Ergothioneine and mitochondria: An important protective mechanism?

Mitochondrial dysfunction is implicated in a wide range of human disorders including many neurodegenerative and cardiovascular diseases, metabolic diseases, cancers, and respiratory disorders. Studies have suggested the potential of l-ergothioneine (ET), a unique dietary thione, to prevent mitochondrial damage and improve disease outcome. Despite this, no studies have definitively demonstrated uptake of ET into mitochondria. Moreover, the expression of the known ET transporter, OCTN1, on the mitochondria remains controversial. In this study, we utilise mass spectrometry to demonstrate direct ET uptake in isolated mitochondria as well as its presence in mitochondria isolated from ET-treated cells and animals. Mitochondria isolated from OCTN1 knockout mice tissues, have impaired but still detectable ET uptake, raising the possibility of alternative transporter(s) which may facilitate ET uptake into the mitochondria. Our data confirm that ET can enter mitochondria, providing a basis for further work on ET in the prevention of mitochondrial dysfunction in human disease.

Managing Bilateral Discontinuous Pulmonary Arteries of Ductal Origin in Single-Ventricle Anatomy.

BACKGROUND: We describe outcomes and management strategies for single-ventricle and bilaterally discontinuous pulmonary arteries (PAs) originating from bilateral ductus arteriosus. METHODS: We reviewed 22 patients with aforementioned anatomy and PA centralization from 1995 to 2023, excluding those with biventricular repair. RESULTS: Median age at centralization was 9 days (minimum-maximum, 0 days-2 years). Centralization was performed with systemic-to-pulmonary shunt (n =20 [91%]; 2 after bilateral ductal stents) or bidirectional cavopulmonary connection (n = 2 [9%]) using pericardial roll (n = 14 [64%]), patch-augmented direct anastomosis (n = 7 [32%]), and interposition graft (n = 1 [5%]) techniques. Concurrent total anomalous pulmonary venous connection (TAPVC, n = 11 [50%]) was associated with significantly inferior survival (P = .01). Five patients (23%) died at a median of 59 days (minimum-maximum, 6-257 days) after centralization, all with noncardiac TAPVC. At the latest follow-up for 17 survivors (median, 13.5 years; minimum-maximum, 0.5-25.1 years after centralization), 12 completed Fontan, 4 completed second-stage palliation, and 1 received a transplant before second-stage palliation. PA reintervention was required in 14 patients (64%), including 3 with reoperations independent of staged palliation. Echocardiography from baseline to before the second stage demonstrated branch PA growth with significantly increased diameters (left, P = .0006; right, P = .0002); z-scores significantly increased for right (P = .004) but not left (P = .11). CONCLUSIONS: Successful single-ventricle palliation is possible, although high risk, for patients with bilateral discontinuous ductal PAs. Early postcentralization mortality remains substantial, particularly with associated noncardiac TAPVC. Many require reintervention to maintain PA growth, typically concurrently with staged palliation.

Operative Repair of Aortopulmonary Window: A 25-Year Experience.

Background: Aortopulmonary window (APW) is a rare anomaly with variable morphology and associated cardiac anomalies. We evaluated impact of patient and operative factors on mid-term outcomes following APW repair. Methods: Twenty-nine patients underwent surgical APW repair at our institution from 1996 to 2022. Eight (28%) had simple APW, accompanied by only atrial septal defect or patent ductus arteriosus; 21 (72%) had complex APW with additional cardiovascular lesions, including nine with interrupted aortic arch. Median operative age was 19 days (range 2 days-1.5 years) via single-patch (n = 12, 41%), double-patch (n = 15, 52%), or ligation and division (n = 2, 7%). Results: The only mortality occurred in-hospital 1.4 years postoperatively following remote myocardial infarction. Factors associated with longer postoperative length of stay were complex APW (P = .003), genetic syndrome (P = .003), noncardiovascular comorbidities (P = .002), lower birth weight (P = .03), and lower operative weight (P = .03). Six patients (21%) with complex APW underwent unplanned cardiothoracic reintervention(s), including two with arch reintervention following arch advancement for interruption. Reintervention-free survival was similar for simple versus complex APW, operative age categories, and repair techniques. At median follow-up 5.5 years postoperatively, no patients had residual APW or persistent pulmonary hypertension, 1 (3%) had greater than mild ventricular dysfunction, and 25 (89% survivors) had NYHA class I functional status. Conclusions: Operative APW repair has excellent mid-term survival, durability, and functional status, regardless of operative age, cardiovascular comorbidities, or repair technique. Cardiac and noncardiac comorbidities may be associated with prolonged length of stay.

