Early Detection of Cardiotoxicity Using [64Cu]Cu-NODAGA-E[(cRGDyK)]2 PET Imaging in a Rat Model of Doxorubicin-Induced Heart Failure.

Doxorubicin (DOX) is a common and highly effective chemotherapeutic. However, its use is limited by cardiotoxic effects and the lack of methods to detect these at early time points. In the present study, we evaluated if [64Cu]Cu-NODAGA-E[(cRGDyK)]2 positron emission tomography-computed tomography ([64Cu]Cu-RGD PET/CT) could detect cardiotoxicity in a rat model of DOX-induced heart failure. Male Lewis rats were divided into two groups and treated with either a cumulative dose of 15 mg/kg of DOX or left untreated. Cardiac anatomy and function were assessed using magnetic resonance imaging at baseline and in week 8. [64Cu]Cu-RGD PET/CT scans were performed in week 4. DOX treatment led to a decline in pump function as well as an increase in cardiac and thymic uptake of [64Cu]Cu-RGD. In addition, DOX altered cardiac gene expression, led to infiltration of immune cells, reduced endothelial content, and increased interstitial fibrosis. Furthermore, concentrations of inflammatory plasma proteins were increased in the DOX group. In conclusion, DOX treatment resulted in the development of cardiotoxicity and heart failure, which could be detected using [64Cu]Cu-RGD PET/CT at early time points. [64Cu]Cu-RGD uptake in the myocardial septum and thymus predicted a low left ventricular ejection fraction in week 8.

In vivo molecular imaging of cardiac angiogenesis in persons with and without type 2 diabetes: A cross-sectional 68 Ga-RGD-PET study.

AIMS: To assess cardiac angiogenesis in type 2 diabetes by positron emission tomography (PET) tracer [68 Ga]Ga-NODAGA-E[(cRGDyK)]2 (68 Ga-RGD) imaging. METHODS: Cross-sectional study including 20 persons with type 2 diabetes and 10 non-diabetic controls (CONs). Primary prespecified outcome was difference in cardiac angiogenesis (cardiac 68 Ga-RGD mean target-to-background ratio [TBRmean ]) between type 2 diabetes and CONs. Secondary outcome was to investigate associations between cardiac angiogenesis and kidney function and other risk factors. RESULTS: Participants with type 2 diabetes had a mean ± SD age of 61 ± 9 years, 30% were women, median (IQR) diabetes duration of 11 (6-19) years and 3 (15%) had a history of cardiovascular disease. The CONs had comparable age and sex distribution to the participants with type 2 diabetes, and none had a history of coronary artery disease. Myocardial flow reserve was lower in type 2 diabetes (2.7 ± 0.6) compared with CONs (3.4 ± 1.2) ( p  = 0.03) and coronary artery calcium score was higher (562 [142-905] vs. 1 [0-150] p  = 0.04). Cardiac 68 Ga-RGD TBRmean was similar in participants with type 2 diabetes (0.89 ± 0.09) and CONs (0.89 ± 0.10) ( p  = 0.92). Cardiac 68 Ga-RGD TBRmean was not associated with estimated glomerular filtration rate, urine albumin creatinine ratio, cardiovascular disease, coronary artery calcium score or baroreflex sensitivity, neither in pooled analyses nor in type 2 diabetes. CONCLUSIONS: Cardiac angiogenesis, evaluated with 68 Ga-RGD PET, was similar in type 2 diabetes and CONs. Cardiac angiogenesis was not associated with kidney function or other risk markers in pooled analyses or in analyses restricted to type 2 diabetes.

[68Ga]Ga-NODAGA-E[(cRGDyK)]2 angiogenesis PET following myocardial infarction in an experimental rat model predicts cardiac functional parameters and development of heart failure.

