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BACKGROUND: Aging-associated left ventricular dysfunction promotes cardiopulmonary fibrogenic remodeling, Group 2 pulmonary hypertension (PH), and right ventricular failure. At the time of diagnosis, cardiac function has declined, and cardiopulmonary fibrosis has often developed. Here, we sought to develop a molecular positron emission tomography (PET)-magnetic resonance imaging (MRI) protocol to detect both cardiopulmonary fibrosis and fibrotic disease activity in a left ventricular dysfunction model. METHODS AND RESULTS: Left ventricular dysfunction was induced by transverse aortic constriction (TAC) in 6-month-old senescence-accelerated prone mice, a subset of mice that received sham surgery. Three weeks after surgery, mice underwent simultaneous PET-MRI at 4.7 T. Collagen-targeted PET and fibrogenesis magnetic resonance (MR) probes were intravenously administered. PET signal was computed as myocardium- or lung-to-muscle ratio. Percent signal intensity increase and Δ lung-to-muscle ratio were computed from the pre-/postinjection magnetic resonance images. Elevated allysine in the heart (P=0.02) and lungs (P=0.17) of TAC mice corresponded to an increase in myocardial magnetic resonance imaging percent signal intensity increase (P<0.0001) and Δlung-to-muscle ratio (P<0.0001). Hydroxyproline in the heart (P<0.0001) and lungs (P<0.01) were elevated in TAC mice, which corresponded to an increase in heart (myocardium-to-muscle ratio, P=0.02) and lung (lung-to-muscle ratio, P<0.001) PET measurements. Pressure-volume loop and echocardiography demonstrated adverse left ventricular remodeling, function, and increased right ventricular systolic pressure in TAC mice. CONCLUSIONS: Administration of collagen-targeted PET and allysine-targeted MR probes led to elevated PET-magnetic resonance imaging signals in the myocardium and lungs of TAC mice. The study demonstrates the potential to detect fibrosis and fibrogenesis in cardiopulmonary disease through a dual molecular PET-magnetic resonance imaging protocol.
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Modelos Animais de Doenças , Fibrose , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Disfunção Ventricular Esquerda , Animais , Tomografia por Emissão de Pósitrons/métodos , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologia , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/metabolismo , Imageamento por Ressonância Magnética/métodos , Camundongos , Miocárdio/patologia , Miocárdio/metabolismo , Fibrose Pulmonar/diagnóstico por imagem , Fibrose Pulmonar/fisiopatologia , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/etiologia , Função Ventricular Esquerda , Masculino , Pulmão/diagnóstico por imagem , Pulmão/patologia , Pulmão/fisiopatologia , Pulmão/metabolismo , Imagem Multimodal/métodos , Colágeno/metabolismo , Remodelação Ventricular , Lisina/análogos & derivadosRESUMO
Neoadjuvant therapy is routinely used in pancreatic ductal adenocarcinoma (PDAC), but not all tumors respond to this treatment. Current clinical imaging techniques are not able to precisely evaluate and predict the response to neoadjuvant therapies over several weeks. A strong fibrotic reaction is a hallmark of a positive response, and during fibrogenesis, allysine residues are formed on collagen proteins by the action of lysyl oxidases. Here, we report the application of an allysine-targeted molecular MRI probe, MnL3, to provide an early, noninvasive assessment of treatment response in PDAC. Allysine increased 2- to 3-fold after one dose of neoadjuvant therapy with FOLFIRINOX in sensitive human PDAC xenografts in mice. Molecular MRI with MnL3 could specifically detect and quantify fibrogenesis in PDAC xenografts. Comparing the MnL3 signal before and 3 days after one dose of FOLFIRINOX predicted subsequent treatment response. The MnL3 tumor signal increased by 70% from day 0 to day 3 in mice that responded to subsequent doses of FOLFIRINOX, whereas no signal increase was observed in FOLFIRINOX-resistant tumors. This study indicates the promise of allysine-targeted molecular MRI as a noninvasive tool to predict chemotherapy outcomes. Significance: Allysine-targeted molecular MRI can quantify fibrogenesis in pancreatic tumors and predict response to chemotherapy, which could guide rapid clinical management decisions by differentiating responders from nonresponders after treatment initiation.
