RTK-Dependent Inducible Degradation of Mutant PI3Kα Drives GDC-0077 (Inavolisib) Efficacy

PIK3CA is one of the most frequently mutated oncogenes; the p110a protein it encodes plays a central role in tumor cell proliferation. Small-molecule inhibitors targeting the PI3K p110a catalytic subunit have entered clinical trials, with early-phase GDC-0077 studies showing antitumor activity and a manageable safety profile in patients with PIK3CA-mutant breast cancer. However, preclinical studies have shown that PI3K pathway inhibition releases negative feedback and activates receptor tyrosine kinase signaling, reengaging the pathway and attenuating drug activity. Here we discover that GDC-0077 and taselisib more potently inhibit mutant PI3K pathway signaling and cell viability through unique HER2-dependent mutant p110a degradation. Both are more effective than other PI3K inhibitors at maintaining prolonged pathway suppression. This study establishes a new strategy for identifying inhibitors that specifically target mutant tumors by selective degradation of the mutant oncoprotein and provide a strong rationale for pursuing PI3Kα degraders in patients with HER2-positive breast cancer. SIGNIFICANCE: The PI3K inhibitors GDC-0077 and taselisib have a unique mechanism of action; both inhibitors lead to degradation of mutant p110a protein. The inhibitors that have the ability to trigger specific degradation of mutant p110a without significant change in wild-type p110a protein may result in improved therapeutic index in PIK3CA-mutant tumors.See related commentary by Vanhaesebroeck et al., p. 20.This article is highlighted in the In This Issue feature, p. 1.

Bone marrow endothelial dysfunction promotes myeloid cell expansion in cardiovascular disease

Abnormal hematopoiesis advances cardiovascular disease by generating excess inflammatory leukocytes that attack the arteries and the heart. The bone marrow niche regulates hematopoietic stem cell proliferation and hence the systemic leukocyte pool, but whether cardiovascular disease affects the hematopoietic organ’s microvasculature is unknown. Here we show that hypertension, atherosclerosis and myocardial infarction (MI) instigate endothelial dysfunction, leakage, vascular fibrosis and angiogenesis in the bone marrow, altogether leading to overproduction of inflammatory myeloid cells and systemic leukocytosis. Limiting angiogenesis with endothelial deletion of Vegfr2 (encoding vascular endothelial growth factor (VEGF) receptor 2) curbed emergency hematopoiesis after MI. We noted that bone marrow endothelial cells assumed inflammatory transcriptional phenotypes in all examined stages of cardiovascular disease. Endothelial deletion of Il6 or Vcan (encoding versican), genes shown to be highly expressed in mice with atherosclerosis or MI, reduced hematopoiesis and systemic myeloid cell numbers in these conditions. Our findings establish that cardiovascular disease remodels the vascular bone marrow niche, stimulating hematopoiesis and production of inflammatory leukocytes.

Continuum beliefs and mental illness stigma: A systematic review and meta-analysis of correlation and Intervention studies

Promulgating a continuum model of mental health and mental illness has been proposed as a way to reduce stigma by decreasing notions of differentness. In a systematic review and meta-analysis, we examined whether continuum beliefs are associated with lower stigma, and whether continuum interventions reduce stigma. We searched three electronic databases (PubMed, Web of Science and PsycINFO) yielding 6726 studies. After screening, we included 33 studies covering continuum beliefs, mental illness and stigma. Of these, 13 studies were included in meta-analysis. Continuum beliefs are consistently associated with lower stigma. Interventions were effective in manipulating continuum beliefs but differ in their effects on stigmatizing attitudes. We discuss whether and to what extent attitudes towards people with mental illness can be improved by providing information on a mental health-mental illness continuum. It appeared to be relevant whether interventions promoted a feeling of “us” and a process of identification with the person with mental illness. We discuss implications for the design of future interventions using the example of our current online anti-stigma intervention, which was developed on the basis of these considerations, containing gamified elements with the purpose of identification and involvement.

Validity and reliability of a clinical non-exercise method for assessment of cardiorespiratory fitness using seismocardiography

Introduction

Low cardiorespiratory fitness expressed as a low maximal oxygen consumption (V̇O2max) is associated with cardiovascular disease and all-cause mortality (1). Thus, V̇O2max is recognised as an important clinical tool in the assessment of patients (1,2). However, assessment of V̇O2max by exercise testing is both physically demanding and methodologically challenging and hence the clinical applicability is limited.

