Cannabinoid Receptor Signaling is Dependent on Sub-Cellular Location

G protein-coupled receptors (GPCRs) are membrane bound signaling molecules that regulate many aspects of human physiology. Recent advances have demonstrated that GPCR signaling can occur both at the cell surface and internal cellular membranes. Our findings suggest that cannabinoid receptor 1 (CB1) signaling is highly dependent on its subcellular location. We find that intracellular CB1 receptors predominantly couple to Gαi while plasma membrane receptors couple to Gαs. Here we show subcellular location of CB1, and its signaling, is contingent on the choice of promoters and receptor tags. Heterologous expression with a strong promoter or N-terminal tag resulted in CB1 predominantly localizing to the plasma membrane and signaling through Gαs. Conversely, CB1 driven by low expressing promoters and lacking N-terminal genetic tags largely localized to internal membranes and signals via Gαi. Lastly, we demonstrate that genetically encodable non-canonical amino acids (ncAA) offer a solution to the problem of non-native N-terminal tags disrupting CB1 signaling. We identified sites in CB1R and CB2R which can be tagged with fluorophores without disrupting CB signaling or trafficking using (trans-cyclooctene attached to lysine (TCO*A)) and copper-free click chemistry to attach fluorophores in live cells. Together, our data demonstrate the origin of location bias in cannabinoid signaling which can be experimentally controlled and tracked in living cells through promoters and novel CBR tagging strategies.

Trifunctional Sphinganine: A New Tool to Dissect Sphingolipid Function

Functions and cell biology of the sphingolipids sphingosine and sphinganine in cells are not well understood. While some signaling roles for sphingosine have been elucidated, the closely related sphinganine has been described only insofar as it does not elicit many of the same signaling responses. Here, we prepared multifunctionalized derivatives of the two lipid species that differ only in a single double bond of the carbon backbone. Using these novel probes, we were able to define their spatiotemporal distributions within cells. Furthermore, we used these tools to systematically map the protein interactomes of both lipids. The lipid-protein conjugates, prepared through photo-crosslinking in live cells and extraction via click chemistry to azide beads, revealed significant differences in the captured proteins, highlighting their distinct roles in various cellular processes. This work elucidates mechanistic differences between these critical lipids and sets the foundation for further studies of the cellular functions of sphingosine and sphinganine.

Exploring the role of professional identity in the implementation of clinical decision support systems-a narrative review

BACKGROUND

Clinical decision support systems (CDSSs) have the potential to improve quality of care, patient safety, and efficiency because of their ability to perform medical tasks in a more data-driven, evidence-based, and semi-autonomous way. However, CDSSs may also affect the professional identity of health professionals. Some professionals might experience these systems as a threat to their professional identity, as CDSSs could partially substitute clinical competencies, autonomy, or control over the care process. Other professionals may experience an empowerment of the role in the medical system. The purpose of this study is to uncover the role of professional identity in CDSS implementation and to identify core human, technological, and organizational factors that may determine the effect of CDSSs on professional identity.

METHODS

We conducted a systematic literature review and included peer-reviewed empirical studies from two electronic databases (PubMed, Web of Science) that reported on key factors to CDSS implementation and were published between 2010 and 2023. Our explorative, inductive thematic analysis assessed the antecedents of professional identity-related mechanisms from the perspective of different health care professionals (i.e., physicians, residents, nurse practitioners, pharmacists).

RESULTS

One hundred thirty-one qualitative, quantitative, or mixed-method studies from over 60 journals were included in this review. The thematic analysis found three dimensions of professional identity-related mechanisms that influence CDSS implementation success: perceived threat or enhancement of professional control and autonomy, perceived threat or enhancement of professional skills and expertise, and perceived loss or gain of control over patient relationships. At the technological level, the most common issues were the system's ability to fit into existing clinical workflows and organizational structures, and its ability to meet user needs. At the organizational level, time pressure and tension, as well as internal communication and involvement of end users were most frequently reported. At the human level, individual attitudes and emotional responses, as well as familiarity with the system, most often influenced the CDSS implementation. Our results show that professional identity-related mechanisms are driven by these factors and influence CDSS implementation success. The perception of the change of professional identity is influenced by the user's professional status and expertise and is improved over the course of implementation.

CONCLUSION

This review highlights the need for health care managers to evaluate perceived professional identity threats to health care professionals across all implementation phases when introducing a CDSS and to consider their varying manifestations among different health care professionals. Moreover, it highlights the importance of innovation and change management approaches, such as involving health professionals in the design and implementation process to mitigate threat perceptions. We provide future areas of research for the evaluation of the professional identity construct within health care.

Overcoming the not-invented-here syndrome in healthcare: The case of German ambulatory physiotherapists' adoption of digital health innovations

Healthcare is characterized by professional, organizational, and institutional boundaries. Digital health innovations can help overcome these boundaries by providing information access to all healthcare professionals. Such innovations emerge from inputs from different health professionals at different positions along the entire care process and have the potential to substantially change the way in which interprofessional tasks are performed among the involved professionals. Consequently, as less empowered professionals, physiotherapists may resist the adoption of digital health innovations in particular if the innovation is dominated by physicians, and thus the not-invented-here syndrome may become a major barrier. We aim to examine whether the origin of a digital health innovation affects German physiotherapists' adoption decision and whether the collaboration quality and physiotherapists' proactive job crafting behavior may help overcome adoption barriers. We applied a mixed-method sequential design with a qualitative study one in which we interviewed 20 physiotherapists to provide exploratory insights, and a quantitative study two in which we tested our proposed hypotheses with survey data including an experimental vignette from 165 physiotherapists. Physiotherapists adopt digital health innovations developed by their own professional group more likely than digital health innovations developed by physicians. Our results also confirm that physiotherapists' job crafting behavior and the quality of the collaboration with physicians weaken the resistance against physician-driven innovations. Our study underlines (1) the need to involve allied health professionals as physiotherapists in digital health innovation development, (2) the relevance of interprofessional collaboration in daily practice and, (3) an open mind set of allied health professionals to cope with innovation adoption barriers.

