| 1. |
- Eide, Per Kristian, et al.
(författare)
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Mechanisms behind changes of neurodegeneration biomarkers in plasma induced by sleep deprivation.
- 2023
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Ingår i: Brain communications. - 2632-1297. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- Acute sleep deprivation has been shown to affect cerebrospinal fluid and plasma concentrations of biomarkers associated with neurodegeneration, though the mechanistic underpinnings remain unknown. This study compared individuals who, for one night, were either subject to total sleep deprivation or free sleep, (i) examining plasma concentrations of neurodegeneration biomarkers the morning after sleep deprivation or free sleep and (ii) determining how overnight changes in biomarkers plasma concentrations correlate with indices of meningeal lymphatic and glymphatic clearance functions. Plasma concentrations of amyloid-β 40 and 42, phosphorylated tau peptide 181, glial fibrillary acid protein and neurofilament light were measured longitudinally in subjects who from Day 1 to Day 2 either underwent total sleep deprivation (n = 7) or were allowed free sleep (n = 21). The magnetic resonance imaging contrast agent gadobutrol was injected intrathecally, serving as a cerebrospinal fluid tracer. Population pharmacokinetic model parameters of gadobutrol cerebrospinal fluid-to-blood clearance were utilized as a proxy of meningeal lymphatic clearance capacity and intrathecal contrast-enhanced magnetic resonance imaging as a proxy of glymphatic function. After one night of acute sleep deprivation, the plasma concentrations of amyloid-β 40 and 42 were reduced, but not the ratio, and concentrations of the other biomarkers were unchanged. The overnight change in amyloid-β 40 and 42 plasma concentrations in the sleep group correlated significantly with indices of meningeal lymphatic clearance capacity, while this was not seen for the other neurodegeneration biomarkers. However, overnight change in plasma concentrations of amyloid-β 40 and 42 did not correlate with the glymphatic marker. On the other hand, the overnight change in plasma concentration of phosphorylated tau peptide 181 correlated significantly with the marker of glymphatic function in the sleep deprivation group but not in the sleep group. The present data add to the evidence of the role of sleep and sleep deprivation on plasma neurodegeneration concentrations; however, the various neurodegeneration biomarkers respond differently with different mechanisms behind sleep-induced alterations in amyloid-β and tau plasma concentrations. Clearance capacity of meningeal lymphatics seems more important for sleep-induced changes in amyloid-β 40 and 42 plasma concentrations, while glymphatic function seems most important for change in plasma concentration of phosphorylated tau peptide 181 during sleep deprivation. Altogether, the present data highlight diverse mechanisms behind sleep-induced effects on concentrations of plasma neurodegeneration biomarkers.
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| 2. |
- Heck, Ansgar, et al.
(författare)
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Intensity of pituitary adenoma on T2-weighted magnetic resonance imaging predicts the response to octreotide treatment in newly diagnosed acromegaly
- 2012
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Ingår i: Clinical Endocrinology. - : Wiley. - 0300-0664 .- 1365-2265. ; 77:1, s. 72-78
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Tidskriftsartikel (refereegranskat)abstract
- Background Primary, preoperative medical treatment is an option in selected patients with acromegaly, but a subset of patients respond poorly. Valid prediction of response to somatostatin analogues (SA) might thus alter treatment stratification. The aims of this study were to assess whether T2 signal intensity could determine long-term response to first-line SA treatment and to assess clinical and biochemical baseline characteristics, as well as histological subtype in relation to the magnetic resonance imaging (MRI) appearances. Methods In 45 newly diagnosed patients, T2-weighted signal intensity of the tumour was classified into hypo-, iso- or hyperintense. Biochemical and clinical baseline variables for the three groups were compared. In 25 patients primarily treated with long-acting SA for a median of 6 months [interquartile range (IQR):155180 days], GH and IGF-1 reduction was assessed, and in 34 cases, immunohistochemical granulation pattern was evaluated. Results The results showed that 12 (27%) adenomas were hypointense, 15 (33%) isointense and 18 (40%) hyperintense. Median IGF-1 [ratio IGF-1/ULN; (upper limit of normal)] was 3.5 (2.34.9), 2.9 (2.63.8) and 1.9 (1.32.6), respectively (P = 0.006 for difference between groups). Median GH values (mu g/l) of a 3- to 5-point profile were 17.5 (6.135), 9.3 (6.032.5) and 4.1 (1.58.3), (P = 0.025). Median IGF-1 reduction (% of baseline) after first-line SA treatment was 51 (4970), 36 (1974) and 13 (542) (P = 0.03); median reduction in GH (% of baseline) was 86 (7294), 78 (6285) and 46 (170) (P = 0.02). T2 hyperintensity was associated with sparse granulation pattern on immunohistochemistry. Conclusion In patients with acromegaly, T2 signal intensity at diagnosis correlates with histological features and predicts biochemical outcome of first-line SA treatment.
