Publications by authors named "Daniel Bergemalm"

13 Publications

  • Page 1 of 1

Platelet proteome and function in X-linked thrombocytopenia with thalassemia and in silico comparisons with gray platelet syndrome.

Haematologica 2020 09 28;Online ahead of print. Epub 2020 Sep 28.

Department of Medicine, Faculty of Medicine and Health, Örebro University, Örebro.

In X-linked thrombocytopenia with thalassemia (XLTT; OMIM 314050), caused by the mutation p.R216Q in exon 4 of the GATA1 gene, male hemizygous patients display macrothrombocytopenia, bleeding diathesis and a β-thalassemia trait. Herein, we describe findings in two unrelated Swedish XLTT families with a bleeding tendency exceeding what is expected from the thrombocytopenia. Blood tests revealed low P-PAI-1 and P-factor 5, and elevated S-thrombopoietin levels. Transmission electron microscopy showed diminished numbers of platelet α- and dense granules. The proteomes of isolated blood platelets from 5 male XLTT patients, compared to 5 gender- and age matched controls, were explored. Quantitative mass spectrometry showed alterations of 83 proteins (fold change ≥±1.2, q< .05). Of 46 downregulated proteins, 39 were previously reported to be associated with platelet granules. Reduced protein levels of PTGS1 and SLC35D3 were validated in megakaryocytes of XLTT bone marrow biopsies by immunohistochemistry. Platelet function testing by flow cytometry revealed low dense- and α-granule release and fibrinogen binding in response to ligation of receptors for ADP, the thrombin receptor PAR4 and the collagen receptor GPVI. Significant reductions of a number of α-granule proteins overlapped with a previous platelet proteomics investigation in the inherited macrothrombocytopenia gray platelet syndrome (GPS). In contrast, Ca2+ transporter proteins that facilitate dense granule release were downregulated in XLTT but upregulated in GPS. Ingenuity Pathway Analysis showed altered Coagulation System and Protein Ubiquitination pathways in the XLTT platelets. Collectively, the results revealed protein and functional alterations affecting platelet α- and dense granules in XLTT, probably contributing to bleeding.
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http://dx.doi.org/10.3324/haematol.2020.249805DOI Listing
September 2020

The use of 5-aminosalicylate for patients with Crohn's disease in a prospective European inception cohort with 5 years follow-up - an Epi-IBD study.

United European Gastroenterol J 2020 10 26;8(8):949-960. Epub 2020 Jul 26.

Hull University Teaching Hospitals NHS Trust, Hull, UK.

Background: The lack of scientific evidence regarding the effectiveness of 5-aminosalicylate in patients with Crohn's disease is in sharp contrast to its widespread use in clinical practice.

Aims: The aim of the study was to investigate the use of 5-aminosalicylate in patients with Crohn's disease as well as the disease course of a subgroup of patients who were treated with 5-aminosalicylate as maintenance monotherapy during the first year of disease.

Methods: In a European community-based inception cohort, 488 patients with Crohn's disease were followed from the time of their diagnosis. Information on clinical data, demographics, disease activity, medical therapy and rates of surgery, cancers and deaths was collected prospectively. Patient management was left to the discretion of the treating gastroenterologists.

Results: Overall, 292 (60%) patients with Crohn's disease received 5-aminosalicylate period during follow-up for a median duration of 28 months (interquartile range 6-60). Of these, 78 (16%) patients received 5-aminosalicylate monotherapy during the first year following diagnosis. Patients who received monotherapy with 5-aminosalicylate experienced a mild disease course with only nine (12%) who required hospitalization, surgery, or developed stricturing or penetrating disease, and most never needed more intensive therapy. The remaining 214 patients were treated with 5-aminosalicylate as the first maintenance drug although most eventually needed to step up to other treatments including immunomodulators (75 (35%)), biological therapy (49 (23%)) or surgery (38 (18%)).

Conclusion: In this European community-based inception cohort of unselected Crohn's disease patients, 5-aminosalicylate was commonly used. A substantial group of these patients experienced a quiescent disease course without need of additional treatment during follow-up. Therefore, despite the controversy regarding the efficacy of 5-aminosalicylate in Crohn's disease, its use seems to result in a satisfying disease course for both patients and physicians.
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http://dx.doi.org/10.1177/2050640620945949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707880PMC
October 2020

Vitamin D deficiency in a European inflammatory bowel disease inception cohort: an Epi-IBD study.

