Reversibility by dipyridamole of thallium-201 myocardial scan defects in patients with sarcoidosis

Radionuclide Assessment of Sarcoidosis

This review provides an overview of the techniques used in nuclear cardiology for the assessment of suspected or known cardiac sarcoidosis, how radionuclide imaging assists with regard to diagnosis, risk stratification, and monitoring response to therapy, and work that is on the horizon with novel tracers.

Clinical Utilization of Multimodality Imaging for Myocarditis and Cardiac Sarcoidosis

Myocarditis is defined as inflammation of the myocardium according to clinical, histological, biochemical, immunohistochemical, or imaging findings. Inflammation can be categorized histologically by cell type or pattern, and many causes have been implicated, including infectious, most commonly viral, systemic autoimmune diseases, vaccine-associated processes, environmental factors, toxins, and hypersensitivity to drugs. Sarcoid myocarditis is increasingly recognized as an important cause of cardiomyopathy and has important diagnostic, prognostic, and therapeutic implications in patients with systemic sarcoidosis. The clinical presentation of myocarditis may include an asymptomatic, subacute, acute, fulminant, or chronic course and may have focal or diffuse involvement of the myocardium depending on the cause and time point of the disease. For most causes of myocarditis except sarcoidosis, myocardial biopsy is the gold standard but is limited due to risk, cost, availability, and variable sensitivity. Diagnostic criteria have been established for both myocarditis and cardiac sarcoidosis and include clinical and imaging findings particularly the use of cardiac magnetic resonance and positron emission tomography. Beyond diagnosis, imaging findings may also provide prognostic value. This case-based review focuses on the current state of multimodality imaging for the diagnosis and management of myocarditis and cardiac sarcoidosis, highlighting multimodality imaging approaches with practical clinical vignettes, with a discussion of knowledge gaps and future directions.

Analysis of in vitro and in vivo metabolism of zidovudine and gemfibrozil in trans-chromosomic mouse line expressing human UGT2 enzymes

UDP-glucuronosyltransferases (UGTs) catalyze the conjugation of various substrates with sugars. Since the UGT2 family forms a large cluster spanning 1.5 Mb, transgenic mouse lines carrying the entire human UGT2 family have not been constructed because of limitations in conventional cloning techniques. Therefore, we made a humanized mouse model for UGT2 by chromosome engineering technologies. The results showed that six UGT2 isoforms examined were expressed in the liver of adult humanized UGT2 (hUGT2) mice. Thus, the functions of human UGT2B7 in the liver of hUGT2 mice were evaluated. Glucuronide of azidothymidine (AZT, zidovudine), a typical UGT2B7 substrate, was formed in the liver microsomes of hUGT2 mice but not in the liver microsomes of wild-type and Ugt2-knockout mice. When AZT was intravenously administered, AZT glucuronide was detected in the bile and urine of hUGT2 mice, but it was not detected in the bile and urine of wild-type and Ugt2-knockout mice. These results indicated that the hUGT2 mice express functional human UGT2B7 in the liver. This finding was also confirmed by using gemfibrozil as an alternative UGT2B7 substrate. Gemfibrozil glucuronide was formed in the liver microsomes of hUGT2 mice and was mainly excreted in the bile of hUGT2 mice after intravenous dosing of gemfibrozil. This hUGT2 mouse model will enable improved predictions of pharmacokinetics, urinary and biliary excretion and drug-drug interactions mediated by human UGT2, at least UGT2B7, in drug development research and basic research.

The prognostic value of positron emission tomography in the evaluation of suspected cardiac sarcoidosis

OBJECTIVES

To assess the prognostic value of positron emission tomography (PET) imaging in patients undergoing evaluation for known or suspected cardiac sarcoidosis (CS) while not on active immunotherapy.

BACKGROUND

Previous studies have attempted to identify the value of PET imaging to aid in risk stratification of patients with CS, however, most cohorts have included patients currently on immunosuppression, which may confound scan results by suppressing positive findings.

METHODS

We retrospectively analyzed 197 patients not on immunosuppression who underwent 18F-fluorodeoxyglucose (FDG) PET scans for evaluation of known or suspected CS. The primary endpoint of the study was time to ventricular arrhythmia (VT/VF), or death. Candidate predictors were identified by univariable Cox proportional hazards regression. Independent predictors were identified by performing multivariable Cox regression with stepwise forward selection.

RESULTS

Median follow-up time was 531 [IQR 309, 748] days. 41 patients met the primary endpoint. After stepwise forward selection, left ventricular ejection fraction (LVEF) (HR 0.98, 95% CI 0.96-0.99, P = 0.02), history of VT/VF (HR 4.19, 95% CI 2.15-8.17, P < 0.001), and summed rest score (SRS) (HR 1.06, 95% CI 1.02-1.12, P = 0.01) were predictive of the primary endpoint. Quantitative and qualitative measures of FDG uptake on PET were not predictive of clinical events.

CONCLUSIONS

Among untreated patients who underwent PET scans to evaluate known or suspected CS, LVEF, history of VT/VF, and SRS were associated with adverse clinical outcomes.

Machine learning predicting mortality in sarcoidosis patients admitted for acute heart failure

Background

Sarcoidosis with cardiac involvement, although rare, has a worse prognosis than sarcoidosis involving other organ systems.

Objective

We used a large dataset to train machine learning models to predict in-hospital mortality among sarcoidosis patients admitted with heart failure (HF).

