Application of laboratory models for sarcoidosis research.

This manuscript will review the implications and applications of sarcoidosis models towards advancing our understanding of sarcoidosis disease mechanisms, identification of biomarkers, and preclinical testing of novel therapies. Emerging disease models and innovative research tools will also be considered.

Multiomic Signatures of Chronic Beryllium Disease Bronchoalveolar Lavage Cells Relate to T-Cell Function and Innate Immunity.

Chronic beryllium disease (CBD) is a Th1 granulomatous lung disease preceded by sensitization to beryllium (BeS). We profiled the methylome, transcriptome, and selected proteins in the lung to identify molecular signatures and networks associated with BeS and CBD. BAL cell DNA and RNA were profiled using microarrays from CBD (n = 30), BeS (n = 30), and control subjects (n = 12). BAL fluid proteins were measured using Olink Immune Response Panel proteins from CBD (n = 22) and BeS (n = 22) subjects. Linear models identified features associated with CBD, adjusting for covariation and batch effects. Multiomic integration methods identified correlated features between datasets. We identified 1,546 differentially expressed genes in CBD versus control subjects and 204 in CBD versus BeS. Of the 101 shared transcripts, 24 have significant cis relationships between gene expression and DNA methylation, assessed using expression quantitative trait methylation analysis, including genes not previously identified in CBD. A multiomic model of top DNA methylation and gene expression features demonstrated that the first component separated CBD from other samples and the second component separated control subjects from remaining samples. The top features on component one were enriched for T-lymphocyte function, and the top features on component two were enriched for innate immune signaling. We identified six differentially abundant proteins in CBD versus BeS, with two (SIT1 and SH2D1A) selected as important RNA features in the multiomic model. Our integrated analysis of DNA methylation, gene expression, and proteins in the lung identified multiomic signatures of CBD that differentiated it from BeS and control subjects.

Application of Proteomics in Sarcoidosis.

Sarcoidosis is a multisystem disease with heterogeneity in manifestations and outcomes. System-level studies leveraging "omics" technologies are expected to define mechanisms contributing to sarcoidosis heterogeneous manifestations and course. With improvements in mass spectrometry (MS) and bioinformatics, it is possible to study protein abundance for a large number of proteins simultaneously. Contemporary fast-scanning MS enables the acquisition of spectral data for deep coverage of the proteins with data-dependent or data-independent acquisition MS modes. Studies leveraging MS-based proteomics in sarcoidosis have characterized BAL fluid (BALF), alveolar macrophages, plasma, and exosomes. These studies identified several differentially expressed proteins, including protocadherin-2 precursor, annexin A2, pulmonary surfactant A2, complement factors C3, vitamin-D-binding protein, cystatin B, and amyloid P, comparing subjects with sarcoidosis with control subjects. Other studies identified ceruloplasmin, complement factors B, C3, and 1, and others with differential abundance in sarcoidosis compared with other interstitial lung diseases. Using quantitative proteomics, most recent studies found differences in PI3K/Akt/mTOR, MAP kinase, pluripotency-associated transcriptional factor, and hypoxia response pathways. Other studies identified increased clathrin-mediated endocytosis and Fcγ receptor-mediated phagocytosis pathways in sarcoidosis alveolar macrophages. Although studies in mixed BAL and blood cells or plasma are limited, some of the changes in lung compartment are detected in the blood cells and plasma. We review proteomics for sarcoidosis with a focus on the existing MS data acquisition strategies, bioinformatics for spectral data analysis to infer protein identity and quantity, unique aspects about biospecimen collection and processing for lung-related proteomics, and proteomics studies conducted to date in sarcoidosis.

Clinical characteristics and organ system involvement in sarcoidosis: comparison of the University of Minnesota Cohort with other cohorts.