Purpose

Therefore, the aim of this study was to investigate the accuracy and precision of a clinical non-exercise method for assessment of V̇O2max.

Methods

On three separate days 20 healthy men (n=10) and women (n=10) with varying age (22–72 years) and fitness levels performed two tests for determination of V̇O2max; (a) a non-exercise test using seismocardiography (SCG V̇O2max) and (b) a graded exercise test to voluntary exhaustion on a cycle ergometer based on indirect calorimetry (IC V̇O2max). These tests were performed in order to examine the day-to-day reliability and the validity of SCG V̇O2max, respectively. Furthermore, SCG V̇O2max was assessed twice on each test day to investigate test-retest reliability. The SCG V̇O2max was performed in prone position following a short resting period by placing the SCG recording device on the xiphisternal joint with double adhesive tape. V̇O2max was assessed during a 5-minute recording of the sternal movement using SCG in combination with demographic data of the participants (3).

In addition, body composition was measured and a resting blood sample collected each test day.

Results

On average SCG V̇O2max was 3.3±2.4 ml/min/kg (mean ± 95% CI) lower than IC V̇O2max (p=0.013, SCG V̇O2max: 36.6±3.3 ml/min/kg, IC V̇O2max: 39.9±3.0 ml/min/kg). A significant positive correlation was found between SCG V̇O2max and IC V̇O2max (Pearson, r=0.72, p<0.001). Both SCG V̇O2max and IC V̇O2max was similar between test days (p=0.972) and the intra-individual coefficient of variation was 4.5±2.9% and 4.0±2.5%, respectively.

Within each test day SCG V̇O2max was highly correlated (r=0.99, p<0.0001) and no difference was observed between tests (p=0.993).

Conclusions

The accuracy of the current non-exercise assessment of cardiorespiratory fitness based on seismocardiography is not optimal as SCG V̇O2max was systematically lower than the gold standard assessment applying indirect calorimetry during a graded exercise test. Despite the abovementioned difference, SCG V̇O2max and IC V̇O2max were highly correlated. Furthermore, the precision of SCG V̇O2max is very high as both day-to-day and test-retest reliability were high.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): VentriJect ApS, Copenhagen, Denmark

[Guidelines-a European project]

Clinical guidelines represent the latest standard of medical knowledge concerning diagnostics, treatment and follow up of diseases and should support doctors and patients to choose the best treatment. Depending on the prevalence of a disease there exist less or more published data. Therefore, several levels of guidelines are possible. In case of few data the expertise of the attending physicians is of greater importance (S1, S2-guidelines). In case of a huge amount of literature, especially phase III studies or metaanalyses, a S3-guideline can be written. The article describes the process of developing a guideline in Germany under the guidance of the Association of the Scientific Medical Societies in Germany (AWMF) in comparison to the process by the European Association of Urology (EAU). The aim for the future is to join resources. Another aspect of the article is to inform about different procedures how to control the implementation of the guidelines.

Insideout project: Using big data and machine learning for prevention in psychiatry

Introduction

Social Media might represent an amazing and valuable source of information on mental health and well-being. Several researches revealed that adolescents aged 13 to 17 years old go “online” daily or stay online “almost constantly”.

Objectives

The aim of this project is to identify distress in pre-clinical stages using Social media screening methods. The system can be modelled to centre on different several health-related topics.

Methods

We created a digital system able to analyse scripts written by adolescents on Twitter. InsideOut works using machine learning techniques and computational linguistic items to catch significant and sense of written messages and it improves its performances with iterations. The system is able to automatically identify semantic information relevant to different topics: in this case “distress in teenagers”.

Results

The task of our system is considered correct when it is able to identify triples of Life Event, Sentiment and Experience of a tweet in agreement with the Gold Standard established among the annotators. The system has around 70% of accuracy in identifying triples. The analysis has been carried out both in Italian and English collecting over 4 million Italian tweets and 30 million English tweets. Comparative analysis with self-report questionnaires show that tweet analysis is able to suggest similar statistics.

Conclusions

This study analyzed contents of messages posted on Social Media Twitter meta-dating them with psychological and health-related information. Using InsideOut, we can plan clinical intervention in district and regions where high levels of uneasiness are revealed.