Synaptotagmin 1-triggered lipid signaling facilitates coupling of exo- and endocytosis

Exocytosis and endocytosis are essential physiological processes and are of prime importance for brain function. Neurotransmission depends on the Ca2+-triggered exocytosis of synaptic vesicles (SVs). In neurons, exocytosis is spatiotemporally coupled to the retrieval of an equal amount of membrane and SV proteins by compensatory endocytosis. How exocytosis and endocytosis are balanced to maintain presynaptic membrane homeostasis and, thereby, sustain brain function is essentially unknown. We combine mouse genetics with optical imaging to show that the SV calcium sensor Synaptotagmin 1 couples exocytic SV fusion to the endocytic retrieval of SV membranes by promoting the local activity-dependent formation of the signaling lipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) at presynaptic sites. Interference with these mechanisms impairs PI(4,5)P2-triggered SV membrane retrieval but not exocytic SV fusion. Our findings demonstrate that the coupling of SV exocytosis and endocytosis involves local Synaptotagmin 1-induced lipid signaling to maintain presynaptic membrane homeostasis in central nervous system neurons.

Challenges in the Implementation of Disruptive Innovations in Health Care Organizations

Health organizations face barriers when seeking to deploy radical innovations, such as innovative telemonitoring approaches or AI based Clinical Decision Support Systems (CDSS) into their clinical workflow. However, these barriers are of various types and rarely known to organizations and their management. This study conducted a systematic literature review of 99 selected studies to identify the implementation barriers and factors encountered in this process. Using a hierarchical framework comprising of strategies, resources and capabilities, and processes, the study examined 16 barriers generated from the analysis of the individual studies. The findings highlight implementation barriers on all three levels of the proposed framework. By addressing these barriers comprehensively, health care organizations can successfully implement radical health innovations and enhance patient care outcomes and health care delivery.

Long-acting injectable progesterone treatment prior to puberty induction in gilts

Progesterone (P4) has a pivotal role on female puberty attainment in most farm animals. However, there are no studies evaluating the effect of P4 treatment previously to boar exposure for puberty induction in gilts. Therefore, serum P4 concentration, estrus expression and reproductive performance after boar stimuli were evaluated in gilts intramuscularly treated with long-acting P4 before boar exposure. In Experiment I, prepubertal gilts received either 1 mL of saline (control) or intramuscular (I.M.) P4 treatment (150 mg, 300 mg or 600 mg; n = 6 per treatment). Serum P4 concentration for P4-treated gilts was greater than for control gilts for at least 8 d for P4300 and P4600 groups (P < 0.05), but greater until after 16 d only for those treated with 600 mg (P < 0.05). In Experiments II (prepubertal) and III (peripubertal), gilts received either saline (control) or 300 mg P4 I.M. and those showing estrus signs were artificially inseminated (AI), whereas gilts without estrus expression were culled. In prepubertal gilts (Exp. II), estrus expression rate did not differ (P < 0.05) for control (79.1%; n = 110) and P4-treated gilts (81.5%; n = 108). In peripubertal gilts (Exp. III), although estrus expression did not differ between control (77.6%; n = 106) and P4-treated (69.6%; n = 102) gilts (P > 0.05), P4-treated gilts presented longer (23.1 ± 1.4 days) interval from treatment to estrus expression than control gilts (17.1 ± 1.3 days; P < 0.05). In Experiments II and III, the proportion of culled gilts with ovarian structures consistent with normal estrous cycles, farrowing rate, and litter size did not differ between treatments (P > 0.05). In conclusion, I.M. treatment with 300 or 600 mg of long-acting P4 was efficient in maintaining high P4 concentrations in prepubertal gilts for at least 8 days. However, P4 treatment over this time interval did not benefit the reproductive performance of prepubertal and peripubertal gilts.

Chemical Tools for Lipid Cell Biology

Lipids are key components of all organisms. We are well educated in their use as fuel and their essential role to form membranes. We also know much about their biosynthesis and metabolism. We are also aware that most lipids have signaling character meaning that a change in their concentration or location constitutes a signal that helps a living cell to respond to changes in the environment or to fulfill its specific function ranging from secretion to cell division. What is much less understood is how lipids change location in cells over time and what other biomolecules they interact with at each stage of their lifetime. Due to the large number of often quite similar lipid species and the sometimes very short lifetime of signaling lipids, we need highly specific tools to manipulate and visualize lipids and lipid-protein interactions. If successfully applied, these tools provide fabulous opportunities for discovery.In this Account, I summarize the development of synthetic tools from our lab that were designed to address crucial properties that allow them to function as tools in live cell experiments. Techniques to change the concentration of lipids by adding a small molecule or by light are described and complemented by examples of biological findings made when applying the tools. This ranges from chemical dimerizer-based systems to synthetic "caged" lipid derivatives. Furthermore, I discuss the problem of locating a lipid in an intact cell. Synthetic molecular probes are described that help to unravel the lipid location and to determine their binding proteins. These location studies require in-cell lipid tagging by click chemistry, photo-cross-linking to prevent further movement and the "caging" groups to avoid premature metabolism. The combination of these many technical features in a single tool allows for the analysis of not only lipid fluxes through metabolism but also lipid transport from one membrane to another as well as revealing the lipid interactome in a cell-dependent manner. This latter point is crucial because with these multifunctional tools in combination with lipidomics we can now address differences in healthy versus diseased cells and ultimately find the changes that are essential for disease development and new therapeutics that prevent these changes.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Developments in the epidemiology and surgical management of patella fractures in Germany

BACKGROUND

Patella fractures account for approximately 1% of all skeletal injuries. Treatment options are vast and no definitive conclusion on what option is the most beneficial could be made so far. Plate osteosynthesis appears to gain in importance. We aim to give insight into the more recent trends and developments as well as establish the epidemiology of patella fractures in Germany by analysing treatment and epidemiological data from a national database.

METHODS

Anonymised data was retrieved form a national database. In the period of 2006 to 2020, all patients with patella fractures as defined in ICD-10 GM as their main diagnosis, who were treated in a German hospital were included. Patients were divided into subgroups based on gender and age. Age groups were created in 10-year intervals from 20 years old up to 80 years old with one group each encompassing all those above the age of 80 years old and below 20 years old and younger. Linear regression was performed were possible to determine statistical significance of possible trends.

RESULTS

A total of 151,435 patellar fractures were reported. 95,221 surgical interventions were performed. Women were about 1.5 times more likely to suffer from patella fracture than men. The relative number of surgical interventions rose from about 50% in 2006 to 75% in 2020. Most surgical interventions are performed in those over the age of 50. The incidence of complex fractures and plate osteosynthesis has significantly increased throughout the analysed period.

