Acinar ATP8b1/LPC pathway promotes macrophage efferocytosis and clearance of inflammation during chronic pancreatitis development.

Noninflammatory clearance of dying cells by professional phagocytes, termed efferocytosis, is fundamental in both homeostasis and inflammatory fibrosis disease but has not been confirmed to occur in chronic pancreatitis (CP). Here, we investigated whether efferocytosis constitutes a novel regulatory target in CP and its mechanisms. PRSS1 transgenic (PRSS1Tg) mice were treated with caerulein to mimic CP development. Phospholipid metabolite profiling and epigenetic assays were performed with PRSS1Tg CP models. The potential functions of Atp8b1 in CP model were clarified using Atp8b1-overexpressing adeno-associated virus, immunofluorescence, enzyme-linked immunosorbent assay(ELISA), and lipid metabolomic approaches. ATAC-seq combined with RNA-seq was then used to identify transcription factors binding to the Atp8b1 promoter, and ChIP-qPCR and luciferase assays were used to confirm that the identified transcription factor bound to the Atp8b1 promoter, and to identify the specific binding site. Flow cytometry was performed to analyze the proportion of pancreatic macrophages. Decreased efferocytosis with aggravated inflammation was identified in CP. The lysophosphatidylcholine (LPC) pathway was the most obviously dysregulated phospholipid pathway, and LPC and Atp8b1 expression gradually decreased during CP development. H3K27me3 ChIP-seq showed that increased Atp8b1 promoter methylation led to transcriptional inhibition. Atp8b1 complementation substantially increased the LPC concentration and improved CP outcomes. Bhlha15 was identified as a transcription factor that binds to the Atp8b1 promoter and regulates phospholipid metabolism. Our study indicates that the acinar Atp8b1/LPC pathway acts as an important "find-me" signal for macrophages and plays a protective role in CP, with Atp8b1 transcription promoted by the acinar cell-specific transcription factor Bhlha15. Bhlha15, Atp8b1, and LPC could be clinically translated into valuable therapeutic targets to overcome the limitations of current CP therapies.

Construction and Evaluation of the Tumor-Targeting, Cell-Penetrating Multifunctional Molecular Probe iCREKA.

A novel tumor stroma targeting and membrane-penetrating cyclic peptide, named iCREKA, was designed and labeled by fluorescein isothiocyanate (FITC) and positron emitter 18F to build the tumor-targeting tracers. The FITC-iCREKA was proved to have significantly higher cellular uptake in the glioma U87 cells in the presence of activated MMP-2 than that in absence of activated MMP-2 by cells fluorescence test in vitro. The tumor tissue fluorescence microscope imaging demonstrated that FITC-iCREKA accumulated in the walls of the blood vessels and the surrounding stroma in the glioma tumor at 1 h after intravenous injection. While at 3 h after injection, FITC-iCREKA was found to be uptaken in the tumor cells. However, the control FITC-CREKA can only be found in the tumor stroma, not in the tumor cells, no matter at 1 h or 3 h after injection. The whole-animal fluorescence imaging showed that the glioma tumor could be visualized clearly with high fluorescence signal. The microPET/CT imaging further demonstrated that 18F-iCREKA could target U87MG tumor in vivo from 30 min to 2 h after injection. The present study indicated the iCREKA had the capacity of tumor stroma targeting and the membrane-penetrating. It was potential to be developed as the fluorescent and PET tracers for tumor imaging.

Low glucose metabolism in hepatocellular carcinoma with GPC3 expression.