Eur J Gastroenterol Hepatol 2018 11;30(11):1297-1303

Pekka Collin Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland.

Background: Serum vitamin D level is commonly low in patients with inflammatory bowel disease (IBD). Although there is a growing body of evidence that links low vitamin D level to certain aspects of IBD such as disease activity and quality of life, data on its prevalence and how it varies across disease phenotype, smoking status and treatment groups are still missing.

Materials And Methods: Patients diagnosed with IBD between 2010 and 2011 were recruited. Demographic data and serum vitamin D levels were collected. Variance of vitamin D level was then assessed across different treatment groups, disease phenotype, disease activity and quality of life scores.

Results: A total of 238 (55.9% male) patients were included. Overall, 79% of the patients had either insufficient or deficient levels of vitamin D at diagnosis. Patients needing corticosteroid treatment at 1 year had significantly lower vitamin D levels at diagnosis (median 36.0 nmol/l) (P=0.035). Harvey-Bradshaw Index (P=0.0001) and Simple Clinical Colitis Activity Index scores (P=0.0001) were significantly lower in patients with higher vitamin D level. Serum vitamin D level correlated significantly with SIBQ score (P=0.0001) and with multiple components of SF12. Smokers at diagnosis had the lowest vitamin D levels (vitamin D: 34 nmol/l; P=0.053).

Conclusion: This study demonstrates the high prevalence of low vitamin D levels in treatment-naive European IBD populations. Furthermore, it demonstrates the presence of low vitamin D levels in patients with IBD who smoke.
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http://dx.doi.org/10.1097/MEG.0000000000001238DOI Listing
November 2018

Subphenotypes of inflammatory bowel disease are characterized by specific serum protein profiles.

PLoS One 2017 5;12(10):e0186142. Epub 2017 Oct 5.

Department of Gastroenterology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.

Objective: Genetic and immunological data indicate that inflammatory bowel disease (IBD) are characterized by specific inflammatory protein profiles. However, the serum proteome of IBD is still to be defined. We aimed to characterize the inflammatory serum protein profiles of Crohn's disease (CD) and ulcerative colitis (UC), using the novel proximity extension assay.

Methods: A panel of 91 inflammatory proteins were quantified in a discovery cohort of CD (n = 54), UC patients (n = 54), and healthy controls (HCs; n = 54). We performed univariate analyses by t-test, with false discovery rate correction. A sparse partial least-squares (sPLS) approach was used to identify additional discriminative proteins. The results were validated in a replication cohort.

Results: By univariate analysis, 17 proteins were identified with significantly different abundances in CD and HCs, and 12 when comparing UC and HCs. Additionally, 64 and 45 discriminant candidate proteins, respectively, were identified with the multivariate approach. Correspondingly, significant cross-validation error rates of 0.12 and 0.19 were observed in the discovery cohort. Only FGF-19 was identified from univariate comparisons of CD and UC, but 37 additional discriminant candidates were identified using the multivariate approach. The observed cross-validation error rate for CD vs. UC remained significant when restricting the analyses to patients in clinical remission. Using univariate comparisons, 16 of 17 CD-associated proteins and 8 of 12 UC-associated proteins were validated in the replication cohort. The area under the curve for CD and UC was 0.96 and 0.92, respectively, when the sPLS model from the discovery cohort was applied to the replication cohort.

Conclusions: By using the novel PEA method and a panel of inflammatory proteins, we identified proteins with significantly different quantities in CD patients and UC patients compared to HCs. Our data highlight the potential of the serum IBD proteome as a source for identification of future diagnostic biomarkers.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186142PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5628935PMC
November 2017

Long-term effectiveness of vedolizumab in inflammatory bowel disease: a national study based on the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG).

Scand J Gastroenterol 2017 Jun - Jul;52(6-7):722-729. Epub 2017 Mar 31.

a Department of Gastroenterology, Faculty of Medicine and Health , Örebro University , Örebro , Sweden.

Objectives: Clinical trials have demonstrated the efficacy of vedolizumab in inflammatory bowel disease (IBD). However, these findings may not reflect the clinical practice. Therefore, we aimed to describe a vedolizumab-treated patient population and assess long-term effectiveness.

