| 1. |
- Rendek, Zlatica, 1983-
(författare)
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Faecal Calprotectin Diagnostics : Focus on Primary Care and Suspected Sources of Error
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Patients with gastrointestinal symptoms often present a diagnostic challenge for general practitioners. Faecal calprotectin (FC) is commonly used as a marker of intestinal inflammation and is useful for differentiating between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), as well as for the follow-up of patients with IBD and monitoring treatment response. However, several other causes of increased FC levels have been acknowledged, including intake of non-steroidal anti-inflammatory drugs or proton pump inhibitors and respiratory infections. Currently, there is insufficient knowledge about how these factors affect FC levels. It is crucial that physicians who use calprotectin as a diagnostic tool have the ability to conduct a sound evaluation of the test result to ensure accurate clinical decisions, and potentially avoid unnecessary referrals and invasive investigations.The aim of this thesis was to investigate the contribution of FC in the diagnostics of gastrointestinal disease in primary care, its diagnostic value and accuracy as a predictor of gastrointestinal disease and the influence of different sources of error on calprotectin levels. In particular, the effects of oral diclofenac (a non-steroidal anti-inflammatory drug [NSAID]), omeprazole (a proton pump inhibitor [PPI]) and respiratory tract infection on FC levels are investigated. The normalization interval after cessation of diclofenac and omeprazole is assessed.The first study is a retrospective analysis of data on all FC tests on adults conducted in primary care in Östergötland County in 2010. A higher proportion of patients with a positive FC result were diagnosed with IBD and organic gastrointestinal disease compared with those with a negative FC result. Predictors of IBD were positive FC, diarrhoea, rectal bleeding and male sex. Predictors of organic gastrointestinal disease were found to be positive FC, age >35 years, abnormal clinical findings and duration <3 months. FC had the highest sensitivity and negative predictive value compared with demographic factors, symptoms and duration. Intake of NSAIDs, PPIs and acetyl salicylic acid showed marginal effects on the diagnostic accuracy of FC for IBD and organic gastrointestinal disease. Among patients with a negative FC test, on whom no further investigations were performed, no missed diagnoses of IBD or organic gastrointestinal disease were detected at a 5-year follow-up.The second study investigates the effect of diclofenac intake on FC levels. We found that shortterm intake of oral diclofenac was associated with increased FC levels and that FC returned to normal within 2 weeks of cessation.The third study reports on a randomized open-label clinical trial and investigates the effect of omeprazole, diclofenac and co-administration of these drugs on FC levels. The findings regarding diclofenac were consistent with those of the second study. Short-term intake of omeprazole alone or when co-administered with diclofenac was associated with increased FC levels. The normalization interval was 3 weeks after cessation.The fourth study, a prospective cohort study, examines the effect of an acute respiratory tract infection on the FC level. Faecal and salivary calprotectin levels were not found to be increased during respiratory tract infections. This study did not confirm any correlation between calprotectin levels in saliva and faeces during infection.In conclusion, FC reliably rules out IBD and contradicts the presence of other organic gastrointestinal diseases in patients with gastrointestinal symptoms attending primary care. Patients with a positive FC test together with other symptoms, such as diarrhoea, rectal bleeding, short duration or age >35 years should be prioritized for further investigations. Short-term intake of diclofenac, omeprazole, or their co-administration in healthy individuals is associated with increased FC levels. In patients with an increased FC level on diclofenac, it is sufficient to repeat the FC test 2 weeks after cessation. In patients on omeprazole alone or when co-administered with diclofenac, the FC test should be repeated 3 weeks after cessation. Acute respiratory tract infections were not found to be associated with increased faecal or salivary calprotectin levels.