CONCLUSIONS

We found a clear trend for surgical treatment in Germany with an increase in surgical procedures. We could also show that this ratio is age-related, making it more likely for younger patients in the age groups from 0 to 70 years old to receive surgical treatment for their patella fracture.

Structurally distinct PARP7 inhibitors provide new insights into the function of PARP7 in regulating nucleic acid-sensing and IFN-β signaling

The mono-ADP-ribosyltransferase PARP7 has emerged as a key negative regulator of cytosolic NA-sensors of the innate immune system. We apply a rational design strategy for converting a pan-PARP inhibitor into a potent selective PARP7 inhibitor (KMR-206). Consistent with studies using the structurally distinct PARP7 inhibitor RBN-2397, co-treatment of mouse embryonic fibroblasts with KMR-206 and NA-sensor ligands synergistically induced the expression of the type I interferon, IFN-β. In mouse colon carcinoma (CT-26) cells, KMR-206 alone induced IFN-β. Both KMR-206 and RBN-2397 increased PARP7 protein levels in CT-26 cells, demonstrating that PARP7's catalytic activity regulates its own protein levels. Curiously, treatment with saturating doses of KMR-206 and RBN-2397 achieved different levels of PARP7 protein, which correlated with the magnitude of type I interferon gene expression. These latter results have important implications for the mechanism of action of PARP7 inhibitors and highlights the usefulness of having structurally distinct chemical probes for the same target.

Recruitment of a splicing factor to the nuclear lamina for its inactivation

Precursor messenger RNA splicing is a highly regulated process, mediated by a complex RNA-protein machinery, the spliceosome, that encompasses several hundred proteins and five small nuclear RNAs in humans. Emerging evidence suggests that the spatial organization of splicing factors and their spatio-temporal dynamics participate in the regulation of splicing. So far, methods to manipulate the spatial distribution of splicing factors in a temporally defined manner in living cells are missing. Here, we describe such an approach that takes advantage of a reversible chemical dimerizer, and outline the requirements for efficient, reversible re-localization of splicing factors to selected sub-nuclear compartments. In a proof-of-principle study, the partial re-localization of the PRPF38A protein to the nuclear lamina in HEK293T cells induced a moderate increase in intron retention. Our approach allows fast and reversible re-localization of splicing factors, has few side effects and can be applied to many splicing factors by fusion of a protein tag through genome engineering. Apart from the systematic analysis of the spatio-temporal aspects of splicing regulation, the approach has a large potential for the fast induction and reversal of splicing switches and can reveal mechanisms of splicing regulation in native nuclear environments.

Through the use of a reversible chemical dimerizer, the splicing factor PRPF38A is re-localized to the nuclear lamina, paving the way for a systematic analysis of spatio-temporal splicing regulation.

Genetic Deletion of Mmp9 Does Not Reduce Airway Inflammation and Structural Lung Damage in Mice with Cystic Fibrosis-like Lung Disease

Elevated levels of matrix metalloprotease 9 (MMP-9) and neutrophil elastase (NE) are associated with bronchiectasis and lung function decline in patients with cystic fibrosis (CF). MMP-9 is a potent extracellular matrix-degrading enzyme which is activated by NE and has been implicated in structural lung damage in CF. However, the role of MMP-9 in the in vivo pathogenesis of CF lung disease is not well understood. Therefore, we used β-epithelial Na+ channel-overexpressing transgenic (βENaC-Tg) mice as a model of CF-like lung disease and determined the effect of genetic deletion of Mmp9 (Mmp9-/-) on key aspects of the pulmonary phenotype. We found that MMP-9 levels were elevated in the lungs of βENaC-Tg mice compared with wild-type littermates. Deletion of Mmp9 had no effect on spontaneous mortality, inflammatory markers in bronchoalveolar lavage, goblet cell metaplasia, mucus hypersecretion and emphysema-like structural lung damage, while it partially reduced mucus obstruction in βENaC-Tg mice. Further, lack of Mmp9 had no effect on increased inspiratory capacity and increased lung compliance in βENaC-Tg mice, whereas both lung function parameters were improved with genetic deletion of NE. We conclude that MMP-9 does not play a major role in the in vivo pathogenesis of CF-like lung disease in mice.

Influence of non-invasive anatomical versus functional testing on physician certainty score among patients assessed within a rapid access chest pain clinic

Background

Recently, rapid access chest pain clinics (RACPC) have been shown to improve clinical and economic efficiency, with some well-established models adopting non-invasive anatomical testing (CTCA) as a universal first test. Physician certainty over the presence of significant coronary artery disease (CAD) and that symptoms are likely secondary to CAD, may influence management decisions. Data directly comparing the performance of anatomical versus functional testing, in regards to their influence on physician certainty scores, remains sparse.

Purpose

To assess the influence of non-invasive anatomical versus functional testing on physician certainty among patients attending a RACPC.

Methods

Patients attending our RACPC were invited to participate. Recruitment to the research registry was via written consent. Registry patients undergoing non-invasive anatomical (CTCA) or functional testing (myocardial perfusion imaging (MPS), exercise treadmill test (ETT) or stress echo (SE)) were included in the current analysis. Physician certainty scores (yes/likely/unlikely/no) were generated at baseline (pre-test) and post-test for all registry patients for (1) the presence of CAD and (2) angina secondary to CAD. Change in physician certainty (frequency and direction) post-test was identified and analysed to determine the influence of each testing modality.

Results

Between December 2015 and October 2021, 2541 patients attended RACPC, with 1542 patients recruited to the registry; mean age 57±12 years, 49% male, 16% typical angina, 30% atypical angina and 54% with non-anginal chest pain. Non-invasive anatomical or functional testing was performed in 1223 (79%) registry patients, with paired (pre and post-test) physician certainty scores available in 1184 (97%); 665 (56%) CTCA, 243 (21%) MPS, 210 (18%) ETT and 66 (5%) SE. Compared with functional testing, CTCA demonstrated a greater frequency of change in physician certainty scores for (1) presence of CAD (92% vs 58%, p&lt;0.001) and (2) angina secondary to CAD (74% vs 61%, p&lt;0.001), Figure 1. In addition, anatomical testing was also associated with greater differentiation in physician certainty for the presence of CAD; increased certainty, 47% vs 21% (p&lt;0.001); decreased certainty, 44% vs 35% (p&lt;0.01), with no change in certainty observed in only 8% anatomical vs 43% functional testing (p&lt;0.001). Certainty for angina due to CAD was similar; increased certainty, 10% vs 8% (p=0.45); decreased certainty, 64% vs 53% (p&lt;0.001); and no change 26% vs 38% (p&lt;0.001), Figure 2.