Method

Utilizing the National Inpatient Sample, we identified 4659 patients hospitalized with a primary diagnosis of HF. In this cohort, we identified patients with a secondary diagnosis of sarcoidosis using International Statistical Classification of Disease, Tenth Revision (ICD-10) codes. Patients were separated into a training group and a testing group in a 7:3 ratio. Least absolute shrinkage and selection operator regression was used to select variables to prevent model overfitting or underfitting. For machine learning models, logistic regression, random forest, and XGBoosting were applied in the training group. Parameters in each of the models were tuned using the GridSearchCV function. After training, all models were further validated in the testing group. Models were then evaluated using the area under curve (AUC) score, sensitivity, and specificity.

Results

A total of 2.3% of sarcoidosis patients died in HF admission. Our machine learning model analysis found the RF model to have the highest AUC score and sensitivity. Feature analysis found that comorbid arrhythmias and fluid electrolyte disorders were the strongest factors in predicting in-hospital mortality.

Conclusion

Machine learning methods can be useful in identifying predictors of in-hospital mortality in a given dataset.

Cardiac Sarcoidosis: Pathophysiology, Diagnosis, and Management

Sarcoidosis is a chronic multi-system disorder with an unknown etiology that can affect the cardiac tissue, resulting in Cardiac Sarcoidosis (CS). The majority of these CS cases are clinically silent, and when there are symptoms, the symptoms are vague and can have a lot in common with other common cardiac diseases. These symptoms can range from arrhythmias to heart failure. If CS goes undetected, it can lead to detrimental outcomes for patients. Diagnosis depends on timely utilization of imaging modalities and non-invasive testing, while in some cases, it does necessitate biopsy. Early diagnosis and treatment with immunosuppressive agents are crucial, and it is essential that follow-up testing be performed to ensure resolution and remission. This manuscript provides an in-depth review of CS and the current literature regarding CS diagnosis and treatment.

Engineered Regulon to Enable Autonomous Azide Ion Biosensing, Recombinant Protein Production, and in Vivo Glycoengineering

Detection of azide-tagged biomolecules (e.g., azido sugars) inside living cells using "click" chemistry has been revolutionary to the field of chemical biology. However, we currently still lack suitable synthetic biology tools to autonomously and rapidly detect azide ions. Here, we have developed an engineered synthetic promoter system called cyn regulon, and complementary Escherichia coli engineered strains, to selectively detect azide ions and autonomously induce downstream expression of reporter genes. The engineered cyn azide operon allowed highly tunable reporter green fluorescent protein (GFP) expression over three orders of inducer azide ion concentrations (0.01-5 mM) and rapidly induced GFP expression by over 600-fold compared to the uninduced control. Next, we showcase the superior performance of this engineered cyn-operon over the classical lac-operon for recombinant protein production. Finally, we highlight how this synthetic biology toolkit can enable glycoengineering-based applications by facilitating in vivo activity screening of mutant carbohydrate-active enzymes (CAZymes), called glycosynthases, using azido sugars as donor substrates.

Pharmacokinetics of nucleoside/nucleotide reverse transcriptase inhibitors for the treatment and prevention of HIV infection

INTRODUCTION

Despite dramatic increases in new drugs and regimens, a combination of two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) remains the backbone of many regimens to treat HIV.

AREA COVERED

This article summarizes the pharmacokinetic characteristics of approved NRTIs that are currently in the international treatment and prevention guidelines.

EXPERT OPINION

Compared to other NRTIs, tenofovir alafenamide fumarate (TAF) is more advantageous in terms of potency and safety. It is therefore a preferred choice in combination with emtricitabine (FTC) in most HIV treatment guidelines. The efficacy of the two-drug combination of NRTI/Integrase strand-transfer inhibitor, i.e. lamivudine/dolutegravir has been approved as an option for initial therapy. This regimen however has some limitations in patients with HBV coinfection. The two NRTI combinations tenofovir disproxil fumarate (TDF)/FTC and TAF/FTC have also been approved for pre-exposure prophylaxis (PrEP). Interestingly, a promising long-acting nucleoside reverse transcriptase translocation inhibitor, islatravir, formulated for implant was well tolerated and remained effective for up to a year, suggesting its potential as a single agent for PrEP. In the next decade, it remains to be seen whether NRTI-based regimens will remain the backbone of preferred ART regimens, or if the treatment will eventually move toward NRTI-sparing regimens to avoid long-term NRTI-toxicity.

Serum angiotensin converting enzyme, Erythrocyte sedimentation rate and high sensitive-C reactive protein levels in diagnosis of cardiac sarcoidosis- where do we stand?

Background

Cardiac sarcoidosis (CS) is increasingly being recognized in the last two decades. The diagnosis of CS depends on clustering of multiple symptoms, investigations and demonstration of a non-caseating granuloma on histopathology. Serum Angiotensin Converting Enzyme (SACE) level, one of the serological markers, is often elevated in systemic sarcoidosis. However, the yield of SACE level among patients with isolated or predominant CS is unclear. We conducted a retrospective study to assess the prevalence of elevated SACE level among patients with proven CS.

Materials and methods

From our Granulomatous myocarditis (GM) registry, 45 biopsy proven CS patients were enrolled. Inclusion criteria: Clinical diagnosis of CS [HRS definition + Lymph Node biopsy/Endomyocardial biopsy (non-caseating granuloma)]. Exclusion criteria - Other causes of GM like cardiac tuberculosis (TB culture/AFB smear -positive) and patients taking medications affecting SACE level.

