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Purpose: Long non-coding RNAs (lncRNAs) constitute a novel class of non-coding RNAs. LncRNAs regulate gene expression, thus having the possibility to modulate disease progression. In this study, we investigated the expression of lncRNAs in the heart after myocardial infarction (MI).Methods: Adult male C57/BL6 mice were subjected to coronary ligation or sham operation. Cardiac gene expression was investigated using whole-genome microarrays with an in-house analytical pipeline dedicated to lncRNAs. Cardiac function was evaluated by 18F-fluorodesoxyglucose positron emission tomography (18F-FDG PET).Results: In a derivation group of 4 MI and 4 sham-operated mice sacrificed 24 hours after surgery, microarray analysis showed that MI significantly affected the cardiac transcriptome. 20 lncRNAs were up-regulated in the MI group, and 10 lncRNAs were down-regulated in the MI group (fold-change >2, false discovery rate <5%). Among these, 2 lncRNAs (called lncRNA1 and lncRNA2) showed robust up-regulation in the MI group: lncRNA1 (5-fold) and lncRNA2 (13-fold). This was confirmed using quantitative PCR, in which lncRNA1 and lncRNA2 displayed 6- and 12-fold up-regulation in the MI group, respectively (both P<0.05). Up-regulation of these 2 lncRNAs after MI was further confirmed in an independent validation group of 8 MI and 8 sham-operated mice (9-fold and 16-fold for lncRNA1 and lncRNA2, P<0.001). In a time-course analysis involving 21 additional MI mice, the expression of both lncRNAs peaked 24 hours after induction of MI and returned to basal levels after 2 days. In situ hybridization revealed an increase of lncRNA1 expression in the left ventricle of MI mice. Both lncRNAs were robustly correlated with left ventricular ejection fraction determined 24 hours after MI by 18F-FDG PET (r>0.8). Bioinformatic analyses of microarray data revealed that lncRNA1 expression displayed strong association with genes coding for proteins involved in angiogenesis, fibrosis, hypertrophy, inflammation, and extracellular matrix remodeling, all pathways involved in the development of left ventricular remodeling and heart failure post MI. Among the genes most highly correlated with lncRNA1 (r>0.80), MMP9, TNFalpha, CXCR4, and BNP were all up-regulated in the heart of MI mice.Conclusion: We show for the first time that expression of lncRNAs is regulated in the infarcted heart. This study provides the basis for future investigations of the role of lncRNAs in the diseased heart. [ABSTRACT FROM PUBLISHER]

The ketogenic diet (KD) has been shown to be effective in refractory epilepsy after long-term administration. However, its interference with short-term brain metabolism and its involvement in the early process leading to epilepsy remain poorly understood. This study aimed to assess the effect of a short-term ketogenic diet on cerebral glucose metabolic changes, before and after status epilepticus (SE) in rats, by using [ 18 F]-FDG PET. Thirty-nine rats were subjected to a one-week KD (KD-rats, n = 24) or to a standard diet (SD-rats, n = 15) before the induction of a status epilepticus (SE) by lithium-pilocarpine administrations. Brain [ 18 F]-FDG PET scans were performed before and 4 h after this induction. Morphological MRIs were acquired and used to spatially normalize the PET images which were then analyzed voxel-wisely using a statistical parametric-based method. Twenty-six rats were analyzed (KD-rats, n = 15; SD-rats, n = 11). The 7 days of the KD were associated with significant increases in the plasma β-hydroxybutyrate level, but with an unchanged glycemia. The PET images, recorded after the KD and before SE induction, showed an increased metabolism within sites involved in the appetitive behaviors: hypothalamic areas and periaqueductal gray, whereas no area of decreased metabolism was observed. At the 4th hour following the SE induction, large metabolism increases were observed in the KD- and SD-rats in areas known to be involved in the epileptogenesis process late-i.e., the hippocampus, parahippocampic, thalamic and hypothalamic areas, the periaqueductal gray, and the limbic structures (and in the motor cortex for the KD-rats only). However, no statistically significant difference was observed when comparing SD and KD groups at the 4th hour following the SE induction. A one-week ketogenic diet does not prevent the status epilepticus (SE) and associated metabolic brain abnormalities in the lithium-pilocarpine rat model. Further explorations are needed to determine whether a significant prevention could be achieved by more prolonged ketogenic diets and by testing this diet in less severe experimental models, and moreover, to analyze the diet effects on the later and chronic stages leading to epileptogenesis., (© 2024. The Author(s).)