[Types of evidence syntheses]

This manuscript outlines various types of review articles as forms of evidence synthesis with special regard to their strengths and limitations. Review articles not only present summarised data, but also offer an evaluation of the quality of the individual studies included in it. The validity and the reliability of outcomes of reviews is strongly dependent on the quality of the data included. For this reason, a comprehensive literature selection process is paramount. Fundamental knowledge of bias and literature assessment is also necessary when reading reviews. This article presents selected tools for evidence appraisal and evaluation of bias risk.

The Dysregulated Galectin Network Activates NF-κB to Induce Disease Markers and Matrix Degeneration in 3D Pellet Cultures of Osteoarthritic Chondrocytes

This work aimed to study the dysregulated network of galectins in OA chondrocyte pellets, and to assess whether their recently discovered activity as molecular switches of functional biomarkers results in degradation of extracellular matrix in vitro. Scaffold-free 3D pellet cultures were established of human OA chondrocytes. Expression and secretion of galectin(Gal)-1, -3, and -8 were monitored relative to 2D cultures or clinical tissue sections by RT-qPCR, immunohistochemistry and ELISAs. Exposure of 2D and 3D cultures to an in vivo-like galectin mixture (Gal-1 and Gal-8: 5 µg/ml, Gal-3: 1 µg/ml) was followed by the assessment of pellet size, immunohistochemical matrix staining, and/or quantification of MMP-1, -3, and -13. Application of inhibitors of NF-κB activation probed into the potential of intervening with galectin-induced matrix degradation. Galectin profiling revealed maintained dysregulation of Gal-1, -3, and -8 in pellet cultures, resembling the OA situation in situ. The presence of the galectin mixture promoted marked reduction of pellet size and loss of collagen type II-rich extracellular matrix, accompanied by the upregulation of MMP-1, -3, and -13. Inhibition of p65-phosphorylation by caffeic acid phenethyl ester effectively alleviated the detrimental effects of galectins, resulting in downregulated MMP secretion, reduced matrix breakdown and augmented pellet size. This study suggests that the dysregulated galectin network in OA cartilage leads to extracellular matrix breakdown, and provides encouraging evidence of the feasible inhibition of galectin-triggered activities. OA chondrocyte pellets have the potential to serve as in vitro disease model for further studies on galectins in OA onset and progression.

Ontogeny of Hepatic Transporters and Drug-Metabolizing Enzymes in Humans and in Nonclinical Species

The liver represents a major eliminating and detoxifying organ, determining exposure to endogenous compounds, drugs, and other xenobiotics. Drug transporters (DTs) and drug-metabolizing enzymes (DMEs) are key determinants of disposition, efficacy, and toxicity of drugs. Changes in their mRNA and protein expression levels and associated functional activity between the perinatal period until adulthood impact drug disposition. However, high-resolution ontogeny profiles for hepatic DTs and DMEs in nonclinical species and humans are lacking. Meanwhile, increasing use of physiologically based pharmacokinetic (PBPK) models necessitates availability of underlying ontogeny profiles to reliably predict drug exposure in children. In addition, understanding of species similarities and differences in DT/DME ontogeny is crucial for selecting the most appropriate animal species when studying the impact of development on pharmacokinetics. Cross-species ontogeny mapping is also required for adequate translation of drug disposition data in developing nonclinical species to humans. This review presents a quantitative cross-species compilation of the ontogeny of DTs and DMEs relevant to hepatic drug disposition. A comprehensive literature search was conducted on PubMed Central: Tables and graphs (often after digitization) in original manuscripts were used to extract ontogeny data. Data from independent studies were standardized and normalized before being compiled in graphs and tables for further interpretation. New insights gained from these high-resolution ontogeny profiles will be indispensable to understand cross-species differences in maturation of hepatic DTs and DMEs. Integration of these ontogeny data into PBPK models will support improved predictions of pediatric hepatic drug disposition processes. SIGNIFICANCE STATEMENT: Hepatic drug transporters (DTs) and drug-metabolizing enzymes (DMEs) play pivotal roles in hepatic drug disposition. Developmental changes in expression levels and activities of these proteins drive age-dependent pharmacokinetics. This review compiles the currently available ontogeny profiles of DTs and DMEs expressed in livers of humans and nonclinical species, enabling robust interpretation of age-related changes in drug disposition and ultimately optimization of pediatric drug therapy.

[COVID-19-associated deaths]

INTRODUCTION

In December 2019, the new infectious coronavirus disease 2019 (COVID-19) first appeared in China. So far, no systematic evaluation of death certificates of COVID-19-associated deaths has been presented.