Results

Among 143 GM cases, 45 CS were analyzed. Mean age:42 ± 11 years (Range 22–63 years, 19 females). With our laboratory reference of SACE (Normal range: 20–70 U/L), 3 out of 45 (6.7%) patients of CS had elevated SACE. In a comparative analysis we found, Erythrocyte Sedimentation Rate (ESR) and High sensitive-C Reactive Protein (Hs-CRP) are much more sensitive, although not specific for CS. Patients with pulmonary involvement more often had elevated SACE level.

Conclusion

Serum ACE is elevated only in approximately 6.7% of patients with biopsy proven CS. Hence, it is insensitive serological tool for diagnosis of CS even in the active phase of the disease. In contrast, ESR and Hs-CRP emerges to be more sensitive markers of active CS.

Review: Contrast-enhanced magnetic resonance in the diagnosis and management of cardiac sarcoidosis

Sarcoidosis is a relatively rare inflammatory condition which potentially carries high morbidity and substantial mortality. Due to the fact that it does not subject patients to ionizing radiation, has high temporal, spatial and contrast resolutions, cardiovascular magnetic resonance imaging (CMR) has become an important diagnostic and prognostic modality in the evaluation for cardiac involvement in this condition. This review provides relevant clinical and pathophysiological background on cardiac sarcoidosis, whilst detailing the role of CMR imaging in the diagnosis, and management of this condition.

Imaging of myocarditis and inflammatory cardiomyopathies

Myocarditis encompasses a wide range of myocardial inflammatory diseases, including acute myocarditis, chronic myocarditis and inflammatory cardiomyopathies, and myocardial inflammation associated with other cardiomyopathies. Because of this heterogeneity in clinical presentation, and the infrequent use of endomyocardial biopsy, cardiac imaging has gradually acquired a key role in the non-invasive detection of myocardial inflammation, the assessment of aetiology and the management of specific therapies. This article summarizes the issue of myocarditis and myocardial inflammation in clinical practice, and reviews the role of different non-invasive imaging techniques in the exploration of myocardial inflammation.

Versatile iron-catechol-based nanoscale coordination polymers with antiretroviral ligand functionalization and their use as efficient carriers in HIV/AIDS therapy

A novel chemical approach integrating the benefits of nanoparticles with versatility of coordination chemistry is reported herein to increase the effectiveness of well-known HIV antiretroviral drugs. The novelty of our approach is illustrated using a catechol ligand tethered to the known antiretroviral azidothymidine (AZT) as a constitutive building block of the nanoparticles. The resulting nanoscale coordination polymers (NCPs) ensure good encapsulation yields and equivalent antiretroviral activity while significantly diminishing its cytotoxicity. Moreover, this novel family of nanoparticles also offers (i) long-lasting drug release that is dissimilar inside and outside the cells depending on pH, (ii) triggered release in the presence of esterases, activating the antiviral activity in an on-off manner due to a proper chemical design of the ligand and (iii) improved colloidal stabilities and cellular uptakes (up to 50-fold increase). The presence of iron nodes also adds multifunctionality as possible contrast agents. The present study demonstrates the suitability of NCPs bearing pharmacologically active ligands as an alternative to conventional antiretroviral treatments.

Lipid-based nanocarrier efficiently delivers highly water soluble drug across the blood-brain barrier into brain

Delivering highly water soluble drugs across blood-brain barrier (BBB) is a crucial challenge for the formulation scientists. A successful therapeutic intervention by developing a suitable drug delivery system may revolutionize treatment across BBB. Efforts were given here to unravel the capability of a newly developed fatty acid combination (stearic acid:oleic acid:palmitic acid = 8.08:4.13:1) (ML) as fundamental component of nanocarrier to deliver highly water soluble zidovudine (AZT) as a model drug into brain across BBB. A comparison was made with an experimentally developed standard phospholipid-based nanocarrier containing AZT. Both the formulations had nanosize spherical unilamellar vesicular structure with highly negative zeta potential along with sustained drug release profiles. Gamma scintigraphic images showed both the radiolabeled formulations successfully crossed BBB, but longer retention in brain was observed for ML-based formulation (MGF) as compared to soya lecithin (SL)-based drug carrier (SYF). Plasma and brain pharmacokinetic data showed less clearance, prolonged residence time, more bioavailability and sustained release of AZT from MGF in rats compared to those data of the rats treated with SYF/AZT suspension. Thus, ML may be utilized to successfully develop drug nanocarrier to deliver drug into brain across BBB, in a sustained manner for a prolong period of time and may provide an effective therapeutic strategy for many diseases of brain. Further, many anti-HIV drugs cannot cross BBB sufficiently. Hence, the developed formulation may be a suitable option to carry those drugs into brain for better therapeutic management of HIV.

Differentiating Isomeric Deprotonated Glucuronide Drug Metabolites via Ion/Molecule Reactions in Tandem Mass Spectrometry

Isomeric O- and N-glucuronides are common drug metabolites produced in phase II of drug metabolism. Distinguishing these isomers by using common analytical techniques has proven challenging. A tandem mass spectrometric method based on gas-phase ion/molecule reactions of deprotonated glucuronide drug metabolites with trichlorosilane (HSiCl₃) in a linear quadrupole ion trap mass spectrometer is reported here to readily enable differentiation of the O- and N-isomers. The major product ion observed upon reactions of HSiCl₃ with deprotonated N-glucuronides is a diagnostic HSiCl₃ adduct that has lost two HCl molecules ([M - H + HSiCl₃ - 2HCl]-). This product ion was not observed for deprotonated O-glucuronides. Reaction mechanisms were explored with quantum chemical calculations at the M06-2X/6-311++G(d,p) level of theory.

