| 1. |
- Nijm, Johnny, 1969-
(författare)
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Inflammation and cortisol response in coronary artery disease
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerosis is characterized by a chronic inflammation, involving autoimmune components, in the arterial wall. An increase in proinflammatory activity relative to anti-inflammatory activity is considered to cause a progression of the disease towards plaque instability and risk of atherothrombotic events, such as acute coronary syndrome (ACS). Cortisol, the end product of the hypothalamus-pituitary-adrenal (HPA) axis, is a powerful endogenous anti-inflammatory mediator. Disturbances in the HPA axis have been reported in chronic inflammatory/autoimmune diseases, like rheumatoid arthritis. The aim of this thesis was to study various markers of systemic inflammation in patients with acute and stable conditions of coronary artery disease (CAD) and relate these findings to the cortisol response.Both patients with ACS and patients with stable CAD had high levels of C-reactive protein (CRP), interleukin (IL)-6 and IL-1 receptor antagonist, compared with healthy controls. In addition, patients with stable CAD had significantly more neutrophil-platelet aggregates than controls, as a possible indicator of neutrophil activation.The cortisol response was determined in two different cohorts of CAD patients; one consisting of patients with a first-time myocardial infarction and one consisting of patients with long-term stable CAD. From the acute phase to 3 months, the patients with a myocardial infarction showed a higher 24-h cortisol secretion and a flattened diurnal slope caused by higher cortisol levels in the evening, as compared with healthy controls. The patients with long-term stable CAD showed similarly high levels of cortisol in the evening. The levels of evening cortisol were strongly correlated with CRP and IL-6. When exposed to acute physical or acute psychological stress at 3 months, the ACS patients showed a markedly blunted cortisol response compared with healthy controls. Following the stress tests, a significant increase in CRP was observed in the patients but not in the controls, indicating a failure of the HPA axis to compensate for stress-induced inflammation in CAD.In the ACS patients, the time course of matrix metalloproteinases (MMPs) and their tissue inhibitor TIMP-1 was determined during the 3 months follow-up. A major finding was that the MMP-9 and TIMP-1 levels remained significantly higher in the patients at all time points compared to the controls. MMP-9 and TIMP-1, but not MMP-2, MMP-3 or MMP-7, were related to inflammatory activity, as assessed by CRP and IL-6. MMP-9 and TIMP-1 showed significant correlation with evening cortisol, even after adjustment for CRP and IL-6, lending further support for a link between ´high´ flat cortisol rhythm and systemic inflammatory activity.The activation status of neutrophils in stable CAD was further examined by measuring the expression, affinity state and signalling capacity of b2-integrins and the innate production of reactive oxygen species (ROS). However, the neutrophils in patients were not more activated in vivo than were cells in healthy controls, neither were they more prone to activation ex vivo. The data rather indicated an impaired function of neutrophils in stable CAD.The neutrophils in CAD patients showed a significantly lower number of total glucocorticoid receptors (GRs) and a lower GRa:GRb ratio compared to healthy controls, indicating a chronic over activation of the HPA axis and, possibly, a state of glucocorticoid resistance. Moreover, the evening cortisol levels in patients were associated with an overexpression of annexin-1, the ´second messenger´ of glucocorticoid action. In contrast to neutrophils in controls, the neutrophils in patients also showed a hyper responsiveness to exogenous annexin-1 resulting in impaired neutrophil function.To conclude, clinically stable CAD was associated with a systemic inflammatory activity, involving a high MMP-9:TIMP-1 ratio and an increased inflammatory response to acute stress but not any activation of neutrophils. This inflammatory activity was associated with a dysregulated cortisol secretion, defined by a flat diurnal rhythm and a blunted cortisol response to stress. Although the clinical relevance remains to be verified, an intriguing hypothesis is that a hyporesponsive HPA axis favours the development towards plaque instability.