Neurocysticercosis: A neglected but preventable cause of seizure in adults.

Neurocysticercosis is an infection of the central nervous system caused by the larval stage of Taenia solium. Although endemic in sub-Saharan Africa, it is neglected but remains a significant cause of preventable seizure in adults. Its diagnosis is challenging and is frequently missed due to its variable clinical manifestations and lack of diagnostic facilities in most areas of sub-Saharan Africa. This report discusses two cases of parenchymal neurocysticercosis in Ghanaians who presented to the emergency unit of a District Hospital with adult-onset seizures. The two cases highlight the need for a high index of suspicion and also underscore the important role of neuroimaging in the evaluation of patients presenting with adult-onset seizures in neurocysticercosis endemic areas. This is necessary for prompt detection and initiation of appropriate therapy in order to improve prognosis.

Mitral Valve Replacement in Infants and Children: Experience Using a 15-mm Mechanical Valve.

BACKGROUND: Reports using a 15-mm mechanical valve for mitral valve replacement (MMVR) in children are limited. We review our center's operative and postoperative experience with this valve. METHODS: We performed a single-center retrospective chart review identifying patients having undergone MMVRs between 2009 and 2022. We analyzed short- and long-term outcomes using descriptive statistics. RESULTS: Fifteen patients underwent 16 MMVRs with no operative deaths. The median age and weight at the time of operation was 6.2 months (interquartile range [IQR] 4.4-13.7), and 5.16 kg (IQR 4.5-6.9), respectively. Ten implants (66%) were placed in the supraannular position. Median postoperative duration of intubation was 1.5 days (IQR 1.0-3.75), cardiac intensive care unit length of stay was 6 days (IQR 3-13.5), and overall hospital length of stay was 17.0 days (IQR 12-48.5). Three patients (20%) experienced major adverse events postoperatively. Four of 13 patients discharged home (31%) required readmission within 30 days for subtherapeutic/supratherapeutic international normalized ratio values. There were no surgical mortalities and 4 late mortalities (27%). Six patients underwent subsequent MMVR at a median time to second MMVR of 6.8 (IQR 3.6-8.9) years. There are 6 patients with the original 15-mm MVR at a median time of 4.7 years since placement. CONCLUSIONS: We present the largest single-center cohort of patients having undergone 15-mm MMVR. Our experience is distinguished by a lower rate of major adverse events than previously reported, durability of the device, and a rapid postoperative recovery time. Appropriate and consistent anticoagulation is a notable challenge in this age group.

Protection against Doxorubicin-Induced Cardiotoxicity by Ergothioneine.