BACKGROUND: Sarcoidosis is a systemic granulomatous disease of unknown etiology. Clinical cohort studies of different populations are important to understand the high variability in clinical presentation and disease course of sarcoidosis. The aim of the study is to evaluate clinical characteristics, including organ involvement, pulmonary function tests, and laboratory parameters, in a sarcoidosis cohort at the University of Minnesota. We compare the organ system involvement of this cohort with other available cohorts. METHODS: We conducted a retrospective data collection and analysis of 187 subjects with biopsy-proven sarcoidosis seen at a tertiary center. Organ system involvement was determined using the WASOG sarcoidosis organ assessment instrument. Clinical phenotype groups were classified using the Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis criteria. RESULTS: Mean subject age at diagnosis was 45.8 ± 12.4, with a higher proportion of males (55.1%), and a higher proportion of blacks (17.1%) compared to the racial distribution of Minnesota residents (5.95%). The majority (71.1%) of subjects required anti-inflammatory therapy for at least 1 month. Compared to the A Case Control Etiologic Study of Sarcoidosis cohort, there was a higher frequency of extra-thoracic lymph node (34.2% vs. 15.2%), eye (20.9% vs. 11.8%), liver (17.6% vs. 11.5%), spleen (20.9% vs. 6.7%), musculoskeletal (9.6% vs. 0.5%), and cardiac (10.7% vs. 2.3%) involvement in our cohort. A multisystem disease with at least five different organs involved was identified in 13.4% of subjects. A restrictive physiological pattern was observed in 21.6% of subjects, followed by an obstructive pattern in 17.3% and mixed obstructive and restrictive pattern in 2.2%. Almost half (49.2%) were Scadding stages II/III. Commonly employed disease activity markers, including soluble interleukin-2 receptor and angiotensin-converting enzyme, did not differ between treated and untreated groups. CONCLUSIONS: This cohort features a relatively high frequency of high-risk sarcoidosis phenotypes including cardiac and multiorgan disease. Commonly-utilized serum biomarkers do not identify subpopulations that require or do better with treatment. Findings from this study further highlight the high-variability nature of sarcoidosis and the need for a more reliable biomarker to predict and measure disease severity and outcomes for better clinical management of sarcoidosis patients.

Proteome Profiling in Lung Injury after Hematopoietic Stem Cell Transplantation.

Pulmonary complications due to infection and idiopathic pneumonia syndrome (IPS), a noninfectious lung injury in hematopoietic stem cell transplant (HSCT) recipients, are frequent causes of transplantation-related mortality and morbidity. Our objective was to characterize the global bronchoalveolar lavage fluid (BALF) protein expression of IPS to identify proteins and pathways that differentiate IPS from infectious lung injury after HSCT. We studied 30 BALF samples from patients who developed lung injury within 180 days of HSCT or cellular therapy transfusion (natural killer cell transfusion). Adult subjects were classified as having IPS or infectious lung injury by the criteria outlined in the 2011 American Thoracic Society statement. BALF was depleted of hemoglobin and 14 high-abundance proteins, treated with trypsin, and labeled with isobaric tagging for relative and absolute quantification (iTRAQ) 8-plex reagent for two-dimensional capillary liquid chromatography (LC) and data dependent peptide tandem mass spectrometry (MS) on an Orbitrap Velos system in higher-energy collision-induced dissociation activation mode. Protein identification employed a target-decoy strategy using ProteinPilot within Galaxy P. The relative protein abundance was determined with reference to a global internal standard consisting of pooled BALF from patients with respiratory failure and no history of HSCT. A variance weighted t-test controlling for a false discovery rate of ≤5% was used to identify proteins that showed differential expression between IPS and infectious lung injury. The biological relevance of these proteins was determined by using gene ontology enrichment analysis and Ingenuity Pathway Analysis. We characterized 12 IPS and 18 infectious lung injury BALF samples. In the 5 iTRAQ LC-MS/MS experiments 845, 735, 532, 615, and 594 proteins were identified for a total of 1125 unique proteins and 368 common proteins across all 5 LC-MS/MS experiments. When comparing IPS to infectious lung injury, 96 proteins were differentially expressed. Gene ontology enrichment analysis showed that these proteins participate in biological processes involved in the development of lung injury after HSCT. These include acute phase response signaling, complement system, coagulation system, liver X receptor (LXR)/retinoid X receptor (RXR), and farsenoid X receptor (FXR)/RXR modulation. We identified 2 canonical pathways modulated by TNF-α, FXR/RXR activation, and IL2 signaling in macrophages. The proteins also mapped to blood coagulation, fibrinolysis, and wound healing-processes that participate in organ repair. Cell movement was identified as significantly over-represented by proteins with differential expression between IPS and infection. In conclusion, the BALF protein expression in IPS differed significantly from infectious lung injury in HSCT recipients. These differences provide insights into mechanisms that are activated in lung injury in HSCT recipients and suggest potential therapeutic targets to augment lung repair.