Conclusion

Compared to functional testing, non-invasive anatomical testing resulted in greater frequency of change and increased differentiation of physician certainty. These observations suggest that non-invasive anatomical testing within a RACPC setting may significantly enhance diagnostic confidence, which may help guide management decisions.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): State Health Research Advisory Council (SHRAC)- Western Australia

"Flash & Click": Multifunctionalized Lipid Derivatives as Tools To Study Viral Infections

In this perspective article, we describe the current status of lipid tools for studying host lipid-virus interactions at the cellular level. We discuss the potential lipidomic changes that viral infections impose on host cells and then outline the tools available and the resulting options to investigate the host cell lipid interactome. The future outcome will reveal new targets for treating virus infections.

Macrophage PD-1 associates with neutrophilia and reduced bacterial killing in early cystic fibrosis airway disease

BACKGROUND

Macrophages are the major resident immune cells in human airways coordinating responses to infection and injury. In cystic fibrosis (CF), neutrophils are recruited to the airways shortly after birth, and actively exocytose damaging enzymes prior to chronic infection, suggesting a potential defect in macrophage immunomodulatory function. Signaling through the exhaustion marker programmed death protein 1 (PD-1) controls macrophage function in cancer, sepsis, and airway infection. Therefore, we sought to identify potential associations between macrophage PD-1 and markers of airway disease in children with CF.

METHODS

Blood and bronchoalveolar lavage fluid (BALF) were collected from 45 children with CF aged 3 to 62 months and structural lung damage was quantified by computed tomography. The phenotype of airway leukocytes was assessed by flow cytometry, while the release of enzymes and immunomodulatory mediators by molecular assays.

RESULTS

Airway macrophage PD-1 expression correlated positively with structural lung damage, neutrophilic inflammation, and infection. Interestingly, even in the absence of detectable infection, macrophage PD-1 expression was elevated and correlated with neutrophilic inflammation. In an in vitro model mimicking leukocyte recruitment into CF airways, soluble mediators derived from recruited neutrophils directly induced PD-1 expression on recruited monocytes/macrophages, suggesting a causal link between neutrophilic inflammation and macrophage PD-1 expression in CF. Finally, blockade of PD-1 in a short-term culture of CF BALF leukocytes resulted in improved pathogen clearance.

CONCLUSION

Taken together, these findings suggest that in early CF lung disease, PD-1 upregulation associates with airway macrophage exhaustion, neutrophil takeover, infection, and structural damage.

A global lipid map reveals host dependency factors conserved across SARS-CoV-2 variants

A comprehensive understanding of host dependency factors for SARS-CoV-2 remains elusive. Here, we map alterations in host lipids following SARS-CoV-2 infection using nontargeted lipidomics. We find that SARS-CoV-2 rewires host lipid metabolism, significantly altering hundreds of lipid species to effectively establish infection. We correlate these changes with viral protein activity by transfecting human cells with each viral protein and performing lipidomics. We find that lipid droplet plasticity is a key feature of infection and that viral propagation can be blocked by small-molecule glycerolipid biosynthesis inhibitors. We find that this inhibition was effective against the main variants of concern (alpha, beta, gamma, and delta), indicating that glycerolipid biosynthesis is a conserved host dependency factor that supports this evolving virus.

Changes in Microbiome Dominance Are Associated With Declining Lung Function and Fluctuating Inflammation in People With Cystic Fibrosis

Airway inflammation and microbiome dysbiosis are hallmarks of cystic fibrosis (CF) lung disease. However, longitudinal studies are needed to decipher which factors contribute to the long-term evolution of these key features of CF. We therefore evaluated the relationship between fluctuation in microbiome and inflammatory parameters in a longitudinal study including a short- (1-year) and a long-term (3+ years) period. We collected 118 sputum samples from 26 CF adult patients and analyzed them by 16S rRNA gene sequencing. We measured the levels of inflammatory cytokines, neutrophil elastase, and anti-proteinases; lung function (FEV1% predicted); and BMI. The longitudinal evolution was analyzed based on (i) the rates of changes; (ii) the intra-patient stability of the variables; and (iii) the dependency of the rates of changes on the baseline values. We observed that the diversity of the microbiome was highly variable over a 1-year period, while the inflammatory markers showed a slower evolution, with significant changes only observed in the 3+ year cohort. Further, the degree of fluctuation of the biomass and the dominance of the microbiome were associated with changes in inflammatory markers, especially IL-1β and IL-8. This longitudinal study demonstrates for the first time that the long-term establishment and periodical variation of the abundance of a dominant pathogen is associated with a more severe increase in inflammation. This result indicates that a single time point or 1-year study might fail to reveal the correlation between microbial evolution and clinical degradation in cystic fibrosis.

Endosomal phosphatidylinositol 3-phosphate controls synaptic vesicle cycling and neurotransmission

Neural circuit function requires mechanisms for controlling neurotransmitter release and the activity of neuronal networks, including modulation by synaptic contacts, synaptic plasticity, and homeostatic scaling. However, how neurons intrinsically monitor and feedback control presynaptic neurotransmitter release and synaptic vesicle (SV) recycling to restrict neuronal network activity remains poorly understood at the molecular level. Here, we investigated the reciprocal interplay between neuronal endosomes, organelles of central importance for the function of synapses, and synaptic activity. We show that elevated neuronal activity represses the synthesis of endosomal lipid phosphatidylinositol 3-phosphate [PI(3)P] by the lipid kinase VPS34. Neuronal activity in turn is regulated by endosomal PI(3)P, the depletion of which reduces neurotransmission as a consequence of perturbed SV endocytosis. We find that this mechanism involves Calpain 2-mediated hyperactivation of Cdk5 downstream of receptor- and activity-dependent calcium influx. Our results unravel an unexpected function for PI(3)P-containing neuronal endosomes in the control of presynaptic vesicle cycling and neurotransmission, which may explain the involvement of the PI(3)P-producing VPS34 kinase in neurological disease and neurodegeneration.