Background: Anthracyclines such as doxorubicin remain a primary treatment for hematological malignancies and breast cancers. However, cardiotoxicity induced by anthracyclines, possibly leading to heart failure, severely limits their application. The pathological mechanisms of anthracycline-induced cardiac injury are believed to involve iron-overload-mediated formation of reactive oxygen species (ROS), mitochondrial dysfunction, and inflammation. The dietary thione, ergothioneine (ET), is avidly absorbed and accumulated in tissues, including the heart. Amongst other cytoprotective properties, ET was shown to scavenge ROS, decrease proinflammatory mediators, and chelate metal cations, including Fe2+, preventing them from partaking in redox activities, and may protect against mitochondrial damage and dysfunction. Plasma ET levels are also strongly correlated to a decreased risk of cardiovascular events in humans, suggesting a cardioprotective role. This evidence highlights ET's potential to counteract anthracycline cardiotoxicity. Methods and Findings: We investigated whether ET supplementation can protect against cardiac dysfunction in mice models of doxorubicin-induced cardiotoxicity and revealed that it had significant protective effects. Moreover, ET administration in a mouse breast cancer model did not exacerbate the growth of the tumor or interfere with the chemotherapeutic efficacy of doxorubicin. Conclusion: These results suggest that ET could be a viable co-therapy to alleviate the cardiotoxic effects of anthracyclines in the treatment of cancers.

Diet-Derived Antioxidants: The Special Case of Ergothioneine.

This article reviews what is presently known about the biological roles of the diet-derived compound ergothioneine (ET). ET seems important to humans because it is rapidly taken up from the diet by a transporter largely or completely specific for ET, and once taken up it is retained within the body for weeks or months. The various possible functions of ET in vivo are explored. Much emphasis has been placed on the antioxidant properties of ET, but although these are well established in vitro, the evidence that antioxidant activity is the principal function of ET in vivo is weak. ET is not unique in this: The evidence for the antioxidant roles of vitamin C and polyphenols such as the flavonoids in vivo is also weak. By contrast, α-tocopherol has demonstrated in vivo antioxidant effects in humans.

Hypoplastic Left Ventricle: Hypoplastic Left Heart Complex.

Hypoplastic left heart syndrome (HLHS) without intrinsic valvar stenosis or atresia is synonymous with the term hypoplastic left heart complex (HLHC) and is defined as a cardiac malformation at the milder end of the spectrum of HLHS with normally aligned great arteries without a common atrioventricular junction, characterized by underdevelopment of the left heart with significant hypoplasia of the left ventricle and hypoplasia of the aortic or mitral valve, or both valves, in the absence of intrinsic valvar stenosis or atresia, and with hypoplasia of the ascending aorta and aortic arch. This article describes the definitions, nomenclature, and classification of HLHC; the indications and contraindications for biventricular repair of HLHC; the surgical treatment of HLHC; and the associated outcomes.

Choosing the Ideal Candidate for a Robotic Valve Intervention.

Robotic cardiac surgery addressing the mitral and tricuspid valves is a highly developed field offering multiple potential advantages regarding postoperative complications, valve repair rates, hospital length of stay, and rapid functional recovery compared with the conventional sternotomy approach for select patients. The unparalleled stereoscopic view within the heart and precision of robotic arms make robotic surgery a highly attractive minimally invasive approach, facilitating repair of even the most complex valvular pathology. Careful candidate selection and surgical planning are paramount to optimising the outcomes of those who undergo robotic valve surgery. As a team's experience grows, the technique can be applied to a wider range of patients that may derive even greater benefit, such as those with significant comorbid conditions, ventricular dysfunction, and previous sternotomy. The goal of this review is to provide clinicians with a practical overview of the factors influencing a patient's candidacy for robotic valve surgery. We discuss key issues such as preoperative diagnostic assessment, concerns regarding demographics and surgical pathology, and additional considerations relating to surgical exposure, cardiopulmonary bypass, and myocardial protection. Diligent patient assessment and a strong team-based approach are paramount to developing and maintaining a successful robotic valve surgery program, with the most seasoned teams being able to safely offer the technique to the vast majority of patients referred for mitral or tricuspid valve repair or replacement.

Heart Rate-Independent 3D Myocardial Blood Oxygen Level-Dependent MRI at 3.0 T with Simultaneous 13N-Ammonia PET Validation.