Background: This translational study explores multi-tracer PET imaging for the non-invasive detection of the IDH1 mutation which is a positive prognostic factor in glioma., Methods: U87 human high-grade glioma (HGG) isogenic cell lines with or without the IDH1 mutation (CRISP/Cas9 method) were stereotactically grafted into rat brains, and examined, in vitro, in vivo and ex vivo. PET imaging sessions, with radiotracers specific for glycolytic metabolism ([ 18 F]FDG), amino acid metabolism ([ 18 F]FDopa), and inflammation ([ 18 F]DPA-714), were performed sequentially during 3-4 days. The in vitro radiotracer uptake was expressed as percent per million cells. For each radiotracer examined in vivo, static analyses included the maximal and mean tumor-to-background ratio (TBR max and TBR mean ) and metabolic tumor volume (MTV). Dynamic analyses included the distribution volume ratio (DVR) and the relative residence time (RRT) extracted from a reference Logan model. Ex vivo analyses consisted of immunological analyses., Results: In vitro, IDH1+ cells (i.e. cells expressing the IDH1 mutation) showed lower levels of [ 18 F]DPA-714 uptake compared to IDH1- cells (p < 0.01). These results were confirmed in vivo with lower [ 18 F]DPA-714 uptake in IDH+ tumors (3.90 versus 5.52 for TBR max , p = 0.03). Different values of [ 18 F]DPA-714 and [ 18 F] FDopa RRT (respectively 11.07 versus 22.33 and 2.69 versus - 1.81 for IDH+ and IDH- tumors, p < 0.02) were also observed between the two types of tumors. RRT [ 18 F]DPA-714 provided the best diagnostic performance to discriminate between the two cell lines (AUC of 100%, p < 0.01). Immuno-histological analyses revealed lower expression of Iba-1 and TSPO antibodies in IDH1+ tumors., Conclusions: [18F]DPA-714 and [18F] FDopa both correlate with the presence of the IDH1 mutation in HGG. These radiotracers are therefore good candidates for translational studies investigating their clinical applications in patients., (© 2022. The Author(s).)

Due to their very poor prognosis and a fatal outcome, secondary brain tumors are one of the biggest challenges in oncology today. From the point of view of the early diagnosis of these brain micro- and macro-tumors, the sensitivity and specificity of the diagnostic tools constitute an obstacle. Molecular imaging, such as Positron Emission Tomography (PET), is a promising technique but remains limited in the search for cerebral localizations, given the commercially available radiotracers. Indeed, the [ 18 F]FDG PET remains constrained by the physiological fixation of the cerebral cortex, which hinders the visualization of cerebral metastases. Tumor angiogenesis is recognized as a crucial phenomenon in the progression of malignant tumors and is correlated with overexpression of the neuropilin-1 (NRP-1) receptor. Here, we describe the synthesis and the photophysical properties of the new gallium-68 radiolabeled peptide to target NRP-1. The KDKPPR peptide was coupled with gallium-68 anchored into a bifunctional NODAGA chelating agent, as well as Cy5 for fluorescence detection. The Cy5 absorbance spectra did not change, whereas the molar extinction coefficient (ε) decreased drastically. An enhancement of the fluorescence quantum yield (φ F ) could be observed due to the better water solubility of Cy5. [ 68 Ga]Ga-NODAGA-K(Cy5)DKPPR was radiosynthesized efficiently, presented hydrophilic properties (log D = -1.86), and had high in vitro stability (>120 min). The molecular affinity and the cytotoxicity of this new chelated radiotracer were evaluated in vitro on endothelial cells (HUVEC) and MDA-MB-231 cancer cells (hormone-independent and triple-negative line) and in vivo on a brain model of metastasis in a nude rat using the MDA-MB-231 cell line. No in vitro toxicity has been observed. The in vivo preliminary experiments showed promising results, with a high contrast between the healthy brain and metastatic foci for [ 68 Ga]Ga-NODAGA-K(Cy5)DKPPR.