AIM: To investigate the relationship between glucose metabolism and glypican-3 (GPC3) expression in hepatocellular carcinoma (HCC). METHODS: Immunohistochemical staining of pathological samples for GPC3 and glucose transporter 1 (GLUT1), and whole-body 18F-FDG PET/CT for measuring tumour glucose uptake were performed in 55 newly diagnosed HCC patients. The maximum standard uptake value (SUVmax) and tumour-to-non-tumourous liver uptake (T/NT) ratio were used to quantify 18F-FDG uptake. In vitro18F-FDG uptake assay of GPC3-expressing HepG2 and non-GPC3-expressing RH7777 cells was used to examine the effect of GPC3 in cellular glucose metabolism. The relationships between GPC3 expression and 18F-FDG uptake, GLUT1 expression, tumour differentiation, and other clinical indicators were analysed using Spearman rank correlation, univariate and multiple logistic regression analyses. RESULTS: Positive GPC3 expression was observed in 67.3% of HCC patients, including 75.0% of those with well or moderately differentiated HCC and 36.4% of those with poorly differentiated HCC. There was an inverse relationship between GPC3 expression and SUVmax (Spearman correlation coefficient = -0.281, P = 0.038) and a positive relationship between GLUT1 expression and SUVmax (Spearman correlation coefficient = 0.681, P < 0.001) in patients with HCC. Univariate analysis showed that two glucose metabolic parameters (SUVmax and T/NT ratio), tumour differentiation, lymph node metastasis, and TNM stage were all significantly associated with GPC3 expression (P < 0.05), whereas GLUT1 expression, sex, age, tumour size, intrahepatic lesion number, and distant metastasis showed no statistical association (P > 0.05). Further multivariate analysis revealed that only the T/N ratio was significantly correlated with GPC3 expression in patients with HCC (P < 0.05). In vitro assay revealed that the uptake of 18F-FDG in GPC3-expressing HepG2 cells was significantly lower than that of non-GPC3-expressing RH7777 cells (t = -20.352, P < 0.001). CONCLUSION: The present study demonstrated that GPC3 expression is inversely associated with glucose metabolism, suggesting that GPC3 may play a role in regulating glucose metabolism in HCC.

Imaging the expression of glypican-3 in hepatocellular carcinoma by PET.

The glypican-3 (GPC3) receptor is overexpressed in hepatocellular carcinoma (HCC) and is a potential diagnostic and therapeutic target. GPC3-targeted molecular imaging will be helpful to differentiate diagnosis and guide therapy. In the present study, we will develop a novel PET probe for imaging the expression of GPC-3. L5 (sequence: RLNVGGTYFLTTRQ), a GPC3 targeting peptide, was labeled with 5-carboxyfluorescein (FAM) and 18F-fluoride. Cell binding tests were performed to identify the binding specificity of FAM-L5 and 18F radiolabeled peptide. MicroPET/CT imaging was used to determine the potential of a novel PET tracer for visualizing HCC tumors with a high expression of GPC3. In vitro binding tests showed that the uptake of FAM-L5 in HepG2 cells (high expression of GPC3) was significantly higher than that of HL-7702 cells (negative expression of GPC3) (mean fluorescent intensity: 14,094 ± 797 vs. 2765 ± 314 events, t = 32.363, P = 0.000). Confocal fluorescent imaging identified that FAM-L5 accumulated where the GPC3 receptor was located. A novel PET tracer (18F-AlF-NODA-MP-6-Aoc-L5) was successfully labeled by chelation chemistry. In vitro cell uptake studies showed that 18F-AlF-NODA-MP-6-Aoc-L5 can bind to HepG2 tumor cells and was stable in PBS and mouse serum stability tests. MicroPET/CT showed that HepG2 tumors could be clearly visualized with a tumor/muscle ratio of 2.46 ± 0.53. However, the tumor/liver ratio was low (0.93 ± 0.16) due to the high physiological uptake in the liver. This study demonstrates that FAM and the 18F-labeled L5 peptide can selectively target HCC with a high expression of GPC3 in vitro and in vivo. 18F-AlF-NODA-MP-C6-L5 has the potential to be a GPC3 target tracer but requires some chemical modifications to achieve a high enough tumor/liver ratio for detection of the tumor in the liver.

Multifunctional superparamagnetic nanoparticles conjugated with fluorescein-labeled designed ankyrin repeat protein as an efficient HER2-targeted probe in breast cancer.

Based on the discordance of human epidermal growth factor receptor-2 (HER2) expression between primary and metastatic/recurrent breast cancer, HER2 molecular imaging, which had potential to systemically assess and dynamically monitor HER2 expression, might improve the selection of patients for anti-HER2 therapy. In this study, designed ankyrin repeat protein (DARPin) G3, a novel binding protein with picomolar affinity for HER2, was used and multifunctional superparamagnetic nanoparticles modified with fluorescein-5-maleimide-labeled DARPin G3 (SPIO-G3-5MF) were developed for HER2 imaging. Our results showed that SPIO-G3-5MF nanoparticles, which possessed uniform size of about 100 nm, favorable dispersity and low cytotoxicity, could selectively bind to HER2-positive breast cancer cells even in the presence of trastuzumab. Biodistribution assay demonstrated that abundant accumulation and long retention of SPIO-G3-5MF were observed in HER2-positive transplantation breast tumors although a portion of SPIO-G3-5MF nanoparticles were unavoidably captured by liver and spleen. Further MR imaging revealed that SPIO-G3-5MF could selectively image HER2-positive transplantation breast tumors, yielding remarkable T2 signal reduction (50.33 ± 2.90% at 6 h and 47.29 ± 9.36% at 24 h). Our study suggested that SPIO-G3-5MF might be a promising MR molecular probe for diagnosing and monitoring HER2 expression state of breast cancer in the future.

