| 1. |
- Boman, Antonia, 1991-
(författare)
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Early rheumatoid arthritis : biomarkers and hormonal factors in relation to disease progression
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rheumatoid arthritis (RA) is a chronic inflammatory joint disease, affecting approximately 0.5 to 1% of the adult population. Although the aetiology is not fully known, a complex interaction between genetic, environmental and stochastic factors is thought to trigger the pathogenic mechanisms. A distinguishing feature of RA is the presence of disease associated autoantibodies, mainly rheumatoid factor (RF) and anti-cyclic citrullinated antibodies (ACPA), which are important in both diagnostic and prognostic purpose. The disease is systemic but primarily affects the joints, and can cause irreversible destructions of cartilage and bone, eventually leading to functional disabilities. Moreover, extra-articular features (i.e., symptoms outside the joints) can occur and the patients have an increased risk for comorbidities, predominantly cardiovascular disease. Since the disease is heterogenous, varying from mild to more severe forms, the prognosis can be difficult to predict. Improvements in early diagnosis and identification of patients at risk of a more severe disease course can lead to better outcomes for the patients. The overall aim of this thesis was to evaluate prognostic biomarkers, and to evaluate hormonal and reproductive factors in relation to cardiovascular events (CVE) in patients with newly diagnosed RA (symptoms <12 months).Methods: The patients were included in a prospective inception cohort from the years of 1996 to 2017 and followed-up regularly at the early RA clinics in the northern region of Sweden. Clinical and laboratory parameters, and treatment were regularly recorded in the Swedish Rheumatology Quality Register (SRQ). Enzyme-linked immunosorbent assays (ELISA) and a multiplex assay were used to analyse bone remodelling factors and ACPA reactivities, respectively. Questionnaires regarding hormonal and reproductive factors were sent out to female patients ≤80 years. Information of CVE was extracted from the Swedish National Health Register and Cause of Death Register. Potential markers for disease progression i.e., bone remodelling factors and autoantibodies were analysed in relation to disease progression. Hormonal and reproductive factors were analysed in relation to CVE. Results: In paper I we found associations between receptor activator of nuclear factor kappa-B (RANKL), a central molecule of bone metabolism, and radiological findings at baseline, 24 months, and radiological progression analysed in 407 RA patients. The combination of RANKL and anti-CCP positivity indicated a more severe disease course in terms of joint destruction. Sclerostin was not associated with radiological outcome. Polymorphisms of the genes for sclerostin (SOST) and RANKL (TNFSF11) did not show significant associations with radiological outcome or with the concentrations, respectively. In paper II, we found that even though antibody status is considered in clinical practice and modern treatment reduces disease activity, the radiographic joint damage remained increased among anti-CCP positive patients. In paper III, 22 different ACPA reactivities were analysed in relation to disease courses of RA. The presence of a higher number of different ACPA reactivities, and different ACPA subtypes could provide prognostic information of disease activity and radiological destruction. In paper IV, we found that hormonal and reproductive factors were associated with CVE in female patients. A higher number of childbirths increased the risk for CVE, whilst oral contraceptives decreased the risk. The majority of patients with later CVE had their RA disease onset after menopause and had a longer duration from menopause until RA onset.Conclusion: RANKL can function as a prognostic marker for the disease course of RA. Even though anti-CCP antibodies are taken into account in clinical practice and treatment reduce disease activity, the joint damage can progress, supporting the direct bone degrading effects by ACPA. The number of, and different subtypes of ACPA, can predict different disease progression. These markers can be valuable to identify patients at need for more aggressive treatment and careful radiographic monitoring, even if disease activity is under control. Finally, hormonal factors such as childbirths, oral contraceptives and the timing of RA onset in relation to hormonal status can add value for the evaluation of CVE risk in female RA patients.