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| 3. |
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| 4. |
- Heck, Ansgar, et al.
(författare)
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Quantitative analyses of T2-weighted MRI as a potential marker for response to somatostatin analogs in newly diagnosed acromegaly
- 2016
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Ingår i: Endocrine. - : Springer Science and Business Media LLC. - 1355-008X .- 1559-0100. ; 52:2, s. 333-343
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Tidskriftsartikel (refereegranskat)abstract
- In growth hormone (GH)-producing adenomas, T2-weighted MRI signal intensity is a marker for granulation pattern and response to somatostatin analogs (SSA). Prediction of treatment response is necessary for individualized treatment, and T2 intensity assessment might improve preoperative classification of somatotropinomas. The objectives of this study are (I) to explore the feasibility of quantitative T2-weighted MRI histogram analyses in newly diagnosed somatotroph adenomas and their relation to clinical and histological parameters and (II) to compare the quantitative method to conventional, visual assessment of T2 intensity. The study was a retrospective cohort study of 58 newly diagnosed patients. In 34 of these, response to primary SSA treatment after median 6 months was evaluated. Parameters from the T2 histogram analyses (T2 intensity ratio and T2 homogeneity ratio) were correlated to visually assessed T2 intensity (hypo-, iso-, hyperintense), baseline characteristics, response to SSA treatment, and histological granulation pattern (anti-Cam5.2). T2 intensity ratio was lowest in the hypointense tumors and highest in the hyperintense tumors (0.66 ± 0.10 vs. 1.07 ± 0.11; p < 0.001). T2 intensity at baseline correlated with reduction in GH (r = -0.67; p < 0.001) and IGF-1 (r = -0.36; p = 0.037) after primary SSA treatment (n = 34). The T2 homogeneity ratio correlated with adenoma size reduction (r = -0.45; p = 0.008). Sparsely granulated adenomas had a higher T2 intensity than densely or intermediately granulated adenomas. T2 histogram analyses are an applicable tool to assess T2 intensity in somatotroph adenomas. Quantitatively assessed T2 intensity ratio in GH-producing adenomas correlates with conventional assessment of T2 intensity, baseline characteristics, response to SSA treatment, and histological granulation pattern.
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| 5. |
- Kolnes, Anders J., et al.
(författare)
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FSH Levels Are Related to E-cadherin Expression and Subcellular Location in Nonfunctioning Pituitary Tumors
- 2020
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : ENDOCRINE SOC. - 0021-972X .- 1945-7197. ; 105:8, s. 2587-2594
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Tidskriftsartikel (refereegranskat)abstract
- Context: Gonadotroph pituitary neuroendocrine tumors (PitNETs) can express follicle-stimulating hormone (FSH) and luteinizing hormone (LH) or be hormone negative, but they rarely secrete hormones. During tumor development, epithelial cells develop a mesenchymal phenotype. This process is characterized by decreased membranous E-cadherin and translocation of E-cadherin to the nucleus. Estrogen receptors (ERs) regulate both E-cadherin and FSH expression and secretion. Whether the hormone status of patients with gonadotroph PitNETs is regulated by epithelial-to-mesenchymal transition (EMT) and ERs is unknown. Objectives: To study the effect of EMT on hormone expression in gonadotroph nonfunctioning (NF)-PitNETs. Design: Molecular and clinical analyses of 105 gonadotroph PitNETs. Immunohistochemical studies and real-time quantitative polymerase chain reaction were performed for FSH, LH, E-cadherin, and ER alpha. Further analyses included blood samples, clinical data, and radiological images. Setting: All patients were operated on in the same tertiary referral center. Results: NF-PitNET with high FSH expression had decreased immunohistochemical staining for membranous E-cadherin (P < .0001) and increased staining for nuclear E-cadherin (P < .0001). Furthermore, high FSH expression was associated with increased ER alpha staining (P = .0002) and ER alpha mRNA (P = .0039). Circulating levels of plasma-FSH (P-FSH) correlated with FSH staining in gonadotroph NF-PitNET (P = .0025). Tumor size and invasiveness was not related to FSH staining, E-cadherin, or ER alpha. LH expression was not associated with E-cadherin or ER alpha. Conclusion: In gonadotroph PitNETs, FSH staining is related to E-cadherin, ER alpha expression, and circulating levels of P-FSH. There was no association between FSH staining and invasiveness. The clinical significance of these findings will be investigated in ongoing prospective studies.
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| 6. |
- Kolnes, Anders Jensen, et al.