FCGR3A and FCGR3B copy number variations are risk factors for sarcoidosis.

Sarcoidosis is a multisystem granulomatous disorder that causes significant morbidity. Genetic factors contribute to sarcoidosis risks. In this study, we investigated whether copy number variations (CNVs) of FCGR3A (coding for FcγRIIIA) and FCGR3B (coding for FcγRIIIB) genes are associated with sarcoidosis susceptibility and whether the expressions of FcγRIIIA on NK cells and FcγRIIIB on neutrophils are altered in sarcoidosis patients. TaqMan real-time PCR assays were used to analyze the CNV of FCGR3A and FCGR3B genes. FCGR3A and FCGR3B CNV genotypes were compared between 671 biopsy-proven sarcoidosis patients and the same number of healthy controls matched with age, sex, race, and geographic area from the ACCESS (A Case Control Etiologic Study of Sarcoidosis) cohort. Flow cytometry analyses were used to determine expressions of FcγRIIIA on NK cells and FcγRIIIB on neutrophils in phenotype analyses. We found that FCGR3A CNVs were significantly associated with sarcoidosis in females (CN = 1 vs. CN = 2 logistic regression adjusted for sex and race, OR 4.0156, SE = 2.2784, P = 0.0143; CN = 3 vs. CN = 2 logistic regression adjusted for sex and race, OR 2.8044, SE = 1.1065, P = 0.0090), suggesting that FCGR3A gene abnormality influences sarcoidosis development in a gender-specific manner. Furthermore, FcγRIIIA expressions were significantly decreased on NK cells from sarcoidosis patients compared to those from healthy controls (P = 0.0007). Additionally, low FCGR3B CN was associated with sarcoidosis (CN <2 vs. CN = 2 logistic regression adjusted for sex and race, OR 1.5025, SE = 0.2682, P = 0.0226), indicating that the functions of FCGR3B gene may also contribute to the pathogenesis of sarcoidosis. We conclude that FCGR3A CNVs are a major risk factor for female sarcoidosis and FCGR3B CNVs may also affect the development of sarcoidosis.

The role for endobronchial biopsy in the era of endobronchial ultrasound guided transbronchial needle aspiration for the diagnosis of sarcoidosis: a single center experience.

BACKGROUND AND AIM: Endobronchial biopsy (EBBX) has been reported to increase diagnostic yield for pulmonary sarcoidosis. The purpose of this study is to investigate the diagnostic yield for EBBX following endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA). METHODS: We identified a cohort of patients in the University of Minnesota Sarcoidosis Registry who had EBBx and EBUS-TBNA as part of workup for abnormal chest imaging. Data regarding demographics, biopsy approach and technique were recorded. RESULTS: Our cohort included 37 patients (53.24±9.5, Male, 22±0.57; 3.8% were African American). In these patients who had EBBX, EBUS-TBNA was performed in 100% of patients and TBBX was performed in 2 patients (5%). EBBX was positive in 9 patients (24%) and EBUS-TBNA was positive in 34 patients (92%). TBBX was diagnostic in one of two patients. EBBX was the only diagnostic tissue in 3 of the 37 patients (8%).  Conclusion: The diagnostic yield of EBBX is lower than previously reported, with only 8% of EBBXs demonstrating granulomatous inflammation. However, instrumentation used for obtaining EBBX as well as the presence of visible lesions does influence the diagnostic yield. Studies with adequate power are needed before implementing changes in clinical practice.  When performed alongside EBUS-TBNA, EBBX did not significantly add to the diagnostic yield in sarcoidosis unless visible lesions were observed.

The active papillary muscle sign in 18F-FDG PET/CT cardiac sarcoidosis exams and its relationship with myocardial suppression.