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Protocolos de Quimioterapia Combinada Antineoplásica , Carcinoma Ductal Pancreático , Irinotecano , Imageamento por Ressonância Magnética , Neoplasias Pancreáticas , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Humanos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/diagnóstico por imagem , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/metabolismo , Camundongos , Irinotecano/farmacologia , Irinotecano/administração & dosagem , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/diagnóstico por imagem , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/metabolismo , Imageamento por Ressonância Magnética/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Fluoruracila/farmacologia , Fluoruracila/administração & dosagem , Oxaliplatina/farmacologia , Oxaliplatina/administração & dosagem , Linhagem Celular Tumoral , Leucovorina/administração & dosagem , Leucovorina/farmacologia , Leucovorina/uso terapêutico , Terapia Neoadjuvante , Feminino , LisinaRESUMO
PURPOSE: Radiation-induced lung injury (RILI) is a progressive inflammatory process seen after irradiation for lung cancer. The disease can be insidious, often characterized by acute pneumonitis followed by chronic fibrosis with significant associated morbidity. No therapies are approved for RILI, and accurate disease quantification is a major barrier to improved management. Here, we sought to noninvasively quantify RILI using a molecular imaging probe that specifically targets type 1 collagen in mouse models and patients with confirmed RILI. METHODS AND MATERIALS: Using a murine model of lung radiation, mice were imaged with EP-3533, a type 1 collagen probe, to characterize the development of RILI and to assess disease mitigation after losartan treatment. The human analog probe 68Ga-CBP8, targeting type 1 collagen, was tested on excised human lung tissue containing RILI and was quantified via autoradiography. 68Ga-CBP8 positron emission tomography was used to assess RILI in vivo in 6 human subjects. RESULTS: Murine models demonstrated that probe signal correlated with progressive RILI severity over 6 months. The probe was sensitive to mitigation of RILI by losartan. Excised human lung tissue with RILI had increased binding versus unirradiated control tissue, and 68Ga-CBP8 uptake correlated with collagen proportional area. Human imaging revealed significant 68Ga-CBP8 uptake in areas of RILI and minimal background uptake. CONCLUSIONS: These findings support the ability of a molecular imaging probe targeted at type 1 collagen to detect RILI in preclinical models and human disease, suggesting a role for targeted molecular imaging of collagen in the assessment of RILI.
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Lesão Pulmonar , Lesões por Radiação , Humanos , Animais , Camundongos , Lesão Pulmonar/diagnóstico por imagem , Lesão Pulmonar/etiologia , Lesão Pulmonar/metabolismo , Colágeno Tipo I/metabolismo , Radioisótopos de Gálio/metabolismo , Losartan/metabolismo , Pulmão/efeitos da radiação , Lesões por Radiação/metabolismo , Colágeno , Imagem MolecularRESUMO
Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology that is characterized by excessive deposition and abnormal remodeling of collagen. IPF has a mean survival time of only 2-5 years from diagnosis, creating a need to detect IPF at an earlier stage when treatments might be more effective. We sought to develop a minimally invasive probe that could detect molecular changes in IPF-associated collagen. Here, we describe the design, synthesis, and performance of [68Ga]Ga·DOTA-CMP, which comprises a positron-emitting radioisotope linked to a collagen-mimetic peptide (CMP). This peptide mimics the natural structure of collagen and detects irregular collagen matrices by annealing to damaged collagen triple helices. We assessed the ability of the peptide to detect aberrant lung collagen selectively in a bleomycin-induced mouse model of pulmonary fibrosis using positron emission tomography (PET). [68Ga]Ga·DOTA-CMP PET demonstrated higher and selective uptake in a fibrotic mouse lung compared to controls, minimal background signal in adjacent organs, and rapid clearance via the renal system. These studies suggest that [68Ga]Ga·DOTA-CMP identifies fibrotic lungs and could be useful in the early diagnosis of IPF.
