| 1. |
- Eriksson, Olof, et al.
(författare)
-
Quantitative Imaging of Serotonergic Biosynthesis and Degradation in the Endocrine Pancreas
- 2014
-
Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 55:3, s. 460-465
-
Tidskriftsartikel (refereegranskat)abstract
- Serotonergic biosynthesis in the endocrine pancreas, of which the islets of Langerhans is the major constituent, has been implicated in insulin release and β cell proliferation. In this study, we investigated the feasibility of quantitative noninvasive imaging of the serotonergic metabolism in the pancreas using the PET tracer (11)C-5-hydroxy-l-tryptophan ((11)C-5-HTP).METHODS: Uptake of (11)C-5-HTP, and its specificity for key enzymes in the serotonergic metabolic pathway, was assessed in vitro (INS-1 and PANC1 cells and human islet and exocrine preparations) and in vivo (nonhuman primates and healthy and diabetic rats).RESULTS: In vitro tracer uptake in endocrine cells (INS-1 and human islets), but not PANC1 and exocrine cells, was mediated specifically by intracellular conversion into serotonin. Pancreatic uptake of (11)C-5-HTP in nonhuman primates was markedly decreased by inhibition of the enzyme dopa decarboxylase, which converts (11)C-5-HTP to (11)C-serotonin and increased after inhibition of monoamine oxidase-A, the main enzyme responsible for serotonin degradation. Uptake in the rat pancreas was similarly modulated by inhibition of monoamine oxidase-A and was reduced in animals with induced diabetes.CONCLUSION: The PET tracer (11)C-5-HTP can be used for quantitative imaging of the serotonergic system in the endocrine pancreas.
|
|
| 2. |
- Eriksson, Olof, et al.
(författare)
-
The Positron Emission Tomography ligand [11C]5-Hydroxy-Tryptophan can be used as a surrogate marker for the human endocrine pancreas
- 2014
-
Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 63:10, s. 3428-3437
-
Tidskriftsartikel (refereegranskat)abstract
- In humans a well-developed serotonin system is localized to the pancreatic islets while being absent in exocrine pancreas. Assessment of pancreatic serotonin biosynthesis could therefore be used to estimate the human endocrine pancreas. Proof of concept was tested in a prospective clinical trial by comparisons of type 1 diabetic (T1D) patients, with extensive reduction of beta cells, with healthy volunteers (HV).C-peptide negative (i.e. insulin-deficient) T1D subjects (n=10) and HV (n=9) underwent dynamic Positron Emission Tomography with the radiolabeled serotonin precursor [(11)C]5-Hydroxy-Tryptophan ([(11)C]5-HTP).A significant accumulation of [(11)C]5-HTP was obtained in the pancreas of the HV, with large inter-individual variation. A substantial and highly significant reduction (66%) in the pancreatic uptake of [(11)C]5-HTP in T1D subjects was observed, and this was most evident in the corpus and caudal regions of the pancreas where beta-cells normally are the major constituent of the islets.[(11)C]5-HTP retention in the pancreas was reduced in T1D compared to non-diabetic subjects. Accumulation of [(11)C]5-HTP in the pancreas of both HV and subjects with T1D were in agreement with previously reported morphological observations on the beta cell volume implying that [(11)C]5-HTP retention is a useful non-invasive surrogate marker for the human endocrine pancreas.
|
|
| 3. |
- Eriksson, John, et al.
(författare)
-
Surgery and radiofrequency ablation for treatment of liver metastases from midgut and foregut carcinoids and endocrine pancreatic tumors
- 2008
-
Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 32:5, s. 930-938
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Many neuroendocrine tumors (NETs) have a tendency to metastasize to the liver. In case of limited number of metastases, liver surgery or radiofrequency ablation (RFA) may result in apparently total clearance of metastases. However, it is not clear whether such therapy will provide symptom reduction or increased survival.METHODS: Seventy-three patients with foregut (n=6) or midgut carcinoids (n=37) or endocrine pancreatic tumors (n=28), and two patients with NETs without discernable origin were studied. Symptoms were evaluated using a Symptom Severity Score. Liver surgery was performed in 42 operations and RFA on 205 lesions.RESULTS:Apparently total clearance of liver metastases was attained in 1 of 6 patients with foregut carcinoids, 15 of 37 with midgut carcinoids, and 13 of 28 with EPT. Symptom improvement was noted in 12 of 17 (70.6%) patients with carcinoid syndrome, and 75% also reduced their 5-HIAA and P-CgA by at least 50%. Patients with nonfunctioning EPT generally had no improvement of symptoms after surgical/RFA liver treatment, but eight patients had functioning EPT, and four of these reduced their biochemical markers by at least 50%. NETs with higher Ki67 index tended to recur more often. Complications occurred in 9 of 45 open surgery procedures, and in 8 of 203 RFA procedures.CONCLUSIONS:Treatment of liver metastases is successful in midgut carcinoid patients with limited liver metastases. Patients with foregut carcinoid and EPTs recur more often, possibly related to higher Ki67 index, and treatment of liver lesions less often reduces symptoms. Liver resections and RFA may be safely performed, and RFA is associated with few complications.
|
|
| 4. |
- Eriksson, Olof, et al.