BACKGROUND: Angiogenesis has increasingly been a target for imaging and treatment over the last decade. The integrin αvß3 is highly expressed in cells during angiogenesis and are therefore a promising target for imaging. In this study, we aimed to investigate the PET tracer [68Ga]Ga-RGD as a marker of angiogenesis following MI and its ability to predict cardiac functional parameters. METHODS: First, the real-time interaction between [68Ga]Ga-RGD and integrin αvß3 was investigated using surface plasmon resonance (SPR). Second, an animal study was performed to investigate the [68Ga]Ga-RGD uptake in the infarcted area after one and four weeks following MI in a rat model (MI = 68, sham surgery = 36). Finally, the specificity of the [68Ga]Ga-RGD tracer was evaluated ex vivo using histology, autoradiography, gamma counting and flow cytometry. RESULTS: SPR showed that [68Ga]Ga-RGD has a high affinity for integrin αvß3, forming a strong and stable binding. PET/CT showed a significantly higher uptake of [68Ga]Ga-RGD in the infarcted area compared to sham one week (p < 0.001) and four weeks (p < 0.001) after MI. The uptake of [68Ga]Ga-RGD after one week correlated to end diastolic volume (r = 0.74, p < 0.001) and ejection fraction (r = - 0.71, p < 0.001) after four weeks. CONCLUSION: This study demonstrates that [68Ga]Ga-RGD has a high affinity for integrin αvß3, which enables the evaluation of angiogenesis and remodeling. The [68Ga]Ga-RGD uptake after one week indicates that [68Ga]Ga-RGD may be used as an early predictor of cardiac functional parameters and possible development of heart failure after MI. These encouraging data supports the clinical translation and future use in MI patients.

Ceramides are decreased after liraglutide treatment in people with type 2 diabetes: a post hoc analysis of two randomized clinical trials.

BACKGROUND: Specific ceramides have been identified as risk markers for cardiovascular disease (CVD) years before onset of disease. Treatment with the glucagon-like peptide-1 receptor agonist (GLP-1RA) liraglutide has been shown to induce beneficial changes in the lipid profile and reduce the risk of CVD. Reducing lipotoxic lipids with an antidiabetic drug therapy could be a path towards precision medicine approaches for the treatment of complications to diabetes. In this post-hoc study, an investigation was carried out on the effect of liraglutide on CVD-risk associated ceramides in two randomized clinical trials including participants with type 2 diabetes (T2D). METHODS: This study analyzed plasma samples from two independent randomized placebo-controlled clinical trials. The first trial, Antiproteinuric Effects of Liraglutide Treatment (LirAlbu12) followed a crossover design where 27 participants were treated for 12 weeks with either liraglutide (1.8 mg/d) or placebo, followed by a four-week washout period, and then another 12 weeks of the other treatment. The second clinical trial, Effect of Liraglutide on Vascular Inflammation in Type-2 Diabetes (LiraFlame26), lasted for 26 weeks and followed a parallel design, where 102 participants were randomized 1:1 to either liraglutide or placebo. Heresix prespecified plasma ceramides were measured using liquid chromatography mass spectrometry and assessed their changes using linear mixed models. Possible confounders were assessed with mediation analyses. RESULTS: In the LiraFlame26 trial, 26-week treatment with liraglutide resulted in a significant reduction of two ceramides associated with CVD risk, C16 Cer and C24:1 Cer (p < 0.05) compared to placebo. None of the remaining ceramides showed statistically significant changes in response to liraglutide treatment compared to placebo. Significant changes in ceramides were not found after 12-weeks of liraglutide treatment in the LirAlbu12 trial. Mediation analyses showed that weight loss did not affect ceramide reduction. CONCLUSIONS: It was demonstrated that treatment with liraglutide resulted in a reduction in C16 Cer and C24:1 Cer after 26 weeks of treatment. These findings suggest the GLP-1RA can be used to modulate ceramides in addition to its other properties. TRIAL REGISTRATION: Clinicaltrial.gov identifier: NCT02545738 and NCT03449654.

123I-MIBG for detection of subacute doxorubicin-induced cardiotoxicity in patients with malignant lymphoma.

BACKGROUND: Doxorubicin is the mainstay of curative lymphoma treatment but is associated with a dose-dependent cardiotoxicity that is often recognized too late to avoid substantial irreversible cardiac injury. Iodine-123 metaiodobenzylguanidine (123I-MIBG) is a gamma-emitting tracer that mimics noradrenaline uptake, storage, and release mechanisms in adrenergic presynaptic neurons. 123I-MIBG scintigraphy can be used for assessment of doxorubicin-induced injury to myocardial adrenergic neurons during treatment and could be the tool for early detection of doxorubicin cardiotoxicity, which is currently lacking. METHODS AND RESULTS: A total of 37 lymphoma patients scheduled for doxorubicin treatment were included in our study. 123I-MIBG imaging was performed prior to chemotherapy and after a median of 4 cycles of doxorubicin. Early and late heart-to-mediastinum ratios (H/Mearly and H/Mlate) and washout rate (WOR) were used for evaluation of cardiotoxicity. The prognostic value of 123I-MIBG results was assessed using left ventricular ejection fraction (LVEF) as measured by cardiac magnetic resonance at 1-year follow-up. We found a post-therapy increase in WOR (including nine patients with > 10% increase), which was not statistically significant (18.6 vs 23.4%, P = 0.09). The difference appeared to be driven by an increase in H/Mearly. LVEF decreased from baseline to 1-year follow-up (64 vs 58%, P = 0.03). LVEF change was not associated with changes in WOR (P = 0.5). CONCLUSION: The present study does not provide evidence for 123I-MIBG imaging as a clinically applicable tool for early detection of doxorubicin-induced cardiotoxicity.