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Radioisótopos de Gálio , Fibrose Pulmonar Idiopática , Camundongos , Animais , Radioisótopos de Gálio/farmacologia , Pulmão/diagnóstico por imagem , Fibrose Pulmonar Idiopática/diagnóstico , Fibrose Pulmonar Idiopática/diagnóstico por imagem , Bleomicina/farmacologia , ColágenoRESUMO
Rationale: Radiation-induced lung injury (RILI) is a progressive inflammatory process commonly seen following irradiation for lung cancer. The disease can be insidious, often characterized by acute pneumonitis followed by chronic fibrosis with significant associated morbidity. No therapies are approved for RILI, and accurate disease quantification is a major barrier to improved management. Objective: To noninvasively quantify RILI, utilizing a molecular imaging probe that specifically targets type 1 collagen in mouse models and patients with confirmed RILI. Methods: Using a murine model of lung radiation, mice were imaged with EP-3533, a type 1 collagen probe to characterize the development of RILI and to assess disease mitigation following losartan treatment. The human analog probe targeted against type 1 collagen, 68Ga-CBP8, was tested on excised human lung tissue containing RILI and quantified via autoradiography. Finally, 68Ga-CBP8 PET was used to assess RILI in vivo in six human subjects. Results: Murine models demonstrated that probe signal correlated with progressive RILI severity over six-months. The probe was sensitive to mitigation of RILI by losartan. Excised human lung tissue with RILI had increased binding vs unirradiated control tissue and 68Ga-CBP8 uptake correlated with collagen proportional area. Human imaging revealed significant 68Ga-CBP8 uptake in areas of RILI and minimal background uptake. Conclusions: These findings support the ability of a molecular imaging probe targeted at type 1 collagen to detect RILI in preclinical models and human disease, suggesting a role for targeted molecular imaging of collagen in the assessment of RILI.Clinical trial registered with www.clinicaltrials.gov (NCT04485286, NCT03535545).
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Background Gadolinium retention has been observed in organs of patients with normal renal function; however, the biodistribution and speciation of residual gadolinium is not well understood. Purpose To compare the pharmacokinetics, distribution, and speciation of four gadolinium-based contrast agents (GBCAs) in healthy rats using MRI, mass spectrometry, elemental imaging, and electron paramagnetic resonance (EPR) spectroscopy. Materials and Methods In this prospective animal study performed between November 2021 and September 2022, 32 rats received a dose of gadoterate, gadoteridol, gadobutrol, or gadobenate (2.0 mmol/kg) for 10 consecutive days. GBCA-naive rats were used as controls. Three-dimensional T1-weighted ultrashort echo time images and R2* maps of the kidneys were acquired at 3, 17, 34, and 52 days after injection. At 17 and 52 days after injection, gadolinium concentrations in 23 organ, tissue, and fluid specimens were measured with mass spectrometry; gadolinium distribution in the kidneys was evaluated using elemental imaging; and gadolinium speciation in the kidney cortex was assessed using EPR spectroscopy. Data were assessed with analysis of variance, Kruskal-Wallis test, analysis of response profiles, and Pearson correlation analysis. Results For all GBCAs, the kidney cortex exhibited higher gadolinium retention at 17 days after injection than all other specimens tested (mean range, 350-1720 nmol/g vs 0.40-401 nmol/g; P value range, .001-.70), with gadoteridol showing the lowest level of retention. Renal cortex R2* values correlated with gadolinium concentrations measured ex vivo (r = 0.95; P < .001), whereas no associations were found between T1-weighted signal intensity and ex vivo gadolinium concentration (r = 0.38; P = .10). EPR spectroscopy analysis of rat kidney cortex samples showed that all GBCAs were primarily intact at 52 days after injection. Conclusion Compared with other macrocyclic GBCAs, gadoteridol administration led to the lowest level of retention. The highest concentration of gadolinium was retained in the kidney cortex, but T1-weighted MRI was not sensitive for detecting residual gadolinium in this tissue. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Tweedle in this issue.
