| 1. |
- Aranda-Guillén, Maribel, et al.
(författare)
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A polygenic risk score to help discriminate primary adrenal insufficiency of different etiologies.
- 2023
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Ingår i: Journal of internal medicine. - : John Wiley & Sons. - 0954-6820 .- 1365-2796. ; 294:1, s. 96-109
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune Addison's disease (AAD) is the most common cause of primary adrenal insufficiency (PAI). Despite its exceptionally high heritability, tools to estimate disease susceptibility in individual patients are lacking. We hypothesized that polygenic risk score (PRS) for AAD could help investigate PAI pathogenesis in pediatric patients.We here constructed and evaluated a PRS for AAD in 1223 seropositive cases and 4097 controls. To test its clinical utility, we reevaluated 18 pediatric patients, whose whole genome we also sequenced. We next explored the individual PRS in more than 120 seronegative patients with idiopathic PAI.The genetic susceptibility to AAD-quantified using PRS-was on average 1.5 standard deviations (SD) higher in patients compared with healthy controls (p<2e-16), and 1.2 SD higher in the young patients compared with the old (p=3e-4). Using the novel PRS, we searched for pediatric patients with strikingly low AAD susceptibility and identified cases of monogenic PAI, previously misdiagnosed as AAD. By stratifying seronegative adult patients by autoimmune comorbidities and disease duration we could delineate subgroups of PRS suggesting various disease etiologies.The PRS performed well for case-control differentiation and susceptibility estimation in individual patients. Remarkably, a PRS for AAD holds promise as a means to detect disease etiologies other than autoimmunity.
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| 2. |
- Botusan, Ileana Ruxandra
(författare)
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Pathogenic mechanisms behind dysregulated angiogenesis with focus on HIF and IGF-I signaling
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Angiogenesis is a complexly regulated process activated to assure cells with normal supplies of nutrients and oxygen. Playing such an essential role in the homeostasis of tissues, it is critical to understand its physiology and pathology to be able to design therapies for several diseases where angiogenesis is dysregulated (either excessive or diminished). We aim to better characterize the angiogenesis during chronic complications of diabetes and tumors, focusing on the roles of two pathogenic factors common for both diseases: hypoxia inducible factor (HIF) and insulin-like growth factor (IGF). Chronic complications of diabetes significantly increase the mortality and morbidity in patients with diabetes and lack for the moment efficient therapies. Hypoxia along with hyperglycemia has been relatively newly identified as a pathogen ic factor for complications in diabetes. We have therefore investigated in our studies the cross-talk between hyperglycemia and hypoxia and we have demonstrated that cells fail to properly adapt to hypoxia due to repression of HIF’s stability and function in the presence of high glucose. Moreover we have shown that hyperglycemia leads to HIF destabilisation through a VHL-mediated mechanism and complexly affects the HIF transactivation. In agreement with the in vitro data, we have detected repressed HIF in ulcers of diabetic mice. Local stabilization of HIF, either pharmacologically or by adenovir us mediated transfer, improves wound healing rate in diabetic mice, which indicates the pathogenic relevance of the hyperglycemia-induced HIF repression for diabetes complications. We further studied the consequences of the HIF repression in diabetes and identified that it is also responsible for increased mitochondrial radical oxygen species (ROS), which are essential for the development of chronic complications of diabetes. In consequence the stabilization of HIF is followed by normaliz ation of ROS production, both in vitro and in vivo, even under the persistence of the high glucose concentrations. In a third study we investigated the role of IGF-I for diabetic wound healing. IGF-I, a growth factor and regulator of angiogenesis, is secreted into the blood stream by the liver but also produced locally in the tissues. The relative contributions of local vs systemic IGF for wound healing is still unclear. This is even more relevant for diabetic wounds where reduced IGF-I levels were detected. We demonstrated here that liver-derived IGF-I does not affect wound healing in mice with or without diabetes. This indicates that local therapy with IGF-I is sufficient for improving wound healing in diabetes, avoiding the potential side effects of a systemic therapy. Dysregulated angiogenesis is also essential for tumor development. Kaposi’s sarcoma (KS) is a highly vascularized tumor and its biology is dependent on angiogenic stimuli. We demonstrated here that the vascularized phenotype characteristic for KS is highly dependent on the interplay between IGF-I and HIF. We showed that IGF-I induced accumulation of both HIF-1α and HIF-2α paralogues. IGF increased also HIF activity as demonstrated by the HRE reporter gene assay and by induction of VEGF (classic target gene of HIF). We have further described that IGF induces HIF accumulation by increasing the translation of the HIF-α subunits. The biological relevance of the HIF signaling in KS biology was highlighted by its expression through all the characteristic progressive stages of the disease. Moreover, we demonstrated that blocking the IGF-IR signaling decreases HIF accumulation and blunts the VEGF expression, offering a promising therapeutic option in the management of KS. In conclusion, we identified new mechanisms of dysregulated angiogenesis in diabetes and tumors and proposed new therapeutic strategies based on our findings.
