| 1. |
- Wickelgren, Ruth, 1965, et al.
(författare)
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Expression of exon 3-retaining and exon 3-excluding isoforms of the human growth hormone-receptor is regulated in an interindividual, rather than a tissue-specific, manner.
- 1995
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Ingår i: The Journal of clinical endocrinology and metabolism. - 0021-972X. ; 80:7, s. 2154-7
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Tidskriftsartikel (refereegranskat)abstract
- GH has multiple effects on growth and metabolism, and these functions are mediated through binding to specific cell surface receptors. The human GH receptor (GHR) exists in two known isoforms; in one form exon 3 is present (GHR3+), and in the other, exon 3 is absent (GHR3-). Recent reports have suggested that the expression of the two isoforms is tissue specific and/or developmentally regulated. We used a reverse transcription-polymerase chain reaction assay to study the expression pattern of the two isoforms in a variety of tissues from normal subjects and patients with acromegaly. In skeletal muscle from both normal subjects and patients with acromegaly, the GHR3+ transcript was expressed, either alone or together with the shorter (GHR3-) transcript. When multiple tissues from six subjects were tested, the expression of the two isoforms varied among subjects, whereas different tissues from the same subject showed the same expression pattern. These results indicate that the expression of the GHR isoforms is not tissue specific. Instead, the expression of the GHR isoforms appears to be specific for each individual, suggesting that it is under the control of factors that affect all tissues in the body.
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| 2. |
- Bjarnason, Ragnar, 1959, et al.
(författare)
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Cartilage oligomeric matrix protein increases in serum after the start of growth hormone treatment in prepubertal children
- 2004
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 89:10, s. 5156-60
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Tidskriftsartikel (refereegranskat)abstract
- Both GH and IGF-I stimulate bone growth, but the molecular mechanisms mediating their effects on the growth plate are not fully understood. We measured gene expression by microarray analysis in primary cultured human chondrocytes treated with either GH or IGF-I. One of the genes found to be up-regulated by both GH and IGF-I was that encoding cartilage oligomeric matrix protein (COMP). This protein is predominantly found in the extracellular matrix of cartilage. Mutations in the COMP gene have been associated with syndromes of short stature. To verify that COMP is regulated by GH in vivo, we measured COMP levels in serum in short children treated with GH. The study included 113 short prepubertal children (14 girls and 99 boys) with a mean (+/- sd) age of 8.84 +/- 2.76 yr, height sd score of -2.74 +/- 0.67, and IGF-I sd score of -1.21 +/- 1.07 at the start of GH administration. Serum levels of COMP were 1.58 +/- 0.28, 1.83 +/- 0.28 (P < 0.0001), 1.91 +/- 0.28 (P < 0.0001), 1.78 +/- 0.28 (P < 0.001), and 1.70 +/- 0.24 (P < 0.05) microg/ml at baseline and after 1 wk and 1, 3, and 12 months, respectively.In conclusion, we have demonstrated that COMP expression is up-regulated by both GH and IGF-I in primary cultured human chondrocytes. Furthermore, serum levels of COMP increase after the start of GH treatment in short children.
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| 3. |
- Lundqvist, Annika, 1969, et al.
(författare)
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The Arachidonate 15-Lipoxygenase Enzyme Product 15-HETE Is Present in Heart Tissue from Patients with Ischemic Heart Disease and Enhances Clot Formation
- 2016
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Ischemic heart disease is a major cause of death and morbidity and the search for novel therapeutic targets is still required. We have previously shown that the enzyme arachidonate 15 lipoxygenase (ALOX15), which catalyzes the conversion of arachidonic acid to 15-hydroxy eicosatetraenoic acid (15-HETE), is highly expressed in ischemic heart tissue, but its role in the pathogenesis of ischemic heart disease is unclear. Here we showed that expression of ALOX15, but not ALOX12 or ALOX15B, was increased in ischemic versus non-ischemic human heart biopsy samples. A similar ALOX expression pattern was found in hypoxic human cardiomyocytes and cardiac endothelial cells. We also showed that levels of 15-HETE were significantly higher in ischemic versus non-ischemic human heart biopsy samples and showed a tendency to increase in serum from the patients with ischemic heart disease. Moreover, hypoxia increased the production of 15-HETE levels from human cardiomyocytes and cardiac endothelial cells. The hypoxia-induced increase in 15-HETE levels from human cardiomyocytes was inhibited by the ALOX15 inhibitor baicalein. Finally, by using intrinsic rotational thromboelastometry, we showed that human whole blood clotted faster in the presence of 15-HETE. In summary, we propose that increased ALOX15 expression in heart tissue under ischemic conditions may lead to increased production of 15-HETE, potentially contributing to thrombosis.
