase, in which tranexamic acid was employed, to group T. In group T, 10 mL of a solution containing 1 g of tranexamic acid in was sprayed into the pericardial cavity and mediastinum before the sternum was closed. We compared the volume of postoperative blood loss, blood transfusion volume, and complications between the 2 groups.

RESULTS

The volume of blood loss in 24 h after intensive care unit admission was 492 mL in group N and 303 mL in group T (p<0.0001); the decrease in blood loss in the group receiving tranexamic acid was approximately 40%. There was no significant difference in the blood transfusion volumes. There were no side effects of tranexamic acid.

CONCLUSION

In patients undergoing off-pump coronary artery bypass, local administration of tranexamic acid may decrease the volume of postoperative blood loss. The local administration method is simple, inexpensive, and safe.

Intrapericardial procedures for cardiac regeneration by stem cells: need for minimal invasive access (AttachLifter) to the normal pericardial cavity

In view of the only modest functional and anatomical improvements achieved by bone marrow-derived cell transplantation in patients with heart disease, the question was addressed whether the intracoronary, transcoronary-venous, and intramyocardial delivery routes are adequate. It is hypothesized that an intrapericardial delivery of stem cells or activators of resident cardiac stem cells increases therapeutic benefits. From such an intrapericardial depot, cells or modulating factors, such as thymosin β4 or Ac-SDKP, are expected to reach the myocardium with sustained kinetics. Novel tools which provide access to the pericardial space even in the absence of pericardial effusion are, therefore, described. When the pericardium becomes attached to the suction head (monitored by an increase in negative pressure), the pericardium is lifted from the epicardium ("AttachLifter"). The opening of the suction head ("Attacher") is narrowed by flexible clamps which grab the tissue and improve the vacuum seal in the case of uneven tissue. A ridge, i.e.,"needle guidance", on the suction head excludes injury to the epicardium, whereby the pericardium is punctured by a needle which resides outside the suction head. A fiberscope can be used to inspect the pericardium prior to puncture. Based on these procedures, the role of the pericardial space and the presence of pericardial effusion in cardiac regeneration can be assessed.

Randomised comparison of growth hormone versus IGF-1 on early post-myocardial infarction ventricular remodelling in rats

OBJECTIVE

Growth hormone and insulin-like growth factor-1 participate in post-myocardial infarction healing, but their relative importance is unclear. We compared the treatment effects of these agents on left ventricular remodelling.

DESIGN

Wistar rats were randomised into a single dose of either growth hormone (0.5microg, n=29), or insulin-like growth factor-1 (0.5microg, n=27), delivered by direct intramyocardial punctures, and were compared with controls (n=30). Five minutes after treatment, myocardial infarction was generated by permanent ligation of the left coronary artery. Twenty-four hours post-ligation, serum levels of catecholamines were measured using radioimmunoassay and infarct size as well as infarct expansion index were calculated. The expression of genes related to extracellular matrix and angiogenesis was measured using polymerase chain reaction.

RESULTS

Infarct expansion index was lower in growth hormone-treated rats (0.28+/-0.03, p=0.007) and in insulin-like growth factor-1-treated rats (0.35+/-0.03, p=0.044) compared to controls (0.51+/-0.06). Infarct size was significantly (p=0.0076) lower in growth hormone-treated rats (32.2+/-2.0%) and marginally (p=0.094) lower in insulin-like growth factor-1-treated rats (36.2+/-2.3%) compared to controls (42.0+/-2.7%). Survival rates were comparable in the three groups. Epinephrine was lower in the growth hormone group (2.8+/-0.2microg/l) compared to either controls (5.0+/-0.6microg/l, p=0.007), or to insulin-like growth factor-1-treated rats (6.3+/-0.6microg/l, p=0.0001). Collagen I and III expression in the infarct zone was higher in the growth hormone group compared to either the insulin-like growth factor-1 group or to controls.

CONCLUSIONS

Both growth hormone and insulin-like-growth factor-1 decrease early infarct expansion, but growth hormone results in more favourable extracellular matrix remodelling and sympathetic activation.

Heart Rate Turbulence Slope Reduction in Imminent Ventricular Tachyarrhythmia and its Implications

INTRODUCTION

The aim of this study was to see whether heart rate turbulence (HRT) parameters change preceding imminent ventricular tachyarrhythmias (VT/VF).

METHODS AND RESULTS

The Spontaneous Ventricular Tachyarrhythmia Database (Medtronic Version 1.0) consisting of 83 paired (control and pre-VT/VF) sets of 1,000 RR intervals recorded by the Medtronic Jewel Plus ICD was used. Sixty-one control records and 69 pre-VT/VF records had two or more ectopic beats, allowing calculation of six HRT indices: means and standard deviations (SD) of turbulence slope (TS), turbulence onset (TO), and turbulence timing (TT). The only index found to be different between control and pre-VT/VF records was SD of TS (4.2 +/- 3.0 control vs 3.1 +/- 1.9 pre-VT/VF, P < 0.05). Thirty-one datasets classified as having normal HRT in control demonstrated a decrease of both TS mean (P < 0.01) and SD (P < 0.01), and loss of correlation between TS mean and left ventricular ejection fraction (LVEF) preceding VT/VF (P < 0.0001 control, P = 0.8 pre-VT/VF).

CONCLUSION

Both mean and SD of TS are reduced before VT/VF, but only in patients who have normal baseline HRT, and are capable of manifesting reduction. This may be why previous studies could not agree on pre-arrhythmia characteristics.

Protein NMR in biomedical research

Nuclear magnetic resonance (NMR) spectroscopy is a versatile biophysical technique with wide applicability in drug discovery research, particularly for the detection and characterization of molecular interactions. This review highlights in a comprehensive manner the aspects of biomolecular NMR which are most beneficial for pharmaceutical research and presents them as contributions to the different stages of a drug discovery program: target selection, assay development, lead generation and lead optimization. Emphasis is put on the concept of the particular NMR application, rather than on technical details, and on recent examples. Finally, an appendix of frequently asked questions is given.