METHODS

The death certificates of all deaths in Munich during the period from 1 March to 31 July 2020 were analyzed. The previously defined inclusion criteria were the indication of corona, COVID-19 and SARS-CoV‑2 in the death certificates. The variables were entered anonymously according to a developed key. The collected data were evaluated descriptively.

RESULTS

In the period under investigation, a total of 5840 people died in the Munich City area. Of these deaths 332 (5.7%) were COVID-19-associated. In 281 deaths (84.6%) there was a definite COVID-19 and in 51 deaths (15.4%) the suspicion of this disease. The most frequent causes of death were acute respiratory distress syndrome or respiratory insufficiency (59.1%), multiple organ failure (21.4%) and sepsis (10%). An average of 1.8 pre-existing illnesses were reported in the death certificates. Most frequently mentioned were diseases of the circulatory system (54.8%), the nervous system (22.8%) and metabolic diseases (18.9%). The average age at death was 79 years and the most frequent place of death was a hospital (85%). An autopsy was attempted by the doctors who issued the death certificates for 18.1% of the collective, most frequently in the case of unexplained or unnatural causes of death and young age of the deceased. Clinical pathological autopsies were performed on 11% of the collective and judicial autopsies on 1%.

DISCUSSION

This study is the first evaluation of death certificates with respect to the novel infectious COVID-19. Number and essential characteristics of COVID-19-associated deaths in Munich during the so-called first wave could be mapped. The interest of physicians in autopsies was rather low despite the appearance of a new infectious disease.

Fish early life stage toxicity prediction from acute daphnid toxicity and quantum chemistry

One step towards reduced animal testing is the use of in silico screening methods to predict toxicity of chemicals, which requires high-quality data to develop models that are reliable and clearly interpretable. We compiled a large data set of fish early life stage no observed effect concentration endpoints (FELS NOEC) based on published data sources and internal studies, containing data for 338 molecules. Furthermore, we developed a new quantitative structure-activity-activity relationship (QSAAR) model to inform estimation of this endpoint using a combination of dimensionality reduction, regularization, and domain knowledge. In particular, we made use of a sparse partial least squares algorithm (sPLS) to select relevant variables from a huge number of molecular descriptors ranging from topological to quantum chemical properties. The final QSAAR model is of low complexity, consisting of 2 latent variables based on 8 molecular descriptors and experimental Daphnia magna acute data (EC50, 48 h). We provide a mechanistic interpretation of each model parameter. The model performs well, with a coefficient of determination r ² of 0.723 on the training set (cross-validated q ² = 0.686) and comparable predictivity on a test data set of chemically related molecules with experimental Daphnia magna data (r ² _test = 0.687, RMSE = 0.793 log units).

CIP2A regulates MYC translation (via its 5'UTR) in colorectal cancer

BACKGROUND

Deregulated expression of MYC is a driver of colorectal carcinogenesis, suggesting that decreasing MYC expression may have significant therapeutic value. CIP2A is an oncogenic factor that regulates MYC expression. CIP2A is overexpressed in colorectal cancer (CRC), and its expression levels are an independent marker for long-term outcome of CRC. Previous studies suggested that CIP2A controls MYC protein expression on a post-transcriptional level.

METHODS

To determine the mechanism by which CIP2A regulates MYC in CRC, we dissected MYC translation and stability dependent on CIP2A in CRC cell lines.

RESULTS

Knockdown of CIP2A reduced MYC protein levels without influencing MYC stability in CRC cell lines. Interfering with proteasomal degradation of MYC by usage of FBXW7-deficient cells or treatment with the proteasome inhibitor MG132 did not rescue the effect of CIP2A depletion on MYC protein levels. Whereas CIP2A knockdown had marginal influence on global protein synthesis, we could demonstrate that, by using different reporter constructs and cells expressing MYC mRNA with or without flanking UTR, CIP2A regulates MYC translation. This interaction is mainly conducted by the MYC 5'UTR.

CONCLUSIONS

Thus, instead of targeting MYC protein stability as reported for other tissue types before, CIP2A specifically regulates MYC mRNA translation in CRC but has only slight effects on global mRNA translation. In conclusion, we propose as novel mechanism that CIP2A regulates MYC on a translational level rather than affecting MYC protein stability in CRC.