The design of bifunctional chelating agents (BFCA) allowing straightforward radiometal labelling of biomolecules is a current challenge. We report herein the development of a bifunctional chelating agent based on a DOTA chelator linked to a C -glycosyl compound, taking advantage of the robustness and hydrophilicity of this type of carbohydrate derivative. This new BFCA was coupled with success by CuAAC with c(RGDfK) for α v β 3 integrin targeting. As attested by in vitro evaluation, the conjugate DOTA- C -glyco-c(RGDfC) demonstrated high affinity for α v β 3 integrins (IC 50 of 42 nM). [ 68 Ga]Ga-DOTA- C -glyco-c(RGDfK) was radiosynthesized straightforwardly and showed high hydrophilic property (log  D 7.4 = -3.71) and in vitro stability (>120 min). Preliminary in vivo PET study of U87MG engrafted mice gave evidence of an interesting tumor-to-non-target area ratio. All these data indicate that [ 68 Ga]Ga-DOTA- C -glyco-c(RGDfK) allows monitoring of α v β 3 expression and could thus be used for cancer diagnosis. The DOTA- C -glycoside BFCA reported here could also be used with various ligands and chelating other (radio)metals opening a broad scope of applications in imaging modalities and therapy., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Background: Tracers triggering αvβ3 integrins, such as certain RGD-containing peptides, were found promising in previous pilot studies characterizing high-grade gliomas. However, only limited comparisons have been performed with current PET tracers. This study aimed at comparing the biodistribution of 18 F-fluorodeoxyglucose ( 18 F-FDG) with that of 68 Ga-NODAGA-RGD, an easily synthesized monomeric RGD compound with rapid kinetics, in two different rodent models of engrafted human glioblastoma., Methods: Nude rodents bearing human U87-MG glioblastoma tumor xenografts in the flank (34 tumors in mice) or in the brain (5 tumors in rats) were analyzed. Kinetics of 68 Ga-NODAGA-RGD and of 18 F-FDG were compared with PET imaging in the same animals, along with additional autohistoradiographic analyses and blocking tests for 68 Ga-NODAGA-RGD., Results: Both tracers showed a primary renal route of clearance, although with faster clearance for 68 Ga-NODAGA-RGD resulting in higher activities in the kidneys and bladder. The tumor activity from 68 Ga-NODAGA-RGD, likely corresponding to true integrin binding (i.e., suppressed by co-injection of a saturating excess of unlabeled RGD), was found relatively high, but only at the 2 nd hour following injection, corresponding on average to 53% of total tumor activity. Tumor uptake of 68 Ga-NODAGA-RGD decreased progressively with time, contrary to that of 18 F-FDG, although 68 Ga-NODAGA-RGD exhibited 3.4 and 3.7-fold higher tumor-to-normal brain ratios on average compared to 18 F-FDG in mice and rat models, respectively. Finally, ex-vivo analyses revealed that the tumor areas with high 68 Ga-NODAGA-RGD uptake also exhibited the highest rates of cell proliferation and αv integrin expression, irrespective of cell density., Conclusions: 68 Ga-NODAGA-RGD has a high potential for PET imaging of glioblastomas, especially for areas with high integrin expression and cell proliferation, although PET recording needs to be delayed until the 2 nd hour following injection in order to provide sufficiently high integrin specificity.