Rubidium-82 positron emission tomography for detection of acute doxorubicin-induced cardiac effects in lymphoma patients.

BACKGROUND: Doxorubicin is a cornerstone in lymphoma treatment, but is limited by dose-dependent cardiotoxicity. Rubidium-82 positron emission tomography (82Rb PET) assesses coronary microvascular function through absolute quantification of myocardial perfusion and myocardial perfusion reserve (MPR). Doxorubicin-induced microvascular injury represents a potential early marker of cardiotoxicity. METHODS AND RESULTS: We included 70 lymphoma patients scheduled for doxorubicin-based treatment. Cardiotoxicity was evaluated with 82Rb PET myocardial perfusion imaging during rest and adenosine stress before chemotherapy and shortly after the first doxorubicin exposure. Patients with a MPR decline > 20% were defined as having a low threshold for cardiotoxicity. In the 54 patients with complete data sets, MPR was significantly lower after the initial doxorubicin exposure (2.69 vs 2.51, P = .03). We registered a non-significant decline in stress perfusion (3.18 vs 3.02 ml/g/min, P = .08), but no change in resting myocardial perfusion. There were 13 patients with a low cardiotoxic threshold. These patients had a significantly higher age, but were otherwise similar to the remaining part of the study population. CONCLUSION: Decreases in MPR after initial doxorubicin exposure in lymphoma patients may represent an early marker of doxorubicin-induced cardiotoxicity. The prognostic value of acute doxorubicin-induced changes in MPR remains to be investigated.

Rubidium-82 PET imaging is feasible in a rat myocardial infarction model.

BACKGROUND: Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (82Rb) in a small-animal scanner using a rat myocardial infarct model. METHODS: 18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure. 82Rb-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI. RESULTS: Follow-up global 82Rb-uptake correlated significantly with infarct size (infarct group: r = -0.81, P < 0.001 and reperfusion group: r = -0.61, P = 0.04). Only 82Rb-uptake in the infarct group correlated with LVEF. At follow-up, a higher segmental 82Rb-uptake in the infarct group was associated with better wall motion (ß = 0.034, CI [0.028;0.039], P < 0.001, R2 = 0.30), and inversely associated with scar transmurality (ß = -2.4 [-2.6; -2.2], P < 0.001, R2 = 0.59). The associations were similar for the reperfusion group. CONCLUSION: 82Rb-PET is feasible in small animal scanners despite the long positron range and enables fast and time-efficient myocardial perfusion imaging in rat models.

Early risk stratification using Rubidium-82 positron emission tomography in STEMI patients.

BACKGROUND: Assessment of infarct size after myocardial infarction is predictive of subsequent morphological changes and clinical outcome. This study aimed to assess subacute post-intervention Rubidium-82 (82Rb)-PET imaging in predicting left ventricle ejection fraction, regional wall motion, and final infarct size by CMR at 3-months after STEMI. METHODS: STEMI patients undergoing percutaneous coronary intervention were included prospectively. Rest-only 82Rb-PET perfusion imaging was performed at median 36 hours [IQR: 22 to 50] after the treatment. The extent of hypoperfusion and absolute blood flow (mL·min·g) were estimated on a global and a 17-segment model with dedicated software. At 3-months follow-up patients completed the CMR functional and late gadolinium enhancement imaging. RESULTS: 42 patients were included, but only 35 had follow-up CMR and constituted the study population. Absolute blood flow was significantly lower in the infarct-related territory compared to remote myocardium, P < .005. Extent of hypoperfusion correlated with final infarct size, r = 0.58, P < .001, while blood flow correlated with ejection fraction, r = 0.41, P < .05. In linear mixed models, higher subacute absolute blood flow (ß = 4.6, confidence interval [3.5; 5.2], P < .001, R2 = 0.67) was associated with greater wall motion. Segmental extent of subacute hypoperfusion (ß = 0.43 [0.38; 0.49], P < .001, R2 = 0.58) was associated with the degree of late gadolinium enhancement at 3-months. CONCLUSIONS: Subacute rest-only 82Rb-PET is feasible following STEMI and seems predictive of myocardial function and infarct size at 3-months.