Membrane-Permeant, Bioactivatable Coumarin Derivatives for In-Cell Labelling

The delivery of small molecule fluorophores with minimal compartmentalization is currently one of the most critical technical problems in intracellular labelling. Here we introduce sulfonated and phosphonated coumarin dyes, demonstrate rapid cell entry via a prodrug approach, and show a lack of interaction with membranes, organelles, or other compartments. The dyes show no specific localization and are evenly distributed in the cells. Our fluorogenic, clickable phosphonate derivatives successfully tagged model targets in intact cells and the increase in brightness upon click reaction was around 60‐fold.

A global lipid map reveals host dependency factors conserved across SARS-CoV-2 variants

A comprehensive understanding of host dependency factors for SARS-CoV-2 remains elusive. We mapped alterations in host lipids following SARS-CoV-2 infection using nontargeted lipidomics. We found that SARS-CoV-2 rewires host lipid metabolism, altering 409 lipid species up to 64-fold relative to controls. We correlated these changes with viral protein activity by transfecting human cells with each viral protein and performing lipidomics. We found that lipid droplet plasticity is a key feature of infection and that viral propagation can be blocked by small-molecule glycerolipid biosynthesis inhibitors. We found that this inhibition was effective against the main variants of concern (alpha, beta, gamma, and delta), indicating that glycerolipid biosynthesis is a conserved host dependency factor that supports this evolving virus.

ATP is an essential autocrine factor for pancreatic β-cell signaling and insulin secretion

ATP has been previously identified as an autocrine signaling factor that is co-released with insulin to modulate and propagate β-cell activity within islets of Langerhans. Here, we show that β-cell activity and insulin secretion essentially rely on the presence of extracellular ATP. For this, we monitored changes of the intracellular Ca2+ concentration ([Ca2+ ]i oscillations) as an immediate read-out for insulin secretion in live cell experiments. Extensive washing of cells or depletion of extracellular ATP levels by recombinant apyrase reduced [Ca2+ ]i oscillations and insulin secretion in pancreatic cell lines and primary β-cells. Following ATP depletion, [Ca2+ ]i oscillations were stimulated by the replenishment of ATP in a concentration-dependent manner. Inhibition of endogenous ecto-ATP nucleotidases increased extracellular ATP levels, along with [Ca2+ ]i oscillations and insulin secretion, indicating that there is a constant supply of ATP to the extracellular space. Our combined results demonstrate that extracellular ATP is essential for β-cell activity. The presented work suggests extracellular ATPases as potential drug targets for the modulation of insulin release. We further found that exogenous fatty acids compensated for depleted extracellular ATP levels by the recovery of [Ca2+ ]i oscillations, indicating that autocrine factors mutually compensate for the loss of others. Thereby, our results contribute to a more detailed and complete understanding of the general role of autocrine signaling factors as a fundamental regulatory mechanism of β-cell activity and insulin secretion.

Visualization of Ectopic Serine Protease Activity by Förster Resonance Energy Transfer-Based Reporters

Channel-activating proteases (CAPs) play a fundamental role in the regulation of sodium transport across epithelial tissues mainly via cleavage-mediated fine-tuning of the activity of the epithelial sodium channel (ENaC). Hyperactivity of CAPs and subsequently increased ENaC activity have been associated with various diseases, including cystic fibrosis (CF). To date, there is only a limited number of tools available to investigate CAP activity. Here, we developed ratiometric, peptide-based Förster resonance energy transfer (FRET) reporters useful to visualize and quantify the activity of ectopic serine proteases including the CAPs prostasin and matriptase in human and murine samples in a temporally and spatially resolved manner. Lipidated varieties were inserted into the outer leaflet of the plasma membrane to detect enzyme activity on the surface of individual cells, that is, close to the protease substrates. The FRET reporters (termed CAPRee) selectively detected the activity of ectopic serine proteases such as CAPs in solution and on the surface of human and murine cells. We found increased CAP activity on the surface of cells with a genetic background of CF. The new reporters will contribute to a better understanding of ectopic serine protease activity and their regulation under physiological and pathophysiological conditions.

Monitoring the cellular metabolism of a membrane-permeant photo-caged phosphatidylinositol 3,4,5-trisphosphate derivative

To deliver charged lipid derivatives to the cell interior, bioactivatable and photo-activatable protecting groups are frequently used. The intracellular metabolism of the protecting groups, as well as the lipid itself, are key factors that determine biological activity. Here we followed the cellular metabolism of cell-permeant photo-activatable ("caged") and non-caged membrane-permeant analogs of dioctanoyl phosphatidylinositol 3,4,5-trisphosphate (diC₈PIP₃) carrying biodegradable protecting groups by mass spectrometry. After successful cell entry, the photo-activatable group can be removed on demand by a light pulse. Hence, UV irradiation acts as a switch to expose the cellular metabolism to a bolus of active compound. To investigate lipid metabolites and to capture a more complete metabolome, we adapted standard extraction methods and employed multi-reaction monitoring mass spectrometry (MRM-MS). This required a previously developed permethylation method that stabilized metabolites and enhanced volatility of the phosphoinositide metabolites. The mass spectrometric analysis allowed for the monitoring of the intracellular removal of photo-activatable caging as well as biodegradable protecting groups from the membrane-permeant phosphoinositides along with cellular turnover, namely by dephosphorylation. We found that phosphate masking groups, namely acetoxymethyl esters, were rapidly removed by endogenous enzymes while butyrates masking hydroxy groups showed a longer lifetime, giving rise to trapped intermediates. We further identified key intermediate metabolites and demonstrated the beneficial effect of caging groups and their removal on the formation of favorable metabolites. Surprisingly, caging and protecting groups were found to influence each other's stability.

Reproductive factors and breast arterial calcification: a systematic review and meta-analysis

BACKGROUND

Breast arterial calcification (BAC) is a common incidental finding on screening mammography. Recent evidence suggests that BAC is associated with cardiovascular disease (CVD). We systematically reviewed the associations between BAC and reproductive factors (menopausal status, hormone replacement therapy [HRT] use, oral contraceptive [OC] use and parity).

METHODS

MEDLINE and EMBASE databases, references of relevant papers and Web of Science were searched up to February 2020 for English-language studies that evaluated these associations. Study quality were determined and a random effects model was used to assess these associations.