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| 3. |
- Chang, Ya-Ting, et al.
(författare)
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Perlecan heparan sulfate deficiency impairs pulmonary vascular development and attenuates hypoxic pulmonary hypertension
- 2015
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Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 107:1, s. 20-31
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Tidskriftsartikel (refereegranskat)abstract
- Aims Excessive vascular cell proliferation is an important component of pulmonary hypertension (PH). Perlecan is the major heparan sulfate (HS) proteoglycan in the vascular extracellular matrix. It binds growth factors, including FGF2, and either restricts or promotes cell proliferation. In this study, we have explored the effects of perlecan HS deficiency on pulmonary vascular development and in hypoxia-induced PH. Methods and results In normoxia, Hspg2(Delta 3/Delta 3) mice, deficient in perlecan HS, had reduced pericytes and muscularization of intra-acinar vessels. Pulmonary angiography revealed a peripheral perfusion defect. Despite these abnormalities, right ventricular systolic pressure (RVSP) and myocardial mass remained normal. After 4 weeks of hypoxia, increases in the proportion of muscularized vessels, RVSP, and right ventricular hypertrophy were significantly less in Hspg2(Delta 3/Delta 3) compared with wild type. The early phase of hypoxia induced a significantly lower increase in fibroblast growth factor receptor-1 (FGFR1) protein level and receptor phosphorylation, and reduced pulmonary artery smooth muscle cell (PASMC) proliferation in Hspg2(Delta 3/Delta 3). At 4 weeks, FGF2 mRNA and protein were also significantly reduced in Hspg2(Delta 3/Delta 3) lungs. Ligand and carbohydrate engagement assay showed that perlecan HS is required for HS-FGF2-FGFR1 ternary complex formation. In vitro, proliferation assays showed that PASMC proliferation is reduced by selective FGFR1 inhibition. PASMC adhesion to fibronectin was higher in Hspg2(Delta 3/Delta 3) compared with wild type. Conclusions Perlecan HS chains are important for normal vascular arborization and recruitment of pericytes to pulmonary vessels. Perlecan HS deficiency also attenuates hypoxia-induced PH, where the underlying mechanisms involve impaired FGF2/FGFR1 interaction, inhibition of PASMC growth, and altered cell-matrix interactions.
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| 4. |
- Eriksson, Daniel, et al.
(författare)
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GWAS for autoimmune Addison’s disease identifies multiple risk loci and highlights AIRE in disease susceptibility
- 2021
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune Addison's disease (AAD) is characterized by the autoimmune destruction of the adrenal cortex. Low prevalence and complex inheritance have long hindered successful genetic studies. We here report the first genome-wide association study on AAD, which identifies nine independent risk loci (P < 5 × 10-8). In addition to loci implicated in lymphocyte function and development shared with other autoimmune diseases such as HLA, BACH2, PTPN22 and CTLA4, we associate two protein-coding alterations in Autoimmune Regulator (AIRE) with AAD. The strongest, p.R471C (rs74203920, OR = 3.4 (2.7-4.3), P = 9.0 × 10-25) introduces an additional cysteine residue in the zinc-finger motif of the second PHD domain of the AIRE protein. This unbiased elucidation of the genetic contribution to development of AAD points to the importance of central immunological tolerance, and explains 35-41% of heritability (h2).