OBJECTIVE: Papillary muscle (PM) activity may demonstrate true active cardiac sarcoidosis (CS) or mimic CS in 18FDG-PET/CT if adequate myocardial suppression (MS) is not achieved. We aim to examine whether PM uptake can be used as a marker of failed MS and measure the rate of PM activity presence in active CS with different dietary preparations. MATERIALS AND METHODS: We retrospectively reviewed PET/CTs obtained with three different dietary preparations. Diet-A: 24-h ketogenic diet with overnight fasting (n = 94); Diet-B: 18-h fasting (n = 44); and Diet-C: 72-h daytime ketogenic diet with 3-day overnight fasting (n = 98). Each case was evaluated regarding CS diagnosis (negative, positive, and indeterminant) and presence of PM activity. MaxSUV was measured from bloodpool, liver, and the most suppressed normal myocardium. Linear mixed-effects models were used to compare these factors between those with PM activity and those without. RESULTS: PM activity was markedly lower in the Diet-C group compared with others: Diet-C: 6 (6.1%), Diet-A: 36 (38.3%), and Diet-B: 26 (59.1%) (p < 0.001). MyocardiumMaxSUV was higher, and MyocardiummaxSUV/BloodpoolmaxSUV, MyocardiummaxSUV/LivermaxSUV ratios were significantly higher in the cases with PM activity (p < 0.001). Among cases that used Diet-C and had PM activity, 66.7% were positive and 16.7% were indeterminate. If Diet-A or Diet-B was used, those with PM activity had a higher proportion of indeterminate cases (Diet-A: 61.1%, Diet-B: 61.5%) than positive cases (Diet-A: 36.1%, Diet-B: 38.5%). CONCLUSION: Lack of PM activity can be a sign of appropriate MS. PM activity is less common with a specific dietary preparation (72-h daytime ketogenic diet with 3-day overnight fasting), and if it is present with this particular preparation, the likelihood that the case being true active CS might be higher than the other traditional dietary preparations.

Protein expression profile of rat type two alveolar epithelial cells during hyperoxic stress and recovery.

In rodent model systems, the sequential changes in lung morphology resulting from hyperoxic injury are well characterized and are similar to changes in human acute respiratory distress syndrome. In the injured lung, alveolar type two (AT2) epithelial cells play a critical role in restoring the normal alveolar structure. Thus characterizing the changes in AT2 cells will provide insights into the mechanisms underpinning the recovery from lung injury. We applied an unbiased systems-level proteomics approach to elucidate molecular mechanisms contributing to lung repair in a rat hyperoxic lung injury model. AT2 cells were isolated from rat lungs at predetermined intervals during hyperoxic injury and recovery. Protein expression profiles were determined by using iTRAQ with tandem mass spectrometry. Of the 959 distinct proteins identified, 183 significantly changed in abundance during the injury-recovery cycle. Gene ontology enrichment analysis identified cell cycle, cell differentiation, cell metabolism, ion homeostasis, programmed cell death, ubiquitination, and cell migration to be significantly enriched by these proteins. Gene set enrichment analysis of data acquired during lung repair revealed differential expression of gene sets that control multicellular organismal development, systems development, organ development, and chemical homeostasis. More detailed analysis identified activity in two regulatory pathways, JNK and miR 374. A novel short time-series expression miner algorithm identified protein clusters with coherent changes during injury and repair. We concluded that coherent changes occur in the AT2 cell proteome in response to hyperoxic stress. These findings offer guidance regarding the specific molecular mechanisms governing repair of the injured lung.

Compartment-specific protein interactions in beryllium lung disease.

The study provides insights into proteins that may be relevant in BeS and CBD. It provides a framework to investigate the global changes in lung compartment-specific inflammatory cells to better understand the potential interplay of proteins in CBD. https://bit.ly/3PLNTXC.

Novel Human FCGR1A Variants Affect CD64 Functions and Are Risk Factors for Sarcoidosis.