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| 4. |
- Rotter Sopasakis, Victoria, 1972, et al.
(författare)
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Elevated Glucose Levels Preserve Glucose Uptake, Hyaluronan Production, and Low Glutamate Release Following Interleukin-1 beta Stimulation of Differentiated Chondrocytes
- 2019
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Ingår i: Cartilage. - : SAGE Publications. - 1947-6035 .- 1947-6043. ; 10:4, s. 491-503
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Tidskriftsartikel (refereegranskat)abstract
- Objective Chondrocytes are responsible for remodeling and maintaining the structural and functional integrity of the cartilage extracellular matrix. Because of the absence of a vascular supply, chondrocytes survive in a relatively hypoxic environment and thus have limited regenerative capacity during conditions of cellular stress associated with inflammation and matrix degradation, such as osteoarthritis (OA). Glucose is essential to sustain chondrocyte metabolism and is a precursor for key matrix components. In this study, we investigated the importance of glucose as a fuel source for matrix repair during inflammation as well as the effect of glucose on inflammatory mediators associated with osteoarthritis. Design To create an OA model, we used equine chondrocytes from 4 individual horses that were differentiated into cartilage pellets in vitro followed by interleukin-1 beta (IL-1 beta) stimulation for 72 hours. The cells were kept at either normoglycemic conditions (5 mM glucose) or supraphysiological glucose concentrations (25 mM glucose) during the stimulation with IL-1 beta. Results We found that elevated glucose levels preserve glucose uptake, hyaluronan synthesis, and matrix integrity, as well as induce anti-inflammatory actions by maintaining low expression of Toll-like receptor-4 and low secretion of glutamate. Conclusions Adequate supply of glucose to chondrocytes during conditions of inflammation and matrix degradation interrupts the detrimental inflammatory cycle and induces synthesis of hyaluronan, thereby promoting cartilage repair.
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| 5. |
- Skiöldebrand, Eva, et al.
(författare)
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Biochemical alterations in inflammatory reactive chondrocytes: evidence for intercellular network communication
- 2018
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Ingår i: Heliyon. - : Elsevier BV. - 2405-8440. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Chondrocytes are effectively involved in the pathophysiological processes of inflammation in joints. They form cellular processes in the superficial layer of the articular cartilage and form gap junction coupled syncytium to facilitate cell-to-cell communication. However, very little is known about their physiological cellular identity and communication. The aim with the present work is to evaluate the physiological behavior after stimulation with the inflammatory inducers interleukin-1 beta and lipopolysaccharide. The cytoskeleton integrity and intracellular Ca2+ release were assessed as indicators of inflammatory state. Cytoskeleton integrity was analyzed through cartilage oligomeric matrix protein and actin labeling with an Alexa 488-conjugated phalloidin probe. Ca2+ responses were assessed through the Ca2+ sensitive fluorophore Fura-2/AM. Western blot analyses of several inflammatory markers were performed. The results show reorganization of the actin filaments. Glutamate, 5-hydoxytryptamine, and ATP evoked intracellular Ca2+ release changed from single peaks to oscillations after inflammatory induction in the chondrocytes. The expression of toll-like receptor 4, the glutamate transporters GLAST and GLT-1, and the matrix metalloproteinase-13 increased. This work demonstrates that chondrocytes are a key part in conditions that lead to inflammation in the cartilage. The inflammatory inducers modulate the cytoskeleton, the Ca2+ signaling, and several inflammatory parameters. In conclusion, our data show that the cellular responses to inflammatory insults from healthy and inflammatory chondrocytes resemble those previously observed in astrocyte and cardiac fibroblasts networks.
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| 6. |
- Walser, M., et al.
