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Knuuti, J.

Publications and source records attributed to Knuuti, J..

4 recordsLinked to original sources

Emotions and bodily sensations evoked by cardiac adenosine stress

Peripheral physiological processes contribute to emotions; however, the extent of the influence of internal signals on subjective emotional experiences remains a subject of debate. MethodsHere we investigated the bodily sensations induced by pharmacological stimulation with adenosine, a potent vasodilator that does not cross the blood-brain barrier, and how these sensations are translated into emotional experiences in 193 patients (94 males, 99 females; mean age 62.6 {+/-} 9.2 years) undergoing pharmacological cardiac stress testing as a part of their clinical assessment for suspected obstructive coronary artery disease. We characterized the subjective experiences induced by adenosine using topographical bodily maps and Likert-rating scales of 16 somatic sensations and 16 emotions. ResultsAdenosine induced strong and consistent bodily sensations related to dyspnea, chest pain, tachycardia, feelings of warmth, and tension in the body. The induced sensations were topographically distinct, with pain and pressure concentrated in the chest, warmth distributed across the upper body, and weakness localized to the torso. These sensations were accompanied by a significant increase in negative emotions, such as anxiety, fear, restlessness, panic, and a decrease in positive emotions of happiness, joy, and calmness. Peak heart rate response predicted the intensity of most bodily and emotional responses. Patients diagnosed with myocardial ischemia did not show heightened sensitivity to adenosine-induced bodily sensations compared to non-ischemic patients, despite exhibiting a blunted tachycardiac reflex. ConclusionThese findings show that peripheral physiological activation alone is sufficient to drive subjective emotional experiences, providing causal evidence for the embodied nature of emotions.

physiology↗

Targeting Macrophage Folate Receptor-β for Diagnosis and Treatment of Autoimmune Myocarditis

We investigated folate receptor-{beta} (FR-{beta}) expressed on activated macrophages as a therapeutic and imaging target in autoimmune myocarditis (AIM). Treatment with a folate-aminopterin conjugate (EC2319) targeting FR-{beta}-positive macrophages significantly reduced macrophage infiltration compared to saline (5.23 {+/-} 2.84% vs. 1.24 {+/-} 0.66%, P < 0.001) in rat experimental AIM. After immunization, FR-{beta} targeting positron emission tomography (PET) tracer [18F]FOL detected myocardial inflammatory lesions and revealed reduction in inflammation following EC2319 treatment relative to saline or tumor necrosis factor-alpha inhibitor Etanercept [standardized uptake value (SUV) 1.07 {+/-} 0.22 vs. 2.38 {+/-} 0.90 vs. 2.59 {+/-} 0.56, P < 0.001]. [18F]FOL PET signal correlated with myocardial CD68-positive macrophage content (r = 0.720, P < 0.001). These findings demonstrate that EC2319 attenuates myocardial inflammation in AIM and underscore the pathogenic role of FR-{beta}-positive macrophages. [18F]FOL PET provides a noninvasive means of detecting myocardial inflammatory activity and therapeutic response. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/686077v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@18e9296org.highwire.dtl.DTLVardef@139b8b3org.highwire.dtl.DTLVardef@8d1a74org.highwire.dtl.DTLVardef@1c3f06d_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

TURBO: Automated Total-body PET Image Processing and Kinetic Modeling Toolbox

Long axial field of view (LAFOV) PET imaging requires a high level of automation and standardization, as the large number of target tissues increases the manual workload significantly. We introduce an automated analysis pipeline (TurBO, Turku total-BOdy) for preprocessing and kinetic modelling of LAFOV [15O]H2O and [18F]FDG PET data, enabling efficient and reproducible analysis of tissue perfusion and metabolism at regional and voxel-levels. The approach employs automated processing including co-registration, motion correction, automated CT segmentation for region of interest (ROI) delineation, image-derived input determination, and region-specific kinetic modelling of PET data. MethodsWe validated the analysis pipeline using Biograph Vision Quadra (Siemens Healthineers) LAFOV PET/CT scans from 21 subjects scanned with [15O]H2O and 16 subjects scanned with [18F]FDG using six segmented CT-based ROIs (cortical brain gray matter, left iliopsoas muscle, right kidney cortex and medulla, pancreas, spleen and liver) representing different levels of blood flow and glucose metabolism. ResultsModel fits showed good quality with consistent parameter estimates at both regional and voxel-levels (R{superscript 2} > 0.83 for [15O]H2O, R{superscript 2} > 0.99 for [18F]FDG). Estimates from manual and automated input functions were in concordance (R{superscript 2} > 0.74 for [15O]H2O, and R{superscript 2} > 0.78 for [18F]FDG) with minimal bias (<4% for [15O]H2O and <10% for [18F]FDG). Manually and automatically (CT-based) extracted ROI level data showed strong agreement (R{superscript 2} > 0.82 for [15O]H2O and R{superscript 2} > 0.83 for [18F]FDG), while motion correction had little impact on parameter estimates (R{superscript 2} > 0.71 for [15O]H2O and R{superscript 2} > 0.78 for [18F]FDG) compared with uncorrected data. ConclusionOur automated analysis pipeline provides reliable and reproducible parameter estimates across different regions, with an approximate processing time of 1-1.5 h per subject. This pipeline completely automates LAFOV PET analysis, reducing manual effort and enabling reproducible studies of inter-organ blood flow and metabolism, including brain-body interactions.

neuroscience↗

Radiosynthesis and Preclinical Evaluation of Ga-NOTA-Folate for PET Imaging of Folate Receptor β Positive Macrophages

Folate receptor {beta} (FR-{beta}) is one of the markers expressed on macrophages and a promising target for imaging of inflammation. Here, we report the radiosynthesis and preclinical evaluation of [68Ga]Ga-NOTA-folate (68Ga-FOL). First, we determined the affinity of 68Ga-FOL using human FR-{beta} expressing cells. Then, we studied atherosclerotic mice with 68Ga-FOL and 18F-FDG PET/CT. After sacrifice, the tissues excised were measured with a {gamma}-counter for ex vivo biodistribution. Further, the tracer distribution and co-localization with macrophages in aorta cryosections were studied using autoradiography, hematoxylin-eosin staining and immunostaining with anti-Mac-3 antibody. Specificity of 68Ga-FOL was assessed in a blocking study with excess of folate glucosamine. As a last step, human radiation doses were extrapolated from rat PET data. We were able to produce 68Ga-FOL at high radioactivity concentration, with high molar activity and radiochemical purity. The cell binding studies showed high (5.1 {+/-} 1.1 nM) affinity of 68Ga-FOL to FR-{beta}. The myocardial uptake of 68Ga-FOL (SUV 0.43 {+/-} 0.06) was 20-folds lower compared to 18F-FDG (SUV 10.6 {+/-} 1.8, P = 0.001). The autoradiography and immunohistochemistry of aorta revealed that 68Ga-FOL radioactivity co-localized with Mac-3-positive macrophage-rich atherosclerotic plaques. The plaque-to-healthy vessel wall ratio of 68Ga-FOL (2.44 {+/-} 0.15) was significantly higher than that of 18F-FDG (1.93 {+/-} 0.22, P = 0.005). Blocking studies verified 68Ga-FOL specificity to FR. As estimated from rat data the human effective dose was 0.0105 mSv/MBq. The organ with highest absorbed dose was kidney (0.1420 mSv/MBq). In conclusion, 68Ga-FOL is a promising new FR-{beta}-targeted tracer for imaging macrophage-associated inflammation. TABLE OF CONTENT/ABSTRACT GRAPHIC O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

biochemistry↗