Analysis of image data from the EuroNet PHL-C2 trial indicates a potential reduction in injected F-18 FDG activities in children: a proposal to update the EANM Paediatric Dosage Card.

BACKGROUND: The aim of this work is to provide the currently missing evidence that may allow an update of the Paediatric Dosage Card provided by the European Association of Nuclear Medicine (EANM) for conventional PET/CT systems. METHODS: In a total of 2082 consecutive [18F]FDG-PET scans performed within the EuroNet-PHL-C2 trial, the administered [18F]FDG activity was compared to the activity recommended by the EANM Paediatric Dosage Card. None of these scans had been rejected beforehand by the reference nuclear medicine panel of the trial because of poor image quality. For detailed quality assessment, a subset of 91 [18F]FDG-PET scans, all performed in different patients at staging, was selected according to pre-defined criteria, which (a) included only patients who had received substantially lower activities than those recommended by the EANM Paediatric Dosage Card, and (b) included as wide a range of different PET systems and imaging parameters as possible to ensure that the conclusions drawn in this work are as generally valid as possible. The image quality of the subset was evaluated visually by two independent readers using a quality scoring system as well as analytically based on a volume-of-interest analysis in 244 lesions and the healthy liver. Finally, recommendations for an update of the EANM Paediatric Dosage Card were derived based on the available data. RESULTS: The activity recommended by the EANM Paediatric Dosage Card was undercut by a median of 99.4 MBq in 1960 [18F]FDG-PET scans and exceeded by a median of 15.1 MBq in 119 scans. In the subset analysis (n = 91), all image data were visually classified as clinically useful. In addition, only a very weak correlation (r = 0.06) between activity reduction and tumour-to-background ratio was found. Due to the intended heterogeneity of the dataset, the noise could not be analysed statistically sound as the high range of different imaging variables resulted in very small subsets. Finally, a suggestion for an update of the EANM Paediatric Dosage Card was developed, based on the analysis presented, resulting in a mean activity reduction by 39%. CONCLUSION: The results of this work allow for a conservative update of the EANM Paediatric Dosage Card for [18F]FDG-PET/CT scans performed with conventional PET/CT systems.

Cardiac human bitter taste receptors contain naturally occurring variants that alter function.

Bitter taste receptors (T2R) are a subfamily of G protein-coupled receptors that enable humans to detect aversive and toxic substances. The ability to discern bitter compounds varies between individuals and is attributed mainly to naturally occurring T2R polymorphisms. T2Rs are also expressed in numerous non-gustatory tissues, including the heart, indicating potential contributions to cardiovascular physiology. In this study. T2Rs that have previously been identified in human cardiac tissues (T2Rs - 10, 14, 30, 31, 46 and 50) and their naturally occurring polymorphisms were functionally characterised. The ligand-dependent signaling responses of some T2R variants were completely abolished (T2R30 Leu252 and T2R46 Met228), whereas other receptor variants had moderate changes in their maximal response, but not potency, relative to wild type. Using a cAMP fluorescent biosensor, we reveal the productive coupling of T2R14, but not the T2R14 Phe201 variant, to endogenous Gαi. Modeling revealed that these variants resulted in altered interactions that generally affected ligand binding (T2R30 Leu252) or Gα protein interactions (T2R46 Met228 and T2R14 Phe201), rather than receptor structural stability. Interestingly, this study is the first to show a difference in signaling for T2R50 Tyr203 (rs1376251) which has been associated with cardiovascular disease. The observation of naturally occurring functional variation in the T2Rs with the greatest expression in the heart is important, as their discovery should prove useful in deciphering the role of T2Rs within the cardiovascular system.

Establishing the Relative Accuracy of Using City Directories as Proxies to Define and Reconstruct Historical Alcohol Environments.

OBJECTIVE: Research on alcohol environments has established that poorer and minoritized communities are frequently overburdened by off-premise outlets (e.g., liquor stores). These outlets have more associated harms, including increased alcohol consumption and crime rates. Little, if any, research has shown how these socio-spatial disparities in exposure have grown or shifted over time, and no studies have established a method for re-creating historical alcohol environments. METHOD: Our results suggest that in our study city of Flint, MI, disparities in the alcohol environment have narrowed since 1950. Although liquor stores are still more likely to be located in poorer and more heavily African American neighborhoods, the pattern has become insignificant over time. Furthermore, the number of alcohol outlets per capita has declined. Thus, although the city remains more overburdened with alcohol outlets than its suburbs, the disparity has shrunk. CONCLUSIONS: This work has implications for those working in alcohol prevention and policy, as well as in urban planning. Practitioners and researchers can use this method to model alcohol availability over time in their own communities, which helps better inform the discussion on disparities experienced in poor and minoritized neighborhoods.