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| 2. |
- Eriksson, Catharina, 1955-
(författare)
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Immunological mechanisms in systemic autoimmunity : autoantibodies and chemokines in systemic lupus erythematosus and during treatment with TNF inhibitors in rheumatoid arthritis
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background. Rheumatoid Arthritis (RA) is an autoimmune inflammatory disease that, without powerful treatment, may lead to irreversible joint damage. During the past decade, anti-cytokine therapy has become available, e.g., infliximab, a chimeric antibody targeting the pro-inflammatory cytokine TNF that has a central role in the inflammatory process in RA patients. Systemic Lupus Erythematosus (SLE) is a systemic autoimmune disease that may affect all organs and is characterized by a massive antibody production. Chemokines, chemokine receptors and lipoprotein receptor-related protein 1(CD91) are regulators of inflammation in autoimmune diseases and T-cell migration. Objectives. The aim of this study was to get a deeper understanding how TNF blocking treatment influences inflammatory mechanisms and autoantibody formation in RA with special reference to similarities and differences with SLE. Methods. In patients with RA treated with anti-TNF, and in SLE patients (ACR criteria) clinical evaluation was performed and blood samples analyzed. Autoantibodies were analyzed using indirect immunofluorescence, ELISA and multiplex flow cytometry in samples from anti-TNF treated RA patients (n=59) followed longitudinally for 54 weeks, in pre-diseased samples from SLE patients (n=38) and matched population-based controls (n=152). T-cell expression of chemokine receptors and CD91 was analyzed by flow cytometry, whilst serum levels of chemokines were determined using ELISA in anti-TNF treated RA-patients (n=24) followed longitudinally (30 weeks), and cross-sectionally in SLE-patients (n=23). Expression of mRNA for chemokines was analyzed in T-cells from SLE-patients (n=10) using PCR. Results. After treatment with infliximab, RA patients produced ANA, anti-dsDNA and anti-nucleosome antibodies, but not anti-ENA antibodies. Although these antibodies are considered typical for SLE only one patient developed a transient lupus-syndrome. Antibodies against cell nuclear antigens, including ENA, were detected several years before the first clinical symptom of SLE; anti-SSA was the earliest detectable antibody. In RA-patients before infliximab treatment, the T-cell expression of several chemokine receptors was elevated compared with healthy controls. In contrast, only one soluble chemokine, IP-10 was elevated. After treatment the levels of soluble MIP-1β, MCP-1 and IP-10, and the T-cell expression of CCR2 were decreased. In SLE-patients MIP-1β, MCP-1, SDF-1, IP-10 and RANTES in blood were elevated, whilst expression of CXCR5 and CCR6 on T-cells was lower than in healthy controls. T-cell expression of CXCR2 and CCR1 was elevated in active disease (measured as SLEDAI index), whereas the CXCR5 and CCR2 expression was lower in inactive SLE. In SLE patients with nephritis IP-10 was lower and T-cell expression of CXCR3 and CCR3 elevated compared with patients without nephritis. The expression of CD91 was higher on T-cells from patients not responsive to infliximab treatment compared with responders. Conclusion. These findings indicate that anti-TNF (infliximab) treatment in RA-patients has a major impact on the production of autoantibodies and chemokines. The autoantibody profile in infliximab-treated patients was similar to that predating disease onset in SLE patients with the exception of anti-ENA being detectable in SLE, but the development of lupus-syndromes was rare. The expression of CD91 on T-cells may predict responsiveness to infliximab. The expression of chemokine receptors in SLE- patients seemed to be related to disease activity. Anti-nuclear antibodies were detectable years before clinical disease onset in patients who developed SLE suggesting a gradual pathogenic process.
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| 3. |
- Grimsholm, Ola, 1979-
(författare)
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Neuropeptides and neurotrophins in arthritis : studies on the human and mouse knee joint
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neuropeptides, such as substance P (SP) and bombesin/gastrin-releasing peptide (BN/GRP), and neurotrophins are involved in neuro-immunomodulatory processes and have marked trophic, growth-promoting and inflammation-modulating properties. The impact of these modulators in rheumatoid arthritis (RA) is, however, unclear. An involvement of the innervation, including the peptidergic innervation, is frequently proposed as an important factor for arthritic disease. Many patients with RA, but not all, benefit from treatment with anti-TNF medications. The studies presented here aimed to investigate the roles of neuropeptides, with an emphasis on BN/GRP and SP, and neurotrophins, especially with attention to brain-derived neurotrophic factor (BDNF), in human and murine knee joint tissue. The expression patterns of these substances and their receptors in synovial tissue from patients with either RA or osteoarthritis (OA) were studied in parallel with the levels of these factors in blood and synovial fluid from patients with RA and from healthy controls. Correlation studies were also performed comparing the levels of neuropeptides with those of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6)]. Furthermore, the impact of anti-TNF treatment on the levels of BDNF in blood was investigated. In a murine model of RA, the expression of these substances on articular chondrocytes along with their expression in synovial tissue was investigated. The expression of BN/GRP in human synovial tissue was confined to fibroblast-like and mononuclear-like cells whereas SP was detected in nerve-related structures. Receptors for these neuropeptides (GRP-R and NK-1R) were frequently present in blood vessel walls, and on fibroblast-like and mononuclear-like cells. The expression of BDNF and its receptors, p75 neurotrophin receptor and TrkB, was mainly