(författare)
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Local overexpression of GH and GH/IGF1 effects in the adult mouse hippocampus
- 2012
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Ingår i: Journal of Endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 215:2, s. 257-268
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Tidskriftsartikel (refereegranskat)abstract
- GH therapy improves hippocampal functions mainly via circulating IGF1. However, the roles of local GH and IGF1 expression are not well understood. We investigated whether transgenic (TG) overexpression in the adult brain of bovine GH (bGH) under the control of the glial fibrillary acidic protein (GFAP) promoter affected cellular proliferation and the expression of transcripts known to be induced by systemic GH in the hippocampus. Cellular proliferation was examined by 5-bromo-2'-deoxyuridine immunohistochemistry. Quantitative PCR and western blots were performed. Although robustly expressed, bGH-Tg did not increase either cell proliferation or survival. However, bGH-Tg modestly increased Igf1 and Gfap mRNAs, whereas other GH-associated transcripts were unaffected, i.e. the GH receptor (Ghr), IGF1 receptor (Igf1r), 2',3'-cyclic nucleotide 3'-phosphodiesterase (Cnp), ionotropic glutamate receptor 2a (Nr2a (Grin2a)), opioid receptor delta (Dor), synapse-associated protein 90/postsynaptic density-95-associated protein (Sapap2 (Dlgap2)), haemoglobin beta (Hbb) and glutamine synthetase (Gs (Glul)). However, IGF1R was correlated with the expression of Dor, Nr2a, Sapap2, Gs and Gfap. In summary, although local bGH expression was robust, it activated local IGF1 very modestly, which is probably the reason for the low response of previous GH-associated response parameters. This would, in turn, indicate that hippocampal GH is less important than endocrine GH. However, as most transcripts were correlated with the expression of IGF1R, there is still a possibility for endogenous circulating or local GH to act via IGF1R signalling. Possible reasons for the relative bio-inactivity of bGH include the bell-shaped dose-response curve and cell-specific expression of bGH. Journal of Endocrinology (2012) 215, 257-268
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| 7. |
- Walser, Marion, 1961, et al.
(författare)
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Local overexpression of GH and GH/IGF1 effects in the adult mouse hippocampus.
- 2012
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Ingår i: The Journal of endocrinology. - 1479-6805. ; 215:2, s. 257-68
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Tidskriftsartikel (refereegranskat)abstract
- GH therapy improves hippocampal functions mainly via circulating IGF1. However, the roles of local GH and IGF1 expression are not well understood. We investigated whether transgenic (TG) overexpression in the adult brain of bovine GH (bGH) under the control of the glial fibrillary acidic protein (GFAP) promoter affected cellular proliferation and the expression of transcripts known to be induced by systemic GH in the hippocampus. Cellular proliferation was examined by 5-bromo-2'-deoxyuridine immunohistochemistry. Quantitative PCR and western blots were performed. Although robustly expressed, bGH-Tg did not increase either cell proliferation or survival. However, bGH-Tg modestly increased Igf1 and Gfap mRNAs, whereas other GH-associated transcripts were unaffected, i.e. the GH receptor (Ghr), IGF1 receptor (Igf1r), 2',3'-cyclic nucleotide 3'-phosphodiesterase (Cnp), ionotropic glutamate receptor 2a (Nr2a (Grin2a)), opioid receptor delta (Dor), synapse-associated protein 90/postsynaptic density-95-associated protein (Sapap2 (Dlgap2)), haemoglobin beta (Hbb) and glutamine synthetase (Gs (Glul)). However, IGF1R was correlated with the expression of Dor, Nr2a, Sapap2, Gs and Gfap. In summary, although local bGH expression was robust, it activated local IGF1 very modestly, which is probably the reason for the low response of previous GH-associated response parameters. This would, in turn, indicate that hippocampal GH is less important than endocrine GH. However, as most transcripts were correlated with the expression of IGF1R, there is still a possibility for endogenous circulating or local GH to act via IGF1R signalling. Possible reasons for the relative bio-inactivity of bGH include the bell-shaped dose-response curve and cell-specific expression of bGH.
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| 8. |
- Walser, Marion, 1961, et al.
(författare)
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Mode of GH administration and gene expression in the female rat brain.