Diminished Reactive Hematopoiesis and Cardiac Inflammation in a Mouse Model of Recurrent Myocardial Infarction

BACKGROUND

Recurrent myocardial infarction (MI) is common in patients with coronary artery disease and is associated with high mortality. Long-term reprogramming of myeloid progenitors occurs in response to inflammatory stimuli and alters the organism's response to secondary inflammatory challenges.

OBJECTIVES

This study examined the effect of recurrent MI on bone marrow response and cardiac inflammation.

METHODS

The investigators developed a surgical mouse model in which 2 subsequent MIs affected different left ventricular regions in the same mouse. Recurrent MI was induced by ligating the left circumflex artery followed by the left anterior descending coronary artery branch. The study characterized the resulting ischemia by whole-heart fluorescent coronary angiography after optical organ clearing and by cardiac magnetic resonance imaging.

RESULTS

A first MI-induced bone marrow "memory" via a circulating signal, reducing hematopoietic maintenance factor expression in bone marrow macrophages. This dampened the organism's reaction to subsequent events. Despite a similar extent of injury according to troponin levels, recurrent MI caused reduced emergency hematopoiesis and less leukocytosis than a first MI. Consequently, fewer leukocytes migrated to the ischemic myocardium. The hematopoietic response to lipopolysaccharide was also mitigated after a previous MI. The increase of white blood count in 28 patients was lower after recurrent MI compared with their first MI.

CONCLUSIONS

The data suggested that hematopoietic and innate immune responses are shaped by a preceding MI.

Rapid, Dose-Dependent Enhancement of Cerebral Blood Flow by transcranial AC Stimulation in Mouse

BACKGROUND

Transcranial electrical stimulation at an appropriate dose may demonstrate intracranial effects, including neuronal stimulation and cerebral blood flow responses.

OBJECTIVE

We performed in vivo experiments on mouse cortex using transcranial alternating current [AC] stimulation to assess whether cerebral blood flow can be reliably altered by extracranial stimulation.

METHODS

We performed transcranial AC electrical stimulation transversely across the closed skull in anesthetized mice, measuring transcranial cerebral blood flow with a laser Doppler probe and intracranial electrical responses as endpoint biomarkers. We calculated a stimulation dose-response function between intracranial electric field and cerebral blood flow.

RESULTS

Stimulation at electric field amplitudes of 5-20 mV/mm at 10-20 Hz rapidly increased cerebral blood flow (within 100 ms), which then quickly decreased with no residual effects. The time to peak and blood flow shape varied with stimulation intensity and duration, showing a linear correlation between stimulation dose and peak blood flow increase. Neither afterdischarges nor spreading depression occurred from this level of stimulation.

CONCLUSIONS

Extracranial stimulation amplitudes sufficient to evoke reliable blood flow changes require electric field strengths higher than what is tolerable in unanesthetized humans (<1 mV/mm), but less than electroconvulsive therapy levels (>40 mV/mm). However, anesthesia effects, spontaneous blood flow fluctuations, and sampling error may accentuate the apparent field strength needed for enhanced blood flow. The translation to a human dose-response function to augment cerebral blood flow (i.e., in stroke recovery) will require significant modification, potentially to pericranial, focused, multi-electrode application or intracranial stimulation.

Copeptin as a novel biomarker for detecting early renal dysfunction after TAVI

Background

Acute kidney injury (AKI) is one of the most prevalent (10–30%) complications after transcatheter aortic valve implantation (TAVI). Furthermore, AKI is accompanied by increased mortality, a higher incidence of dialysis and blood transfusion, and a prolonged hospital stay. Although measurement of serum creatinine is the gold standard in diagnosing AKI, changes in serum creatinine may lag behind compromised renal function. Arginine vasopressin (AVP), or antidiuretic hormone, is a nine-amino acid peptide member of the hypothalamo-neurohypophysial axis. Copeptin is the C-terminal moiety of the AVP precursor pre-proAVP that is secreted into the circulation. Recently, copeptin has been suggested to play a role in chronic kidney injury. We evaluated the value of copeptin in the prediction of AKI in patients undergoing TAVI.

Methods

All patients with severe aortic valve stenosis undergoing TAVI between May 2011 and May 2016 were included in our study. AKI was defined by the VARC-2 definition. Patients with no AKI and stage 1 AKI were compared with patients with stage 2 or 3 AKI. Routine laboratory parameters, including creatinine, were measured immediately after blood draw. Additionally, venous blood samples were collected on admission and after 24, 48, and 72 hours, processed immediately, and stored at −80°C until assay. The copeptin concentration in serum was measured by a sandwich immunoluminometric assay.