confined to nerve structures. The levels of SP, and particularly those of BN/GRP, in synovial fluid and peripheral blood correlated with the levels of pro-inflammatory cytokines. There were clearly more correlations between SP-BN/GRP and inflammatory parameters than between BDNF and these factors. Plasma levels of BDNF were decreased following anti-TNF-treatment. In the joints of the murine model, there was a marked expression of neurotrophins, neurotrophin receptors and NK-1R/GRP-R in the articular chondrocytes. The expression was down-regulated in the arthritic animals. A neurotrophin system was found to develop in the inflammatory infiltrates of the synovium in the arthritic mice. The results presented suggest that there is a local, and not nerve-related, supply of BN/GRP in the human synovial tissue. Furthermore, BN/GRP and SP have marked effects in the synovial tissue of patients with RA, i.e., there were abundant receptor expressions, and these neuropeptides are, together with cytokines, likely to be involved in the neuro-immunomodulation that occurs in arthritis. The observations do on the whole suggest that the neuropeptides, rather than BDNF, are related to inflammatory processes in the human knee joint. A new effect of anti-TNF treatment; i.e., lowering plasma levels of BDNF, was observed. Severe arthritis, as in the murine model, lead to a decrease in the levels of neurotrophin, and neurotrophin and neuropeptide receptor expressions in the articular cartilage. This fact might be a drawback for the function of the chondrocytes. Certain differences between the expression patterns in the synovial tissue of the murine model and those of human arthritic synovial tissue were noted. It is obvious that local productions in the synovial tissue, nerve-related supply in this tissue and productions in chondrocytes to different extents occur for the investigated substances.
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| 4. |
- Innala, Lena, 1960-
(författare)
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Early rheumatoid arthritis aspects of severity and co-morbidity
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Rheumatoid arthritis (RA) is a systemic progressive destructive joint disease with an increased risk for co-morbidity and premature death if untreated. Cardiovascular disease (CVD) is the main cause of death but also other co-morbid conditions contribute to the patient’s shorter life expectancy. Inflammation is important for the development of CVD, but knowledge of its relationship with other co-morbidities is sparse. Early disease modifying anti rheumatic drugs (DMARDs) can suppress disease activity and improve the long-term outcome. The aim of this thesis was to evaluate prospectively aspects of disease activity and severity in a large cohort of patients with early RA. Predictive and prognostic markers, e.g., antibodies against citrullinated proteins/peptides (ACPAs), occurring in early disease and with implications for disease outcome and co-morbidity were evaluated.Methods Patients with early RA (i.e., symptomatic for ≤12 months) have, since December 1995, been consecutively included in a large survey of prospective and observational studies on the progression of RA and the development of co-omorbidity. Autoantibodies, inflammatory, genetic markers and radiographs have been analyzed. In paper I, 210 RA patients and 102 controls were followed regularly for two years. The predictive value of four different ACPAs in relation to disease activity and radiological progression was evaluated. In Paper II (n = 700) and in Papers III-IV (n =950), patients with early RA from the four northern-most counties of Sweden were followed regularly for 5 years. Data on risk factors and co-morbidity was collected, according to the study protocol, from clinical records and self-reported questionnaires from patients at inclusion into the study cohort and after five years. The predictive value of traditional and potential disease related risk factors for new cardiovascular events (CVE) was evaluated (II). In Paper III, the impact of age at the onset RA, stratified as being young onset RA (<58 years; YORA) and late onset RA (≥58 years; LORA) on disease activity, severity and chosen treatment, was evaluated. In Paper IV, the development of new co-morbidities after RA onset and their relation to inflammatory activity was assessed.Results The presence of anti-mutated citrullinated vimentin (MCV ) antibodies was associated with a more severe disease course, estimated by disease activity score, erythrocyte sedimentation rate (ESR) and swollen joint count after 24 months, compared with anti-CCP2, anti-CCP3, and anti CCP3.1 antibodies. In Paper II, the incidence of a new CVE during 5 years was explained by several of the traditional CV risk factors, and potentiated by a high disease activity. Treatment with DMARDs decreased the risk. In Paper III, LORA patients were associated with greater disease activity/severity at disease onset and over time compared with YORA who were more often ACPA positive. YORA patients were treated earlier with DMARDs, whilst LORA patients were more often treated with corticosteroids and less so with DMARDs early in the course of their disease. In Paper IV, 53%of patients already had one or more co-morbidities already at the onset of RA. After 5 years, 41% of the patients had developed at least one new co-morbidity. ESR at baseline and accumulated disease activity were associated with a new co-morbidity after five years.Conclusion Early RA patients sero-positive for anti- MCV antibodies appeared to have a higher disease activity over time. The occurrence of a new CVE in early RA patients was predicted by traditional risk factors for CVD which were potentiated by a high disease activity. Treatment with DMARDs decreased the risk. Patients with young onset of RA were associated with a higher frequency of ACPA. Late onset of RA was associated with higher disease activity/severity at inclusion and over time. However, LORA patients were more often treated with corticosteroids and less so with DMARDs early in the disease course. Development of a new co-morbidity during the five years following diagnosis was related to ESR.