- 2017
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Ingår i: The Journal of endocrinology. - 1479-6805. ; 233:2, s. 187-196
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Tidskriftsartikel (refereegranskat)abstract
- The endogenous secretion of growth hormone (GH) is sexually dimorphic in rats with females having a more even and males a more pulsatile secretion and low trough levels. The mode of GH administration, mimicking the sexually dimorphic secretion, has different systemic effects. In the brains of male rats, we have previously found that the mode of GH administration differently affects neuron-haemoglobin beta (Hbb) expression whereas effects on other transcripts were moderate. The different modes of GH administration could have different effects on brain transcripts in female rats. Hypophysectomised female rats were given GH either as injections twice daily or as continuous infusion and GH-responsive transcripts were assessed by quantitative reverse transcription polymerase chain reaction in the hippocampus and parietal cortex (cortex). The different modes of GH-administration markedly increased Hbb and 5'-aminolevulinate synthase 2 (Alas2) in both brain regions. As other effects were relatively moderate, a mixed model analysis (MMA) was used to investigate general effects of the treatments. In the hippocampus, MMA showed that GH-infusion suppressed glia- and neuron-related transcript expression levels, whereas GH-injections increased expression levels. In the cortex, GH-infusion instead increased neuron-related transcripts, whereas GH-injections had no significant effect. Interestingly, this contrasts to previous results obtained from male rat cortex where GH-infusion generally decreased expression levels. In conclusion, the results indicate that there is a small but significant difference in response to mode of GH administration in the hippocampus as compared to the cortex. For both modes of GH administration, there was a robust effect on Hbb and Alas2.
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| 9. |
- Wickelgren, Ruth, 1965
(författare)
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The growth hormone receptor and growth hormone sensitivity in man
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is well established that the response to endogenous and exogenous growth hormone (GH) varies between individuals. For example, conditions with increased catabolic rate, such as trauma, sepsis and surgery, are believed to be associated with acquired GH insensitivity. To overcome the GH resistance, high doses of GH have therefore been used in attempt to preserve lean body mass in catabolic patients. However, in two recent studies the mortality rate was dramatically increased in critically ill patients given GH, indicating that the patients did not have generalised GH resistance. With the exception of patients with complete GH insensitivity due to GH receptor (GHR) mutations, little is known about the mechanisms behind the variation in GH sensitivity. Detailed studies of GH sensitivity in man have been hampered by the lack of methods sensitive enough to allow measurements in small tissue biopsies. The general aim of this thesis was to study GH sensitivity in man. To measure the expression of the GHR and insulin-like growth factor I (IGF-I) in GH target tissues, novel PCR based methods were developed and used on samples from patients with post surgical catabolism and patients with psoriasis. In addition, the expression of two GHR isoforms (GHR3+ and GHR3-) and 5´-untranslated regions (UTR) of GHR transcripts were examined. The first study showed that the alternative splicing of GHR transcripts, generating GHR3+ and GHR3- isoforms, is regulated in an interindividual rather than a tissue-specific manner and the splicing was not regulated by GH.The effects of surgically induced catabolism on GH sensitivity were investigated in three different studies in patients undergoing elective abdominal surgery. In patients given standardised glucose infusion postoperatively, GHR expression in skeletal muscle was decreased three days after surgery (day 3) compared to the time of surgery (day 0). In two other studies, where the patients were given total parenteral nutrition with or without glutamine postoperatively, GHR expression in skeletal muscle did not change significantly. IGF-I mRNA levels were decreased or not altered in skeletal muscle in response to surgery. Furthermore, GH administration prevented a postsurgical decrease in IGF-I mRNA in skeletal muscle. In one study, where both skeletal muscle and adipose tissue were available, the changes in GHR expression correlated with the changes in IGF-I expression from day 0 to day 3 in both tissues. In contrast to skeletal muscle, IGF-I mRNA levels increased in adipose tissue in response to surgery, suggesting tissue differences in GH sensitivity. This was further investigated in a patient in whom GHR expression increased in adipose tissue and decreased in skeletal muscle after surgery. In this patient, the use of different 5´-UTRs in GHR transcripts differed between skeletal muscle and adipose tissue, suggesting that the tissue-specific variation in GH sensitivity may be explained by differential activation of specific GHR promoter regions. The studies in patients undergoing surgery also demonstrate that the changes in GHR and IGF-I gene expression in GH target tissues are not reflected by similar changes in plasma levels of the corresponding gene products, GH-binding protein and IGF-I.In patients with psoriasis, GHR mRNA levels in epidermis and serum levels of GH-binding protein, IGF-I and IGF-binding protein 3 were similar to those in control subjects, indicating that alterations in the GH/IGF-I axis do not play a major role in the pathogenesis of psoriasis.In contrast to the belief that catabolism is associated with generalised GH insensitivity, data in this study indicate that GH sensitivity can differ between tissues. Therefore, the high doses of GH that are used to prevent muscle breakdown in catabolic patients could result in undesired effects in some tissues, e.g. adipose tissue, where GH sensitivity appears to be increased.
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