CD64 (or FcγRIA) is the sole functional high affinity IgG Fc receptor coded by FCGR1A gene in humans. The FCGR1A genetics has not been comprehensively investigated and effects of human FCGR1A variants on immune functions remain unknown. In the current study, we identified three novel FCGR1A variants including the single nucleotide variant (SNV) rs1848781 (c.-131) in the proximal FCGR1A gene promoter region, the rs587598788 indel variant within the FCGR1A intron 5, and the non-synonymous SNV rs1050204 (c.970G>A or FcγRIA-p.D324N) in the FCGR1A coding region. Genotype-phenotype analyses revealed that SNV rs1848781 genotypes were significantly associated with CD64 expression levels. Promoter reporter assays show that rs1848781G allele had significantly higher promoter activity than the rs1848781C, confirming that the rs1848781 is a functional FCGR1A SNV affecting promoter activity and gene expression. The rs587598788 indel genotypes were also significantly associated with levels of CD64 expression. Moreover, the non-synonymous SNV rs1050204 (FcγRIA-p.D324N) alleles significantly affected CD64-mediated phagocytosis, degranulation, and pro-inflammatory cytokine productions. Genetic analyses revealed that FCGR1A genotypes were significantly associated with sarcoidosis susceptibility and severity. Our data suggest that FCGR1A genetic variants may affect immune responses and play a role in sarcoidosis.

The landscape of transcriptomic and proteomic studies in sarcoidosis.

Multiple overlapping pathways are identified in tissue, BAL cells, PBMCs and a sarcoidosis in vitro granuloma model. Inferences from omic studies are constrained by small sample sizes. Studies comparing differences between sarcoidosis phenotypes are needed. https://bit.ly/30NaHz4.

Cardiovascular Magnetic Resonance Imaging Phenotypes and Long-term Outcomes in Patients With Suspected Cardiac Sarcoidosis.

Importance: In patients with sarcoidosis with suspected cardiac involvement, late gadolinium enhancement (LGE) on cardiovascular magnetic resonance imaging (CMR) identifies those with an increased risk of adverse outcomes. However, these outcomes are experienced by only a minority of patients with LGE, and identifying this subgroup may improve treatment and outcomes in these patients. Objective: To assess whether CMR phenotypes based on left ventricular ejection fraction (LVEF) and LGE in patients with suspected cardiac sarcoidosis (CS) are associated with adverse outcomes during follow-up. Design, Setting, and Participants: This cohort study included consecutive patients with histologically proven sarcoidosis who underwent CMR for the evaluation of suspected CS from 2004 to 2020 with a median follow-up of 4.3 years at an academic medical center in Minnesota. Demographic data, medical history, comorbidities, medications, and outcome data were collected blinded to CMR data. Exposures: CMR phenotypes were identified based on LVEF and LGE presence and features. LGE was classified as pathology-frequent or pathology-rare based on the frequency of cardiac damage features on gross pathology assessment of the hearts of patients with CS who had sudden cardiac death or cardiac transplant. Main Outcomes and Measures: Composite of ventricular arrhythmic events and composite of heart failure events. Results: Among 504 patients (mean [SD] age, 54.1 [12.5] years; 242 [48.0%] female and 262 [52.0%] male; 2 [0.4%] American Indian or Alaska Native, 6 [1.2%] Asian, 90 [17.9%] Black or African American, 399 [79.2%] White, 5 [1.0%] of 2 or more races (including the above-mentioned categories and Native Hawaiian or Other Pacific Islander), and 2 [0.4%] of unknown race; 4 [0.8%] Hispanic or Latino, 498 [98.8%] not Hispanic or Latino, and 2 [0.4%] of unknown ethnicity), 4 distinct CMR phenotypes were identified: normal LVEF and no LGE (n = 290; 57.5%), abnormal LVEF and no LGE (n = 53; 10.5%), pathology-frequent LGE (n = 103; 20.4%), and pathology-rare LGE (n = 58; 11.5%). The phenotype with pathology-frequent LGE was associated with a high risk of arrhythmic events (hazard ratio [HR], 12.12; 95% CI, 3.62-40.57; P < .001) independent of LVEF and extent of left ventricular late gadolinium enhancement (LVLGE). It was also associated with a high risk of heart failure events (HR, 2.49; 95% CI, 1.19-5.22; P = .02) independent of age, pulmonary hypertension, LVEF, right ventricular ejection fraction, and LVLGE extent. Risk of arrhythmic events was greater with an increasing number of pathology-frequent LGE features. The absence of the pathology-frequent LGE phenotype was associated with a low risk of arrhythmic events, even in the presence of LGE or abnormal LVEF. Conclusions and Relevance: This cohort study found that a CMR phenotype involving pathology-frequent LGE features was associated with a high risk of arrhythmic and heart failure events in patients with sarcoidosis. The findings indicate that CMR phenotypes could be used to optimize clinical decision-making for treatment options, such as implantable cardioverter-defibrillators.