Subacute cardiac rubidium-82 positron emission tomography (82Rb-PET) to assess myocardial area at risk, final infarct size, and myocardial salvage after STEMI.

BACKGROUND: Determining infarct size and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) is important when assessing the efficacy of new reperfusion strategies. We investigated whether rest 82Rb-PET myocardial perfusion imaging can estimate area at risk, final infarct size, and myocardial salvage index when compared to cardiac SPECT and magnetic resonance (CMR). METHODS: Twelve STEMI patients were injected with 99mTc-Sestamibi intravenously immediate prior to reperfusion. SPECT, 82Rb-PET, and CMR imaging were performed post-reperfusion and at a 3-month follow-up. An automated algorithm determined area at risk, final infarct size, and hence myocardial salvage index. RESULTS: SPECT, CMR, and PET were performed 2.2 ± 0.5, 34 ± 8.5, and 32 ± 24.4 h after reperfusion, respectively. Mean (± SD) area at risk were 35.2 ± 16.6%, 34.7 ± 11.3%, and 28.1 ± 16.1% of the left ventricle (LV) in SPECT, CMR, and PET, respectively, P = 0.04 for difference. Mean final infarct size estimates were 12.3 ± 15.4%, 13.7 ± 10.4%, and 11.9 ± 14.6% of the LV in SPECT, CMR, and PET imaging, respectively, P = .72. Myocardial salvage indices were 0.64 ± 0.33 (SPECT), 0.65 ± 0.20 (CMR), and 0.63 ± 0.28 (PET), (P = .78). CONCLUSIONS: 82Rb-PET underestimates area at risk in patients with STEMI when compared to SPECT and CMR. However, our findings suggest that PET imaging seems feasible when assessing the clinical important parameters of final infarct size and myocardial salvage index, although with great variability, in a selected STEMI population with large infarcts. These findings should be confirmed in a larger population.

64Cu-DOTATATE PET/MRI for Detection of Activated Macrophages in Carotid Atherosclerotic Plaques: Studies in Patients Undergoing Endarterectomy.

OBJECTIVE: A feature of vulnerable atherosclerotic plaques of the carotid artery is high activity and abundance of lesion macrophages. There is consensus that this is of importance for plaque vulnerability, which may lead to clinical events, such as stroke and transient ischemic attack. We used positron emission tomography (PET) and the novel PET ligand [(64)Cu] [1,4,7,10-tetraazacyclododecane-N,N',N″,N‴-tetraacetic acid]-d-Phe1,Tyr3-octreotate ((64)Cu-DOTATATE) to specifically target macrophages via the somatostatin receptor subtype-2 in vivo. APPROACH AND RESULTS: Ten patients underwent simultaneous PET/MRI to measure (64)Cu-DOTATATE uptake in carotid artery plaques before carotid endarterectomy. (64)Cu-DOTATATE uptake was significantly higher in symptomatic plaque versus the contralateral carotid artery (P<0.001). Subsequently, a total of 62 plaque segments were assessed for gene expression of selected markers of plaque vulnerability using real-time quantitative polymerase chain reaction. These results were compared with in vivo (64)Cu-DOTATATE uptake calculated as the mean standardized uptake value. Univariate analysis of real-time quantitative polymerase chain reaction and PET showed that cluster of differentiation 163 (CD163) and CD68 gene expression correlated significantly but weakly with mean standardized uptake value in scans performed 85 minutes post injection (P<0.001 and P=0.015, respectively). Subsequent multivariate analysis showed that CD163 correlated independently with (64)Cu-DOTATATE uptake (P=0.031) whereas CD68 did not contribute significantly to the final model. CONCLUSIONS: The novel PET tracer (64)Cu-DOTATATE accumulates in atherosclerotic plaques of the carotid artery. CD163 gene expression correlated independently with (64)Cu-DOTATATE uptake measured by real-time quantitative polymerase chain reaction in the final multivariate model, indicating that (64)Cu-DOTATATE PET is detecting alternatively activated macrophages. This association could potentially improve noninvasive identification and characterization of vulnerable plaques.