(författare)
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TGFBR3L is associated with gonadotropin production in non-functioning gonadotroph pituitary neuroendocrine tumours
- 2023
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Ingår i: Pituitary. - : Springer. - 1386-341X .- 1573-7403. ; 26:2, s. 227-236
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Transforming growth factor-beta receptor 3-like (TGFBR3L) is a pituitary enriched membrane protein selectively detected in gonadotroph cells. TGFBR3L is named after transforming growth factor-beta receptor 3 (TGFBR3), an inhibin A co-receptor in mice, due to sequence identity to the C-terminal region. We aimed to characterize TGFBR3L detection in a well-characterized, prospectively collected cohort of non-functioning pituitary neuroendocrine tumours (NF-PitNETs) and correlate it to clinical data.Methods 144 patients operated for clinically NF-PitNETs were included. Clinical, radiological and biochemical data were recorded. Immunohistochemical (IHC) staining for FSH beta and LH beta was scored using the immunoreactive score (IRS), TGFBR3L and TGFBR3 were scored by the percentage of positive stained cells.Results TGFBR3L staining was selectively present in 52% of gonadotroph tumours. TGFBR3L was associated to IRS of LH beta (median 2 [IQR 0-3] in TGFBR3L negative and median 6 [IQR 3-9] in TGFBR3L positive tumours, p < 0.001), but not to the IRS of FSH beta (p = 0.32). The presence of TGFBR3L was negatively associated with plasma gonadotropin concentrations in males (P-FSH median 5.5 IU/L [IQR 2.9-9.6] and median 3.0 [IQR 1.8-5.6] in TGFBR3L negative and positive tumours respectively, p = 0.008) and P-LH (median 2.8 IU/L [IQR 1.9-3.7] and median 1.8 [IQR 1.1-3.0] in TGFBR3L negative and positive tumours respectively, p = 0.03). TGFBR3 stained positive in 22% (n = 25) of gonadotroph tumours with no correlation to TGFBR3L.Conclusion TGFBR3L was selectively detected in half (52%) of gonadotroph NF-PitNETs. The association to LH beta staining and plasma gonadotropins suggests that TGFBR3L may be involved in hormone production in gonadotroph NF-PitNETs.
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| 7. |
- Lekva, Tove, et al.
(författare)
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Epithelial Splicing Regulator Protein 1 and Alternative Splicing in Somatotroph Adenomas
- 2013
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 154:9, s. 3331-3343
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Tidskriftsartikel (refereegranskat)abstract
- Somatotroph adenomas secrete supraphysiological amounts of GH, causing acromegaly. We have previously hypothesized that epithelial mesenchymal transition (EMT) may play a central role in the progression of these adenomas and that epithelial splicing regulator 1 (ESRP1) may function prominently as a master regulator of the EMT process in pituitary adenomas causing acromegaly. To further elucidate the role of ESRP1 in somatotroph adenomas and in EMT progression, we used RNA sequencing (RNAseq) to sequence somatotroph adenomas characterized by high and low ESRP1 levels. Transcripts identified by RNAseq were analyzed in 65 somatotroph adenomas and in GH-producing pituitary rat cells with a specific knockdown of Esrp1. The clinical importance of the transcripts was further investigated by correlating mRNA expression levels with clinical indices of disease activity and treatment response. Many of the transcripts and isoforms identified by RNAseq and verified by quantitative PCR were involved in vesicle transport and calcium signaling and were associated with clinical outcomes. Silencing Esrp1 in GH3 cells resulted in changes of gene expression overlapping the data observed in human somatotroph adenomas and revealed a decreased granulation pattern and attenuated GH release. We observed an alternative splicing pattern for F-box and leucine-rich repeat protein 20, depending on the ESPR1 levels and on changes in circulating IGF-I levels after somatostatin analog treatment. Our study indicates that ESRP1 in somatotroph adenomas regulates transcripts that may be essential in the EMT progression and in the response to somatostatin analog treatment.
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| 8. |
- Oystese, Kristin Astrid, et al.