Content and Activities of UGT2B7 in Human Liver In Vitro and Predicted In Vivo: A Bottom-Up Approach

UDP-glucuronosyltransferase 2B7 (UGT2B7) is one of the most significant isoforms of UGTs in human liver. This research measured UGT2B7 protein content and activities, including maximum velocity (V_max) and intrinsic clearance (CL_int), in human liver at isoform, microsomal, liver tissue, and liver levels and identified the factors that influence expression. We determined absolute protein content by liquid chromatography-tandem mass spectroscopy and activities using the probe drug zidovudine in 82 normal human liver microsomes. Using a bottom-up method for derivation, we showed UGT2B7 content at the microsomal, liver tissue, and liver levels, as well as activities at the isoform, microsomal, liver tissue, and liver levels in vitro, and predicted hepatic clearance in vivo, with median, range, variation, and 95% and 50% prediction intervals. With regard to the intrinsic activities, the maximum velocity (V_max) had a median (range) of 7.5 (2-24) pmol/min per picomole of 2B7, and the CL_int was 0.08 (0.02-0.31) μl/min per picomole of 2B7. Determinations at liver level showed larger variations than at microsomal level, so it was more suitable for evaluating individual differences. By analyzing factors that affect UGT2B7, we found that: 1) The content at the liver tissue and liver levels correlated positively with activities; 2) the mutant heterozygotes of -327G>A, -900A>G, -161C>T may lead to decreased protein content and increased intrinsic CL_int; and 3) the transcription factor pregnane X receptor mRNA expression level was positively associated with the measured protein content. In all, we showed that protein content and activities at different levels and the factors that influence content provide valuable information for UGT2B7 research and clinically individualized medication.

Coronary Microcirculatory Dysfunction in Human Cardiomyopathies: A Pathologic and Pathophysiologic Review

Cardiomyopathies are a heterogeneous group of diseases of the myocardium. The term cardiomyopathy involves a wide range of pathogenic mechanisms that affect the structural and functional states of cardiomyocytes, extravascular tissues, and coronary vasculature, including both epicardial coronary arteries and the microcirculation. In the developed phase, cardiomyopathies present with various clinical symptoms: dyspnea, chest pain, palpitations, swelling of the extremities, arrhythmias, and sudden cardiac death. Due to the heterogeneity of cardiomyopathic patterns and symptoms, their diagnosis and therapies are great challenges. Despite extensive research, the relation between the structural and functional abnormalities of the myocardium and the coronary circulation are still not well understood in the various forms of cardiomyopathy. The main pathological characteristics of cardiomyopathies and the coronary microcirculation develop in a progressive manner due to (1) genetic-immunologic-systemic factors; (2) comorbidities with endothelial, myogenic, metabolic, and inflammatory changes; (3) aging-induced arteriosclerosis; and (4) myocardial fibrosis. The aim of this review is to summarize the most important common pathological features and/or adaptations of the coronary microcirculation in various types of cardiomyopathies and to integrate the present understanding of the underlying pathophysiological mechanisms responsible for the development of various types of cardiomyopathies. Although microvascular dysfunction is present and contributes to cardiac dysfunction and the potential outcome of disease, the current therapeutic approaches are not specific for the given types of cardiomyopathy.

Cardiac Sarcoidosis: A Review of Contemporary Challenges in Diagnosis and Treatment

Sarcoidosis is a systemic disease characterized by noncaseating granulomas and is often a diagnosis of exclusion. The actual prevalence of cardiac sarcoidosis (CS) is unknown, as studies have demonstrated mixed data. CS may be asymptomatic and is likely more frequently encountered than previously thought. Sudden death may often be the presenting feature of CS. Most deaths attributed to CS are caused by arrhythmias or conduction system disease, and congestive heart failure may occur. Current expert consensus on diagnosis of CS continues to rely on endomyocardial biopsy, in the absence of which, histologic proof of extracardiac sarcoid involvement is necessitated. Emergence of newer noninvasive imaging modalities such as cardiac magnetic resonance imaging and positron emission tomography, have become increasingly popular tools utilized in patients with both clinical and asymptomatic CS, and have demonstrated good diagnostic capability. The main therapeutic approaches in patients with CS can be broadly divided into the following 2 categories: pharmacological management and invasive or device oriented. However, much remains unknown about the optimal screening protocols of asymptomatic patients with extracardiac sarcoidosis and treatment of biopsy-proven CS. Our knowledge about CS has amplified significantly over the last 30 years and the growing realization that this process is often asymptomatic is paving the way for better screening protocols and earlier detection of this serious condition.

Strain Imaging Echocardiography: What Imaging Cardiologists Should Know

Despite recent advances in clinical imaging, echocardiography remains as the most accessi-ble and reliable noninvasive. Since knowledge of left ventricular systolic function remains so critically important in determining prognosis; every effort should be made to prevent subjective estimations. The advent of strain imaging echocardiography now offers a readily available and portable imaging tool that not only offers an objective characterization of myocardial dynamics; but also allows for early detection of subclinical left ventricular dysfunction. This review outlines the basic concepts of strain imaging to better understand the mechanism of myocardial function as well their applicability in the least common cardiac diagnosis among current clinical practice.