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Meios de Contraste , Compostos Organometálicos , Ratos , Humanos , Animais , Gadolínio/farmacocinética , Distribuição Tecidual , Estudos Prospectivos , Encéfalo , Gadolínio DTPA , Imageamento por Ressonância Magnética/métodosRESUMO
PURPOSE: Idiopathic pulmonary fibrosis (IPF) is a destructive lung disease with a poor prognosis, an unpredictable clinical course, and inadequate therapies. There are currently no measures of disease activity to guide clinicians making treatment decisions. The aim of this study was to develop a PET probe to identify lung fibrogenesis using a pre-clinical model of pulmonary fibrosis, with potential for translation into clinical use to predict disease progression and inform treatment decisions. METHODS: Eight novel allysine-targeting chelators, PIF-1, PIF-2, , PIF-8, with different aldehyde-reactive moieties were designed, synthesized, and radiolabeled with gallium-68 or copper-64. PET probe performance was assessed in C57BL/6J male mice 2 weeks after intratracheal bleomycin challenge and in naïve mice by dynamic PET/MR imaging and with biodistribution at 90 min post injection. Lung hydroxyproline and allysine were quantified ex vivo and histological staining for fibrosis and aldehyde was performed. RESULTS: In vivo screening of probes identified 68GaPIF-3 and 68GaPIF-7 as probes with high uptake in injured lung, high uptake in injured lung versus normal lung, and high uptake in injured lung versus adjacent liver and heart tissue. A crossover, intra-animal PET/MR imaging study of 68GaPIF-3 and 68GaPIF-7 confirmed 68GaPIF-7 as the superior probe. Specificity for fibrogenesis was confirmed in a crossover, intra-animal PET/MR imaging study with 68GaPIF-7 and a non-binding control compound, 68GaPIF-Ctrl. Substituting copper-64 for gallium-68 did not affect lung uptake or specificity indicating that either isotope could be used. CONCLUSION: A series of allysine-reactive PET probes with variations in the aldehyde-reactive moiety were evaluated in a pre-clinical model of lung fibrosis. The hydrazine-bearing probe, 68GaPIF-7, exhibited the highest uptake in fibrogenic lung, low uptake in surrounding liver or heart tissue, and low lung uptake in healthy mice and should be considered for further clinical translation.
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During fibroproliferation, protein-associated extracellular aldehydes are formed by the oxidation of lysine residues on extracellular matrix proteins to form the aldehyde allysine. Here we report three Mn(II)-based, small-molecule magnetic resonance probes that contain α-effect nucleophiles to target allysine in vivo and report on tissue fibrogenesis. We used a rational design approach to develop turn-on probes with a 4-fold increase in relaxivity upon targeting. The effects of aldehyde condensation rate and hydrolysis kinetics on the performance of the probes to detect tissue fibrogenesis non-invasively in mouse models were evaluated by a systemic aldehyde tracking approach. We showed that, for highly reversible ligations, off-rate was a stronger predictor of in vivo efficiency, enabling histologically validated, three-dimensional characterization of pulmonary fibrogenesis throughout the entire lung. The exclusive renal elimination of these probes allowed for rapid imaging of liver fibrosis. Reducing the hydrolysis rate by forming an oxime bond with allysine enabled delayed phase imaging of kidney fibrogenesis. The imaging efficacy of these probes, coupled with their rapid and complete elimination from the body, makes them strong candidates for clinical translation.
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Ácido 2-Aminoadípico , Aldeídos , Camundongos , Animais , Ácido 2-Aminoadípico/química , Imageamento por Ressonância Magnética , PulmãoRESUMO
During fibroproliferation, protein-associated extracellular aldehydes are formed by the oxidation of lysine residues on extracellular matrix proteins to form the aldehyde allysine. Here we report three Mn(II)-based, small molecule magnetic resonance (MR) probes that contain α-effect nucleophiles to target allysine in vivo and report on tissue fibrogenesis. We used a rational design approach to develop turn-on probes with a 4-fold increase in relaxivity upon targeting. The effects of aldehyde condensation rate and hydrolysis kinetics on the performance of the probes to detect tissue fibrogenesis noninvasively in mouse models were evaluated by a systemic aldehyde tracking approach. We showed that for highly reversible ligations, off-rate was a stronger predictor of in vivo efficiency, enabling histologically validated, three-dimensional characterization of pulmonary fibrogenesis throughout the entire lung. The exclusive renal elimination of these probes allowed for rapid imaging of liver fibrosis. Reducing the hydrolysis rate by forming an oxime bond with allysine enabled delayed phase imaging of kidney fibrogenesis. The imaging efficacy of these probes, coupled with their rapid and complete elimination from the body, make them strong candidates for clinical translation.