Materials And Methods: Patients initiating vedolizumab between 1 June 2014 and 30 May 2015 were identified through the Swedish National Quality Registry for IBD. Prospectively collected data on treatment and disease activity were extracted. Clinical remission was defined as Patient Harvey Bradshaw index <5 in Crohn's disease (CD) and Patient Simple Clinical Colitis Activity index <3 in ulcerative colitis (UC).

Results: Two-hundred forty-six patients (147 CD, 92 UC and 7 IBD-Unclassified) were included. On study entry, 86% had failed TNF-antagonist and 48% of the CD patients had undergone ≥1 surgical resection. After a median follow-up of 17 (IQR: 14-20) months, 142 (58%) patients remained on vedolizumab. In total, 54% of the CD- and 64% of the UC patients were in clinical remission at the end of follow-up, with the clinical activity decreasing (p < .0001 in both groups). Faecal-calprotectin decreased in CD (p < .0001) and in UC (p = .001), whereas CRP decreased in CD (p = .002) but not in UC (p = .11). Previous anti-TNF exposure (adjusted HR: 4.03; 95% CI: 0.96-16.75) and elevated CRP at baseline (adjusted HR: 2.22; 95% CI: 1.10-4.35) seemed to be associated with discontinuation because of lack of response. Female sex was associated with termination because of intolerance (adjusted HR: 2.75; 95% CI: 1.16-6.48).

Conclusion: Vedolizumab-treated patients represent a treatment-refractory group. A long-term effect can be achieved, even beyond 1 year of treatment.
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http://dx.doi.org/10.1080/00365521.2017.1304987DOI Listing
October 2017

Elevated fecal peptidase D at onset of colitis in Galphai2-/- mice, a mouse model of IBD.

PLoS One 2017 21;12(3):e0174275. Epub 2017 Mar 21.

School of Medical Sciences, Faculty of Medicine and Health, University of Örebro, Örebro, Sweden.

Background: The identification of novel fecal biomarkers in inflammatory bowel disease (IBD) is hampered by the complexity of the human fecal proteome. On the other hand, in experimental mouse models there is probably less variation. We investigated the fecal protein content in mice to identify possible biomarkers and pathogenic mechanisms.

Methods: Fecal samples were collected at onset of inflammation in Galphai2-/- mice, a well-described spontaneous model of chronic colitis, and from healthy littermates. The fecal proteome was analyzed by two-dimensional electrophoresis and quantitative mass spectrometry and results were then validated in a new cohort of mice.

Results: As a potential top marker of disease, peptidase D was found at a higher ratio in Galphai2-/- mouse feces relative to controls (fold change 27; p = 0.019). Other proteins found to be enriched in Gαi2-/- mice were mainly pancreatic proteases, and proteins from plasma and blood cells. A tendency of increased calprotectin, subunit S100-A8, was also observed (fold change 21; p = 0.058). Proteases are potential activators of inflammation in the gastrointestinal tract through their interaction with the proteinase-activated receptor 2 (PAR2). Accordingly, the level of PAR2 was found to be elevated in both the colon and the pancreas of Galphai2-/- mice at different stages of disease.

Conclusions: These findings identify peptidase D, an ubiquitously expressed intracellular peptidase, as a potential novel marker of colitis. The elevated levels of fecal proteases may be involved in the pathogenesis of colitis and contribute to the clinical phenotype, possibly by activation of intestinal PAR2.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0174275PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5360340PMC
September 2017

Novel antibodies reveal inclusions containing non-native SOD1 in sporadic ALS patients.

PLoS One 2010 Jul 14;5(7):e11552. Epub 2010 Jul 14.

Department of Medical Biosciences, Umeå University, Umeå, Sweden.

Mutations in CuZn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) and are found in 6% of ALS patients. Non-native and aggregation-prone forms of mutant SOD1s are thought to trigger the disease. Two sets of novel antibodies, raised in rabbits and chicken, against peptides spaced along the human SOD1 sequence, were by enzyme-linked immunosorbent assay and an immunocapture method shown to be specific for denatured SOD1. These were used to examine SOD1 in spinal cords of ALS patients lacking mutations in the enzyme. Small granular SOD1-immunoreactive inclusions were found in spinal motoneurons of all 37 sporadic and familial ALS patients studied, but only sparsely in 3 of 28 neurodegenerative and 2 of 19 non-neurological control patients. The granular inclusions were by confocal microscopy found to partly colocalize with markers for lysosomes but not with inclusions containing TAR DNA binding protein-43, ubiquitin or markers for endoplasmic reticulum, autophagosomes or mitochondria. Granular inclusions were also found in carriers of SOD1 mutations and in spinobulbar muscular atrophy (SBMA) patients and they were the major type of inclusion detected in ALS patients homozygous for the wild type-like D90A mutation. The findings suggest that SOD1 may be involved in ALS pathogenesis in patients lacking mutations in the enzyme.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011552PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904380PMC
July 2010