Species Differences in the Metabolism and Disposition of Antiviral Nucleoside Analogues: 2. Zidovudine

Preclinical and clinical studies on the disposition of zidovudine, a thymidine analogue with potent activity against human immunodeficiency virus, identified significant species differences in the metabolism and elimination of the drug. Zidovudine was extensively metabolized to the 5′-O-glucuronide in man and other primates. Rabbits and dogs were intermediate in their extent of biotransformation to the glucuronide conjugate, whereas rats and mice excreted the drug largely unchanged. Decreased metabolism was compensated by increased renal elimination, such that plasma elimination phase half-lives for zidovudine were similar (0.6–1.1 h) in all species. Rapid and extensive absorption and considerable penetration into tissues were also observed for all species studied. Only in the brain and testes were drug levels less than in plasma, although effective antiviral concentrations of zidovudine were achieved in brain and CSF. This review summarizes the variety of studies of the absorption, distribution, metabolism, and elimination of zidovudine in several species, including humans.

Clinical and radiological features of extra-pulmonary sarcoidosis: a pictorial essay

Abstract

The aim of this manuscript is to describe radiological findings of extra-pulmonary sarcoidosis. Sarcoidosis is an immune-mediated systemic disease of unknown origin, characterized by non-caseating epitheliod granulomas. Ninety percent of patients show granulomas located in the lungs or in the related lymph nodes. However, lesions can affect any organ. Typical imaging features of liver and spleen sarcoidosis include visceromegaly, with multiple nodules hypodense on CT images and hypointense on T2-weighted MRI acquisitions. Main clinical and radiological manifestations of renal sarcoidosis are nephrolithiasis, nephrocalcinosis, and acute interstitial nephritis. Brain sarcoidosis shows multiple or solitary parenchymal nodules on MRI that enhance with a ring-like appearance after gadolinium. In spinal cord localization, MRI demonstrates enlargement and hyperintensity of spinal cord, with hypointense lesions on T2-weighted images. Skeletal involvement is mostly located in small bone, showing many lytic lesions; less frequently, bone lesions have a sclerotic appearance. Ocular involvement includes uveitis, conjunctivitis, optical nerve disease, chorioretinis. Erythema nodosum and lupus pernio represent the most common cutaneous manifestations encountered. Sarcoidosis in various organs can be very insidious for radiologists, showing different imaging features, often non-specific. Awareness of these imaging features helps radiologists to obtain the correct diagnosis.

Teaching Points

• Systemic sarcoidosis can exhibit abdominal, neural, skeletal, ocular, and cutaneous manifestations.

• T2 signal intensity of hepatosplenic nodules may reflect the disease activity.

• Heerfordt’s syndrome includes facial nerve palsy, fever, parotid swelling, and uveitis.

• In the vertebrae, osteolytic and/or diffuse sclerotic lesions can be found.

• Erythema nodosum and lupus pernio represent the most common cutaneous manifestations.

The Clinical Features of Sarcoidosis: A Comprehensive Review

Sarcoidosis has innumerable clinical manifestations, as the disease may affect every body organ. Furthermore, the severity of sarcoidosis involvement may range from an asymptomatic state to a life-threatening condition. This manuscript reviews a wide variety of common and less common clinical characteristics of sarcoidosis. These manifestations are presented organ by organ, although additional sections describe systemic and multiorgan presentations of sarcoidosis. The lung is the organ most commonly involved with sarcoidosis with at least 90 % of sarcoidosis patients demonstrating lung involvement in most series. The skin, eye, liver, and peripheral lymph node are the next most commonly clinically involved organs in most series, with the frequency of involvement ranging from 10 to 30 %. The actual frequency of sarcoidosis organ involvement is probably much higher as it is frequently asymptomatic and may avoid detection. This is particularly common with lung, liver, cardiac, and bone involvement. Cardiac sarcoidosis is present in 25 % of all sarcoidosis but only causes clinical problems in 5 % of them. Nevertheless, unlike sarcoidosis involvement of most other organs, it may be suddenly fatal. Therefore, it is important to screen for cardiac sarcoidosis in all sarcoidosis patients. All sarcoidosis patients should also be screened for eye involvement as asymptomatic patients may have eye involvement that may cause permanent vision impairment. Pulmonary fibrosis from sarcoidosis is usually slowly progressive but may be life-threatening because of the development of respiratory failure, pulmonary hypertension, or hemoptysis related to a mycetoma or bronchiectasis. Some manifestations of sarcoidosis are not organ-specific and probably are the result of a release of mediators from the sarcoid granuloma. Two such manifestations include small fiber neuropathy and fatigue syndromes, and they are observed in a large percentage of patients.

A Diagnostic and Therapeutic Approach to Arrhythmias in Cardiac Sarcoidosis

OPINION STATEMENT

Cardiac sarcoidosis is a protean disease, capable of causing nearly any cardiac abnormality. Electrical abnormalities including heart block and ventricular tachyarrhythmias are some of the most feared manifestations of cardiac sarcoidosis. Despite increasing awareness, cardiac sarcoidosis remains underdiagnosed in clinical practice, and as a result, many patients do not receive potentially disease-altering immunosuppressant therapy. In this review, we discuss cardiac sarcoidosis and its management, focusing diagnostic and therapeutic approaches to arrhythmias in cardiac sarcoidosis.