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SNIO-CBP, a single-nanometer iron oxide (SNIO) nanoparticle functionalized with a type I collagen-binding peptide (CBP), was developed as a T1-weighted MRI contrast agent with only endogenous elements for fast and noninvasive detection of liver fibrosis. SNIO-CBP exhibits 6.7-fold higher relaxivity compared to a molecular gadolinium-based collagen-binding contrast agent CM-101 on a per CBP basis at 4.7 T. Unlike most iron oxide nanoparticles, SNIO-CBP exhibits fast elimination from the bloodstream with a 5.7 min half-life, high renal clearance, and low, transient liver enhancement in healthy mice. We show that a dose of SNIO-CBP that is 2.5-fold lower than that for CM-101 has comparable imaging efficacy in rapid (within 15 min following intravenous injection) detection of hepatotoxin-induced liver fibrosis using T1-weighted MRI in a carbon tetrachloride-induced mouse liver injury model. We further demonstrate the applicability of SNIO-CBP in detecting liver fibrosis in choline-deficient L-amino acid-defined high-fat diet mouse model of nonalcoholic steatohepatitis. These results provide a platform with potential for the development of high relaxivity, gadolinium-free molecular MRI probes for characterizing chronic liver disease.
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Nanopartículas de Magnetita , Nanopartículas , Camundongos , Animais , Meios de Contraste/química , Cirrose Hepática/patologia , Fígado/patologia , Imageamento por Ressonância Magnética/métodos , Modelos Animais de Doenças , Nanopartículas Magnéticas de Óxido de Ferro , Colágeno/análiseRESUMO
BACKGROUND: In most CKDs, lysyl oxidase oxidation of collagen forms allysine side chains, which then form stable crosslinks. We hypothesized that MRI with the allysine-targeted probe Gd-oxyamine (OA) could be used to measure this process and noninvasively detect renal fibrosis. METHODS: Two mouse models were used: hereditary nephritis in Col4a3-deficient mice (Alport model) and a glomerulonephritis model, nephrotoxic nephritis (NTN). MRI measured the difference in kidney relaxation rate, ΔR1, after intravenous Gd-OA administration. Renal tissue was collected for biochemical and histological analysis. RESULTS: ΔR1 was increased in the renal cortex of NTN mice and in both the cortex and the medulla of Alport mice. Ex vivo tissue analyses showed increased collagen and Gd-OA levels in fibrotic renal tissues and a high correlation between tissue collagen and ΔR1. CONCLUSIONS: Magnetic resonance imaging using Gd-OA is potentially a valuable tool for detecting and staging renal fibrogenesis.
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Rim , Nefrite Hereditária , Camundongos , Animais , Rim/diagnóstico por imagem , Rim/patologia , Nefrite Hereditária/patologia , Fibrose , Imageamento por Ressonância Magnética/métodos , Modelos Animais de DoençasRESUMO
PURPOSE: New generation of receptor tyrosine kinase inhibitors (RTKIs) have shown to improve survival in many solid tumors. However, an imaging biomarker is needed for patient selection and prediction of treatment response. This study evaluates the use of quantitative changes of HER3 on 68 Ga-NOTA-HER3P1 PET/MRI for prediction of early response to pan-RTKIs in gastric cancer (GCa). PROCEDURES: GCa cell lines were evaluated for expression of RTKs, and downstream signaling pathways (AKT and MAPK). Cell viability was assessed following 24-72 h of treatment with 0.01-1 µmol/L of afatinib, a pan-RTKI. HER3-expressing afatinib-sensitive (NCI-N87) and resistant cells (SNU16) were selected for evaluation of changes in RTKs expression and downstream pathways, with 24-72 h of 0.1 µmol/L afatinib treatment. 68 Ga-NOTA-HER3P1 PET/MRI was performed in subcutaneous NCI-N87 and SNU16 xenografts (nu:nu, n = 12/group) at baseline and 4 days after afatinib treatment (10 mg/kg, PO, daily). Temporal changes in PET measures were correlated to HER3 expression in tumors, tumor growth rate, and treatment response. RESULTS: With afatinib therapy, NCI-N87 cells showed increased total HER3 expression, and reduction of other RTKs and downstream nodes within 72 h, while SNU16 cells showed no significant change in total HER3 and downstream nodes. 68 Ga-HER3P1 PET/MRI showed increased uptake in NCI-N87 and no significant change in SNU16 tumors (day 4 vs. baseline SUVmean: 3.8 ± 0.7 vs. 1.6 ± 0.6, p < 0.05 in NCI-N87, and 1.5 ± 0.7 vs. 1.7 ± 0.7, p > 0.05 in SNU16). These findings were in concordance with HER3 expression in histopathological analyses and tumor growth over 3 weeks of treatment (mean tumor volume in treated vs. control: 11 ± 17 mm3 vs. 293 ± 79 mm3, p < 0.001 in NCI-N87, and 238 ± 91 mm3 vs. 282 ± 35 mm3, p > 0.05 in SNU16). CONCLUSIONS: Quantitative changes in HER3 PET could be used to predict response to pan-RTKI within few days after initiation of treatment and can help with personalizing GCa management.