Prognostic value of baseline and early response FDG-PET/CT in patients with refractory and relapsed aggressive B-cell lymphoma undergoing CAR-T cell therapy.

PURPOSE: Chimeric antigen receptor (CAR)-T cells are a viable treatment option for patients with relapsed or refractory (r/r) aggressive B-cell lymphomas. The prognosis of patients who relapse after CAR-T cell treatment is dismal and factors predicting outcomes need to be identified. Our aim was to assess the value of FDG-PET/CT in terms of predicting patient outcomes. METHODS: Twenty-two patients with r/r B-cell lymphoma who received CAR-T cell treatment with tisagenlecleucel (n = 17) or axicabtagene ciloleucel (n = 5) underwent quantitative FDG-PET/CT before (PET-0) and 1 month after infusion of CAR-T cells (PET-1). PET-1 was classified as complete metabolic response (CMR, Deauville score 1-3) or non-CMR (Deauville score 4-5). RESULTS: At the time of PET-1, 12/22 (55%) patients showed CMR, ten (45%) patients non-CMR. 7/12 (58%) CMR patients relapsed after a median of 223 days, three of them (25%) died. 9/10 (90%) non-CMR patients developed relapse or progressive disease after a median of 91 days, eight of them (80%) died. CMR patients demonstrated a significantly lower median total metabolic tumor volume (TMTV) in PET-0 (1 ml) than non-CMR patients (225 ml). CONCLUSION: Our results confirm the prognostic value of PET-1. 42% of all CMR patients are still in remission 1 year after CAR T-cell treatment. 90% of the non-CMR patients relapsed, indicating the need for early intervention. Higher TMTV before CAR-T cell infusion was associated with lower chances of CMR.

Linking Historical Discriminatory Housing Patterns to the Contemporary Alcohol Environment.

Research on alcohol outlet density consistently shows greater disparities in exposure in disinvested communities. Likewise, structural racism via discriminatory housing practices has created many of the issues that beset contemporary disinvested neighborhoods. Little work, however, has examined the relationship between housing practices and alcohol outlet disparities. The central premise of our work is that these discriminatory and inequitable practices create distinctions in the alcohol environment, and that such disparities have implications for work on alcohol policy. Here we link alcohol outlet density with a spatial database examining redlining, blockbusting, and gentrification in Baltimore, Maryland, and Flint, Michigan (two cities with common experiences of urban disinvestment over the last 50 years). Standard measures are used to account for the impacts of neighborhood racial, socioeconomic, and housing composition in a multilevel model. Our findings highlight that gentrification and redlining are strongly associated with alcohol outlet density, while blockbusting is not. Gentrification and redlining also frequently co-occur in inner-urban areas, while the more suburban phenomenon of blockbusting rarely overlaps with either. These findings further contextualize nascent work on structural racism in housing that illustrates important disparities along the lines of these distinct practices. Future work should consider how legacy impacts of discriminatory housing patterns impact our communities today.

Early cardiac aging linked to impaired stress-resistance and transcriptional control of stress response, quality control and mitochondrial pathways.

Phenotypic and transcriptomic evidence of early cardiac aging, and associated mechanisms, were investigated in young to middle-aged male mice (C57Bl/6; ages 8, 16, 32, 48 wks). Left ventricular gene expression (profiled via Illumina MouseWG-6 BeadChips), contractile and coronary function, and stress-resistance were assessed in Langendorff perfused hearts under normoxic conditions and following ischemic insult (20 min global ischemia-45 min reperfusion; I-R). Baseline or normoxic contractile function was unaltered by age, while cardiac and coronary 'reserves' (during ß-adrenoceptor stimulation; 1 µM isoproterenol) declined by 48 wks. Resistance to I-R injury fell from 16 to 32 wks. Age-dependent transcriptional changes In un-stressed hearts were limited to 104 genes (>1.3-fold; 0.05 FDR), supporting: up-regulated innate defenses (glutathione and xenobiotic metabolism, chemotaxis, interleukins) and catecholamine secretion; and down-regulated extracellular matrix (ECM), growth factor and survival (PI3K/Akt) signaling. In stressed (post-ischemic) myocardium, ∼15-times as many genes (1528) were age-dependent, grouped into 6 clusters (>1.3-fold change; 0.05 FDR): most changing from 16 wks (45 % up/44 % down), a further 5 % declining from 32 wks. Major age-dependent Biological Processes in I-R hearts reveal: declining ATP metabolism, oxidative phosphorylation, cardiac contraction and morphogenesis, phospholipid metabolism and calcineurin signaling; increasing proteolysis and negative control of MAPK; and mixed changes in nuclear transport and angiogenic genes. Pathway analysis supports reductions in: autophagy, stress response, ER protein processing, mRNA surveillance and ribosome/translation genes; with later falls in mitochondrial biogenesis, oxidative phosphorylation and proteasome genes in I-R hearts. Summarizing, early cardiac aging is evident from 16 to 32 wks in male mice, characterized by: declining cardiovascular reserve and stress-resistance, transcriptomic evidence of constitutive stress and altered catecholamine and survival/growth signaling in healthy hearts; and declining stress response, quality control, mitochondrial energy metabolism and cardiac modeling processes in stressed hearts. These very early changes, potentially key substrate for advanced aging, may inform approaches to healthy aging and cardioprotection in the adult heart.