Background Despite advances, blood oxygen level-dependent (BOLD) cardiac MRI for myocardial perfusion is limited by inadequate spatial coverage, imaging speed, multiple breath holds, and imaging artifacts, particularly at 3.0 T. Purpose To develop and validate a robust, contrast agent-unenhanced, free-breathing three-dimensional (3D) cardiac MRI approach for reliably examining changes in myocardial perfusion between rest and adenosine stress. Materials and Methods A heart rate-independent, free-breathing 3D T2 mapping technique at 3.0 T that can be completed within the period of adenosine stress (≤4 minutes) was developed by using computer simulations, ex vivo heart preparations, and dogs. Studies in dogs were performed with and without coronary stenosis and validated with simultaneously acquired nitrogen 13 (13N) ammonia PET perfusion in a clinical PET/MRI system. The MRI approach was also prospectively evaluated in healthy human volunteers (from January 2017 to September 2017). Myocardial BOLD responses (MBRs) between normal and ischemic myocardium were compared with mixed model analysis. Results Dogs (n = 10; weight range, 20-25 kg; mongrel dogs) and healthy human volunteers (n = 10; age range, 22-53 years; seven men) were evaluated. In healthy dogs, T2 MRI at adenosine stress was greater than at rest (mean rest vs stress, 38.7 msec ± 2.5 [standard deviation] vs 45.4 msec ± 3.3, respectively; MBR, 1.19 ± 0.08; both, P < .001). At the same conditions, mean rest versus stress PET perfusion was 1.1 mL/mg/min ± 0.11 versus 2.3 mL/mg/min ± 0.82, respectively (P < .001); myocardial perfusion reserve (MPR) was 2.4 ± 0.82 (P < .001). The BOLD response and PET MPR were positively correlated (R = 0.67; P < .001). In dogs with coronary stenosis, perfusion anomalies were detected on the basis of MBR (normal vs ischemic, 1.09 ± 0.05 vs 1.00 ± 0.04, respectively; P < .001) and MPR (normal vs ischemic, 2.7 ± 0.08 vs 1.7 ± 1.1, respectively; P < .001). Human volunteers showed increased myocardial T2 at stress (rest vs stress, 44.5 msec ± 2.6 vs 49.0 msec ± 5.5, respectively; P = .004; MBR, 1.1 msec ± 8.08). Conclusion This three-dimensional cardiac blood oxygen level-dependent (BOLD) MRI approach overcame key limitations associated with conventional cardiac BOLD MRI by enabling whole-heart coverage within the standard duration of adenosine infusion, and increased the magnitude and reliability of BOLD contrast, which may be performed without requiring breath holds. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Almeida in this issue.

Ergothioneine - a diet-derived antioxidant with therapeutic potential.

Ergothioneine is a thiol/thione molecule synthesised only by some fungi and bacteria. Nonetheless, it is avidly taken up from the diet by humans and other animals through a transporter, OCTN1, and accumulates to high levels in certain tissues. Ergothioneine is not rapidly metabolised, or excreted in urine and is present in many, if not all, human tissues and body fluids. Ergothioneine has powerful antioxidant and cytoprotective properties in vitro and there is evidence that the body may concentrate it at sites of tissue injury by raising OCTN1 levels. Decreased blood and/or plasma levels of ergothioneine have been observed in some diseases, suggesting that a deficiency could be relevant to the disease onset or progression. This brief Review explores the possible roles of ergothioneine in human health and disease.

Arterial CO2 as a Potent Coronary Vasodilator: A Preclinical PET/MR Validation Study with Implications for Cardiac Stress Testing.