Rationale: Optimal outcome after myocardial infarction (MI) depends on a coordinated healing response in which both debris removal and repair of the myocardial extracellular matrix play a major role. However, adverse remodeling and excessive inflammation can promote heart failure, positioning leucocytes as central protagonists and potential therapeutic targets in tissue repair and wound healing after MI., Objective: In this study, we examined the role of triggering receptor expressed on myeloid cells-1(TREM-1) in orchestrating the inflammatory response that follows MI. TREM-1, expressed by neutrophils and mature monocytes, is an amplifier of the innate immune response., Methods and Results: After infarction, TREM-1 expression is upregulated in ischemic myocardium in mice and humans. Trem-1 genetic invalidation or pharmacological inhibition using a synthetic peptide (LR12) dampens myocardial inflammation, limits neutrophils recruitment and monocyte chemoattractant protein-1 production, thus reducing classical monocytes mobilization to the heart. It also improves left ventricular function and survival in mice (n=20-22 per group). During both permanent and transient myocardial ischemia, Trem-1 blockade also ameliorates cardiac function and limits ventricular remodeling as assessed by fluorodeoxyglucose-positron emission tomographic imaging and conductance catheter studies (n=9-18 per group). The soluble form of TREM-1 (sTREM-1), a marker of TREM-1 activation, is detectable in the plasma of patients having an acute MI (n=1015), and its concentration is an independent predictor of death., Conclusions: These data suggest that TREM-1 could constitute a new therapeutic target during acute MI., (© 2015 American Heart Association, Inc.)

Background: Long non-coding RNAs (lncRNAs) constitute a novel class of non-coding RNAs. LncRNAs regulate gene expression, thus having the possibility to modulate disease progression. In this study, we investigated the changes of lncRNAs expression in the heart after myocardial infarction (MI)., Results: Adult male C57/BL6 mice were subjected to coronary ligation or sham operation. In a derivation group of 4 MI and 4 sham-operated mice sacrificed 24 hours after surgery, microarray analysis showed that MI was associated with up-regulation of 20 lncRNAs and down-regulation of 10 lncRNAs (fold-change >2). Among these, 2 lncRNAs, called myocardial infarction-associated transcript 1 (MIRT1) and 2 (MIRT2), showed robust up-regulation in the MI group: 5-fold and 13-fold, respectively. Up-regulation of these 2 lncRNAs after MI was confirmed by quantitative PCR in an independent validation group of 8 MI and 8 sham-operated mice (9-fold and 16-fold for MIRT1 and MIRT2, P < 0.001). In a time-course analysis involving 21 additional MI mice, the expression of both lncRNAs peaked 24 hours after MI and returned to baseline after 2 days. In situ hybridization revealed an up-regulation of MIRT1 expression in the left ventricle of MI mice. Expression of MIRT1 and MIRT2 correlated with the expression of multiple genes known to be involved in left ventricular remodeling. Mice with high level of expression of MIRT1 and MIRT2 had a preserved ejection fraction., Conclusion: Myocardial infarction induces important changes in the expression of lncRNAs in the heart. This study motivates further investigation of the role of lncRNAs in left ventricular remodeling.

Background: Adenosine may have beneficial effects on left ventricular function after myocardial infarction (MI), but the magnitude of this effect on remote and MI areas is controversial. We assessed the long-term effects of adenosine after MI using electrocardiogram-triggered 18 F-fluorodeoxyglucose positron emission tomography., Methods: Wistar rats were subjected to coronary ligation and randomized into three groups treated daily for 2 months by NaCl (control; n = 7), 2-chloroadenosine (CADO; n = 8) or CADO with 8-sulfophenyltheophilline, an antagonist of adenosine receptors (8-SPT; n = 8)., Results: After 2 months, control rats exhibited left ventricular remodelling, with increased end-diastolic volume and decreased ejection fraction. Left ventricular remodelling was not significantly inhibited by CADO. Segmental contractility, as assessed by the change in myocardial thickening after 2 months, was improved in CADO rats compared to control rats (+1.6% ± 0.8% vs. -2.3% ± 0.8%, p < 0.001). This improvement was significant in border (+5.6% ± 0.8% vs. +1.5% ± 0.8%, p < 0.001) and remote (-4.0% ± 1.0% vs. -10.4% ± 1.3%, p < 0.001) segments, but absent in MI segments. Histological analyses revealed that CADO reduced fibrosis, cardiomyocyte hypertrophy and apoptosis. Protective effects of CADO were blunted by 8-SPT., Conclusion: Long-term administration of adenosine protects the left ventricle from contractile dysfunction following MI.