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| 5. |
- Johansson, Linda, 1991-
(författare)
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Insights into the processes preceding the onset of rheumatoid arthritis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by the production of anti-citrullinated protein antibodies (ACPA) in the majority of all patients and a persistent inflammation in the synovial tissue leading to joint destruction. The aetiology of RA remains to a large extent unknown but is believed to be a complex interplay between genetic, environmental and stochastic factors. Recently, several infectious agents have been shown to have the capacity to induce citrullination of both endogenous and exogenous antigens e.g., Epstein-Barr virus (EBV) and Porphyromonas gingivalis (P.gingivalis). Disease progression in patients with RA is suggested to be a longstanding process that begins several years before symptom onset of RA. This hypothesis is supported by studies showing increased antibody levels against ACPA and disease related cytokines/chemokines several years before symptom onset of RA. The presence of ACPA is highly specific for RA and is already used as an indicator of progression and prognosis of the disease. This thesis is aimed to further investigate the origin and role of ACPA and the processes preceding the development of RA. New insights into these processes are of importance in order to be able to prevent the disease onset, achieve better diagnostic methods and treatments in the future.All of the individuals included in these papers, had attended to the Department of Rheumatology at Umeå University to receive their diagnosis of RA. The register of the patients were thereafter co-analysed with the register of the Medical Biobank of Northern Sweden. Plasma/sera samples were analysed for antibodies and receptor activator of nuclear factor kappa-B ligand (RANKL) using different ELISA techniques from individuals before symptom onset (pre-symptomatic individuals) and at disease onset (patients). Cytokines/chemokines were analysed using Meso Scale Discovery methods. Levels of marginal jawbone loss were measured using dental radiographs from premolar/molar regions. The Larsen score at disease onset was used to grade radiographs of hands and feet.In Paper I antibodies against Epstein-Barr virus nuclear antigen (EBNA) 1 and 2 (VCP1 and VCP2) and histone 4 (H4) derived citrullinated peptides (HCP1 and HCP2) were found to predate symptom onset of RA. In Paper II, antibodies against anti-P.gingivalis (anti-CPP3 and -RgpB IgG) were significantly increased in pre-symptomatic individuals and were detectable several years before symptom onset of RA. In Paper III the concentration of RANKL was shown to be increased several years before symptom onset of RA, especially in ACPA/rheumatoid factor (RF)/anti-carbamylated (CarP) antibody positive individuals. Positivity for RANKL was found to appear later in time than both positivity for ACPA, RF and anti-CarP antibodies. The highest Larsen score at disease onset was yielded when combining positivity for RANKL and anti-CarPivantibodies. In Paper IV periodontitis, defined as marginal jawbone loss was significantly higher in pre-symptomatic individuals who never smoked, compared with matched controls. RANKL positive individuals particularly those that were also ACPA positive, had a significantly greater extent of jawbone loss in comparison to those individuals who were RANKL negative.Antibodies against citrullinated exogenous and endogenous peptides were found to be associated with the symptom onset of RA. No hierarchy among the citrullinated epitopes could be identified. RANKL levels were particular increased in ACPA-positive individuals, and RANKL positivity appeared later in time than the general ACPA response. Periodontitis, defined as marginal jawbone loss was significantly higher in pre-symptomatic individuals, who never smoked.