(författare)
-
Detection of Metastatic Insulinoma by Positron Emission Tomography with [(68)Ga]Exendin-4 - : a case report
- 2014
-
Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 99:5, s. 1519-1524
-
Tidskriftsartikel (refereegranskat)abstract
- Context: Insulinomas are the most common cause of endogenous hyperinsulinaemic hypoglycaemia in non-diabetic adult patients. They are usually benign and curative surgery is the "gold standard" treatment if they can be localized. Malignant insulinomas are seen in less than 10% and their prognosis is poor. The Glucagon Like Peptide-1 receptor (GLP-1R) is markedly upregulated in insulinomas - especially benign lesions which are difficult to localize with current imaging techniques.Objective:To assess the possibility of the detection of primary and metastatic insulinoma by PET using [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 ([(68)Ga]Exendin-4) in a patient with severe hypoglycemia.Design:Dynamic and static PET/CT examination of a patient using [68Ga]Exendin-4.Setting:Uppsala University Hospital, Uppsala, Sweden.Patients:A patient presented with hypoglycemia requiring continuous intravenous glucose infusions. A pancreatic insulinoma was suspected and an exploratory laparotomy was urgently performed. At surgery, a tumor in the pancreatic tail with an adjacent metastasis was found and a distal pancreatic resection (plus splenectomy) and removal of lymph node was performed. Histopathology showed a WHO grade II insulinoma. Postoperatively hypoglycemia persisted but a PET/CT examination using the neuroendocrine marker [(11)C]-5-hydroxy-L-tryptophan was negative.Interventions:The patient was administered with [(68)Ga]Exendin-4 and examined by dynamic PET over the liver and pancreas.Main Outcome Measures:N/AResults:The stable GLP-1 analogue Exendin-4 was labeled with (68)Ga for PET imaging of GLP-1R expressing tumors. The patient was examined by [(68)Ga]Exendin-4-PET/CT which confirmed several small GLP-1R positive lesions in the liver and a lymph node that could not be conclusively identified by other imaging techniques. The results obtained from the [(68)Ga]Exendin-4-PET/CT examination provided the basis for continued systemic treatment.Conclusion:The results of the [(68)Ga]Exendin-4-PET/CT examination governed the treatment strategy of this particular patient and demonstrated the potential of this technique for future management of patients with this rare, but potentially fatal disease.
|
|
| 5. |
- Eriksson, Olof, et al.
(författare)
-
Species differences in pancreatic binding of DO3A-VS-Cys40-Exendin4
- 2017
-
Ingår i: Acta Diabetologica. - : Springer Science and Business Media LLC. - 0940-5429 .- 1432-5233. ; 54:11, s. 1039-1045
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: Radiolabeled Exendin-4 has been proposed as suitable imaging marker for pancreatic beta cell mass quantification mediated by Glucagon-like peptide-1 receptor (GLP-1R). However, noticeable species variations in basal pancreatic uptake as well as uptake reduction degree due to selective beta cell ablation were observed.METHODS: -Exendin4 Positron Emission Tomography (PET) in the same species. In vitro, ex vivo, and in vivo data formed the basis for calculating the theoretical in vivo contribution of each pancreatic compartment.RESULTS: -Exendin4.CONCLUSIONS: IPR as well as the exocrine GLP-1R density is the main determinants of the species variability in pancreatic uptake. Thus, the IPR in human is an important factor for assessing the potential of GLP-1R as an imaging biomarker for pancreatic beta cells.
|
|
| 6. |
|
|
| 7. |
- Granberg, Dan, et al.
(författare)
-
Liver embolization with trisacryl gelatin microspheres (embosphere) in patients with neuroendocrine tumors
- 2007
-
Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 48:2, s. 180-185
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To report our experience of liver embolization with trisacryl gelatin microspheres (Embospheretrade mark) in patients with metastatic neuroendocrine tumors. MATERIAL AND METHODS: Fifteen patients underwent selective embolization of the right or left hepatic artery with Embosphere. One lobe was embolized in seven patients and both lobes, on separate occasions, in eight patients. Seven patients had midgut carcinoids, two had lung carcinoids, one suffered from a thymic carcinoid, and five had endocrine pancreatic tumors. Eight patients suffered from endocrine symptoms, seven of whom had carcinoid syndrome and one WDHA (watery diarrhea, hypokalemia, achlorhydria) syndrome. RESULTS: Partial radiological response was seen after eight embolizations (in six different patients), stable disease was observed after 13 embolizations (after three of these, necroses occurred), while radiological progression was noted after only two embolizations. Only two patients experienced a biochemical response. Clinical improvement of carcinoid syndrome was observed after five embolizations. There were no major complications. Fever >38 degrees C was seen after all but four embolizations, and urinary tract infections were diagnosed after eight embolizations. CONCLUSION: Selective hepatic artery embolization with Embosphere particles is a safe treatment for patients with metastatic neuroendocrine tumors and may lead to partial radiological response as well as symptomatic improvement of disabling endocrine symptoms.