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| 2. |
- Sandberg, Camilla, 1971-
(författare)
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Physical performance, physical activity, body composition and exercise training in adults with congenital heart disease
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Adults with congenital heart disease (CHD) is a growing population and related to advances in surgical and medical treatment, they now outnumber the children with corresponding lesions. Since a congenital heart lesion often results in reduced exercise capacity, this population is a potential target for physiotherapy. To what extent this reduction in exercise capacity is caused by abnormal cardiovascular anatomy and physiology or to what degree insufficient physical activity contributes is not known. To support the advancements in paediatric cardiac care, increased knowledge regarding physical performance, physical activity level, body composition and the effects of exercise training among adults with CHD is required.Methods In a cross-sectional study skeletal- and respiratory muscle function, physical activity level and exercise self-efficacy was investigated among 85 adults with various forms of CHD and 42 control subjects. A second study was conducted to analyse height, weight and body mass index (BMI) in 538 adults with complex CHD and 1886 adults with simple CHD. Data were extracted from the Swedish registry on congenital heart disease (SWEDCON) and compared to data from a national population survey. In a third study, factors associated with self-reported quality of life (QoL) were analysed using SWEDCON data on 315 adults with congenital aortic valve disease. Finally, a randomised controlled trial was conducted to investigate the effects of interval exercise training among adults with complex CHD.Results Adults with complex CHD showed impaired muscle function compared to both patients with simple CHD and controls. In addition, patients with complex CHD had a lower exercise self-efficacy compared to controls. Patients with CHD were equally active at moderate-to-vigorous level as the controls. However, approximately 50% of both patients and controls failed to reach the recommended physical activity level. In general patients with CHD had the same height, weight and BMI, as the general population. However, compared to the general population, men with CHD were more commonly underweight and less commonly overweight/obese. Additionally, especially male patients with complex CHD were shorter compared to the general population. Among adults with congenital aortic valve disease, a higher physical activity level was associated with better QoL. Furthermore, interval training increased exercise capacity and endurance among adults with complex CHD.Conclusion A higher physical activity level was associated with better self-reported QoL in patients with congenital aortic valve disease which implies that QoL might be possible to improve, by adopting a physically active life-style. Adults with CHD were equally active as controls at a moderate-to-vigorous physical activity level. However, approximately half of both groups were insufficiently physically active based on current recommendations. This indicates that low physical activity, on group level, does not explain the lower exercise capacity commonly found among patients with CHD. In addition, this is consistent the finding that the majority of patients followed the same pattern regarding BMI as seen in the general population. However, impaired muscle function in combination with the shorter stature and higher prevalence of underweight found in men, especially with complex CHD, implies an altered body composition in this group. The findings of the present thesis suggests an indication for physiotherapy targeting increased physical activity level and individualized exercise training in this patient population. Moreover, regular evaluation of muscle function, exercise self-efficacy and QoL, in addition to exercise capacity, might be useful for monitoring disease development over time.
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| 3. |
- Eriksson, Maria, 1965-
(författare)
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Adipocyte-derived hormones and cardiovascular disease
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is increasing globally and related to major changes in lifestyle. This increase is associated with an increased risk of cardiovascular disease (CVD). Knowledge about adipose tissue as a metabolic-endocrine organ has increased during the last few decades. Adipose tissue produces a number of proteins with increased body weight, many of which are important for food intake and satiety, insulin sensitivity, and vessel integrity, and aberrations have been related to atherosclerosis. Notably, the risk for developing CVD over the course of a lifetime differs between men and women. In Northern Sweden, men have a higher risk for myocardial infarction (MI). However, the incidence is declining in men but not in women. These sex differences could be due to functional and anatomical differences in the fat mass and its functions. The primary aim of this thesis was to evaluate associations between the adipocyte-derived hormones leptin and adiponectin, and fibrinolysis and other variables associated with the metabolic syndrome, and particularly whether these associations differ between