Superoxide dismutase-1 and other proteins in inclusions from transgenic amyotrophic lateral sclerosis model mice.

J Neurochem 2010 Jul 19;114(2):408-18. Epub 2010 Apr 19.

Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden.

Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from four different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intra-subunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, four were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.
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http://dx.doi.org/10.1111/j.1471-4159.2010.06753.xDOI Listing
July 2010

Changes in the spinal cord proteome of an amyotrophic lateral sclerosis murine model determined by differential in-gel electrophoresis.

Mol Cell Proteomics 2009 Jun 8;8(6):1306-17. Epub 2009 Apr 8.

Clinical Chemistry, Dept. of Medical Biosciences, Umeå University, SE-90185 Umeå, Sweden.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by loss of motor neurons resulting in progressive paralysis. To date, more than 140 different mutations in the gene encoding CuZn-superoxide dismutase (SOD1) have been associated with ALS. Several transgenic murine models exist in which various mutant SOD1s are expressed. We used DIGE to analyze the changes in the spinal cord proteome induced by expression of the unstable SOD1 truncation mutant G127insTGGG (G127X) in mice. Unlike mutants used in most other models, G127X lacks SOD activity and is present at low levels, thus reducing the risk of overexpression artifacts. The mice were analyzed at their peak body weights just before onset of symptoms. Variable importance plot analysis showed that 420 of 1,800 detected protein spots contributed significantly to the differences between the groups. By MALDI-TOF MS analysis, 54 differentially regulated proteins were identified. One spot was found to be a covalently linked mutant SOD1 dimer, apparently analogous to SOD1-immunoreactive bands migrating at double the molecular weight of SOD1 monomers previously detected in humans and mice carrying mutant SOD1s and in sporadic ALS cases. Analyses of affected functional pathways and the subcellular representation of alterations suggest that the toxicity exerted by mutant SODs induces oxidative stress and affects mitochondria, cellular assembly/organization, and protein degradation.
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http://dx.doi.org/10.1074/mcp.M900046-MCP200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2690489PMC
June 2009

Inclusions of amyotrophic lateral sclerosis-linked superoxide dismutase in ventral horns, liver, and kidney.

Ann Neurol 2008 May;63(5):671-5

Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden.

Mutant superoxide dismutases type 1 (SOD1s) cause amyotrophic lateral sclerosis by an unidentified toxic property. In a patient carrying the G127X truncation mutation, minute amounts of SOD1 were found in ventral horns using a mutant-specific antibody. Still, both absolute levels and ratios versus wild-type SOD1 were considerably greater than in other central nervous system areas and peripheral organs. Inclusions of mutant SOD1 were abundant in motoneurons but were also seen in hepatocytes and kidney epithelium. This first examination of mutant SOD1 in both central nervous system and peripheral organs supports the notion that enrichment of misfolded SOD1s might explain the particular vulnerability of motor areas.
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http://dx.doi.org/10.1002/ana.21356DOI Listing
May 2008

Soluble misfolded subfractions of mutant superoxide dismutase-1s are enriched in spinal cords throughout life in murine ALS models.

Proc Natl Acad Sci U S A 2007 Aug 21;104(35):14157-62. Epub 2007 Aug 21.

Department of Medical Biosciences, Umeå University, SE-901 85 Umeå, Sweden.