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| 6. |
- Johansson, Martin, 1981-
(författare)
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Systemic lupus erythematosus and rheumatoid arthritis : analyses of candidate genes involved in immune functions, for susceptibility and severity
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune rheumatic disease with systemic manifestations characterized by auto-antibodies directed against different parts of the cell nucleus including DNA, histones and ribosomes. The systemic inflammation can cause damage to multiple organs, e.g., kidneys, skin, heart, lungs and the nervous system. Rheumatoid arthritis (RA) is another autoimmune rheumatic disease characterized by auto-antibodies, mainly directed against the Fc-part of immunoglobulin G (rheumatoid factor (RF)) but also against citrullinated peptides/proteins (ACPAs). The inflammation in RA primarily involves the joints resulting in inflamed synovial tissue and destruction of cartilage. The aetiology of both SLE and RA is unclear but there is a genetic contribution predominantly of genes involved in inflammation. The diseases are believed to be multifactorial, or complex, meaning that multiple genes interact with environmental, infectious and hormonal factors, thus increasing the risk of developing disease. The aim of this study was to investigate different candidate genes involved in functions of the immune system and their relationship with SLE and RA susceptibility and severity. The patients and controls were from the four northernmost counties of Sweden, which is a fairly homogenous population well suited for genetic studies. Two single nucleotide polymorphisms (SNPs) in the oestrogen receptor α (ESR1) gene were analysed in SLE. No association was found between the SNPs and SLE per se however the minor alleles (PvuII C and XbaI G) were associated with skin manifestations and later disease onset, thus representing a milder form of the disease. A SNP in the programmed cell-death 1 (PDCD1) gene, which codes for PD-1, an inhibitory molecule involved in T-cell activation, was studied. No association was seen between the risk allele (PD-1.3A) and SLE susceptibility but a strong association was found with renal disease. A risk allele of the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene that codes for a protein called Lyp which acts as a negative regulator of T-cell receptor (TCR) signalling was significantly associated with SLE in three different case-control sets across Sweden. Both PDCD1 and PTPN22 were independently associated with renal disease. The PTPN22 gene has been associated with numerous autoimmune diseases and was evaluated in another auto-antibody producing disease, RA. From the Medical Biobank of northern Sweden samples donated before the development of symptoms of RA were identified. In these individuals, who subsequently developed RA, the 1858T risk allele in combination with ACPAs gave a high relative risk (>132) for developing RA. The association between PTPN22 and RA was confirmed in a larger material of patients with early RA. The 1858T allele, of the three SNPs investigated, was shown to be the true risk allele associated with auto-antibody positive RA. A functional role of PTPN22 in TCR-mediated activation of T cells from patients with SLE and RA was not demonstrated. In conclusion, minor alleles of two SNPs in the ESR1 gene were associated with a milder form of SLE. The risk allele in the PDCD1 gene was associated with renal disorder in SLE. The risk allele 1858T of the PTPN22 gene was associated with SLE, particularly with renal disease. The 1858T allele in combination with auto-antibodies was a risk factor for developing RA. In early diagnosed RA, the 1858T allele was highly associated with RA and in particular with auto-antibody positive RA.