men and women. Another aim was to evaluate these associations during physical exercise and pharmacological intervention (i.e. enalapril). Finally, whether leptin and adiponectin predict a first MI or sudden cardiac death with putative sex differences was also investigated. The first study used a cross-sectional design and included 72 men and women recruited from the WHO MONICA project. We found pronounced sex differences in the associations with fibrinolytic variables. Leptin was associated with fibrinolytic factors in men, whereas insulin resistance was strongly associated with all fibrinolytic factors in women. The second study was an experimental observational study with 20 men exposed to strenuous physical exercise. During exercise, leptin levels decreased and adiponectin levels increased, and both were strongly associated with an improved fibrinolytic capacity measured as decreased PAI-1 activity. Changes in insulin sensitivity were not associated with changing adiponectin levels. The third study was a randomised, double-blind, single centre clinical trial including 46 men and 37 women who had an earlier MI. The study duration was one year, and participating subjects were randomised to either placebo or ACE inhibitor (i.e. enalapril). Circulating leptin levels were not associated with enalapril treatment. During the one-year study, changes in leptin levels were associated with changes in circulating levels of tPA mass, PAI-1 mass, and tPA-PAI complex in men, but not vWF. These associations were found in all men and men on placebo treatment. In women on enalapril treatment there was an association between changes in leptin and changes in vWF. In the fourth study, the impact of leptin, adiponectin, and their ratio on future MI risk or sudden cardiac death was tested in a prospective nested casecontrol study within the framework of the WHO MONICA, Västerbotten Intervention Project (VIP), and Västerbotten Mammary Screening Program (MSP). A total 564 cases (first-ever MI or sudden cardiac death) and 1082 matched controls were selected. High leptin, low adiponectin, and a high leptin/adiponectin ratio independently predicted a first-ever MI, possibly with higher risk in men in regards to leptin. The association was found for non-fatal cases with ST-elevation MI. Subjects with low adiponectin levels had their MI earlier than those with high levels. In conclusion, the adipocyte-derived hormones leptin and adiponectin are related to the development of CVD with a sex difference, and fibrinolytic mechanisms could be possible contributors to CVD risk.
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| 4. |
- Hellström, Martin, 1979-
(författare)
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Hyaluronan and the receptor CD 44 in the heart and vessels : a study in normal and pathological conditions
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tissues are not solely composed of cells. The extracellular matrix is important for the cell well-being and cell-cell communication. The glycosaminoglycan hyaluronan (HYA) is a widely distributed extracellular matrix (ECM) component. The molecule has prominent physicochemical properties, foremost viscoelastic and osmotic, but participates in many biological processes such as cell migration, proliferation, tissue turnover, wound healing and angiogenesis. HYA is synthesised by either of three different hyaluronan-synthesising enzymes, HAS1-3, and its main ligand is the transmembrane receptor CD44. In the heart and vessels the matrix components are of great importance for endurance and elasticity which are prerequisites for a normal function. The aims of the study were to describe the distribution of HYA and its receptor CD44 in normal cardiovascular tissue and to investigate the ECM composition in myocardial hypertrophy. Normal conditions were studied in a rat model. These studies showed that the tunica adventitia in almost all vessels stained strongly for HYA. The expression in the tunica intima and media on the venous side, differed between the vessels and was almost absent on the arterial side. In the adult animals only minute amounts of CD44 were detected. The expression of both HYA and CD44 was increased in newborn rats. In the heart HYA was unevenly distributed in the interstitium. Strong HYA-staining was seen in the valves and in the adventitia of intramyocardial vessels. Almost no CD44-staining was observed. Notably, there was no obvious difference between newborn and adult animals. In an experimental rat model of pressure-induced cardiac hypertrophy the mRNA-levels of HAS1, HAS2, CD44, basic Fibroblast Growth Factor (FGF-2) and Fibroblast Growth Factor Receptor-1 (FGFR-1) were elevated on day 1 after aortic banding. HAS2, CD44 and FGFR-1 were at basal levels on day 42. The HYA-concentration was significally elevated on day 1. HYA was detected in the interstitium by histochemistry and CD44 was detected mainly in and around the intramyocardial vessels. The HYA-staining was increased in myectomi specimens from patients with HCM compared to controls. HYA was detected in the interstitium, in fibrous septas and in the adventitia of intramyocardial vessels. No CD44 was detected in HCM or in control specimens. Our results indicate that HYA and CD44 play an active role in the maturing vessel tree and that the ECM content of HYA is increased in experimental myocardial hypertrophy and human hypertrophic cardiomyopathy.