(författare)
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Early postoperative growth in non-functioning pituitary adenomas : A tool to tailor safe follow-up
- 2017
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Ingår i: Endocrine. - : Springer Science and Business Media LLC. - 1355-008X .- 1559-0100. ; 57:1, s. 35-45
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Tidskriftsartikel (refereegranskat)abstract
- Non-functioning pituitary adenomas are common, and the treatment and follow-up of these patients represent a multidisciplinary challenge. First line treatment is transphenoidal surgery, with debulking or total removal of tumour. A substantial portion of the tumours relapse after surgery, and there is no consensus of how to follow these patients postoperatively. Our aim was to characterize the postoperative growth of non-functioning pituitary adenomas and correlate it to clinical and paraclinical data.We retrospectively registered 52 patients operated for non-functioning pituitary adenomas, with four or more consecutive MR-investigations not interrupted by secondary treatment. Adenoma volumes were estimated by the Cavalieri principle with summation of manually drawn areas multiplied by slice interval. Growth curves were modelled and tumour volume doubling time was calculated for 39 tumours with regrowth after surgery.A total of 13 tumours showed exponential growth, 10 linear growth and 16 logistic growth after surgery. The remaining 13 did not show regrowth of tumour. Seven of the exponential growing tumours underwent secondary surgery, compared to one and two of linear and logistic growing tumours (p = 0.03), respectively. Initial tumour volume doubling time was significantly lower in logistic growing tumours than in exponential growing tumours (p < 0.01). Men had tumours with lower tumour volume doubling time than women (p = 0.03). None of the tumours demonstrated signs of accelerated growth.Residual tumours following surgery frequently grow. The logistic growing tumours had the fastest initial growth in our cohort. We found no indication of accelerated growth, whereby the tumour volume doubling time might be used to predict a "worst-case" scenario when planning follow-up of these patients.
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| 9. |
- Stoverud, Karen-Helene, et al.
(författare)
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Computational Investigation of Cerebrospinal Fluid Dynamics in the Posterior Cranial Fossa and Cervical Subarachnoid Space in Patients with Chiari I Malformation
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Previous computational fluid dynamics (CFD) studies have demonstrated that the Chiari malformation is associated with abnormal cerebrospinal fluid (CSF) flow in the cervical part of the subarachnoid space (SAS), but the flow in the SAS of the posterior cranial fossa has received little attention. This study extends previous modelling efforts by including the cerebellomedullary cistern, pontine cistern, and 4th ventricle in addition to the cervical subarachnoid space. Methods The study included one healthy control, Con1, and two patients with Chiari I malformation, P1 and P2. Meshes were constructed by segmenting images obtained from T2-weighted turbo spin-echo sequences. CFD simulations were performed with a previously verified and validated code. Patient-specific flow conditions in the aqueduct and the cervical SAS were used. Two patients with the Chiari malformation and one control were modelled. Results The results demonstrated increased maximal flow velocities in the Chiari patients, ranging from factor 5 in P1 to 14.8 in P2, when compared to Con1 at the level of Foramen Magnum (FM). Maximal velocities in the cervical SAS varied by a factor 2.3, while the maximal flow in the aqueduct varied by a factor 3.5. The pressure drop from the pontine cistern to the cervical SAS was similar in Con1 and P1, but a factor two higher in P2. The pressure drop between the aqueduct and the cervical SAS varied by a factor 9.4 where P1 was the one with the lowest pressure jump and P2 and Con1 differed only by a factor 1.6. Conclusion This pilot study demonstrates that including the posterior cranial fossa is feasible and suggests that previously found flow differences between Chiari I patients and healthy individuals in the cervical SAS may be present also in the SAS of the posterior cranial fossa.
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| 10. |
- van Osch, Matthias J. P., et al.
(författare)
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Human brain clearance imaging : pathways taken by magnetic resonance imaging contrast agents after administration in cerebrospinal fluid and blood
- 2024
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Ingår i: NMR in Biomedicine. - : John Wiley & Sons. - 0952-3480 .- 1099-1492. ; 37:9
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Forskningsöversikt (refereegranskat)abstract
- Over the last decade, it has become evident that cerebrospinal fluid (CSF) plays a pivotal role in brain solute clearance through perivascular pathways and interactions between the brain and meningeal lymphatic vessels. Whereas most of this fundamental knowledge was gained from rodent models, human brain clearance imaging has provided important insights into the human system and highlighted the existence of important interspecies differences. Current gold standard techniques for human brain clearance imaging involve the injection of gadolinium-based contrast agents and monitoring their distribution and clearance over a period from a few hours up to 2 days. With both intrathecal and intravenous injections being used, which each have their own specific routes of distribution and thus clearance of contrast agent, a clear understanding of the kinetics associated with both approaches, and especially the differences between them, is needed to properly interpret the results. Because it is known that intrathecally injected contrast agent reaches the blood, albeit in small concentrations, and that similarly some of the intravenously injected agent can be detected in CSF, both pathways are connected and will, in theory, reach the same compartments. However, because of clear differences in relative enhancement patterns, both injection approaches will result in varying sensitivities for assessment of different subparts of the brain clearance system. In this opinion review article, the "EU Joint Programme – Neurodegenerative Disease Research (JPND)" consortium on human brain clearance imaging provides an overview of contrast agent pharmacokinetics in vivo following intrathecal and intravenous injections and what typical concentrations and concentration–time curves should be expected. This can be the basis for optimizing and interpreting contrast-enhanced MRI for brain clearance imaging. Furthermore, this can shed light on how molecules may exchange between blood, brain, and CSF.
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