RESULTS

Nineteen observational studies (n = 47,249; three cohort studies, seven case-control studies, nine cross-sectional studies) were included. BAC was associated with menopause (nine studies; n = 15,870; odds ratio [OR] 2.67; 95% confidence interval [CI] 1.50-4.77) and parity (seven studies; n = 27,728; OR 2.50; 95% CI 1.68-3.71) and inversely with HRT use (10 studies; n = 33,156; OR 0.57; 95% CI 0.40-0.80). No association was found with OC use. Eleven studies were considered good in quality. Marked heterogeneity existed across all analyses.

CONCLUSIONS

BAC is associated with HRT use, menopause and parity. However, careful interpretation is required as marked heterogeneity existed across all analyses. Traditional cardiovascular risk factors may need to be taken into account in future investigations of associations between BAC and reproductive factors.

PROSPERO

CRD42020141644.

Connected Hearing Devices and Audiologists: The User-Centered Development of Digital Service Innovations

Today, medical technology manufacturers enter the service market through the development of digital service innovations. In the field of audiology, these developments increasingly shift the service capacities from audiologists to manufacturers and technical systems. However, the technology-driven developments of manufacturers lack acceptance of hearing device users and undermine the important role of audiologists within the service provision. By following a user-centered design approach in order to deal with the technological and social challenges of disruptive services, we aim to develop service innovations on an integrated service platform in the field of tele-audiology. To ensure the acceptance of technology-driven service innovations among hearing device users and audiologists, we systematically integrated these actors in a participatory innovation process. With qualitative and quantitative data we identified several requirements and preferences for different service innovations in the field of tele-audiology. According to the preferences of the different actors, we proposed a service platform approach based on a connected hearing device in three pillars of application: 1) one-to-one (1:1) service innovations based on a remote fitting concept directly improve the availability of services offered by audiologists without being physically present. Based on this, 2) one-to-many (1:N) service innovations allow the use of the connected hearing device as an indirect data source for training a machine learning algorithm that empowers users through the automation of service processes. A centralized server system collects the data and performs the training of this algorithm. The optimized algorithm is provided to the connected hearing devices to perform automatic acoustic scene classification. This in turn allows optimization of the hearing devices within each acoustic scene. After the user-centered development of the different service innovations which are designed to converge on an integrated service platform, we experimentally evaluated the functionality and applicability of the system as well as the associated role models between the technical system, the hearing device users and audiologists. As a future outlook, we show potentials to use the connected hearing device for 3) cross-industry (N:M) service innovations in contexts outside the healthcare domain and give practical implications for the market launch of successful service innovations in the field of tele-audiology.

Synthesis and Cellular Labeling of Multifunctional Phosphatidylinositol Bis- and Trisphosphate Derivatives

We synthesized the first multifunctionalized phosphoinositide polyphosphate derivatives featuring a photo-removable protecting group ("cage"), a photo-crosslinkable diazirine group, and a terminal alkyne group useful for click chemistry. We demonstrate that the lipid derivatives readily enter cells. After photo-crosslinking, cell fixation and fluorescent tagging via click chemistry, we determined the intracellular location of the lipid derivatives before and after uncaging of the lipids. We find that there is rapid trafficking of PI(3,4)P2 and PI(3,4,5)P3 derivatives to the plasma membrane, opening the intriguing possibility that there is active transport of these lipids involved. We employed the photo-crosslinking and click chemistry functions to analyze the proteome of PI(3,4,5)P3 -binding proteins. From the latter, we validated by RNAi that the putative lipid binding proteins ATP11A and MPP6 are involved in the transport of PI(3,4,5)P3 to the plasma membrane.

Bioaccumulation of therapeutic drugs by human gut bacteria

Bacteria in the gut can modulate the availability and efficacy of therapeutic drugs. However, the systematic mapping of the interactions between drugs and bacteria has only started recently¹ and the main underlying mechanism proposed is the chemical transformation of drugs by microorganisms (biotransformation). Here we investigated the depletion of 15 structurally diverse drugs by 25 representative strains of gut bacteria. This revealed 70 bacteria-drug interactions, 29 of which had not to our knowledge been reported before. Over half of the new interactions can be ascribed to bioaccumulation; that is, bacteria storing the drug intracellularly without chemically modifying it, and in most cases without the growth of the bacteria being affected. As a case in point, we studied the molecular basis of bioaccumulation of the widely used antidepressant duloxetine by using click chemistry, thermal proteome profiling and metabolomics. We find that duloxetine binds to several metabolic enzymes and changes the metabolite secretion of the respective bacteria. When tested in a defined microbial community of accumulators and non-accumulators, duloxetine markedly altered the composition of the community through metabolic cross-feeding. We further validated our findings in an animal model, showing that bioaccumulating bacteria attenuate the behavioural response of Caenorhabditis elegans to duloxetine. Together, our results show that bioaccumulation by gut bacteria may be a common mechanism that alters drug availability and bacterial metabolism, with implications for microbiota composition, pharmacokinetics, side effects and drug responses, probably in an individual manner.

Maturation of the matrix and viral membrane of HIV-1

Gag, the primary structural protein of HIV-1, is recruited to the plasma membrane for virus assembly by its matrix (MA) domain. Gag is subsequently cleaved into its component domains, causing structural maturation to repurpose the virion for cell entry. We determined the structure and arrangement of MA within immature and mature HIV-1 through cryo-electron tomography. We found that MA rearranges between two different hexameric lattices upon maturation. In mature HIV-1, a lipid extends out of the membrane to bind with a pocket in MA. Our data suggest that proteolytic maturation of HIV-1 not only assembles the viral capsid surrounding the genome but also repurposes the membrane-bound MA lattice for an entry or postentry function and results in the partial removal of up to 2500 lipids from the viral membrane.

Caged lipids for subcellular manipulation

We present recently developed strategies to manipulate lipid levels in live cells by light. We focus on photoremovable protecting groups that lead to subcellular restricted localization and activation and discuss alternative techniques. We emphasize the development of organelle targeting of caged lipids and discuss recent advances in chromatic orthogonality of caging groups for future applications.

IL-17A from innate and adaptive lymphocytes contributes to inflammation and damage in cystic fibrosis lung disease

BACKGROUND

Elevated levels of interleukin (IL)-17A were detected in the airways of patients with cystic fibrosis (CF), but its cellular sources and role in the pathogenesis of CF lung disease remain poorly understood. The aim of this study was to determine the sources of IL-17A and its role in airway inflammation and lung damage in CF.