There is evidence that survival remains possible for infarction greater than 50% of the left ventricle in human, as well as in the rat infarct model. To our knowledge, survival has not been documented for infarctions involving the anterior, inferior and lateral wall leaving intact only the septal wall. An adult rat underwent a ligation of the left anterior descending coronary artery. ECG-triggered (18)F-ffluorodeoxyglucose Positron Emission Tomography revealed that 72% of the left ventricle was necrotic and totally akinetic. Although the left ventricular ejection fraction was severely impaired (9%), this rat survived and was asymptomatic after 2 months. The exact reasons for this incredible survival are still unclear.

Background: Administration of endothelial progenitor cells (EPC) represents a promising option to regenerate the heart after myocardial infarction, but is limited because of low recruitment and engraftment in the myocardium. Mobilization and migration of EPC are mainly controlled by stromal cell-derived factor 1α (SDF-1α) and its receptor CXCR4. We hypothesized that adenosine, a cardioprotective molecule, may improve the recruitment of EPC to the heart., Methods: EPC were obtained from peripheral blood mononuclear cells of healthy volunteers. Expression of chemokines and their receptors was evaluated using microarrays, quantitative PCR, and flow cytometry. A Boyden chamber assay was used to assess chemotaxis. Recruitment of EPC to the infarcted heart was evaluated in rats after permanent occlusion of the left anterior descending coronary artery., Results: Microarray analysis revealed that adenosine modulates the expression of several members of the chemokine family in EPC. Among these, CXCR4 was up-regulated by adenosine, and this result was confirmed by quantitative PCR (3-fold increase, P<0.001). CXCR4 expression at the cell surface was also increased. This effect involved the A(2B) receptor. Pretreatment of EPC with adenosine amplified their migration towards recombinant SDF-1α or conditioned medium from cardiac fibroblasts. Both effects were abolished by CXCR4 blocking antibodies. Adenosine also increased CXCR4 under ischemic conditions, and decreased miR-150 expression. Binding of miR-150 to the 3' untranslated region of CXCR4 was verified by luciferase assay. Addition of pre-miR-150 blunted the effect of adenosine on CXCR4. Administration of adenosine to rats after induction of myocardial infarction stimulated EPC recruitment to the heart and enhanced angiogenesis., Conclusion: Adenosine increases the migration of EPC. The mechanism involves A(2B) receptor activation, decreased expression of miR-150 and increased expression of CXCR4. These results suggest that adenosine may be used to enhance the capacity of EPC to revascularize the ischemic heart.

Background: Prediction of left ventricular (LV) remodeling after acute myocardial infarction (MI) is clinically important and would benefit from the discovery of new biomarkers., Methods: Blood samples were obtained upon admission in patients with acute ST-elevation MI who underwent primary percutaneous coronary intervention. Messenger RNA was extracted from whole blood cells. LV function was evaluated by echocardiography at 4-months., Results: In a test cohort of 32 MI patients, integrated analysis of microarrays with a network of protein-protein interactions identified subgroups of genes which predicted LV dysfunction (ejection fraction ≤ 40%) with areas under the receiver operating characteristic curve (AUC) above 0.80. Candidate genes included transforming growth factor beta receptor 1 (TGFBR1). In a validation cohort of 115 MI patients, TGBFR1 was up-regulated in patients with LV dysfunction (P < 0.001) and was associated with LV function at 4-months (P = 0.003). TGFBR1 predicted LV function with an AUC of 0.72, while peak levels of troponin T (TnT) provided an AUC of 0.64. Adding TGFBR1 to the prediction of TnT resulted in a net reclassification index of 8.2%. When added to a mixed clinical model including age, gender and time to reperfusion, TGFBR1 reclassified 17.7% of misclassified patients. TGFB1, the ligand of TGFBR1, was also up-regulated in patients with LV dysfunction (P = 0.004), was associated with LV function (P = 0.006), and provided an AUC of 0.66. In the rat MI model induced by permanent coronary ligation, the TGFB1-TGFBR1 axis was activated in the heart and correlated with the extent of remodeling at 2 months., Conclusions: We identified TGFBR1 as a new candidate prognostic biomarker after acute MI.