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| 7. |
- Juneblad, Kristina, 1965-
(författare)
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Psoriatic arthritis: a complex disease : analyses on genetic and serological biomarkers and of comorbidity
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Psoriatic Arthritis (PsA) is a heterogonous inflammatory arthritis associated with psoriasis. The disease leads to inflammation of peripheral joints, axial skeleton and/or enthesites, and can result in severe destruction of affected joints. In contrast to rheumatoid arthritis (RA), most individuals with PsA are seronegative for rheumatoid factor (RF) and/or anti-citrullinated protein/peptide antibodies (ACPA) and the distal interphalangeal (DIP) joints are often involved. Dactylitis, a diffuse swelling of an entire digit (finger or toe), is also common. Traditional markers of systemic inflammation, such as erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) are elevated in only 50% of the individuals with PsA.Underlying genetic factors are considered important for the aetiology, disease expression and prognosis of PsA. To date no specific biomarker for PsA disease or disease activity/severity is available and there is a need for diagnostic and prognostic tools to meet the challenge of early diagnosis and assessment of disease severity.An increased risk of co-morbidity, particularly cardiovascular disease (CVD), has been demonstrated in patients suffering from different rheumatic diseases, e.g. systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Corresponding data for patients with PsA are more limited, but evidence exists for an increased risk of mortality and cardiovascular morbidity. However, published results are conflicting and heterogeneity among studies makes interpretation of data difficult.The aim of this study was to investigate genetic and serological biomarkers, and also mortality and cardiovascular comorbidity, in different phenotypes of PsA and in comparison with healthy controls. Patients with PsA were included between 1995 and 2015, the majority from the county of Västerbotten, except for two cohorts from Örnsköldsvik (n=55) and Östersund (n=98).The genetic polymorphism PTPN22+1858C/T, previously found to be associated with several autoimmune diseases, was also found associated with PsA, the results were later confirmed in a genome wide association study (GWAS). Additionally, among PsA patients, the minor allele, T, was associated with the number of deformed joints and dactylitis (Paper I). Genetic polymorphisms in genes related to the inflammasome were also investigated, both in comparison with healthy controls and in relation to different phenotypes of PsA (Paper II). An association was identified between patients with PsA and the polymorphism CARD8-C10X in comparison with controls. In addition, associations between various inflammasome polymorphisms and different clinical phenotypes of PsA were detected.To investigate the relation of serological biomarkers and PsA, individuals with blood samples collected in conjunction with clinical investigation were selected (Paper III). Associations with different biomarkers and different clinical phenotypes of PsA were identified In addition, associations were found with different biomarkers and patients with moderate/high disease activity at clinical investigation, confirming the inflammatory nature of the disease.Mortality and incidence of acute cardiovascular disease were investigated with standardized mortality rateratio (SMR) and standardized incidence ratio (SIR) compared with the general population of Västerbotten (Paper IV). An increased SMR for diseases of the circulatory system in PsA compared with controls was found. Among PsA patients, death was associated with a composite disease activity index (DAI) and with a disease phenotype including both axial- and peripheral joint involvement. In conclusion, associations were found with different clinical phenotypes of PsA, both with genetic polymorphisms and serological biomarkers that confirm the inflammatory nature of the disease and illustrate the disease heterogeneity. As in many other inflammatory diseases, an increased cardiovascular mortality was found that highlights the importance of considering cardiovascular risk factors in patients with PsA.
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| 8. |
- Kling, Anders, 1965-
(författare)
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5-HT2A : a serotonin receptor with a possible role in joint diseases
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundSerotonin (5-HT), an amino acid derivative and neurotransmitter, has for long been studied in relation to inflammation. It is an endogenous ligand for several different types of serotonin receptors. The serotonin receptor 5-HT2A has been reported to have a role in the pathophysiology of arthritis in animal experiment models. However, no studies into this subject have been reported in man.ObjectiveThe objectives of this project were firstly, to examine possible associations for the 5-HT2A receptor and also for the gene (HTR2A) encoding for the receptor with arthritis in man and secondly, to explore possible mechanisms underlying such associations.MethodsThe density and affinity of platelet 5-HT2A receptors were determined in 43 patients with a common inflammatory joint disease, i. e., rheumatoid arthritis (RA), in comparison with matched controls using a radio-ligand assay. The effects of treatment with prednisolone on 5-HT2A density and affinity were also examined in 27 individuals diagnosed with polymyalgia rheumatica before and after start of treatment. In addition, possible candidate HTR2A genes were studied in relation to RA in two Swedish cohorts incorporating a total of 2450 RA patients. Furthermore, a register study using reports of joint symptoms as adverse drug reactions (ADRs) in the Swedish and the WHO ADR databases was undertaken. The proportion of reports concerning joint symptoms in relation to all ADR reports and to sales figures was analysed for 5-HT2A blocking atypical antidepressant substances compared with another group of antidepressants, i. e., selective serotonin re-uptake inhibitors (SSRIs), used for similar clinical indications.ResultsThe mean density of 5-HT2A receptors in RA patients was significantly lower than in controls, 45.3 versus 57.4 fmol/mg protein (p = 0.004). There was no significant difference in affinity. Variation of four single nucleotide polymorphisms (SNPs) (rs6314, rs1328674, rs6313 and rs6311) in the HTR2A gene was associated with RA, although not significantly so for all SNPs after testing for multiple comparisons. The proportion of joint symptoms reported as ADRs, relative to all ADRs was significantly higher for the 5-HT2A blocking antidepressants compared with the SSRIs in both databases (p< 0.001). In the Swedish material the comparison of ADRs was also related to sales figures, showing a considerable higher frequency of joint symptoms for the 5-HT2A antagonists (p< 0.001). The density of 5-HT2A receptors increased after treatment with prednisolone in 23 out of 27 individuals. The mean density at baseline was 45.2 versus 64.9 fmol/mg protein at the end of the study (p=0.001). There were no significant differences in affinity during the treatment period, although a low affinity at baseline was a predictor for higher density following treatment with prednisolone.ConclusionsThe density of 5-HT2A receptors, reflecting the number of receptors, was markedly reduced in a cohort of patients with RA from Northern Sweden. This may depend, at least in part, on an association between RA and certain HTR2A SNPs. Genetically determined or acquired low levels of accessible 5-HT2A receptors may contribute to susceptibility for development of joint symptoms, not only in RA but more generally, e. g., joint ADRs caused by 5-HT2A blocking atypical antidepressants. The benefits of treatment with glucocorticoids may, at least partially, be mediated by an effect on 5-HT2A receptors.
