Marie Svedberg

Background: Stress may have an impact on the course of inflammatory bowel disease (IBD), but evidence is still lacking regarding a potential association between perceived (subjective) stress and objectively measured stress and whether patients’ levels of stress in relapse differ from those in remission. The aim of this study was to investigate patients’ level of stress in relapse and in remission. Methods: Twenty-three patients with active IBD participated in the study. Cortisol was assessed in saliva and in blood to obtain objective measurements. For subjective measurements, the patients completed the Short Health Scale (SHS) and Perceived Stress Scale (PSS) questionnaires. Physiological measurements were taken, and questionnaires were completed at the beginning of relapse and when the patient was classified as being in remission. Relapses and remissions were determined by endoscopic examination and faecal calprotectin. Results: Cortisol levels did not differ between measurements in active disease and in remission (7.50 ± 5.52 vs. 5.55 ± 2.65). PSS showed no differences between the two measurements (13 vs. 16, p-value 0.83). Inflammatory cytokines IL-6 (1.97 ± 2.47 vs. 0.72 ± 0.43, p < 0.05) and IL-8 (6.84 ± 3.57 vs. 2.94 ± 2.79, p < 0.001) were significantly lower during remission compared with active disease. Conclusions: This study demonstrated low to moderate levels of perceived stress in patients with IBD during active disease and remission. The results also showed significantly elevated levels of the pro-inflammatory cytokines IL-6 and IL-8 in serum during relapse compared with remission. However, no evidence of elevated objective stress was found when levels of cortisol in saliva were measured. Further research is needed to establish the possible association between stress and IBD and how it affects patients.

Background: Stress may have an impact on the course of inflammatory bowel disease (IBD), but evidence is still lacking regarding a potential association between perceived (subjective) stress and objectively measured stress, and whether patients’ levels of stress in relapse differ from those in remission. The aim of this study was to investigate patients’ level of stress in relapse and in remission. Methods: Twenty-three patients with active IBD participated in the study. Cortisol was assessed in saliva and in blood to obtain objective measurements. For subjective meas-urements, the patients completed the Short Health Scale (SHS) and Perceived Stress Scale (PSS) questionnaires. Physiological measurements were taken and questionnaires com-pleted at the beginning of relapse and when the patient was classified as being in re-mission. Relapses and remissions were determined by endoscopic examination and faecal calprotectin. Results: Cortisol levels did not differ between measurements in active disease and in remission. PSS showed no differences between the two measurements, but on both oc-casions medium-high levels of stress were shown. Inflammatory cytokines IL-6 and IL-8 showed significantly lowered values at remission. Conclusion: This study demonstrated moderate levels of perceived stress in patients with IBD, both during active disease and remission. However, no evidence of elevated ob-jective stress was found when levels of cortisol in saliva were measured. Further research is needed to establish the possible association between stress and IBD and how it affects patients.

Background/Objectives: Leucine-rich repeat kinase 2 (LRRK2) is an enzyme implicated in Parkinson’s disease (PD) and a potential therapeutic target. LRRK2 PET radioligands could therefore function as imaging biomarkers for PD and as tools to measure enzyme occupancy of novel therapeutic candidates. This study aimed at developing novel radioligands for imaging using positron emission tomography (PET). Specific objectives were to synthesize fluorine-18-labeled pyrrolopyridine 1 ([¹⁸F]1), pyrrolo-pyrimidine 2 ([¹⁸F]2), as well as carbon-11-labeled pyrrolo-pyrimidine 3 ([¹¹C]3), and examine their binding specificity, using in vitro autoradiography (ARG) and in vivo positron emission tomography (PET) imaging in non-human primates (NHPs). Methods: Radiolabeling was achieved either by classical one-step fluorine-18 nucleophilic substitution reaction or by methylation using carbon-11 methane. [¹⁸F]1 and [¹⁸F]2 were tested in NHP and human whole-hemisphere ARG experiments. PET imaging was performed in cynomolgus monkeys. Radiometabolites were measured in monkey plasma using gradient HPLC. Results: The results demonstrated successful radiolabeling of all three ligands. In ARG studies, both [¹⁸F]1 and [¹⁸F]2 displayed binding in brain slices from NHP and human samples. The binding of [¹⁸F]1 was blocked by cold Compound 1 and structurally distinct Compound 3, but not by the structurally distinct LRRK2 inhibitor PFE-360. On the other hand, the binding of [¹⁸F]2 was blocked by PFE-360 in certain regions of the brain, indicating some level of specific binding to LRRK2. All three ligands showed relevant brain uptake (>3%ID), with highest uptake being observed for [¹⁸F]1, particularly in the thalamus. In contrast, brain uptake of [¹⁸F]2 and [¹¹C]3 was evenly distributed across all brain regions. No blocking effect of [¹⁸F]1 was observed after pretreatment with the structurally distinct LRRK2 inhibitors PFE-360 (0.5 mg/kg, iv) and GEN-7915 (40 mg/kg). Conclusions: PET imaging indicated a low in vivo specific binding of the radioligands in the cynomolgus monkey brain, suggesting that the radioligands are not suitable for LRRK2 imaging in vivo with PET. This study emphasizes the challenges in the development of PET radioligands for imaging LRRK2 and the need for additional work to achieve this goal.

The G-protein-coupled receptor 44 (GPR44) is a beta cell-restricted target that may serve as a marker for beta cell mass (BCM) given the development of a suitable PET ligand. The binding characteristics of the selected candidate, AZ12204657, at human GPR44 were determined using in vitro ligand binding assays. AZ12204657 was radiolabeled using 11C- or 3H-labeled methyl iodide ([11C/3H]CH3I) in one step, and the conversion of [11C/3H]CH3I to the radiolabeled product [11C/3H]AZ12204657 was quantitative. The specificity of radioligand binding to GPR44 and the selectivity for beta cells were evaluated by in vitro binding studies on pancreatic sections from human and non-human primates as well as on homogenates from endocrine and exocrine pancreatic compartments. The radiochemical purity of the resulting radioligand [11C]AZ12204657 was > 98%, with high molar activity (MA), 1351 ± 575 GBq/μmol (n = 18). The radiochemical purity of [3H]AZ12204657 was > 99% with MA of 2 GBq/μmol. Pancreatic binding of [11C/3H]AZ12204657 was co-localized with insulin-positive islets of Langerhans in non-diabetic individuals and individuals with type 2 diabetes (T2D). The binding of [11C]AZ12204657 to GPR44 was > 10 times higher in islet homogenates compared to exocrine homogenates. In human islets of Langerhans GPR44 was co-expressed with insulin, but not glucagon as assessed by co-staining and confocal microscopy. We radiolabeled [11C]AZ12204657, a potential PET radioligand for the beta cell-restricted protein GPR44. In vitro evaluation demonstrated that [3H]AZ12204657 and [11C]AZ12204657 selectively target pancreatic beta cells. [11C]AZ12204657 has promising properties as a marker for human BCM.