Unlabelled: Cell therapy-induced changes in the perfusion of areas of myocardial infarction (MI) remain unclear. This study investigated whether an original pinhole SPECT technique could be applied to a rat MI model to analyze local improvement in myocardial perfusion relating to engraftment sites of bone marrow-derived stem cells (BMSCs)., Methods: Four-month-old MI rats were either untreated (n = 8) or treated (n = 10) by intramyocardial injection of (111)In-labeled BMSCs. Early distribution of (111)In-BMSCs within the MI target was evidenced by dual (111)In/(99m)Tc pinhole SPECT 48 h later. Myocardial perfusion was serially monitored by (99m)Tc-sestamibi pinhole gated SPECT up to 3 mo after transplantation., Results: Forty-eight hours after transplantation, (111)In-BMSCs were observed in all treated rats and in 18 of their 32 underperfused MI segments (<70% sestamibi uptake before transplantation). During the subsequent 3-mo follow-up, the perfusion of MI segments worsened in untreated rats (absolute change in sestamibi uptake, -3% +/- 3%; P < 0.05) but improved in treated rats (+4% +/- 7%; P < 0.05). This perfusion improvement was unrelated to the initial detection of (111)In-BMSCs (+2% +/- 6% in segments with (111)In-BMSCs vs. +5% +/- 7% in those without; not statistically significant) but was strongly associated with less severe perfusion defects before transplantation (+6% +/- 6% in segments with 60%-70% sestamibi uptake [n = 19] vs. -1% +/- 6% in those with <60% uptake [n = 13]; P = 0.003)., Conclusion: When BMSCs are injected within chronic MI, perfusion enhancement predominates in the MI areas showing a high enough residual perfusion before treatment but not in those of the initial cell engraftment, giving evidence of dependency on the perfusion and metabolic environment at implantation sites.

Unlabelled: The rat infarct model is widely used to study left ventricular (LV) remodeling, a main cause of heart failure characterized by progressive LV dilatation. Using pinhole collimators and advances in data processing, gated SPECT was recently adapted to image the rat heart. The aim of this study was to assess this new imaging technique for predicting and quantifying variable LV remodeling from the rat infarct model., Methods: Pinhole 99mTc-sestamibi gated SPECT was validated for determining LV volume and identifying the necrotic and nonviable LV segments (<50% of 99mTc-sestamibi uptake) in rats, and it was applied to monitor rat LV function from 48 h to 12 wk after occlusion of the left anterior descending coronary artery (LAD) (n = 20) or sham operation (n = 9)., Results: In LAD-occluded rats, 48-h SPECT necrosis was large (> or =30% LV) in 6, limited (<30% LV) in 6, and undetectable in 8. End-diastolic volume of LAD-occluded rats was equivalent to that of sham-operated rats at 48 h (320 +/- 84 microL vs. 293 +/- 48 microL; not significant) but became higher at 12 wk (501 +/- 191 microL vs. 343 +/- 46 microL; P = 0.01). The follow-up increase in end-diastolic volume, which reflects the remodeling process, was closely related to the initial extent of necrosis revealed by the SPECT images (P < 0.001; R2= 0.85). This increase was limited in sham-operated rats (50 +/- 15 microL) and in the LAD-occluded rats with undetectable necrosis (55 +/- 35 microL) but it was around 3- and 7-fold higher in the LAD-occluded rats with limited (165 +/- 57 microL) and large (366 +/- 113 microL) necrosis, respectively., Conclusion: The variable LV remodeling documented after coronary occlusion in rats closely relates to the variable extent of necrosis provided by this model. Pinhole gated SPECT allows this remodeling to be predicted and quantified and, hence, constitutes an original tool for the experiments scheduled on the rat infarct model.