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Neoplasias Gástricas , Humanos , Afatinib/farmacologia , Neoplasias Gástricas/patologia , Linhagem Celular Tumoral , Tomografia por Emissão de Pósitrons/métodos , Receptor ErbB-3RESUMO
Liver fibrosis plays a critical role in the evolution of most chronic liver diseases and is characterized by a buildup of extracellular matrix, which can progress to cirrhosis, hepatocellular carcinoma, liver failure, or death. Now, there are no noninvasive methods available to accurately assess disease activity (fibrogenesis) to sensitively detect early onset of fibrosis or to detect early response to treatment. Here, we hypothesized that extracellular allysine aldehyde (LysAld) pairs formed by collagen oxidation during active fibrosis could be a target for assessing fibrogenesis with a molecular probe. We showed that molecular magnetic resonance imaging (MRI) using an extracellular probe targeting these LysAld pairs acts as a noninvasive biomarker of fibrogenesis and demonstrated its high sensitivity and specificity in detecting fibrogenesis in toxin- and dietary-induced mouse models, a cholestasis rat model of liver fibrogenesis, and in human fibrotic liver tissues. Quantitative molecular MRI was highly correlated with fibrogenesis markers and enabled noninvasive detection of early onset fibrosis and response to antifibrotic treatment, showing high potential for clinical translation.
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Aldeídos , Fígado , Animais , Biomarcadores , Colágeno , Fibrose , Humanos , Fígado/diagnóstico por imagem , Fígado/patologia , Cirrose Hepática/patologia , Imageamento por Ressonância Magnética , Camundongos , Sondas Moleculares , RatosRESUMO
Liver fibrogenesis is accompanied by upregulation of lysyl oxidase enzymes, which catalyze oxidation of lysine ε-amino groups on the extracellular matrix proteins to form the aldehyde containing amino acid allysine (LysAld). Here, we describe the design and synthesis of novel manganese-based MRI probes with high signal amplification for imaging liver fibrogenesis. Rational design of a series of stable hydrazine-equipped manganese MRI probes gives Mn-2CHyd with the highest affinity and turn-on relaxivity (4-fold) upon reaction with LysAld. A dynamic PET-MRI study using [52Mn]Mn-2CHyd showed low liver uptake of the probe in healthy mice. The ability of the probe to detect liver fibrogenesis was then demonstrated in vivo in CCl4-injured mice. This study enables further development and application of manganese-based hydrazine-equipped probes for imaging liver fibrogenesis.
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Meios de Contraste , Manganês , Animais , Meios de Contraste/química , Hidrazinas , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Manganês/química , CamundongosRESUMO
PURPOSE: To evaluate the use of hyperpolarized [1-13C]pyruvate magnetic resonance spectroscopic imaging (HP-13C MRSI) for quantitative measurement of early changes in glycolytic metabolism and its ability to predict response to pan-tyrosine kinase inhibitor (Pan-TKI) therapy in gastric cancer (GCa). PROCEDURES: Pan-TKI afatinib-sensitive NCI-N87 and resistant SNU16 human GCa cells were assessed for GLUT1, hexokinase-II (HKII), lactate dehydrogenase (LDHA), phosphorylated AKT (pAKT), and phosphorylated MAPK (pMAPK) at 0-72 h of treatment with 0.1 µM afatinib. Subcutaneous NCI-N87 tumor-bearing nude mice underwent [18F]FDG PET/MRI and HP-13C MRSI at baseline and 4 days after treatment with afatinib 10 mg/kg/day or vehicle (n = 10/group). Changes in PET and HP-13C MRSI metabolic parameters were compared between the two groups. Imaging findings were correlated with tumor growth and histopathology over 3 weeks of treatment. RESULTS: In vitro analysis showed a continuous decrease in LDHA, pAKT, and pMAPK in NCI-N87 compared to SNU16 cells within 72 h of treatment with afatinib, without a significant change in GLUT1 and HKII in either cell type. [18F]FDG PET of NCI-N87 tumors showed no significant change in PET measures at baseline and day 4 of treatment in either treatment group (SUVmean day 4/day 0: 2.7 ± 0.42/2.34 ± 0.38, p = 0.57 in the treated group vs. 1.73 ± 0.66/2.24 ± 0.43, p = 0.4 in the control group). HP-13C MRSI demonstrated significantly decreased lactate-to-pyruvate ratio (L/P) in treated tumors (L/P day 4/day 0: 0.83 ± 0.30/1.10 ± 0.20, p = 0.012 vs. 0.94 ± 0.20/0.98 ± 0.30, p = 0.75, in the treated vs. control group, respectively). Response to afatinib was confirmed with decreased tumor size over 3 weeks (11.10 ± 16.50 vs. 293.00 ± 79.30 mm3, p < 0.001, treated group vs. control group, respectively) and histopathologic evaluation. CONCLUSIONS: HP-13C MRSI is a more representative biomarker of early metabolic changes in response to pan-TKI in GCa than [18F]FDG PET and could be used for early prediction of response to targeted therapies.