Sarcoidosis and the heart: A review of the literature

Sarcoidosis is a chronic multisystem disorder without any defined etiology. Cardiac sarcoidosis (CS) is detected in 2-7% of patients with sarcoidosis and more than 20% of the cases of sarcoidosis are clinically silent. Cardiac involvement in systemic sarcoidosis (SS) and isolated cardiac sarcoidosis (iCS) are associated with arrhythmia and severe heart failure (HF) and have a poor prognosis. Early diagnosis of CS and prompt initiation of corticosteroid therapy with or without other immunosuppressants is crucial. Electrocardiography, Holter monitoring, and Doppler echocardiography with speckle tracking imaging can serve as the initial steps to diagnosis of CS. Cardiac magnetic resonance (CMR) imaging and positron emission tomography (PET) are promising techniques for both diagnosis and follow-up of CS. This review discusses the main aspects of cardiac involvement in sarcoidosis.

Cardiac sarcoidosis: clinical manifestations, imaging characteristics, and therapeutic approach

Sarcoidosis is a multi-system disease pathologically characterized by the accumulation of T-lymphocytes and mononuclear phagocytes into the sine qua non pathologic structure of the noncaseating granuloma. Cardiac involvement remains a key source of morbidity and mortality in sarcoidosis. Definitive diagnosis of cardiac sarcoidosis, particularly early enough in the disease course to provide maximal therapeutic impact, has proven a particularly difficult challenge. However, major advancements in imaging techniques have been made in the last decade. Advancements in imaging modalities including echocardiography, nuclear spectroscopy, positron emission tomography, and magnetic resonance imaging all have improved our ability to diagnose cardiac sarcoidosis, and in many cases to provide a more accurate prognosis and thus targeted therapy. Likewise, therapy for cardiac sarcoidosis is beginning to advance past a “steroids-only” approach, as novel immunosuppressant agents provide effective steroid-sparing options. The following focused review will provide a brief discussion of the epidemiology and clinical presentation of cardiac sarcoidosis followed by a discussion of up-to-date imaging modalities employed in its assessment and therapeutic approaches.

Low Third-Trimester Serum Levels of Lamivudine/Zidovudine and Lopinavir/Ritonavir in an HIV-Infected Pregnant Woman with Gastric Bypass

Pharmacokinetics of lamivudine (3TC)/zidovudine (ZDV) and lopinavir/ritonavir (LPV/r) are described in a gravid 27-year-old HIV-infected woman with gastric bypass. Blood levels were obtained for these medications at time points 0 (predose) and 1, 2, 4, 6, 8, and 12 hours postdose. For these times, the levels (µg/mL) of 3TC were 0.0801, 0.69, 0.339, 0.237, 0.202, 0.108, and 0.0461; the levels of ZDV were 0.0153, 0.433, 0.0717, 0.0481, 0.0107, 0.0214, and 0.00864; the levels of lopinavir (LPV) were 2.45, 2.64, 1.95, 2.78, 3.83, 3.20, and 1.92; and the levels of ritonavir (RTV) were 0.09, 0.10, 0.07, 0.11, 0.15, 0.15, and 0.06. These data suggest that gastric bypass affected these antiretroviral drug levels. A functional, intact small bowel is responsible for absorption of these medications.

Reduced oxygen uptake efficiency slope in patients with cardiac sarcoidosis

BACKGROUND

The non-invasive diagnosis of cardiac sarcoidosis (CS) is difficult. Cardiovascular magnetic resonance (CMR) has become a very valuable diagnostic tool in patients with suspected CS, but usually a combination of different tests is used. Oxygen uptake efficiency slope (OUES) is a parameter of cardiopulmonary exercise testing (CPET), which is used as an indicator for cardiovascular impairment. We investigated the predictive value of OUES for the diagnosis of myocardial involvement in sarcoid patients.

METHODS

Retrospectively 37 consecutive patients (44.9±13.8 years) with histologically confirmed sarcoidosis and clinical suspicion of heart involvement underwent noninvasive diagnostic testing including CMR. CS was diagnosed according to the guidelines from the Japanese Society of Sarcoidosis and other Granulomatous Disorders with additional consideration of CMR findings. Furthermore, CPET with calculation of predicted OUES according to equations by Hollenberg et al. was carried out.

RESULTS

Patients with CS (11/37; 30%) had a worse cardiovascular response to exercise. OUES was significantly lower in CS-group compared to non-CS-group (59.3±19.1 vs 88.0±15.4%pred., p<0.0001). ROC curve method identified 70%pred. as the OUES cut-off point, which maximized sensitivity and specificity for detection of CS (96% sensitivity, 82% specificity, 89% overall accuracy). OUES <70%pred. was the single best predictor of CS (Odds ratio: 100.43, 95% CI: 1.99 to 5064, p<0.001) even in multivariate analyses.

CONCLUSION

OUES assessed in CPET may be helpful in identifying patient with cardiac involvement of sarcoidosis. Patient selection for CMR may be assisted by CPET findings in patients with sarcoidosis.

Myocardial Perfusion Imaging in Takayasu Arteritis

Objective.

Myocardial perfusion defects using scintigraphy have been frequently observed in patients with Takayasu arteritis (TA) without coronary stenosis. The aim of our study was to evaluate coronary microcirculation in TA using thallium-201 (201Tl) myocardial scintigraphy and dipyridamole (DPM) as vasodilator agent.