Mutants of superoxide dismutase-1 (SOD1) cause ALS by an unidentified cytotoxic mechanism. We have previously shown that the stable SOD1 mutants D90A and G93A are abundant and show the highest levels in liver and kidney in transgenic murine ALS models, whereas the unstable G85R and G127X mutants are scarce but enriched in the CNS. These data indicated that minute amounts of misfolded SOD1 enriched in the motor areas might exert the ALS-causing cytotoxicity. A hydrophobic interaction chromatography (HIC) protocol was developed with the aim to determine the abundance of soluble misfolded SOD1 in tissues in vivo. Most G85R and G127X mutant SOD1s bound in the assay, but only minute subfractions of the D90A and G93A mutants. The absolute levels of HIC-binding SOD1 were, however, similar and broadly inversely related to lifespans in the models. They were generally enriched in the susceptible spinal cord. The HIC-binding SOD1 was composed of disulfide-reduced subunits lacking metal ions and also subunits that apparently carried nonnative intrasubunit disulfide bonds. The levels were high from birth until death and were comparable to the amounts of SOD1 that become sequestered in aggregates in the terminal stage. The HIC-binding SOD1 species ranged from monomeric to trimeric in size. These species form a least common denominator amongst SOD1 mutants with widely different molecular characteristics and might be involved in the cytotoxicity that causes ALS.
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http://dx.doi.org/10.1073/pnas.0700477104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1955813PMC
August 2007

Overloading of stable and exclusion of unstable human superoxide dismutase-1 variants in mitochondria of murine amyotrophic lateral sclerosis models.

J Neurosci 2006 Apr;26(16):4147-54

Department of Medical Biosciences, Umeå University, SE-901 85 Umeå, Sweden.

Mutants of human superoxide dismutase-1 (hSOD1) cause amyotrophic lateral sclerosis (ALS), and mitochondria are thought to be primary targets of the cytotoxic action. The high expression rates of hSOD1s in transgenic ALS models give high levels of the stable mutants G93A and D90A as well as the wild-type human enzyme, significant proportions of which lack Cu and the intrasubunit disulfide bond. The endogenous murine SOD1 (mSOD1) also lacks Cu and is disulfide reduced but is active and oxidized in mice expressing the low-level unstable mutants G85R and G127insTGGG. The possibility that the molecular alterations may cause artificial loading of the stable hSOD1s into mitochondria was explored. Approximately 10% of these hSOD1s were localized to mitochondria, reaching levels 100-fold higher than those of mSOD1 in control mice. There was no difference between brain and spinal cord and between stable mutants and the wild-type hSOD1. mSOD1 was increased fourfold in mitochondria from high-level hSOD1 mice but was normal in those with low levels, suggesting that the Cu deficiency and disulfide reduction cause mitochondrial overloading. The levels of G85R and G127insTGGG mutant hSOD1s in mitochondria were 100- and 1000-fold lower than those of stable mutants. Spinal cords from symptomatic mice contained hSOD1 aggregates covering the entire density gradient, which could contaminate isolated organelle fractions. Thus, high hSOD1 expression rates can cause artificial loading of mitochondria. Unstable low-level hSOD1s are excluded from mitochondria, indicating other primary locations of injury. Such models may be preferable for studies of ALS pathogenesis.
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http://dx.doi.org/10.1523/JNEUROSCI.5461-05.2006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6673995PMC
April 2006

Minute quantities of misfolded mutant superoxide dismutase-1 cause amyotrophic lateral sclerosis.

Brain 2004 Jan 8;127(Pt 1):73-88. Epub 2003 Oct 8.

Clinical Chemistry, Department of Medical Biosciences, Umeå University Hospital, Sweden.

Mutant forms of superoxide dismutase-1 (SOD1) cause amyotrophic lateral sclerosis (ALS) by an unknown noxious mechanism. Using an antibody against a novel epitope in the G127insTGGG mutation, mutant SOD1 was studied for the first time in spinal cord and brain of an ALS patient. The level was below 0.5% of the SOD1 level in controls. In corresponding transgenic mice the content of mutant SOD1 was also low, although it was enriched in spinal cord and brain compared with other tissues. In the mice the misfolded mutant SOD1 aggregated rapidly and 20% occurred in steady state as detergent-soluble protoaggregates. The misfolded SOD1 and the protoaggregates form, from birth until death, a potentially noxious burden that may induce the motor neuron injury. Detergent-resistant aggregates, as well as inclusions of mutant SOD1 in motor neurons and astrocytes, accumulated in spinal cord ventral horns of the patient and mice with terminal disease. The inclusions and aggregates may serve as terminal markers of long-term assault by misfolded SOD1 and protoaggregates.
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http://dx.doi.org/10.1093/brain/awh005DOI Listing
January 2004