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| 9. |
- Neumann Andersen, Grethe, 1951-
(författare)
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Systemic sclerosis : vascular, pulmonary and immunological aspects
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In systemic sclerosis (SSc), interstitial lung disease (ILD) and engagement of the vascular system lead to increased morbidity and mortality. The aim of this thesis was to elucidate, in a consecutively included cohort of SSc (limited and diffuse) patients (n = 33), the T cell cytokine profile driving the disease in ILD and to explore the role of matrix metalloproteinase 9 (MMP-9) and its inhibitor: tissue inhibitor of metalloproteinase 1 (TIMP-1) in the extracellular matrix (ECM) degrading process leading to fibrous scarring and honey combing. Moreover, to characterize the role of nitric oxide (NO) in vascular engagement. Peripheral arterial changes cause Raynaud’s phenomenon and digital ulcers. Nitric oxide (NO) a main inducer of vasodilation is produced by endothelial nitric oxide synthase (eNOS) in response to changes in blood flow or by inflammatory cytokine inducible (i) NOS. In the vascular smooth muscle cell (VSMC) NO activates guanylate cyclase to produce cGMP, causing relaxation. We showed elevated plasma nitrate, a degradation product of NO, and increased urinary excretion of nitrate and cGMP. Plasma nitrate correlated with elevated levels of endothelial adhesion molecules: endothelial (E) selectin and vascular adhesion molecule 1, indicating that the activated endothelium is the site of NO synthesis by iNOS. Endothelial staining for E-selectin and the finding of iNOS and eNOS in SSc skin biopsies supported this notion. In SSc increased vascular stiffness may limit the NO vasodilatory effects. We found normal endothelium-dependent (i.e. flow mediated (FMD%)) and endothelium-independent (i.e. nitroglycerin-induced (NTG%)) vasodilation in the brachial artery. Radial arterial wall stiffness measured as maximum increase in pulse pressure (dP/dtmax) was increased. FMD% and especially NTG% correlated negatively and dP/dtmax positively to measures of endothelial inflammation: plasma- nitrate and adhesion molecule levels. Thus inflammatory vascular wall changes may interfere with dilation as may the presence of nitrate tolerance. We found elevated alveolar MMP-9 in both its pro- and active form in ILD. The levels correlated to decline in lung capacity, pointing at a causal relation. We suggest that neutrophils secrete MMP-9, which may degrade collagen IV, (the main constituent of basal membranes), collagen V, gelatins, proteoglycans and elastin. MMP-9 activity is partly regulated by the binding of pro- and active form to TIMP-1. Alveolar TIMP-1, which even stimulates fibroblast ECM synthesis, was increased independent of ILD. The inflammatory process in ILD is orchestrated by activated T helper (h) lymphocytes. We found a mixed Th1/Th2 reaction in SSc alveolar T cells expressing messenger for interferon gamma (Th1), IL-6 and IL-10 (both Th2). No particular cytokine mRNA profile distinguished alveolar T cells in ILD. Neutrophils invaded the bronchial epithelium, which seemed otherwise inert as levels of inflammatory cytokine sensitive transcription factors and their nuclear translocation tended to be low. The neutrophil recruitment pathway is uncertain as chemoattractants and endothelial adhesion molecules were normally expressed. In conclusion, MMP-9 probably causes degradation of lung tissue in ILD and may represent a future therapeutic target. Alveolar T cells show a mixed Th1/Th2 cytokine profile independent of ILD. Neutrophils invade the bronchial epithelium. Activated endothelium produces increased amounts of NO and adhesion molecules and the level of activation influences brachial arterial FMD% and NTG% and radial arterial compliance. Nitrate tolerance may be present.