Myocardial blood flow (MBF) is the critical determinant of cardiac function. However, its response to increases in partial pressure of arterial CO2 (PaCO2), particularly with respect to adenosine, is not well characterized because of challenges in blood gas control and limited availability of validated approaches to ascertain MBF in vivo. Methods: By prospectively and independently controlling PaCO2 and combining it with 13N-ammonia PET measurements, we investigated whether a physiologically tolerable hypercapnic stimulus (∼25 mm Hg increase in PaCO2) can increase MBF to that observed with adenosine in 3 groups of canines: without coronary stenosis, subjected to non-flow-limiting coronary stenosis, and after preadministration of caffeine. The extent of effect on MBF due to hypercapnia was compared with adenosine. Results: In the absence of stenosis, mean MBF under hypercapnia was 2.1 ± 0.9 mL/min/g and adenosine was 2.2 ± 1.1 mL/min/g; these were significantly higher than at rest (0.9 ± 0.5 mL/min/g, P < 0.05) and were not different from each other (P = 0.30). Under left-anterior descending coronary stenosis, MBF increased in response to hypercapnia and adenosine (P < 0.05, all territories), but the effect was significantly lower than in the left-anterior descending coronary territory (with hypercapnia and adenosine; both P < 0.05). Mean perfusion defect volumes measured with adenosine and hypercapnia were significantly correlated (R = 0.85) and were not different (P = 0.12). After preadministration of caffeine, a known inhibitor of adenosine, resting MBF decreased; and hypercapnia increased MBF but not adenosine (P < 0.05). Conclusion: Arterial blood CO2 tension when increased by 25 mm Hg can induce MBF to the same level as a standard dose of adenosine. Prospectively targeted arterial CO2 has the capability to evolve as an alternative to current pharmacologic vasodilators used for cardiac stress testing.

Administration of Pure Ergothioneine to Healthy Human Subjects: Uptake, Metabolism, and Effects on Biomarkers of Oxidative Damage and Inflammation.

AIM: We investigated the uptake and pharmacokinetics of l-ergothioneine (ET), a dietary thione with free radical scavenging and cytoprotective capabilities, after oral administration to humans, and its effect on biomarkers of oxidative damage and inflammation. RESULTS: After oral administration, ET is avidly absorbed and retained by the body with significant elevations in plasma and whole blood concentrations, and relatively low urinary excretion (<4% of administered ET). ET levels in whole blood were highly correlated to levels of hercynine and S-methyl-ergothioneine, suggesting that they may be metabolites. After ET administration, some decreasing trends were seen in biomarkers of oxidative damage and inflammation, including allantoin (urate oxidation), 8-hydroxy-2'-deoxyguanosine (DNA damage), 8-iso-PGF2α (lipid peroxidation), protein carbonylation, and C-reactive protein. However, most of the changes were non-significant. INNOVATION: This is the first study investigating the administration of pure ET to healthy human volunteers and monitoring its uptake and pharmacokinetics. This compound is rapidly gaining attention due to its unique properties, and this study lays the foundation for future human studies. CONCLUSION: The uptake and retention of ET by the body suggests an important physiological function. The decreasing trend of oxidative damage biomarkers is consistent with animal studies suggesting that ET may function as a major antioxidant but perhaps only under conditions of oxidative stress. Antioxid. Redox Signal. 26, 193-206.

Persistent Microvascular Obstruction After Myocardial Infarction Culminates in the Confluence of Ferric Iron Oxide Crystals, Proinflammatory Burden, and Adverse Remodeling.