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Fluordesoxiglucose F18 , Neoplasias Gástricas , Animais , Camundongos , Humanos , Ácido Pirúvico/metabolismo , Hexoquinase/metabolismo , Transportador de Glucose Tipo 1 , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/tratamento farmacológico , Proteínas Tirosina Quinases/metabolismo , Afatinib , Camundongos Nus , Proteínas Proto-Oncogênicas c-akt/metabolismo , Imageamento por Ressonância Magnética/métodos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Espectroscopia de Ressonância Magnética/métodos , Lactato Desidrogenases/metabolismo , LactatosRESUMO
BACKGROUND AND PURPOSE: High-risk atherosclerosis is an underlying cause of cardiovascular events, yet identifying the specific patient population at immediate risk is still challenging. Here, we used a rabbit model of atherosclerotic plaque rupture and human carotid endarterectomy specimens to describe the potential of molecular fibrin imaging as a tool to identify thrombotic plaques. METHODS: Atherosclerotic plaques in rabbits were induced using a high-cholesterol diet and aortic balloon injury (N=13). Pharmacological triggering was used in a group of rabbits (n=9) to induce plaque disruption. Animals were grouped into thrombotic and nonthrombotic plaque groups based on gross pathology (gold standard). All animals were injected with a novel fibrin-specific probe 68Ga-CM246 followed by positron emission tomography (PET)/magnetic resonance imaging 90 minutes later. 68Ga-CM246 was quantified on the PET images using tissue-to-background (back muscle) ratios and standardized uptake value. RESULTS: Both tissue-to-background (back muscle) ratios and standardized uptake value were significantly higher in the thrombotic versus nonthrombotic group (P<0.05). Ex vivo PET and autoradiography of the abdominal aorta correlated positively with in vivo PET measurements. Plaque disruption identified by 68Ga-CM246 PET agreed with gross pathology assessment (85%). In ex vivo surgical specimens obtained from patients undergoing elective carotid endarterectomy (N=12), 68Ga-CM246 showed significantly higher binding to carotid plaques compared to a D-cysteine nonbinding control probe. CONCLUSIONS: We demonstrated that molecular fibrin PET imaging using 68Ga-CM246 could be a useful tool to diagnose experimental and clinical atherothrombosis. Based on our initial results using human carotid plaque specimens, in vivo molecular imaging studies are warranted to test 68Ga-CM246 PET as a tool to stratify risk in atherosclerotic patients.