[Combined use of thin-section CT and 18F-FDG PET/CT for characterization of solitary pulmonary nodules].

OBJECTIVE: To investigate whether fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) combined with thin-section CT improves the diagnostic performance for solitary pulmonary nodules (SPNs). METHODS: A total of 267 patients underwent examinations with 18F-FDG PET/CT and thin-section CT for evaluating the SPNs with undetermined nature, which was further confirmed by pathological examination or clinical follow-up. The performance of two diagnostic criteria based on findings in PET/CT alone (Criterion 1) and in PET/CT combined with thin-section CT (Criterion 2) were compared. RESULTS: Thin-section CT provided greater diagnostic information for SPNs in 84.2% of the patients. Compared with Criterion 1, the diagnosis based on Criterion 2 significantly increased the diagnostic sensitivity (80.4% vs 91%, P<0.01) and accuracy (76.4% vs 87.2%, P<0.01) for lung cancer. The lesion size and the CT features including lobulation, air bronchogram, and feeding vessel, but not SUVmax, were all helpful for characterizing non-solid SPNs. Thin-section CT rectified diagnostic errors in 50% (20/40) of the cancerous lesions, which had been diagnosed as benign by PET due to their low metabolism. For non-solid SPNs, Criterion 2 showed a significantly higher diagnostic sensitivity than Criterion 1 (90.0% vs 40.0%, P=0.000) but their diagnostic specificity were comparable (75.2% vs 58.3%, P=0.667). For solid nodules, the use of thin-section CT resulted in no significant improvement in the diagnostic performance (P<0.05). CONCLUSION: The combination of PET/CT and thin-section CT creates a synergistic effect for the characterization of SPNs, especially non-solid nodules.

Whole-body 18F-FDG PET/CT for M staging in the patient with newly diagnosed nasopharyngeal carcinoma: Who needs?

OBJECTIVE: Although whole-body fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) (18F-FDG PET/CT) is commonly used for M staging of newly diagnosed nasopharyngeal carcinoma (NPC), some patients may not benefit from this procedure. The present study investigated which patients require this modality for M staging. METHODS: Whole-body 18F FDG PET/CT results and clinical data were collected for 264 patients with newly diagnosed NPC. The relationships between distant metastasis and age, gender, pathological type, lesion size, SUVmax-T, T staging, N staging, SUVmax-N and Epstein-Barr virus (EBV) quantity were retrospectively analysed to identify factors associated with increased risk. RESULTS: Of the 264 patients, only 37 (14.0%) were diagnosed with distant metastasis. Using multiple logistic regression analysis, EBV-positivity (OR=13.1; 95% CI:1.61,106.80), N staging (OR=3.05; 95% CI:1.41,6.63) and T staging (OR=2.16; 95% CI:1.10, 4.24) were significantly related to distant metastasis (all P<0.05). EBV DNA levels≥9000copies/ml, N3 stage and T4 stage were identified as high risk factors. A low risk of distant metastasis was found in patients with 0-1 risk factors and in those with 2 specific risk factors, T3/T4 and N2/N3 staging. Patients with EBV DNA levels ≥9000copies/ml and N3 or T4 staging and those with 3 risk factors had a medium or high risk, with a much higher incidence of distant metastasis (χ2=29.896, P=0.000), and needed a whole-body 18F FDG PET/CT for M staging. CONCLUSIONS: Due to the low incidence of distant metastasis, only patients with medium or high risk need to undergo a whole-body scan.

18F-FDG super bone marrow uptake: A highly potent indicator for the malignant infiltration.