METHODS

We performed flow cytometry to identify IL-17A-producing cells in lungs and peripheral blood from CF patients and β-epithelial Na⁺ channel transgenic (Scnn1b-Tg) mice with CF-like lung disease, and determined the effects of genetic deletion of Il17a and Rag1 on the pulmonary phenotype of Scnn1b-Tg mice.

RESULTS

T-helper 17 cells, CD3⁺CD8⁺ T-cells, γδ T-cells, invariant natural killer T-cells and innate lymphoid cells contribute to IL-17A secretion in lung tissue, lymph nodes and peripheral blood of patients with CF. Scnn1b-Tg mice displayed increased pulmonary expression of Il17a and elevated IL-17A-producing innate and adaptive lymphocytes with a major contribution by γδ T-cells. Lack of IL-17A, but not the recombination activating protein RAG1, reduced neutrophilic airway inflammation in Scnn1b-Tg mice. Genetic deletion of Il17a or Rag1 had no effect on mucus obstruction, but reduced structural lung damage and revealed an IL-17A-dependent macrophage activation in Scnn1b-Tg mice.

CONCLUSIONS

We identify innate and adaptive sources of IL-17A in CF lung disease. Our data demonstrate that IL-17A contributes to airway neutrophilia, macrophage activation and structural lung damage in CF-like lung disease in mice. These results suggest IL-17A as a novel target for anti-inflammatory therapy of CF lung disease.

Monitoring Neutrophil Elastase and Cathepsin G Activity in Human Sputum Samples

Proteases are regulators of countless physiological processes and the precise investigation of their activities remains an intriguing biomedical challenge. Among the ~600 proteases encoded by the human genome, neutrophil serine proteases (NSPs) are thoroughly investigated for their involvement in the onset and progression of inflammatory conditions including respiratory diseases. Uniquely, secreted NSPs not only diffuse within extracellular fluids but also localize to plasma membranes. During neutrophil extracellular trap (NETs) formation, NSPs become an integral part of the secreted chromatin. Such complex behavior renders the understanding of NSPs pathophysiology a challenging task. Here, detailed protocols are shown to visualize, quantify and discriminate free and membrane-bound neutrophil elastase (NE) and cathepsin G (CG) activities in sputum samples. NE and CG are NSPs whose activities have pleiotropic roles in the pathogenesis of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD): they promote tissue remodeling, regulate downstream immune responses and correlate with lung disease severity. The protocols show how to separate fluid and cellular fraction, as well as the isolation of neutrophils from human sputum for enzymatic activity quantification via small-molecule Förster resonance energy transfer-based (FRET) reporters. To gather specific insights into the relative role of NE and CG activities, a FRET readout can be measured by different technologies: i) in vitro plate reader measurements allow for high-throughput and bulk detection of protease activity; ii) confocal microscopy spatiotemporally resolves membrane-bound activity at the cell surface; iii) small-molecule FRET flow cytometry enables for the rapid evaluation of anti-inflammatory treatments via single-cell protease activity quantification and phenotyping. The implementation of such methods opens the doors to explore NSPs pathobiology and their potential as biomarkers of disease severity for CF and COPD. Given their standardization potential, their robust readout and simplicity of transfer, the described techniques are immediately shareable for implementation across research and diagnostic laboratories.

Synthesis and Evaluation of Novel Ring-Strained Noncanonical Amino Acids for Residue-Specific Bioorthogonal Reactions in Living Cells

Bioorthogonal reactions are ideally suited to selectively modify proteins in complex environments, even in vivo. Kinetics and product stability of these reactions are crucial parameters to evaluate their usefulness for specific applications. Strain promoted inverse electron demand Diels–Alder cycloadditions (SPIEDAC) between tetrazines and strained alkenes or alkynes are particularly popular, as they allow ultrafast labeling inside cells. In combination with genetic code expansion (GCE)‐a method that allows to incorporate noncanonical amino acids (ncAAs) site‐specifically into proteins in vivo. These reactions enable residue‐specific fluorophore attachment to proteins in living mammalian cells. Several SPIEDAC capable ncAAs have been presented and studied under diverse conditions, revealing different instabilities ranging from educt decomposition to product loss due to β‐elimination. To identify which compounds yield the best labeling inside living mammalian cells has frequently been difficult. In this study we present a) the synthesis of four new SPIEDAC reactive ncAAs that cannot undergo β‐elimination and b) a fluorescence flow cytometry based FRET‐assay to measure reaction kinetics inside living cells. Our results, which at first sight can be seen conflicting with some other studies, capture GCE‐specific experimental conditions, such as long‐term exposure of the ring‐strained ncAA to living cells, that are not taken into account in other assays.

amTCO, a new trans-cyclooctene derivative to study drug-target interactions in cells

Click chemistry probes have improved the study of drug interactions in live cells and relevant disease models. Proper design of the probes, including the choice of the click moiety coupled to the drug, is crucial to ensure good performance and broad application. A new trans-cyclooctene derivative, amTCO, was synthesised via a novel route using a phthalimide protecting group as a built-in photosensitiser for the cyclooctene isomerization. amTCO improved the physical chemical properties of click chemistry probes compared to standard TCO moieties. An amTCO probe targeting indoleamine 2,3-dioxygenase (IDO1) was a superior tool for visualizing IDO1 and measuring the binding affinities of small molecule inhibitors to IDO1 in cells.

Regulation of Calcium Oscillations in β-Cells by Co-activated Cannabinoid Receptors

Pharmacological treatment of pancreatic β cells targeting cannabinoid receptors 1 and 2 (CB1 and CB2) has been shown to result in significant effects on insulin release, possibly by modulating intracellular calcium levels ([Ca²⁺]_i). It is unclear how the interplay of CB1 and CB2 affects insulin secretion. Here, we demonstrate by the use of highly specific receptor antagonists and the recently developed photo-releasable endocannabinoid 2-arachidonoylglycerol that both receptors have counteracting effects on cytosolic calcium oscillations. We further show that both receptors are juxtaposed in a way that increases [Ca²⁺]_i oscillations in silent β cells but dampens them in active ones. This study highlights a functional role of CB1 and CB2 acting in concert as a compensator/attenuator switch for regulating β cell excitability.