HIV infection and arterial inflammation assessed by (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET): a prospective cross-sectional study.

BACKGROUND: HIV-infected patients are at increased risk of myocardial infarction and arterial inflammation has been suggested as a pathophysiological explanation. We compared the uptake of (18)F-fluorodeoxyglucose (FDG) by PET in four arterial regions, and factors associated with FDG uptake in well-treated HIV-infected patients without cardiovascular disease (CVD) and healthy controls. METHODS AND RESULTS: We prospectively scanned 26 HIV-infected patients on stable antiretroviral therapy and 25 healthy volunteers with FDG PET/CT, measuring standardized uptake values (SUV) in the carotid arteries, the ascending, descending, and abdominal aorta. We performed correlation analyses between FDG uptake and intima-media thickness (IMT), and soluble biomarkers of inflammation. We found no difference in arterial FDG uptake between the HIV-infected patients and healthy controls quantified either as mean SUVmax or target-to background ratio in the carotid region, the ascending aorta, the descending aorta, or the abdominal aorta. Correlations between SUV, IMT, and soluble biomarkers were scarce in both groups. CONCLUSION: In a group of optimally treated HIV-infected patients with full viral suppression, low Framingham risk score and no known CVD, we found no evidence of increased arterial inflammation as assessed by FDG PET/CT compared to healthy volunteers.

Non-invasive imaging for subclinical coronary atherosclerosis in patients with peripheral artery disease.

Patients with peripheral artery disease are at high risk of coronary artery disease. An increasing number of studies show that a large proportion of patients with peripheral artery disease have significant coronary atherosclerosis, even in the absence of symptoms. Although the reported prevalence of subclinical coronary artery disease varies widely in patients with peripheral artery disease, it could include more than half of patients. No consensus exists to date on either the rationale for screening patients with peripheral artery disease for coronary atherosclerosis or the optimal algorithm and method for screening. An increasing number of imaging modalities are emerging that allow improved in vivo non-invasive characterization of atherosclerotic plaques. These novel imaging methods may lead to early detection of high-risk vulnerable plaques, enabling clinicians to improve risk stratification of patients with peripheral artery disease, and thus paving the way for individualized therapy.

Increased Subclinical Coronary Artery Pathology in Type 2 Diabetes With Albuminuria.

Diabetes affects the kidneys, and the presence of albuminuria reflects widespread vascular damage and is a risk factor for cardiovascular disease (CVD). Still, the pathophysiological association between albuminuria and CVD remains incompletely understood. Recent advances in noninvasive imaging enable functional assessment of coronary artery pathology and present an opportunity to explore the association between albuminuria and CVD. In this cross-sectional study, we evaluated the presence of subclinical coronary artery pathology in people with type 2 diabetes, free of overt CVD. Using multimodal imaging, we assessed the coronary microcalcification activity (18F-sodium fluoride positron emission tomography/computed tomography [PET/CT], plaque inflammation [64Cu-DOTATATE PET/CT], and myocardial flow reserve [82Rb PET/CT]). The study population consisted of 90 participants, stratified by albuminuria; 60 had historic or current albuminuria (urine albumin-to-creatinine ratio [UACR] ≥30 mg/g]), and 30 had normoalbuminuria (UACR <30 mg/g). We demonstrated that any albuminuria (historic or current) was associated with a more severe phenotype, in particular, higher levels of microcalcifications and impaired myocardial microvascular function; however, coronary inflammation activity was similar in people with and without albuminuria. Our findings establish a potential underlying mechanism connecting cardiovascular and kidney diseases and could indicate the initial stages of the cardiorenal syndrome.

[68Ga]Ga-NODAGA-E[(cRGDyK)]2 and [64Cu]Cu-DOTATATE PET Predict Improvement in Ischemic Cardiomyopathy.