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| 5. |
- Johnston, Nina, 1961-
(författare)
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Low-Density Lipoprotein Oxidation and Renal Dysfunction : New Markers of Poor Prognosis in Patients with Unstable Coronary Artery Disease
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In patients with unstable coronary artery disease (CAD) biochemical markers are emerging as useful tools in clinical management. In this thesis we studied the use of markers of low-density lipoprotein (LDL) oxidation and renal function.Our study populations consisted of unstable CAD patients included in the Fast Revascularisation during Instability in Coronary artery disease (FRISC)-II trial and healthy controls. Patients were followed for 2 years regarding death and myocardial infarction (MI).Using receiver operating characteristic curve analysis, we found that oxidized low-density lipoprotein (OxLDL), especially when combined with high-density lipoprotein, compared to traditionally measured lipids/lipoproteins, and a new lipoprotein marker, lipoprotein associated-phospholipase A2, was better at discriminating between healthy controls and CAD patients. In patients, OxLDL was found to be an independent prognostic marker associated with an increased risk of MI, of particular use in patients with no evidence of myocardial necrosis. In our study on the effects of an early invasive treatment strategy in unstable CAD patients with mild to moderate renal dysfunction (i.e. creatinine clearance <90mL/min) we found that in patients randomized to invasive treatment, the rates of death/MI and MI alone were significantly lower than in patients randomized to non-invasive treatment. In patients treated invasively, no detrimental effects were seen on renal function at follow-up at 6 months. In healthy controls, we investigated new markers of renal (cystatin C) and cardio-renal function (N-terminal probrain natriuretic peptide, [NT-proBNP]) regarding reference levels and physiological determinants. We found that cystatin C is influenced by age whereas NT-proBNP is influenced by age and gender.Our studies suggest that OxLDL and renal dysfunction are associated with a poor prognosis in unstable CAD patients and that these markers demonstrate potential for clinical use. In the search for new markers related to renal function we have contributed with reference levels of cystatin C and NT-proBNP.
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| 6. |
- Jönsson, Simon, 1983-
(författare)
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Leukocyte-derived matrix metalloproteinase-9 in patients with coronary artery disease : Associations with psychological stress and glucocorticoid sensitivity
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Inflammation is closely associated with development of atherosclerosis. The proteolytic enzyme matrix metalloproteinase (MMP)-9 is considered to play a prominent role in this process. MMP-9 has also been introduced as a marker for plaque vulnerability. Still, the possible mechanisms behind altered levels of MMP-9 and its tissue inhibitors (TIMPs) in patients with atherosclerotic disease remain unclear. The general aim of this thesis was to compare leukocyte-derived MMP-9 and TIMPs in patients with coronary artery disease (CAD) and healthy controls and to further relate the findings to psychological stress and glucocorticoid sensitivity.Levels of leukocyte-derived MMP-9 and TIMP-1 showed a significant difference between CAD patients and controls. Neutrophils in CAD patients were more prone to release MMP-9 and furthermore, PBMCs in patients expressed higher levels of MMP-9 and TIMP-1 and -2 mRNA than PBMCs in controls while there were no differences in plasma or serum levels. The increase in leukocyte-derived levels of MMP-9 and TIMPs indicate the presence of preactivated leukocytes in CAD.Inflammation has been proposed as a mechanistic link between cardiovascular risk and depressive symptoms. We investigated whether the overexpression of leukocyte-derived MMP-9 and TIMPs in CAD patients was associated with psychological factors. Patients exhibited sustained elevations in depressive symptoms, however, these symptoms were not related to any MMP-9 or TIMP variables. The findings suggest that overexpression of leukocyte-derived MMP-9 and TIMPs and elevated depressive scores represent two parallel phenomena in CAD.Chronic inflammation may be associated with reduced glucocorticoid sensitivity. We found that PBMCs in CAD patient expressed significantly increased levels of glucocorticoid receptor (GR)-α mRNA, whereas GR-β mRNA levels did not differ between patients and controls. Moreover, in ex vivo assays, dexamethasone efficiently suppressed MMP-9 and TIMPs equally or even more in patients compared to controls. The findings provide evidence for enhanced glucocorticoid sensitivity in CAD patients and also suggest that a state of relative hypocortisolism may contribute to the overexpression of leukocyte-derived MMP-9 and TIMPs.Lastly, we explored the release of MMP-9, TIMPs and cortisol in response to acute mental stress in CAD patients. Patients who exhibited a significant stress-induced increase in serum MMP-9 also exhibited an altered cortisol response. Moreover, the susceptibility to stressinduced increase in serum MMP-9 was associated with shorter leukocyte telomere length and atherosclerotic plaque burden. The findings highlight the existence of a high-risk group which may be in need of improved diagnostic and therapeutic strategies.
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