[Artificial intelligence in cardiology : Relevance, current applications, and future developments]

Big data and applications of artificial intelligence (AI), such as machine learning or deep learning, will enrich healthcare in the future and become increasingly important. Among other things, they have the potential to avoid unnecessary examinations as well as diagnostic and therapeutic errors. They could enable improved, early and accelerated decision-making. In the article, the authors provide an overview of current AI-based applications in cardiology. The examples describe innovative solutions for risk assessment, diagnosis and therapy support up to patient self-management. Big data and AI serve as a basis for efficient, predictive, preventive and personalised medicine. However, the examples also show that research is needed to further develop the solutions for the benefit of the patient and the medical profession, to demonstrate the effectiveness and benefits in health care and to establish legal and ethical standards.

Relationship between airway dysbiosis, inflammation and lung function in adults with cystic fibrosis

Airway dysbiosis has been associated with lung disease severity in patients with cystic fibrosis (CF). However, the relationship between dysbiosis, airway inflammation and lung function impairement remains poorly understood. The aim of this study was therefore to determine how the structure of the sputum microbiota, airway inflammation markers and spirometry are related in patients with CF. Sputum samples were collected from 106 CF patients between 12 and 72 years. These were analyzed by 16S rRNA gene amplicon sequencing. Moreover, levels of pro-inflammatory cytokines (IL-1β, IL-8, IL-6 and TNF-α) and Neutrophil elastase (NE) were determined. The relationship between the microbiota, inflammation markers and forced expiratory volume in one second percent predicted (FEV₁% predicted) was evaluated by multi-parameter analysis. The microbiota α-diversity correlated inverse with inflammation markers IL-1β, IL-8, TNF-α, NE and positively with FEV₁% predicted. Patients could be divided into 7 clusters based on their microbiota structure. The most diverse cluster was defined by oropharyngeal-like flora (OF) while the others were characterized by the dominance of a single pathogen. Patients with the diverse OF microbiota cluster had lower sputum inflammatory markers and higher FEV₁% predicted compared to patients with a pathogen-dominated microbiota including Pseudomonas aeruginosa. Our results suggest that the diversity of the airway microbiota is an important biomarker of the severity of airway inflammation linking dysbiosis to lung function decline in patients with CF.

Protease FRET Reporters Targeting Neutrophil Extracellular Traps

Neutrophil extracellular traps (NETs) consist of DNA released by terminally stimulated neutrophils. They fine-tune inflammation, kill pathogens, activate macrophages, contribute to airway mucus obstruction in cystic fibrosis, and facilitate tumor metastasis after dormancy. Neutrophil proteases such as elastase (NE) and cathepsin G (CG) attach to NETs and contribute to the diverse immune outcome. However, because of the lack of suitable tools, little spatiotemporal information on protease activities on NETs is available in a pathophysiological context to date. Here, we present H-NE and H-CG, two FRET-based reporters armed with a DNA minor groove binder, which monitor DNA-bound NE and CG activity, respectively. The probes revealed that only NE maintains its catalytic ability when localized to DNA. Further, we demonstrated elevated protease activity within the extracellular DNA of sputum from cystic fibrosis patients. Finally, H-NE showed NE activity at single-cell and free DNA resolution within mouse lung slices, a difficult to achieve task with available substrate-based reporters.

Inositol-requiring enzyme-1 regulates phosphoinositide signaling lipids and macrophage growth

The ER-bound kinase/endoribonuclease (RNase), inositol-requiring enzyme-1 (IRE1), regulates the phylogenetically most conserved arm of the unfolded protein response (UPR). However, the complex biology and pathology regulated by mammalian IRE1 cannot be fully explained by IRE1's one known, specific RNA target, X box-binding protein-1 (XBP1) or the RNA substrates of IRE1-dependent RNA degradation (RIDD) activity. Investigating other specific substrates of IRE1 kinase and RNase activities may illuminate how it performs these diverse functions in mammalian cells. We report that macrophage IRE1 plays an unprecedented role in regulating phosphatidylinositide-derived signaling lipid metabolites and has profound impact on the downstream signaling mediated by the mammalian target of rapamycin (mTOR). This cross-talk between UPR and mTOR pathways occurs through the unconventional maturation of microRNA (miR) 2137 by IRE1's RNase activity. Furthermore, phosphatidylinositol (3,4,5) phosphate (PI(3,4,5)P₃ ) 5-phosphatase-2 (INPPL1) is a direct target of miR-2137, which controls PI(3,4,5)P₃ levels in macrophages. The modulation of cellular PI(3,4,5)P₃ /PIP₂ ratio and anabolic mTOR signaling by the IRE1-induced miR-2137 demonstrates how the ER can provide a critical input into cell growth decisions.

Predicting the change in the coronary calcium score in patients with diabetes

Background

The rate of increase of coronary arterial calcification score (CCS) on serial CT-scans years apart is a potent marker of cardiovascular risk but identifies risk only after irreversible damage has occurred. Molecular imaging may assist in identifying patients who are at risk of developing severe arterial calcification.

Purpose

To determine if 18F-Sodium Fluoride Positron Emission Tomography (18F-NaF PET) can predict and anatomically locate the progression of CCS over 2 years.

Methods

Subjects with diabetes mellitus underwent a baseline 18F-NaF PET scan and a CT CCS. The CT CCS was repeated after 2 years. 18F-NaF PET tracer uptake was measured as the maximum tissue to background ratio (TBRmax) and using a pre-defined cut-off for positivity, arteries were dichotomised into 18F-NaF positive and negative. We compared the change in the CCS between coronary arteries that were positive and negative for 18F-NaF uptake.

Results

In forty-one participants (mean age 65.0±7.1, male: 63.4%) a total of 163 coronary arteries were included in the analysis. Fifty-two (31.9%) coronary arteries were 18F-NaF positive at baseline and 111 (68.1%) were negative. After 2.8 [2.4–3.2] years follow-up, the TBRmax at baseline correlated with the time-standardised change in the CCS (Spearmans' rho 0.33, p&lt;0.001). The time-standardised change in the CCS was higher in coronary arteries that were 18F-NaF positive compared to negative (48.9 [13.6–119.7] v 3.3 [0–27.9], p&lt;0.001). The time-standardised change in coronary calcium score increased across patients with increasing number of 18F-NaF positive arteries at baseline (p=0.006) (Figure 1).

Conclusions

18F-NaF PET activity at baseline is associated with new co-localised calcifications 2.8 years later

Figure 1

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Royal Perth Hospital Research Foundation