Granulomatous-Lymphocytic Interstitial Lung Disease Mimicking Sarcoidosis.

Common variable immunodeficiency (CVID) is one of the most common primary immunodeficiency disorders characterized by hypogammaglobulinemia and inadequate antibody response to immunizations. The impaired antibody response occurs due to the failure of B cells to differentiate into plasma cells resulting in low immunoglobulins levels and increased frequency of infections. Granulomatous and Lymphocytic Interstitial Lung Disease (GLILD) is a non-infectious complication of CVID that is seen in 10-30% of cases. GLILD is a multisystem inflammatory disease involving the lungs, lymph node, liver, spleen and gastrointestinal tract that mimics sarcoidosis. This report describes a series of cases who presented with dyspnea, recurrent respiratory infections or autoimmunity and on further evaluation revealed features suggestive of GLILD. There is very limited understanding of GLILD in terms of clinical presentation, the histo-pathological logical findings, and the diagnostic criteria by itself are limited. A diagnosis of GLILD is established in cases of CVID when there is evidence of lymphoproliferation, cytopenia, autoimmune processes and a lung biopsy demonstrating lymphocytic interstitial pneumonia, follicular bronchiolitis, lymphoid hyperplasia, and/or non-necrotizing granulomas. We review the treatment strategies, including replacement of immunoglobulin and agents targeting B and T lymphocytes. Systematic characterization of GLILD cases and long term follow up studies are sorely needed to understand the natural history of GLILD.

Clinical Presentation and Treatment of High-Risk Sarcoidosis.

Sarcoidosis is a multisystem disease of unknown cause with heterogeneous clinical manifestations and variable course. Spontaneous remissions occur in some patients, whereas others have progressive disease impacting survival, organ function, and quality of life. Four high-risk sarcoidosis phenotypes associated with chronic inflammation have recently been identified as high-priority areas for research. These include treatment-refractory pulmonary disease, cardiac sarcoidosis, neurosarcoidosis, and multiorgan sarcoidosis. Significant gaps currently exist in the understanding of these high-risk manifestations of sarcoidosis, including their natural history, diagnostic criteria, biomarkers, and the treatment strategy, such as the ideal agent, optimal dose, and treatment duration. The use of registries with well-phenotyped patients is a critical first step to study high-risk sarcoidosis manifestations systematically. We review the diagnostic and treatment approach to high-risk sarcoidosis manifestations. Appropriately identifying these disease subgroups will help enroll well-phenotyped patients in sarcoidosis registries and clinical trials, a necessary step to narrow existing gaps in understanding of this enigmatic disease.

COMPARISON OF THE EFFECT OF THREE DIFFERENT DIETARY MODIFICATIONS ON MYOCARDIAL SUPPRESSION IN 18F-FDG PET/CT EVALUATION OF PATIENTS FOR SUSPECTED CARDIAC SARCOIDOSIS.

Rationale: A definitive dietary preparation recommendation is not possible based on literature in achievement of myocardial suppression for diagnosis of cardiac sarcoidosis (CS) with 18F-FDG PET/CT. Our goal is to compare three different dietary preparations in achievement of the best myocardial suppression and CS diagnosis. Methods: We retrospectively reviewed and compared three dietary preparations used at our institution. Three different diets were applied from 03/2014 to 12/2019. 24-h ketogenic diet with overnight fasting (n = 94); 18h-fasting (n = 44); 72-h daytime ketogenic diet with 3-day overnight fasting (n = 98). The interpretation of initial reports was recorded, and an independent radiologist (observer) retrospectively re-evaluated each case regarding CS diagnosis (Negative, Positive, Indeterminant) and myocardial suppression (Complete, Failed, Partial). Interobserver agreement was analyzed. We measured MaxSUV from bloodpool, liver, and the most suppressed normal myocardium. Results: We identified superior myocardial suppression with the 72-h preparation indicated by a higher bloodpool/myocardium and liver/myocardium ratios (P<0.001). Myocardial suppression rates for 72-h ketogenic diet, 24-h ketogenic diet and 18-h fasting preparations are as follows; Complete myocardial suppression: 96.9%/68.1%/52.3%, Failed myocardial suppression: 0%/23.4%/25%, Partial myocardial suppression: 3.1%/8.5%/22.7%) (P<0.001). The 72-hour preparation had significantly fewer "indeterminant" and "positive" exams. CS diagnosis rates for 72-h ketogenic diet, 24-h ketogenic diet and 18-h fasting preparations are as follows; Negative: 82.7%/52.1%/27.3%, Indeterminant: 2.0%/24.5%/40.9%, Positive: 15.3%/23.4%/31.8% (P<0.001). High agreement was present with the observer and the report (κ=0.88) Conclusion: A 72-h daytime ketogenic diet with 3-day overnight fasting, achieved substantially superior myocardial suppression versus 24-h ketogenic diet with overnight fasting and 18h-fasting using 18F-FDG PET/CT. This 72-h preparation results in significantly fewer "indeterminant" and potentially "false positive" CS results.