A peptide toxin in ant venom mimics vertebrate EGF-like hormones to cause long-lasting hypersensitivity in mammals.

Venoms are excellent model systems for studying evolutionary processes associated with predator-prey interactions. Here, we present the discovery of a peptide toxin, MIITX2-Mg1a, which is a major component of the venom of the Australian giant red bull ant Myrmecia gulosa and has evolved to mimic, both structurally and functionally, vertebrate epidermal growth factor (EGF) peptide hormones. We show that Mg1a is a potent agonist of the mammalian EGF receptor ErbB1, and that intraplantar injection in mice causes long-lasting hypersensitivity of the injected paw. These data reveal a previously undescribed venom mode of action, highlight a role for ErbB receptors in mammalian pain signaling, and provide an example of molecular mimicry driven by defensive selection pressure.

Trajectory Modeling of Spatio-Temporal Trends in COVID-19 Incidence in Flint and Genesee County, Michigan.

PURPOSE: The establishment of community-academic partnerships to digest data and create actionable policy and advocacy steps is of continuing importance. In this paper, we document COVID-19 racial and geographic disparities uncovered via a collaboration between a local health department and university research center. METHODS: We leverage individual level data for all COVID-19 cases aggregated to the census block group level, where group-based trajectory modeling was employed to identify latent patterns of change and continuity in COVID-19 diagnoses. RESULTS: Linking with socioeconomic data from the census, we identified the types of communities most heavily affected by each of Michigan's two waves (in spring and fall of 2020). This includes a geographic and racial gap in COVID-19 cases during the first wave, which is largely eliminated during the second wave. CONCLUSIONS: Our work has been extremely valuable for community partners, informing community-level response toward testing, treatment, and vaccination. In particular, identifying and conducting advocacy on the sizeable racial disparity in COVID-19 cases during the first wave in spring 2020 helped our community nearly eliminate disparities throughout the second wave in fall 2020.

Akt acts as a switch for GPCR transactivation of the TGF-ß receptor type 1.

Transforming growth factor (TGF)-ß signalling commences with the engagement of TGF-ß ligand to cell surface TGF-ß receptors (TGFBR) stimulating Smad2 carboxyl-terminal phosphorylation (phospho-Smad2C) and downstream biological responses. In several cell models, G protein-coupled receptors (GPCRs) transactivate the TGF-ß receptors type-1 (TGFBR1) leading to phospho-Smad2C, however, we have recently published that in keratinocytes thrombin did not transactivate the TGFBR1. The bulk of TGFBRs reside in the cytosol and in response to protein kinase B (Akt phosphorylation) can translocate to the cell surface increasing the cell's responsiveness to TGF-ß. In this study, we investigate the role of Akt in GPCR transactivation of the TGFBR1. We demonstrate that angiotensin II and thrombin do not phosphorylate Smad2C in human vascular smooth muscle cells and in keratinocytes respectively. We used Akt agonist, SC79 to sensitise the cells to Akt and observed that Ang II and thrombin phosphorylate Smad2C via Akt/AS160-dependent pathways. We show that SC79 rapidly translocates TGFBRs to the cell surface thus increasing the cell's response to the GPCR agonist. These findings highlight novel mechanistic insight for the role of Akt in GPCR transactivation of the TGFBR1.

Type I Diabetes Mellitus Increases the Cardiovascular Complications of Influenza Virus Infection.

People with diabetes mellitus are susceptible to both cardiovascular disease and severe influenza A virus infection. We hypothesized that diabetes also increases risks of influenza-associated cardiac complications. A murine type 1 (streptozotocin-induced) diabetes model was employed to investigate influenza-induced cardiac distress. Lung histopathology and viral titres revealed no difference in respiratory severity between infected control and diabetic mice. However, compared with infected control mice, infected diabetic mice had increased serum cardiac troponin I and creatine-kinase MB, left ventricular structural changes and right ventricular functional alterations, providing the first experimental evidence of type I diabetes increasing risks of influenza-induced cardiovascular complications.