An increasing number of patients are living with chronic ischemic cardiomyopathy (ICM) and/or heart failure. Treatment options and prognostic tools are lacking for many of these patients. Our aim was to investigate the prognostic value of imaging angiogenesis and macrophage activation via positron emission tomography (PET) in terms of functional improvement after cell therapy. Myocardial infarction was induced in rats. Animals were scanned with [18F]FDG PET and echocardiography after four weeks and randomized to allogeneic adipose tissue-derived stromal cells (ASCs, n = 18) or saline (n = 9). Angiogenesis and macrophage activation were assessed before and after treatment by [68Ga]Ga-RGD and [64Cu]Cu-DOTATATE. There was no overall effect of the treatment. Rats that improved left ventricular ejection fraction (LVEF) had higher uptake of both [68Ga]Ga-RGD and [64Cu]Cu-DOTATATE at follow-up (p = 0.006 and p = 0.008, respectively). The uptake of the two tracers correlated with each other (r = 0.683, p = 0.003 pre-treatment and r = 0.666, p = 0.004 post-treatment). SUVmax at follow-up could predict improvement in LVEF (p = 0.016 for [68Ga]Ga-RGD and p = 0.045 for [64Cu]Cu-DOTATATE). High uptake of [68Ga]Ga-RGD and [64Cu]Cu-DOTATATE PET after injection of ASCs or saline preceded improvement in LVEF. The use of these tracers could improve the monitoring of heart failure patients in treatment.

Feasibility of positron range correction in 82-Rubidium cardiac PET/CT.

BACKGROUND: Myocardial perfusion imaging (MPI) using positron emission tomography (PET) tracers is an essential tool in investigating diseases and treatment responses in cardiology. 82Rubidium (82Rb)-PET imaging is advantageous for MPI due to its short half-life, but cannot be used for small animal research due to the long positron range. We aimed to correct for this, enabling MPI with 82Rb-PET in rats. METHODS: The effect of positron range correction (PRC) on 82Rb-PET was examined using two phantoms and in vivo on rats. A NEMA NU-4-inspired phantom was used for image quality evaluation (%standard deviation (%SD), spillover ratio (SOR) and recovery coefficient (RC)). A cardiac phantom was used for assessing spatial resolution. Two rats underwent rest 82Rb-PET to optimize number of iterations, type of PRC and respiratory gating. RESULTS: NEMA NU-4 metrics (no PRC vs PRC): %SD 0.087 versus 0.103; SOR (air) 0.022 versus 0.002, SOR (water) 0.059 versus 0.019; RC (3 mm) 0.219 versus 0.584, RC (4 mm) 0.300 versus 0.874, RC (5 mm) 0.357 versus 1.197. Cardiac phantom full width at half maximum (FWHM) and full width at tenth maximum (FWTM) (no PRC vs. PRC): FWTM 6.73 mm versus 3.26 mm (true: 3 mm), FWTM 9.27 mm versus 7.01 mm. The in vivo scans with respiratory gating had a homogeneous myocardium clearly distinguishable from the blood pool. CONCLUSION: PRC improved the spatial resolution for the phantoms and in vivo at the expense of slightly more noise. Combined with respiratory gating, the spatial resolution achieved using PRC should allow for quantitative MPI in small animals.

Liraglutide Lowers Palmitoleate Levels in Type 2 Diabetes. A Post Hoc Analysis of the LIRAFLAME Randomized Placebo-Controlled Trial.

Background: Liraglutide is a glucose-lowering medication used to treat type 2 diabetes and obesity. It is a GLP-1 receptor agonist with downstream metabolic changes beyond the incretin system, such as reducing the risk of cardiovascular complications. The understanding of these changes is critical for improving treatment outcomes. Herein, we present a post hoc experimental analysis using metabolomic phenotyping to discover molecular mecphanisms in response to liraglutide. Method: Plasma samples were obtained from The LiraFlame Study (ClinicalTrials.gov identifier: NCT03449654), a randomized double-blinded placebo-controlled clinical trial, including 102 participants with type 2 diabetes randomized to either liraglutide or placebo treatment for 26 weeks. Mass spectrometry-based metabolomics analyses were carried out on samples from baseline and the end of the trial. Metabolites (n=114) were categorized into pathways and linear mixed models were constructed to evaluate the association between changes in metabolites and liraglutide treatment. Results: We found the free fatty acid palmitoleate was significantly reduced in the liraglutide group compared to placebo (adjusted for multiple testing p-value = 0.04). The activity of stearoyl-CoA desaturase-1 (SCD1), the rate limiting enzyme for converting palmitate into palmitoleate, was found significantly downregulated by liraglutide treatment compared to placebo (p-value = 0.01). These metabolic changes have demonstrated to be linked to insulin sensitivity and cardiovascular health.