|
|
| 8. |
|
|
| 9. |
- Selvaraju, Ram Kumar, et al.
(författare)
-
Dosimetry of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 in rodents, pigs, non-human primates and human - : repeated scanning in human is possible.
- 2015
-
Ingår i: American journal of nuclear medicine and molecular imaging. - 2160-8407. ; 5:3, s. 259-69
-
Tidskriftsartikel (refereegranskat)abstract
- Quantitative PET imaging with [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 has potential use in diabetes and cancer. However, the radiation dose to the kidneys has been a concern for the possibility of repeated imaging studies in humans. Therefore, we investigated the dosimetry of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 based on the biodistribution data in rats, pigs, non-human primates (NHP) and a human.Organ distribution of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 in rats (Male Lewis; n=12; 30, 60, and 80 min) was measured ex vivo. The dynamic uptake of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 in the abdomen was assessed by PET/CT scanning of pigs (male; n = 4, 0-60 min), NHP (Female; cynomolgus; n=3; 0-90 min), and human (female; n=1; 0-40, 100, 120 min).The organ distribution data in each species were extrapolated to those of a human, assuming similar distribution between the species. Residence times were assessed by trapezoidal approximation of the kinetic data. Organ doses (mGy/MBq) and the whole body effective dose (mSv/MBq), was extrapolated by using the OLINDA/EXM 1.1 software. The extrapolated human whole body effective dose was 0.017 ± 0.004 (rats), 0.014 ± 0.004 (pigs), 0.017 ± 0.004 (NHP), and 0.016 (human) mSv/MBq. The absorbed dose to the kidneys was limiting:0.33 ± 0.06 (rats), 0.28±0.05 (pigs), 0.65 ± 0.11 (NHP), and 0.28 (human) mGy/MBq, which corresponded to the maximum yearly administered amounts of 455 (rat), 536 (pig), 231 (NHP), and 536 (human) MBq before reaching the yearly kidney limiting dose of 150 mGy. More than 200 MBq of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 can be administered yearly in a human, allowing for repeated (2-4 times) scanning. This potentially enables longitudinal clinical PET imaging studies of the GLP-1R in the pancreas, transplanted islets, or insulinoma.
|
|
| 10. |
- Selvaraju, Ram Kumar, et al.
(författare)
-
Pre-clinical evaluation of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 for imaging of insulinoma
- 2014
-
Ingår i: Nuclear Medicine and Biology. - : Elsevier BV. - 0969-8051 .- 1872-9614. ; 41:6, s. 471-476
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Insulinoma is the most common form of pancreatic endocrine tumors responsible for hyperinsulinism in adults. These tumors overexpress glucagon like peptide-1 (GLP-1) receptor, and biologically stable GLP-1 analogs have therefore been proposed as potential imaging agents. Here, we evaluate the potential of a positron emission tomography (PET) tracer, [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4, for imaging and quantification of GLP-1 receptors (GLP-1R) in insulinoma.METHODS: [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 was evaluated for binding to GLP-1R by in vitro autoradiography binding studies in INS-1 tumor from xenografts. In vivo biodistribution was investigated in healthy control mice, INS-1 xenografted and PANC1 xenografted immunodeficient mice at two different doses of peptide: 2.5μg/kg (baseline) and 100μg/kg (block). In vivo imaging of [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 in xenografted mice was evaluated by small animal PET/CT using a direct comparison with the clinically established insulinoma marker [(11)C]5-hydroxy-tryptophan ([(11)C]5-HTP).RESULTS: GLP-1 receptor density could be quantified in INS-1 tumor biopsies. [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 showed significant uptake (p≤0.05) in GLP1-R positive tissues such as INS-1 tumor, lungs and pancreas upon comparison between baseline and blocking studies. In vivo imaging showed concordant results with higher tumor-to-muscle ratio in INS-1 xenografted mice compared with [(11)C]5-HTP.CONCLUSION: [(68)Ga]Ga-DO3A-VS-Cys(40)-Exendin-4 has high affinity and specificity for GLP-1R expressed on insulinoma in vitro and in vivo.
|
|