Therapeutic Inhibition of Acid-Sensing Ion Channel 1a Recovers Heart Function After Ischemia-Reperfusion Injury.

BACKGROUND: Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the buildup of acidic metabolites results in decreased intracellular and extracellular pH, which can reach as low as 6.0 to 6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly affects cardiac function. METHODS: We used genetic and pharmacologic methods to investigate the role of acid-sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole-organ level. Human induced pluripotent stem cell-derived cardiomyocytes as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and postconditioning therapeutic agents. RESULTS: Analysis of human complex trait genetics indicates that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using human induced pluripotent stem cell-derived cardiomyocytes in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacologic inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction and 2 models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as preconditioning or postconditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no effect on cardiac ion channels regulating baseline electromechanical coupling and physiologic performance. CONCLUSIONS: Our data provide compelling evidence for a novel pharmacologic strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

Stimulation of the four isoforms of receptor tyrosine kinase ErbB4, but not ErbB1, confers cardiomyocyte hypertrophy.

Epidermal growth factor (EGF) receptors (ErbB1-ErbB4) promote cardiac development and growth, although the specific EGF ligands and receptor isoforms involved in growth/repair versus pathology remain undefined. We challenged ventricular cardiomyocytes with EGF-like ligands and observed that selective activation of ErbB4 (the receptor for neuregulin 1 [NRG1]), but not ErbB1 (the receptor for EGF, EGFR), stimulated hypertrophy. This lack of direct ErbB1-mediated hypertrophy occurred despite robust activation of extracellular-regulated kinase 1/2 (ERK) and protein kinase B. Hypertrophic responses to NRG1 were unaffected by the tyrosine kinase inhibitor (AG1478) at concentrations that are selective for ErbB1 over ErbB4. NRG1-induced cardiomyocyte enlargement was suppressed by small interfering RNA (siRNA) knockdown of ErbB4 and ErbB2, whereas ERK phosphorylation was only suppressed by ErbB4 siRNA. Four ErbB4 isoforms exist (JM-a/JM-b and CYT-1/CYT-2), generated by alternative splicing, and their expression declines postnatally and following cardiac hypertrophy. Silencing of all four isoforms in cardiomyocytes, using an ErbB4 siRNA, abrogated NRG1-induced hypertrophic promoter/reporter activity, which was rescued by coexpression of knockdown-resistant versions of the ErbB4 isoforms. Thus, ErbB4 confers cardiomyocyte hypertrophy to NRG1, and all four ErbB4 isoforms possess the capacity to mediate this effect.

[Lymphoma in children and adolescents]. / Lymphomerkrankungen im Kindes- und Jugendalter.

CLINICAL/METHODOLOGICAL ISSUE: Lymphoma is the third most common neoplasm in children. Detection, accurate staging, and restaging are important for all radiologists involved in the diagnosis of children. STANDARD RADIOLOGICAL METHODS: Magnetic resonance imaging (MRI), positron emission tomography/computed tomography (PET/CT), CT, ultrasound, X­ray. METHODOLOGICAL INNOVATIONS: Whole-body imaging (MRI and PET-MRI or PET-CT) play a key role in diagnostics and for therapy selection in Hodgkin lymphoma. PERFORMANCE: In particular, hybrid imaging using 18F­FDG PET is proving to be a powerful method for staging and restaging. ACHIEVEMENTS: Standardization of imaging and inclusion in therapy studies (e.g. within the framework of the EuroNet-PHL-C2 study) improves diagnostics and simultaneously reduces therapy-related side effects. PRACTICAL RECOMMENDATIONS: In Hodgkin lymphoma, deviations from the prescribed diagnostic procedure should be avoided. In clinically very heterogeneous non-Hodgkin lymphoma (NHL), on the other hand, the diagnostic procedure should be adapted to the actual clinical condition of the child. The role of interim PET in NHL is currently still the subject of clinical discussion.

Complex interactions between the angiotensin II type 1 receptor, the epidermal growth factor receptor and TRIO-dependent signaling partners.