Methods.

Twenty-five consecutive patients with TA were prospectively recruited. They were asymptomatic for cardiac issues and examined using 201Tl myocardial scintigraphy at rest and after coronary artery vasodilation with intravenous DPM. Factors associated with improvement in myocardial perfusion after DPM were identified in patients with TA.

Results.

Among 25 patients with TA, 21 (84%) had 201Tl myocardial perfusion defects and 4 (16%) had normal resting myocardial perfusion. Using a 17-segments model for quantitative image analysis, DPM significantly improved resting 201Tl myocardial perfusion in 14 patients (61%) versus 9 patients without improvement (39%). We were able to examine coronary artery stenoses in 11 patients, including 10 patients with thallium perfusion defects, and significant coronary artery stenoses were present in only 2 patients (18.2%). No significant difference was found in traditional cardiovascular risk factors between TA patients with or without improvement of myocardial perfusion after DPM. The absence of improvement in myocardial perfusion after DPM tended to be closely associated with specific features and prognostic factors of TA, such as aortic regurgitation at diagnosis, renovascular hypertension, longer duration of TA disease, and male sex.

Conclusion.

We found the significantly high prevalence of myocardial perfusion defects mostly improved after vasodilation with DPM, which may indicate the major role of microcirculatory dysfunction in myocardial ischemia in TA.

HIV treatment and associated mitochondrial pathology: review of 25 years of in vitro, animal, and human studies

Antiretroviral therapy has dramatically reduced mortality in human immunodeficiency virus (HIV) infection. In 1988, the suggestion that the first antiretroviral drug, zidovudine, was the potential cause of muscle pathology in HIV-infected persons resulted in structural and biochemical patient studies demonstrating acquired mitochondrial dysfunction. Assessment of subsequent nucleoside analog reverse transcriptase inhibitor (NRTI) antiretroviral drugs has indicated that mitochondria are a common target of NRTI toxicity in multiple tissues, leading to a wide variety of pathology ranging from lipodystrophy to neuropathy. Overwhelmingly, these complications have emerged during post-licensing human studies. Subsequent animal and in vitro studies have then elucidated the potential pathological mechanisms, suggesting that NRTI-associated mitochondrial toxicity arises principally from inhibition of the sole mitochondrial DNA (mtDNA) polymerase gamma, leading to a reduction in mtDNA content (depletion). Millions of patients have been treated with mitochondrially toxic NRTIs and these drugs remain the backbone of antiretroviral rollout in much of sub-Saharan Africa. Here we describe the 25-year history of antiretroviral associated mitochondrial pathology and critically review the strength of evidence linking clinical, histopathological, and molecular data. We discuss recently described novel mechanisms of NRTI-associated mitochondrial damage and whether or not recently licensed NRTIs may be considered free from mitochondrial toxicity.

Current state of knowledge on aetiology, diagnosis, management, and therapy of myocarditis: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases

In this position statement of the ESC Working Group on Myocardial and Pericardial Diseases an expert consensus group reviews the current knowledge on clinical presentation, diagnosis and treatment of myocarditis, and proposes new diagnostic criteria for clinically suspected myocarditis and its distinct biopsy-proven pathogenetic forms. The aims are to bridge the gap between clinical and tissue-based diagnosis, to improve management and provide a common reference point for future registries and multicentre randomised controlled trials of aetiology-driven treatment in inflammatory heart muscle disease.

Clinical value of a high-fat and low-carbohydrate diet before FDG-PET/CT for evaluation of patients with suspected cardiac sarcoidosis

BACKGROUND

We hypothesized that a high-fat and low-carbohydrate (HFLC) diet before FDG-PET/CT could identify patients with active cardiac sarcoidosis (CS).

METHODS

Fifty-eight sarcoidosis patients with a suspicion of CS consumed a HFLC diet before FDG-PET/CT. Clinical, electrical, and other imaging investigations were compared to PET results.

RESULTS

Using Japanese Ministry of Health and Welfare (JMHW) criteria as a gold standard, 21% (12/58) of patients had a CS. Sensitivity and specificity of PET (visual analysis) were 83% (10/12) and 78% (36/46), respectively, with a very good interobserver agreement (k = 0.86). 70% (7/10) of the patients with a positive PET and negative JMHW criteria exhibited abnormalities suggestive of CS either on MR (n = 3) or SPECT (n = 4). Comparison with the presence of delayed enhancement on magnetic resonance imaging helped to classify patients with active (PET positive) or non-active CS (PET negative). In addition, when MR and PET were both negative, none of the patients met the JMHW criteria. PET response under treatment was concordant with clinical evolution in 11/13 patients.

CONCLUSIONS

FDG-PET/CT after HFLC diet is a sensitive tool for the diagnosis of active CS. Combined use of PET and MR is promising for the detection and characterization of CS lesions.

Sarcoidosis, microvascular angina and aortitis: New dimensions of the 'Takayasu syndrome' - A case report

A case of Takayasu aortitis associated with sarcoidosis presenting with recurrent angina is reported. This association has been called 'Takayasu syndrome', which reflects what is likely a shared etiology. Myocardial perfusion abnormalities have recently been documented in sarcoidosis, but this case clarifies for the first time that the angina in Takayasu syndrome is likely due to small vessel coronary arteritis. Corticosteroids and cytotoxic therapy have been shown to be beneficial in all forms of sarcoidosis related to vasculitis. Initiation of steroid therapy may provide relief of angina in patients with evidence of reversible ischemia in normal coronary arteries.