The present study was performed to investigate whether the markedly 2-deoxy-2-(fluorine-18) fluoro-D-glucose (F-FDG) uptake in the bone marrow (BM) is a presentation of malignant infiltration (MI).Super bone marrow uptake (super BMU) was used to name the markedly F-FDG uptake on BM, which was similar to or higher than that of the brain. From April 2008 to December 2015, 31 patients with such presentation were retrospectively reviewed. The F-FDG uptake was semiquantified using SUVmax and BM to cerebellum (BM/C) ratio. The origin of super BMU was diagnosed by pathology. Some blood parameters, as well as fever, were also collected and analyzed. For comparison, 106 patients with mildly and moderately uptake in BM and 20 healthy subjects were selected as the control group.Bone marrow MI was diagnosed in 93.5% (29/31) patients with super BMU, which mostly originated from acute leukemia and highly aggressive lymphoma. The super BMU group had markedly higher F-FDG uptake in the BM than those of mildly and moderately uptake, and the control subjects (all P = 0.000) and the BM/C ratio reached a high of 1.24 ±â€Š0.36. The incidence of bone marrow MI in the super BMU group was markedly higher than that of mildly and moderately uptake (93.5% vs 36.8%, P = 0.000). Based on the receiver operating characteristic analysis, when cut-off values of BM/C and SUVmax were set at 0.835 and 6.560, the diagnostic specificity for bone marrow MI reached the high levels of 91.4% and 95.7%, respectively. In 15 patients with bone marrow MI, the extra-BM malignant lesions were simultaneously detected by F-FDG PET/CT. The liver and the nasal cavity involvements were only found in the patients with lymphoma, but not in those with leukemia. A decrease of leukocyte, hemoglobin, and platelet counts was noted in 48.4%, 86.2%, and 51.5% of patients with bone marrow MI, respectively.The present study revealed that super BMU was a highly potent indicator for the bone marrow MI.

Anti-inflammatory Effect of Mesenchymal Stromal Cell Transplantation and Quercetin Treatment in a Rat Model of Experimental Cerebral Ischemia.

Here, we have investigated the synergistic effect of quercetin administration and transplantation of human umbilical cord mesenchymal stromal cells (HUMSCs) following middle cerebral artery occlusion in rat. Combining quercetin treatment with delayed transplantation of HUMSCs after local cerebral ischemia significantly (i) improved neurological functional recovery; (ii) reduced proinflammatory cytokines (interleukin(IL)-1ß and IL-6), increased anti-inflammatory cytokines (IL-4, IL-10, and transforming growth factor-ß1), and reduced ED-1 positive areas; (iii) inhibited cell apoptosis (caspase-3 expression); and (iv) improved the survival rate of HUMSCs in the injury site. Altogether, our results demonstrate that combined HUMSC transplantation and quercetin treatment is a potential strategy for reducing secondary damage and promoting functional recovery following cerebral ischemia.

Utility of F-18 FDG PET/CT on the evaluation of primary bone lymphoma.

PURPOSE: Primary bone lymphoma (PBL) is a rare type of malignant lymphoma. Few data have been reported regarding the utility of F-18 FDG PET/CT in this disease. The aim of this study was to assess the role of F-18 FDG PET/CT in the diagnosis and therapeutic effect evaluation of PBL. MATERIALS AND METHODS: A total of 19 consecutive patients with PBL were enrolled. Whole-body PET/CT scan was performed for all patients. The diagnosis of PBL was established by histopathology and immunohistochemistry. RESULTS: F-18 FDG PET/CT was positive in 94.7% (18/19) of patients. Uptake of FDG in lesions was intense with SUVmax of 15.14 ± 11.82. Multiple involved lesions were found in 47.4% (9/19) patients, while 52.6% presented with a single involved lesion. Based on the lesions, PET detected 98.9% (87/88) lesions. Among them, 71.6% (63/88) lesions were found to be located in axial skeleton and 28.4% (25/88) in the extremity skeleton. FDG PET/CT also found the lesions infiltrate to the surrounding soft tissue in 84.2% (16/19) patients. On the syn-modality CT, the bone destruction was noted in 43.2% (38/88) of the lesions, of which 50.0% lesions presented as slight change in bone density and 50.0% as severe change. The diagnostic sensitivity of PET was much higher than that of CT (98.9% vs. 43.2%, P=0.000). PET/CT was performed for evaluation of treatment response in 13 patients. In 12 patients with complete response(CR), PET/CT found the 25 lesions were F-18 FDG fully resoluted after treatment, however, bone destruction was still presented in 72.0% (18/25) lesions. CONCLUSIONS: The present study suggests that F-18 FDG PET/CT was a sensitive imaging modality for diagnosis and treatment response evaluation of PBL.

[Incorporation of TV regularization in deconvolution for partial volume correction in PET imaging].