Results

Copeptin levels were available in 642 patients who were treated by TAVI in our centre from 2012–2016. AKI was detected in 113 patients (17.6%), including 61 patients with stage 1 (9.5%), 29 with stage 2 (4.5%), and 23 with stage 3 (3.6%).

There were no differences among these patients in baseline measurements, but serum copeptin increased in all patients with AKI 24 h post-procedure according to the AKI stage: no AKI 34.5 (18.0–59.3 pmol/L), AKI stage 1: 68.7 (34.6–130.1 pmol/L); AKI stage 2: 96.0 (48.1–185.1 pmol/L); AKI stage 3: 154.9 (79.5–280.7 pmol/L); ANOVA p&lt;0.001 (Fig. 1). Copeptin showed an earlier and sharper increase than creatinine (Fig. 1), with a negative predictive value of 0.97 to rule out AKI after 24 h.

Conclusion

AKI subsequent to TAVI is a common and harmful complication that occurred in almost every 5th patient (17.6%) in our cohort. AVP is secreted in response to hypotension, which commonly occurs during TAVI. In our cohort of TAVI patients, those who developed AKI after TAVI showed a rapid increase in copeptin that was earlier than that of creatinine. In light of these observations, copeptin could be a new parameter for detecting early renal dysfunction.

Figure 1

Funding Acknowledgement

Type of funding source: None

A Prospective Study on Structural and Attitudinal Barriers to Professional Help-Seeking for Currently Untreated Mental Health Problems in the Community

To date, little is known about the concurrent impact of structural and attitudinal factors on help-seeking behaviour for mental health problems. Therefore, this study investigated a longitudinal German community sample of adults with currently untreated mental health problems (N = 188, mean age = 50.34, 70.7% female) regarding perceived structural (e.g. accessibility) as well as attitudinal barriers (e.g. anticipated self-stigma) to help-seeking intentions and behaviour. Overall, perceived accessibility, spatial and temporal distance from mental health services predicted help-seeking. Among attitudinal factors, treatment efficacy beliefs were strongly connected to help-seeking. In addition, among people who knew where to find a psychologist or psychotherapist, anticipated self-stigma emerged as a significant barrier to help-seeking. Therefore, creating positive treatment expectancies and dismantling erroneous perceptions of structural aspects of mental health services hold promise to further close the gap in mental health care utilisation. However, the role of anticipated self-stigma within the help-seeking process requires further research.

Imaging Cardiovascular and Lung Macrophages With the Positron Emission Tomography Sensor 64Cu-Macrin in Mice, Rabbits, and Pigs

BACKGROUND

Macrophages, innate immune cells that reside in all organs, defend the host against infection and injury. In the heart and vasculature, inflammatory macrophages also enhance tissue damage and propel cardiovascular diseases.

METHODS

We here use in vivo positron emission tomography (PET) imaging, flow cytometry, and confocal microscopy to evaluate quantitative noninvasive assessment of cardiac, arterial, and pulmonary macrophages using the nanotracer ⁶⁴Cu-Macrin-a 20-nm spherical dextran nanoparticle assembled from nontoxic polyglucose.

RESULTS

PET imaging using ⁶⁴Cu-Macrin faithfully reported accumulation of macrophages in the heart and lung of mice with myocardial infarction, sepsis, or pneumonia. Flow cytometry and confocal microscopy detected the near-infrared fluorescent version of the nanoparticle (^VT680Macrin) primarily in tissue macrophages. In 5-day-old mice, ⁶⁴Cu-Macrin PET imaging quantified physiologically more numerous cardiac macrophages. Upon intravenous administration of ⁶⁴Cu-Macrin in rabbits and pigs, we detected heightened macrophage numbers in the infarcted myocardium, inflamed lung regions, and atherosclerotic plaques using a clinical PET/magnetic resonance imaging scanner. Toxicity studies in rats and human dosimetry estimates suggest that ⁶⁴Cu-Macrin is safe for use in humans.

CONCLUSIONS

Taken together, these results indicate ⁶⁴Cu-Macrin could serve as a facile PET nanotracer to survey spatiotemporal macrophage dynamics during various physiological and pathological conditions. ⁶⁴Cu-Macrin PET imaging could stage inflammatory cardiovascular disease activity, assist disease management, and serve as an imaging biomarker for emerging macrophage-targeted therapeutics.