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| 5. |
- Zheng, Xiaowei, et al.
(författare)
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Repression of hypoxia-inducible factor-1 contributes to increased mitochondrial reactive oxygen species production in diabetes
- 2022
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Excessive production of mitochondrial reactive oxygen species (ROS) is a central mechanism for the development of diabetes complications. Recently, hypoxia has been identified to play an additional pathogenic role in diabetes. In this study, we hypothesized that ROS overproduction was secondary to the impaired responses to hypoxia due to the inhibition of hypoxia-inducible factor-1 (HIF-1) by hyperglycemia. Methods: The ROS levels were analyzed in the blood of healthy subjects and individuals with type 1 diabetes after exposure to hypoxia. The relation between HIF-1, glucose levels, ROS production and its functional consequences were analyzed in renal mIMCD-3 cells and in kidneys of mouse models of diabetes. Results: Exposure to hypoxia increased circulating ROS in subjects with diabetes, but not in subjects without diabetes. High glucose concentrations repressed HIF-1 both in hypoxic cells and in kidneys of animals with diabetes, through a HIF prolyl-hydroxylase (PHD)-dependent mechanism. The impaired HIF-1 signaling contributed to excess production of mitochondrial ROS through increased mitochondrial respiration that was mediated by Pyruvate dehydrogenase kinase 1 (PDK1). The restoration of HIF-1 function attenuated ROS overproduction despite persistent hyperglycemia, and conferred protection against apoptosis and renal injury in diabetes. Conclusions: We conclude that the repression of HIF-1 plays a central role in mitochondrial ROS overproduction in diabetes and is a potential therapeutic target for diabetic complications. These findings are timely since the first PHD inhibitor that can activate HIF-1 has been newly approved for clinical use. Funding: This work was supported by grants from the Swedish Research Council, Stockholm County Research Council, Stockholm Regional Research Foundation, Bert von Kantzows Foundation, Swedish Society of Medicine, Kung Gustaf V:s och Drottning Victorias Frimurarestifelse, Karolinska Institute's Research Foundations, Strategic Research Programme in Diabetes, and Erling-Persson Family Foundation for S-B.C.; grants from the Swedish Research Council and Swedish Heart and Lung Foundation for T.A.S.; and ERC consolidator grant for M.M.
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| 6. |
- Öster, Sara, et al.
(författare)
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Self-management and hospitalization in 615 Swedish patients with Addison's disease during the COVID-19 pandemic : a retrospective study
- 2023
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Ingår i: European Journal of Endocrinology. - : Bioscientifica. - 0804-4643 .- 1479-683X. ; 188:2
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Autoimmune Addison's disease (AAD) entails a chronic adrenal insufficiency and is associated with an increased risk of severe infections. It is, however, unknown how patients with AAD were affected by the coronavirus disease 2019 (COVID-19) pandemic of 2020-2021. The aim of this study was to investigate the incidence of COVID-19 in patients with AAD in Sweden, the self-adjustment of medications during the disease, impact on social aspects and treatment during hospitalization. Additionally, we investigated if there were any possible risk factors for infection and hospitalization.DESIGN AND METHODS: Questionnaires were sent out from April to October 2021 to 813 adult patients with AAD in the Swedish Addison registry. The questionnaires included 55 questions inquiring about COVID-19 sickness, hospital care, medications, and co-morbidities, focusing on the pre-vaccine phase.RESULTS: Among the 615 included patients with AAD, COVID-19 was reported by 17% of which 8.5% required hospital care. Glucocorticoid treatment in hospitalized patients varied. For outpatients 85% increased their glucocorticoid dosage during sickness. Older age (p=0.002) and hypertension (p=0.014) were associated with an increased risk of hospital care while younger age (p<0.001) and less worry about infection (p=0.030) correlated with a higher risk of COVID-19.CONCLUSIONS: In the largest study to date examining AAD during the COVID-19 pandemic, we observed that although one fifth of the cohort contracted COVID-19 few patients required hospital care. A majority of the patients applied general recommended sick-rules despite reporting limited communication with healthcare during the pandemic.
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