OBJECTIVE: We propose a method using total variation (TV) regularization in deconvolution for partial volume correction in PET imaging. In the degraded image model, we used TV regularization procedure in Van Cittert (VC) and Richardson-Lucy (RL) deconvolution algorithms. These methods were tested in simulated NCAT images and images of NEMA NU4-2008 IQ phantom and tumor-bearing mouse scanned by Simens Invoen microPET. The simulated experiment and tumor-bearing mouse experiment showed that the algorithms using TV regularization provided superior qualitative and quantitative appearance compared with traditional VC and RL algorithms. When the mean intensity of the tumor increased by (10±1.8)%, the SD increase percentage was decreased from 49.98% to 14.26% and from 42.76% to 4.70%, suggesting the efficiency of the proposed algorithms for reducing PVEs in PET.

Usefulness of 18F-FDG PET/CT in the detection of neurolymphomatosis.

PURPOSE: Neurolymphomatosis (NL) is an uncommon complication of lymphoma and leukemia. Few data have been reported regarding the utilization of fluorine-18 fluorodeoxyglucose PET/computed tomography (F-FDG PET/CT) in this disease. The aim of this study was to assess the role of F-FDG PET/CT in the diagnosis of NL. PATIENTS AND METHODS: Eight patients who suffered from NL due to lymphoma or leukemia were studied. The diagnosis of NL lesions was established according to ;the combination of neurologic symptoms, and imaging techniques including MRI and PET/CT, and/or analysis of cerebrospinal fluid, pathology, and clinical follow-up. RESULTS: Eight patients with lymphoma or leukemia were diagnosed with NL during or after treatment. F-FDG PET/CT was positive in all eight patients. A total of 19 NL lesions were detected by F-FDG PET/CT. Morphological abnormality was seen in seven of 19 lesions on the syn-modality CT. However, all lesions were F-FDG avid with a maximum standardized uptake value of 6.42 ± 3.02, and presented with linear and nodular hypermetabolic patterns. There was a significant difference in the detection of NL lesions between PET and syn-modality CT [100% (19/19) vs. 36.8% (7/19), χ=14.74, P<0.001]. The NL lesions were located predominantly in the nerve root of the thoracic and lumbar segments (63.2%). In four patients, PET/CT was performed after treatment and was useful for assessing the treatment response. CONCLUSION: F-FDG PET/CT is a sensitive imaging modality for the detection of NL lesions. Further research involving more patients is needed to confirm our findings.

Biological characters of [18F]O-FEt-PIB in a rat model of Alzheimer's disease using micro-PET imaging.

AIM: To evaluate whether the newly-synthesized positron emission tomography (PET) tracer, [18F]2-(4'-(methylamino)phenyl)-6-fluoroethoxy- benzothiazole ([18F] O-FEt-PIB), could bind to beta-amyloid aggregates in a rat model of Alzheimer's disease (AD) using micro-PET. METHOD: [18F]O-FEt-PIB was synthesized and purified by radio HPLC. PET imaging was performed with a R4 rodent model scanner in 3 model and 3 control rats. Dynamic PET scans were performed for 40 min in each rat following an injection of approximately 37 MBq of [18F]O-FEt-PIB. Static scans were also performed for 15 min in each rat. PET data were reconstructed by a maximum posteriori probability algorithm. On the coronal PET images, regions of interest were respectively placed on the cortex, hemicerebrum [including the hippocampus and thalamus (HT)], and were guided by a 3-D digital map of the rat brain or the brain images of [18F]2-Deoxy-2-fluoro-D-glucose ([18F]FDG) in normal rats. Time-activity curves (TAC) were obtained for the cerebrum and cerebellum. The activity difference value (ADV) between 2 hemicerebrums was also calculated. RESULTS: The TAC for [18F]O-FEt-PIB in the cerebrum or cerebellum peaked early (at approximately 2 min), but washed out a little slowly. In the dynamic and static micro-PET images, increased radioactivity was found in the area of the right HT in the model rats where infused with beta-amyloid (1-40). No distinct difference of radioactivity was found between the right and left HT areas in the control rats. The ADV(HT) was approximately 14.6% in the AD model rats and approximately 4 times greater than that of the control rats (3.9%). CONCLUSION: To our knowledge, this study is the first to evaluate a small molecular PET probe for the beta-amyloid deposits in vivo using micro-PET imaging in an AD-injected rat model. The suitable biological characters showed that the tracer had potential to be developed as a probe for detecting beta-amyloid plaques in AD.