Positron emission tomography for the evaluation and treatment of cardiomyopathy

Congestive heart failure accounts for tremendous morbidity and mortality worldwide. There are numerous causes of cardiomyopathy, the most common of which is coronary artery disease. Positron emission tomography (PET) has an established and expanding role in the evaluation of patients with cardiomyopathy. The specific application of PET to hypertrophic cardiomyopathy, cardiac sarcoidosis, and diabetic cardiomyopathy has been studied extensively and promises to be a useful tool for managing these patients. Furthermore, evaluating the efficacy of standard treatments for congestive heart failure is important as health care costs continue to rise. Recently, there have been significant developments in the field of cardiovascular stem cell research. Familiarity with the mechanisms by which stem cells benefit patients with cardiovascular disease is the key to understanding these advances. Molecular imaging techniques including PET/CT imaging play an important role in monitoring stem cell therapy in both animals and humans. These noninvasive imaging techniques will be highlighted in this paper.

Cardiac sarcoidosis: a comprehensive review

Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by noncaseating granulomas in involved organs. Organs involved with sarcoidosis include lymph nodes, skin, lung, central nervous system, and eye. Only 40-50% of patients with cardiac sarcoidosis diagnosed at autopsy have the diagnosis made during their lifetime. Cardiac sarcoidosis can manifest itself as complete heart block, ventricular arrhythmias, congestive heart failure, pericardial effusion, pulmonary hypertension, and ventricular aneurysms. Diagnostic tests such as the electrocardiogram, two-dimensional echocardiography, cardiac magnetic resonance imaging, positron emission tomography scan, radionuclide scan, and endomyocardial biopsy can be helpful in the early detection of cardiac sarcoidosis. Considering the increased risk of sudden death, cardiac sarcoidosis is an indication for early treatment with corticosteroids or other immunosuppressive agents. Other treatments include placement of a pacemaker or implantable defibrillator to prevent sudden death. In refractory cases, cardiac transplantation should be considered.

Prevalence of echocardiographic features suggesting cardiac sarcoidosis in patients with pacemaker or implantable cardiac defibrillator

BACKGROUND AND OBJECTIVES

Basal septal thinning or localized aneurysmal dilatation without coronary artery disease has been described as a characteristic finding suggestive of cardiac sarcoidosis. We sought to assess the prevalence of this characteristic echocardiographic finding in patients with pacemaker (PM) or implantable cardiac defibrillator (ICD).

SUBJECTS AND METHODS

Echocardiography of patients who received PM or ICD were retrospectively analyzed. Patients with marked thinning and akinesia confined to the basal septum (type 1), or posterolateral wall resulting in localized aneurysmal outward bulging (type 2) without history of myocardial infarction or significant coronary stenosis were included for analysis.

RESULTS

Among 1,357 consecutive patients, 21 exhibited suggestive echocardiographic findings (type 1/2=15/6) with a mean ejection fraction of 37±11%. The prevalence was 1.2% in the PM group and 4.0% in the ICD group. Only 3 patients showed histologically confirmable sarcoidosis in lymph nodes, lung and heart, respectively. Endomyocardial biopsy was attempted in 6 patients, but failed to demonstrate sarcoidosis. The 1-, 2-, 4- and 6-year clinical events (death, cardiac transplantation and hospital admission)-free survival rates were 100%, 85.7±7.6%, 75.0±9.7% and 48.6±12.4%, respectively. During follow-up, two patients with PM underwent ICD implantation, and another underwent heart transplantation.

CONCLUSION

Prevalence of echocardiographic features suggesting prevalence of cardiac sarcoidosis is low in patients who underwent device implantation. However, considering the very low yield of endomyocardial biopsy and the rare extracardiac manifestations in cardiac sarcoidosis, characteristic echocardiographic findings could be an adjunctive diagnostic criterion in these patients.

¹⁸F-Fluoro-2-deoxyglucose positron emission tomography in cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a rare and potentially life-threatening disease that causes conduction disturbance, systolic dysfunction, and most notably sudden cardiac death. Accurate diagnosis of CS is thus mandatory; however, a reliable approach that enables diagnosis of CS with high sensitivity and specificity has yet to be established. Recent studies have demonstrated the promising potential of (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) in the diagnosis and assessment of CS. Indeed, (18)F-FDG PET provides a wide variety of advantages over previous imaging modalities; however, there are pitfalls and limitations that should be recognized. In this review article, (1) the rationale for (18)F-FDG PET application in CS, (2) suitable pretest preparations, and (3) evaluation protocols for the (18)F-FDG PET images obtained will be addressed. In particular, sufficient suppression of physiological (18)F-FDG uptake in the heart is essential for accurate assessment of CS. Also, (4) recent studies addressing the diagnostic role of (18)F-FDG PET and (5) the clinically important differences between (18)F-FDG PET and other imaging technologies will be reviewed. For example, active sarcoid lesions and their response to steroid treatment will be better detected by (18)F-FDG PET, whereas fibrotic lesions might be shown more clearly by magnetic resonance imaging or other nuclear myocardial perfusion imaging. In the last decade, (18)F-FDG PET has substantially enhanced detection of CS; however, CS would be better evaluated by a combination of multiple modalities. In the future, advances in (18)F-FDG PET and other emerging imaging modalities are expected to enable better management of patients with sarcoidosis.