Transactivation of the epidermal growth factor receptor (EGFR) by the angiotensin II (AngII) type 1 (AT1) receptor is involved in AT1 receptor-dependent growth effects and cardiovascular pathologies, however the mechanisms underpinning this transactivation are yet to be fully elucidated. Recently, a potential intermediate of this process was identified following the discovery that a kinase called TRIO was involved in AngII/AT1 receptor-mediated transactivation of EGFR. To investigate the mechanisms by which TRIO acts as an intermediate in AngII/AT1 receptor-mediated EGFR transactivation we used bioluminescence resonance energy transfer (BRET) assays to investigate proximity between the AT1 receptor, EGFR, TRIO and other proteins of interest. We found that AngII/AT1 receptor activation caused a Gαq-dependent increase in proximity of TRIO with Gγ2 and the AT1-EGFR heteromer, as well as trafficking of TRIO towards the Kras plasma membrane marker and into early, late and recycling endosomes. In contrast, we found that AngII/AT1 receptor activation caused a Gαq-independent increase in proximity of TRIO with Grb2, GRK2 and PKCζ, as well as trafficking of TRIO up to the plasma membrane from the Golgi. Furthermore, we confirmed the proximity between the AT1 receptor and the EGFR using the Receptor-Heteromer Investigation Technology, which showed AngII-induced recruitment of Grb2, GRK2, PKCζ, Gγ2 and TRIO to the EGFR upon AT1 coexpression. In summary, our results provide further evidence for the existence of the AT1-EGFR heteromer and reveal potential mechanisms by which TRIO contributes to the transactivation process.

Antibody evasion by the Brazilian P.1 strain of SARS-CoV-2

Terminating the SARS-CoV-2 pandemic relies upon pan-global vaccination. Current vaccines elicit neutralizing antibody responses to the virus spike derived from early isolates. However, new strains have emerged with multiple mutations: P.1 from Brazil, B.1.351 from South Africa and B.1.1.7 from the UK (12, 10 and 9 changes in the spike respectively). All have mutations in the ACE2 binding site with P.1 and B.1.351 having a virtually identical triplet: E484K, K417N/T and N501Y, which we show confer similar increased affinity for ACE2. We show that, surprisingly, P.1 is significantly less resistant to naturally acquired or vaccine induced antibody responses than B.1.351 suggesting that changes outside the RBD impact neutralisation. Monoclonal antibody 222 neutralises all three variants despite interacting with two of the ACE2 binding site mutations, we explain this through structural analysis and use the 222 light chain to largely restore neutralization potency to a major class of public antibodies.

Modular transient nanoclustering of activated ß2-adrenergic receptors revealed by single-molecule tracking of conformation-specific nanobodies.

None of the current superresolution microscopy techniques can reliably image the changes in endogenous protein nanoclustering dynamics associated with specific conformations in live cells. Single-domain nanobodies have been invaluable tools to isolate defined conformational states of proteins, and we reasoned that expressing these nanobodies coupled to single-molecule imaging-amenable tags could allow superresolution analysis of endogenous proteins in discrete conformational states. Here, we used anti-GFP nanobodies tagged with photoconvertible mEos expressed as intrabodies, as a proof-of-concept to perform single-particle tracking on a range of GFP proteins expressed in live cells, neurons, and small organisms. We next expressed highly specialized nanobodies that target conformation-specific endogenous ß2-adrenoreceptor (ß2-AR) in neurosecretory cells, unveiling real-time mobility behaviors of activated and inactivated endogenous conformers during agonist treatment in living cells. We showed that activated ß2-AR (Nb80) is highly immobile and organized in nanoclusters. The Gαs-GPCR complex detected with Nb37 displayed higher mobility with surprisingly similar nanoclustering dynamics to that of Nb80. Activated conformers are highly sensitive to dynamin inhibition, suggesting selective targeting for endocytosis. Inactivated ß2-AR (Nb60) molecules are also largely immobile but relatively less sensitive to endocytic blockade. Expression of single-domain nanobodies therefore provides a unique opportunity to capture highly transient changes in the dynamic nanoscale organization of endogenous proteins.

A Bitter Taste in Your Heart.

The human genome contains ∼29 bitter taste receptors (T2Rs), which are responsible for detecting thousands of bitter ligands, including toxic and aversive compounds. This sentinel function varies between individuals and is underpinned by naturally occurring T2R polymorphisms, which have also been associated with disease. Recent studies have reported the expression of T2Rs and their downstream signaling components within non-gustatory tissues, including the heart. Though the precise role of T2Rs in the heart remains unclear, evidence points toward a role in cardiac contractility and overall vascular tone. In this review, we summarize the extra-oral expression of T2Rs, focusing on evidence for expression in heart; we speculate on the range of potential ligands that may activate them; we define the possible signaling pathways they activate; and we argue that their discovery in heart predicts an, as yet, unappreciated cardiac physiology.