Flow Cytometric Evaluation of the Ongoing Angiogenic Response in Rat Cardiac Tissue Following Myocardial Infarction.

Angiogenesis is involved in regeneration of cardiac tissue following acute myocardial infarction (MI), a disease often investigated in rat models. Therefore, the ability to thoroughly evaluate the angiogenic response following experimentally induced MI in rats, and distinguish it from inflammation, is desired. This would enable evaluation of the angiogenic potential of new therapeutics and improve knowledge on MI pathophysiology. Due to the complex response to MI involving multiple cell types and the limited selection of rat-specific antibodies, careful optimization is crucial to capture this complexity. Here, we present an 8-color flow cytometry-based multicolor panel that will enable quantification of the ongoing angiogenic response as well as characterize the cells involved. A detailed description of tissue preparation, immunostaining, and gating strategy is provided. © 2021 Wiley Periodicals LLC. Basic Protocol: Cardiac tissue preparation and staining to investigate the ongoing angiogenic response in rat cardiac tissue following myocardial infarction Support Protocol: Titration of all antibodies in the presented panel.

Plasma YKL-40 and recovery of left ventricular function after acute myocardial infarction.

BACKGROUND: Plasma YKL-40 is increased early in patients with ST-elevation myocardial infarction (STEMI). It is not known whether plasma YKL-40 is related to infarct size and recovery of ventricular function after primary percutaneous coronary intervention (PCI) of STEMI and whether granulocyte colony-stimulating factor (G-CSF) therapy influence plasma YKL-40 concentration. MATERIALS AND METHODS: A total of 72 patients (age: 56 +/- 9 years (mean +/- SD), 56 men and 16 women) with STEMI treated with PCI were included in a double-blind, randomized, placebo-controlled trial with subcutaneous G-CSF or placebo injections from day 1 to 7 after the STEMI. Plasma YKL-40, high-sensitivity C-reactive protein (hs-CRP) and CK-MB concentrations were measured at baseline and during the first month. Infarct size and left ventricular ejection fraction (LVEF) were measured by magnetic resonance imaging at baseline and after 6 months. RESULTS: Baseline plasma YKL-40 was increased (median 92 microg/L) compared to healthy subjects (median 34 microg/L, p <0.001). In the placebo group hs-CRP and YKL-40 correlated at baseline (p = 0.04) and day 3 (p = 0.01), but not at day 7 and 30. Moreover, YKL-40 correlated negatively to LVEF recovery (p = 0.04) but not infarct size. G-CSF injections increased YKL-40 compared to placebo (p <0.001), but were not associated with infarct size or LVEF recovery. CONCLUSION: Plasma YKL-40 was significantly increased in STEMI patients at admission and G-CSF treatment caused a further increase in YKL-40. Plasma YKL-40 may be an indirect marker of LVEF recovery, independent of hs-CRP, and higher plasma YKL-40 indicates a lower recovery.

The influence of genotype on vascular endothelial growth factor and regulation of myocardial collateral blood flow in patients with acute and chronic coronary heart disease.

OBJECTIVE: To test the hypothesis that mutations in the vascular endothelial growth factor (VEGF) gene are associated with plasma concentration of VEGF and subsequently the ability to influence coronary collateral arteries in patients with coronary heart disease (CHD). METHODS: Blood samples from patients with chronic ischemic heart disease (n=53) and acute coronary syndrome (n=61) were analysed. Coronary collaterals were scored from diagnostic biplane coronary angiograms. RESULTS: The plasma concentration of VEGF was increased in patients with acute compared to chronic CHD (p=0.01). The genotype frequencies differed significantly from Hardy-Weinberg equilibrium in three of 15 examined loci. Four new mutations in addition to the already described were identified. The VEGF haplotype did not seem to predict plasma VEGF concentration (p=0.5). There was an association between the genotype in locus VEGF-1154 and coronary collateral size (p=0.03) and a significant association between the VEGF plasma concentration and the collateral size (p=0.03). CONCLUSION: VEGF plasma concentration seems related to coronary collateral function in patients with CHD. The results did not support the hypothesis that polymorphisms in the untranslated region of the VEGF gene were associated with the concentration of circulating VEGF. Increased understanding of VEGF in the regulation of myocardial collateral flow may lead to new therapies in CHD.