BACKGROUND: Emerging evidence indicates that persistent microvascular obstruction (PMO) is more predictive of major adverse cardiovascular events than myocardial infarct (MI) size. But it remains unclear how PMO, a phenomenon limited to the acute/subacute period of MI, drives adverse remodeling in chronic MI setting. We hypothesized that PMO resolves into chronic iron crystals within MI territories, which in turn are proinflammatory and favor adverse remodeling post-MI. METHODS AND RESULTS: Canines (n=40) were studied with cardiac magnetic resonance imaging to characterize the spatiotemporal relationships among PMO, iron deposition, infarct resorption, and left ventricular remodeling between day 7 (acute) and week 8 (chronic) post-MI. Histology was used to assess iron deposition and to examine relationships between iron content with macrophage infiltration, proinflammatory cytokine synthesis, and matrix metalloproteinase activation. Atomic resolution transmission electron microscopy was used to determine iron crystallinity, and energy-dispersive X-ray spectroscopy was used to identify the chemical composition of the iron composite. PMO with or without reperfusion hemorrhage led to chronic iron deposition, and the extent of this deposition was strongly related to PMO volume (r>0.8). Iron deposits were found within macrophages as aggregates of nanocrystals (≈2.5 nm diameter) in the ferric state. Extent of iron deposits was strongly correlated with proinflammatory burden, collagen-degrading enzyme activity, infarct resorption, and adverse structural remodeling (r>0.5). CONCLUSIONS: Crystallized iron deposition from PMO is directly related to proinflammatory burden, infarct resorption, and adverse left ventricular remodeling in the chronic phase of MI in canines. Therapeutic strategies to combat adverse remodeling could potentially benefit from taking into account the chronic iron-driven inflammatory process.

Insulin-Like Growth Factor-1 Receptor Deficiency in Macrophages Accelerates Atherosclerosis and Induces an Unstable Plaque Phenotype in Apolipoprotein E-Deficient Mice.

BACKGROUND: We have previously shown that systemic infusion of insulin-like growth factor-1 (IGF-1) exerts anti-inflammatory and antioxidant effects and reduces atherosclerotic burden in apolipoprotein E (Apoe)-deficient mice. Monocytes/macrophages express high levels of IGF-1 receptor (IGF1R) and play a pivotal role in atherogenesis, but the potential effects of IGF-1 on their function are unknown. METHODS AND RESULTS: To determine mechanisms whereby IGF-1 reduces atherosclerosis and to explore the potential involvement of monocytes/macrophages, we created monocyte/macrophage-specific IGF1R knockout (MΦ-IGF1R-KO) mice on an Apoe(-/-) background. We assessed atherosclerotic burden, plaque features of stability, and monocyte recruitment to atherosclerotic lesions. Phenotypic changes of IGF1R-deficient macrophages were investigated in culture. MΦ-IGF1R-KO significantly increased atherosclerotic lesion formation, as assessed by Oil Red O staining of en face aortas and aortic root cross-sections, and changed plaque composition to a less stable phenotype, characterized by increased macrophage and decreased α-smooth muscle actin-positive cell population, fibrous cap thinning, and decreased collagen content. Brachiocephalic artery lesions of MΦ-IGF1R-KO mice had histological features implying plaque vulnerability. Macrophages isolated from MΦ-IGF1R-KO mice showed enhanced proinflammatory responses on stimulation by interferon-γ and oxidized low-density lipoprotein and elevated antioxidant gene expression levels. Moreover, IGF1R-deficient macrophages had decreased expression of ABCA1 and ABCG1 and reduced lipid efflux. CONCLUSIONS: Our data indicate that macrophage IGF1R signaling suppresses macrophage and foam cell accumulation in lesions and reduces plaque vulnerability, providing a novel mechanism whereby IGF-1 exerts antiatherogenic effects.

Liver ergothioneine accumulation in a guinea pig model of non-alcoholic fatty liver disease. A possible mechanism of defence?

L-ergothioneine (ET), a putative antioxidant compound acquired by animals through dietary sources, has been suggested to accumulate in certain cells and tissues in the body that are predisposed to high oxidative stress. In the present study, we identified an elevation of ET in the liver of a guinea pig model of non-alcoholic fatty liver disease (NAFLD), elucidated a possible mechanism for the increased uptake and investigated the possible role for this accumulation. This increase in liver ET levels correlated with cholesterol accumulation and disease severity. We identified an increase in the transcriptional factor, RUNX1, which has been shown to upregulate the expression of the ET-specific transporter OCTN1, and could consequently lead to the observable elevation in ET. An increase was also seen in heat shock protein 70 (HSP70) which seemingly corresponds to ET elevation. No significant increase was observed in oxidative damage markers, F2-isoprostanes, and protein carbonyls, which could possibly be attributed to the increase in liver ET through direct antioxidant action, induction of HSP70, or by chelation of Fe(2+), preventing redox chemistry. The data suggest a novel mechanism by which the guinea pig fatty liver accumulates ET via upregulation of its transporter, as a possible stress response by the damaged liver to further suppress oxidative damage and delay tissue injury. Similar events may happen in other animal models of disease, and researchers should be aware of the possibility.