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| 10. |
- Ärlestig, Lisbeth, 1954-
(författare)
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Genetic studies in rheumatoid arthritis : familial studies and analysis of relationships to atherothrombotic comorbidity
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background. Rheumatoid arthritis (RA) is an autoimmune disease mainly affecting the joints but has also extra articular manifestations and an increased cardiovascular (CV) co-morbidity. Rheumatoid factor (RF) and antibodies against citrullinated proteins/peptides (ACPA) are diagnostically important and are related to a more severe disease. The aetiology is unknown but RA is considered a complex disease caused by both genetic and environmental factors. The heritability is estimated to be 60% with the main contribution from the HLA region. The relative homogeneity of the population in northern Sweden due to low immigration and founder effects has shown to be suitable for genetic studies. Objectives. The aim of this thesis has been to identify genes contributing to the susceptibility of RA and the CV co-morbidity in particular. To achieve this, multi-case families from the four northern most counties of Sweden were collected for linkage studies to identify susceptibility genes. Association studies with genetic polymorphisms in genes, involved in inflammation or being of importance for atherothrombotic manifestations (ATM) in the general population, were performed in RA-patients concerning ATM e.g. myocardial infarction, angina pectoris with intervention, stroke/TIA, deep vein thrombosis/pulmonary embolism (DVT/PE) at follow-up. Methods & Results. 47 families with 134 affected and 216 unaffected relatives were included in a genome-wide linkage study (GWL) performed with microsatellite markers at an average of 10cM resolution analysed using ABI PRISM 3730 DNA sequencer and non-parametric multipoint linkage in the Merlin program. Eight linked loci were identified with HLA as the most significant and a novel region on chromosome 14. In a follow-up analysis on a custom Illumina chip, with 13 additional families, yielding a total of 198 affected and 197 unaffected relatives. The majority of the 1536 single nucleotide polymorphisms (SNPs) used in the Illumina follow-up analyses was focused on chromosome 14. Statistical analyses with linkage and transmission disequilibrium test narrowed the region to 4 cM, a region containing multiple plausible RA candidate genes (Paper I). In Paper II serum samples from 163 affected and 157 first degree relatives were analysed with EliA ACPA assay on ImmunoCAP250 for ACPA (IgA, IgG, IgM) and RF (IgA, IgM) isotypes. Both concentrations and frequencies were increased among the relatives compared with controls but lower compared with RA-patients and with a different relative distribution of the isotypes. The genetic contribution to ATM was studied in Paper III and IV using selected SNPs analysed using ABI PRISM 7900HT sequence detector system. In Paper III, RA-patients (n=467) were compared with age and sex matched controls (n=696) with respect to SNPs in tumor necrosis factor receptor II (TNFRII)(M196R), ß-fibrinogen -455 (G-455A), plasminogen activator inhibitor type-1 (PAI-1) (4G/5G) and Factor XIIIA (Val34Leu). Hypertension was predicted by TNFRII R allele and to a higher extent in combination with the A-allele in ß-fibrinogen. The 4G allele in PAI-1 was more frequent in patients with ischemic heart disease (IHD) and the FXIIIA Leu34 variant in patients with DVT/PE. In Paper IV, the minor allele of the polymorphism in growth differentiation factor 15 (GDF15) was found to be associated with RA (n=696) per se but also to ATM, a SNP in the 9p21.3 locus was also associated with ATM. A significant association to stroke was found in female patients homozygote for the minor allele of GDF15. Stoke among male patients was significantly associated with carrying the major allele of two SNPs in the CD40 gene. DVT/PE was associated with the minor allele of GDF15. Conclusion. A novel locus on chromosome 14 of importance for RA susceptibility in northern Sweden was found. The minor allele of TNFRII separately and together with the minor allele of ß-fibrinogen -455 was associated with hypertension and the 4G allele in PAI-1 was associated with IHD and the Leu34 variant was associated with DVT/PE in RA patients. The GDF15 minor allele was associated with RA per se, ATM and DVT/PE in RA patients and a genotype in the SNP on 9p21.3 was associated with ATM. Stroke among females was associated with GDF15 and stroke among males with two SNPs in CD40.
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