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Fibrina , Trombose Intracraniana/diagnóstico por imagem , Placa Aterosclerótica/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Animais , Aorta Abdominal/diagnóstico por imagem , Músculos do Dorso/diagnóstico por imagem , Artérias Carótidas/diagnóstico por imagem , Feminino , Radioisótopos de Gálio , Humanos , Processamento de Imagem Assistida por Computador , Trombose Intracraniana/etiologia , Imageamento por Ressonância Magnética , Masculino , Placa Aterosclerótica/complicações , CoelhosRESUMO
BACKGROUND: In our earlier work, we identified microRNA-10b (miR10b) as a master regulator of the viability of metastatic tumor cells. This knowledge allowed us to design a miR10b-targeted therapeutic consisting of anti-miR10b and ultrasmall iron oxide magnetic nanoparticles (MN), termed MN-anti-miR10b. In mouse models of breast cancer, we demonstrated that MN-anti-miR10b caused durable regressions of established metastases with no evidence of systemic toxicity. As a first step towards translating MN-anti-miR10b for the treatment of metastatic breast cancer, we needed to determine if MN-anti-miR10b, which is so effective in mice, will also accumulate in human metastases. RESULTS: In this study, we devised a method to efficiently radiolabel MN-anti-miR10b with Cu-64 (64Cu) and evaluated the pharmacokinetics and biodistribution of the radiolabeled product at two different doses: a therapeutic dose, referred to as macrodose, corresponding to 64Cu-MN-anti-miR10b co-injected with non-labeled MN-anti-miR10b, and a tracer level dose of 64Cu-MN-anti-miR10b, referred to as microdose. In addition, we evaluated the uptake of 64Cu-MN-anti-miR10b by metastatic lesions using both in vivo and ex vivo positron emission tomography-magnetic resonance imaging (PET-MRI). A comparable distribution of the therapeutic was observed after administration of a microdose or macrodose. Uptake of the therapeutic by metastatic lymph nodes, lungs, and bone was also demonstrated by PET-MRI with a significantly higher PET signal than in the same organs devoid of metastatic lesions. CONCLUSION: Our results demonstrate that PET-MRI following a microdose injection of the agent will accurately reflect the innate biodistribution of the therapeutic. The tools developed in the present study lay the groundwork for the clinical testing of MN-anti-miR10b and other similar therapeutics in patients with cancer.
RESUMO
Non-alcoholic steatohepatitis (NASH) is an increasing cause of chronic liver disease characterized by steatosis, inflammation, and fibrosis which can lead to cirrhosis, hepatocellular carcinoma, and mortality. Quantitative, noninvasive methods for characterizing the pathophysiology of NASH at both the preclinical and clinical level are sorely needed. We report here a multiparametric magnetic resonance imaging (MRI) protocol with the fibrogenesis probe Gd-Hyd to characterize fibrotic disease activity and steatosis in a common mouse model of NASH. Mice were fed a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) to induce NASH with advanced fibrosis. Mice fed normal chow and CDAHFD underwent MRI after 2, 6, 10 and 14 weeks to measure liver T1, T2*, fat fraction, and dynamic T1-weighted Gd-Hyd enhanced imaging of the liver. Steatosis, inflammation, and fibrosis were then quantified by histology. NASH and fibrosis developed quickly in CDAHFD fed mice with strong correlation between morphometric steatosis quantification and liver fat estimated by MRI (r = 0.90). Sirius red histology and collagen quantification confirmed increasing fibrosis over time (r = 0.82). Though baseline T1 and T2* measurements did not correlate with fibrosis, Gd-Hyd signal enhancement provided a measure of the extent of active fibrotic disease progression and correlated strongly with lysyl oxidase expression. Gd-Hyd MRI accurately detects fibrogenesis in a mouse model of NASH with advanced fibrosis and can be combined with other MR measures, like fat imaging, to more accurately assess disease burden.
Assuntos
Meios de Contraste/farmacologia , Complexos de Coordenação/farmacologia , Gadolínio/farmacologia , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Hepatopatia Gordurosa não Alcoólica/diagnóstico por imagem , Animais , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Masculino , Camundongos , Hepatopatia Gordurosa não Alcoólica/induzido quimicamenteRESUMO
METHODS: Three groups of mice that develop either mild type 2 inflammation and fibrosis (wild type), severe fibrosis with exacerbated type 2 inflammation (Il10-/-Il12b-/-Il13ra2-/-), or minimal fibrosis with marked type 1 inflammation (Il4ra∂/∂) after infection with S. mansoni were imaged using both probes for determination of signal enhancement. Schistosoma mansoni-infected wild-type mice developed chronic liver fibrosis. RESULTS: The liver MR signal enhancement after either probe administration was significantly higher in S. mansoni-infected wild-type mice compared with naive animals. The S. mansoni-infected Il4ra∂/∂ mice presented with little liver signal enhancement after probe injection despite the presence of substantial inflammation. Schistosoma mansoni-infected Il10-/-Il12b-/-Il13ra2-/- mice presented with marked fibrosis, which correlated to increased signal enhancement after injection of either probe. CONCLUSIONS: Both MR probes, EP-3533 and Gd-Hyd, were specific for fibrosis in this model of chronic liver disease regardless of the presence or severity of the underlying inflammation. These results, in addition to previous findings, show the potential application of both molecular MR probes for detection and quantification of fibrosis from various etiologies.