Iron-Sensitive Cardiac Magnetic Resonance Imaging for Prediction of Ventricular Arrhythmia Risk in Patients With Chronic Myocardial Infarction: Early Evidence.

BACKGROUND: Recent canines studies have shown that iron deposition within chronic myocardial infarction (CMI) influences the electric behavior of the heart. To date, the link between the iron deposition and malignant ventricular arrhythmias in humans with CMI is unknown. METHODS AND RESULTS: Patients with CMI (n=94) who underwent late-gadolinium-enhanced cardiac magnetic resonance imaging before implantable cardioverter-defibrillator implantation for primary and secondary preventions were retrospectively analyzed. The predictive values of hypointense cores (HIC) in balanced steady-state free precession images and conventional cardiac magnetic resonance imaging and ECG malignant ventricular arrhythmia parameters for the prediction of primary combined outcome (appropriate implantable cardioverter-defibrillator therapy, survived cardiac arrest, or sudden cardiac death) were studied. The use of HIC within CMI on balanced steady-state free precession as a marker of iron deposition was validated in a canine MI model (n=18). Nineteen patients met the study criteria with events occurring at a median of 249 (interquartile range of 540) days after implantable cardioverter-defibrillator placement. Of the 19 patients meeting the primary end point, 18 were classified as HIC+, whereas only 1 was HIC-. Among the cohort in whom the primary end point was not met, there were 28 HIC+ and 47 HIC- patients. Receiver operating characteristic curve analysis demonstrated an additive predictive value of HIC for malignant ventricular arrhythmias with an increased area under the curve of 0.87 when added to left ventricular ejection fraction (left ventricular ejection fraction alone, 0.68). Both cardiac magnetic resonance imaging and histological validation studies performed in canines demonstrated that HIC regions in balanced steady-state free precession images within CMI likely result from iron depositions. CONCLUSIONS: Hypointense cores within CMI on balanced steady-state free precession cardiac magnetic resonance imaging can be used as a marker of iron deposition and yields incremental information toward improved prediction of malignant ventricular arrhythmias.

In vivo delivery of transcription factors with multifunctional oligonucleotides.

Therapeutics based on transcription factors have the potential to revolutionize medicine but have had limited clinical success as a consequence of delivery problems. The delivery of transcription factors is challenging because it requires the development of a delivery vehicle that can complex transcription factors, target cells and stimulate endosomal disruption, with minimal toxicity. Here, we present a multifunctional oligonucleotide, termed DARTs (DNA assembled recombinant transcription factors), which can deliver transcription factors with high efficiency in vivo. DARTs are composed of an oligonucleotide that contains a transcription-factor-binding sequence and hydrophobic membrane-disruptive chains that are masked by acid-cleavable galactose residues. DARTs have a unique molecular architecture, which allows them to bind transcription factors, trigger endocytosis in hepatocytes, and stimulate endosomal disruption. The DARTs have enhanced uptake in hepatocytes as a result of their galactose residues and can disrupt endosomes efficiently with minimal toxicity, because unmasking of their hydrophobic domains selectively occurs in the acidic environment of the endosome. We show that DARTs can deliver the transcription factor nuclear erythroid 2-related factor 2 (Nrf2) to the liver, catalyse the transcription of Nrf2 downstream genes, and rescue mice from acetaminophen-induced liver injury.