Sex Differences in Patients With Suspected Cardiac Sarcoidosis Assessed by Cardiovascular Magnetic Resonance Imaging.

Background: There are few data on sex differences in suspected cardiac sarcoidosis. Methods: Consecutive patients with histologically proven sarcoidosis and suspected cardiac involvement were studied. We investigated sex differences in presenting features, cardiac involvement, and the long-term incidence of a primary composite end point of all-cause death or significant ventricular arrhythmia and secondary end points of all-cause death and significant ventricular arrhythmia. Results: Among 324 patients, 163 (50.3%) were female and 161 (49.7%) were male patients. Female patients had a greater prevalence of chest pain (37.4% versus 23.6%; P=0.010) and palpitations (39.3% versus 26.1%; P=0.016) than male patients but not dyspnea, presyncope, syncope, or arrhythmias at presentation. Female patients had a lower prevalence of late gadolinium enhancement on cardiovascular magnetic resonance imaging (20.2% versus 35.4%; P=0.003) and less often met criteria for a clinical diagnosis of cardiac sarcoidosis (Heart Rhythm Society consensus criteria, 22.7% versus 36.0%; P=0.012 and 2016 Japanese Circulation Society guideline criteria, 8.0% versus 19.3%; P=0.005), indicating lesser cardiac involvement. However, the long-term incidence of all-cause death or significant ventricular arrhythmia was not different between female and male patients (23.2% versus 23.2%; P=0.46). Among the secondary end points, the incidence of all-cause death was not different between female and male patients (20.7% versus 14.3%; P=0.51), while female patients had a lower incidence of significant ventricular arrhythmia compared with male patients (4.3% versus 13.0%; P=0.022). On multivariable analyses, sex was not associated with the primary end point (hazard ratio for female patients, 1.36 [95% CI, 0.77­2.43]; P=0.29). Conclusions: We observed distinct sex differences in patients with suspected cardiac sarcoidosis. A paradox was identified wherein female patients had a greater prevalence of chest pain and palpitations than male patients, but lesser cardiac involvement, and a similar long-term incidence of all-cause death or significant ventricular arrhythmia.

Does vitamin D deficiency increase the severity of COVID-19?

The severity of coronavirus 2019 infection (COVID-19) is determined by the presence of pneumonia, severe acute respiratory distress syndrome (SARS-CoV-2), myocarditis, microvascular thrombosis and/or cytokine storms, all of which involve underlying inflammation. A principal defence against uncontrolled inflammation, and against viral infection in general, is provided by T regulatory lymphocytes (Tregs). Treg levels have been reported to be low in many COVID-19 patients and can be increased by vitamin D supplementation. Low vitamin D levels have been associated with an increase in inflammatory cytokines and a significantly increased risk of pneumonia and viral upper respiratory tract infections. Vitamin D deficiency is associated with an increase in thrombotic episodes, which are frequently observed in COVID-19. Vitamin D deficiency has been found to occur more frequently in patients with obesity and diabetes. These conditions are reported to carry a higher mortality in COVID-19. If vitamin D does in fact reduce the severity of COVID-19 in regard to pneumonia/ARDS, inflammation, inflammatory cytokines and thrombosis, it is our opinion that supplements would offer a relatively easy option to decrease the impact of the pandemic.