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| 2. |
- Ahmad, Awais, 1987-
(författare)
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Autoantibodies in healthy blood donors, rheumatic and autoimmune liver diseases
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Autoimmunity is a common phenomenon where the immune system recognises the body's own tissues. Autoimmunity can lead to disease if tissue damage occurs. Autoimmune diseases affect 5–10% of the global population and in many of these autoantibodies can be detected. The autoantibodies can be detected with several different methods. In this thesis, line immunoassays and fluorescence enzyme immunoassay were used to investigate the presence of autoantibodies in blood donors and various disease groups. Line immunoassays use strips while fluorescence enzyme immunoassay uses wells. The strips and wells are coated with proteins that are allowed to react with serum samples from the patient. In the presence of autoantibodies, either a color change (line immunoassay) or a light reaction (fluorescence enzyme immunoassay) occurs.Study I and II: With the EuroLine -Autoimmune Liver Diseases- (IgG) line immunoassay, the presence of autoantibodies associated with autoimmune liver diseases was analysed in blood donors, patients with autoimmune liver diseases and patients with SLE. Autoantibodies could be detected in several blood donors. A very rare autoantibody, anti-LC- 1, was more common in blood donors than in patients with autoimmune liver diseases. Despite the presence of the autoantibodies, no association was seen with abnormal liver values in blood donors or patients with SLE. By raising the cut-off, the number of "false positive" results decreased. However, this could not correct the problem with anti-LC-1, which seems to indicate that there is a problem with the LC-1 antigen so that non-specific reactions are detected. The risk of developing autoimmune liver disease was considered to be low in the SLE patients, as none of these patients developed autoimmune liver disease despite several years of follow-up. Most of the positive findings with the EuroLine immunoassay could not be confirmed with other methods, indicating that this method is very sensitive.Study III: With the EuroLine Systemic Sclerosis (Nucleoli) Profile (IgG) line immunoassay, the rare autoantibodies anti-Th/To and anti-NOR90 could be detected as frequently in blood donors as in patients with systemic sclerosis. Most of the other autoantibodies were more common in patients with systemic sclerosis compared to blood donors and other disease groups. Some of these autoantibodies were associated with specific clinical manifestations, including renal involvement in patients with SLE. These findings need to be verified.Study IV: Autoantibodies that bind the U1-RNP protein (anti-U1-RNP) can be detected in patients with SLE. Patients with anti-U1-RNP can be further analysed for the presence of autoantibodies against the protein RNP 70kDa (anti-RNP70). However, the clinical value of further analysis of anti-RNP70 is uncertain. In this study, fluorescence enzyme immunoassay was used to analyse anti-U1-RNP positive samples for anti-RNP70 to evaluate whether it added anything of clinical value in SLE patients. Presence of anti-U1-RNP was associated with low white blood cell counts and less organ damage. However, analysis of anti-RNP70 in patients with SLE did not add any additional clinical information.Conclusion: Euroline -Autoimmune Liver Diseases- (IgG) and EuroLine Systemic Sclerosis (Nucleoli) Profile (IgG) are tools that are of value in the diagnosis of autoimmune liver diseases and systemic sclerosis, but the methods have high sensitivity which can lead to false positive results. By raising the cut-off, the risk of this can be reduced. Some rare antibodies were found more frequently in blood donors than in patients with the different disease groups, suggesting potential problems with the antigen source. Subtyping of anti-RNP70 in SLE patients with anti-U1-RNP did not add anything of clinical value.
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| 3. |
- Karlsson, Markus, 1990-
(författare)
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Non-Invasive Characterization of Liver Disease : By Multimodal Quantitative Magnetic Resonance
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a large and unmet need for diagnostic tool that can be used to characterize chronic liver diseases (CLD). In the earlier stages of CLD, much of the diagnostics involves performing biopsies, which are evaluated by a histopathologist for the presence of e.g. fat, iron, inflammation, and fibrosis. Performing biopsies, however, have two downsides: i) biopsies are invasive and carries a small but non-negligible risk for serious complications, ii) biopsies only represents a tiny portion of the liver and are thus prone to sampling error. Moreover, in the later stages of CLD, when the disease has progressed far enough, the ability of the liver to perform its basic function will be compromised. In this stage, there is a need for better methods for accurately measuring liver function. Additionally, measures of liver function can also be used when developing new drugs, as biomarkers for drug-induced liver injury (DILI), which is a serious drug-safety issue.Magnetic resonance imaging (MRI) is a non-invasive medical imaging modality, which have shown much promise with regards to characterizing liver disease in all of the abovementioned aspects. The aim of this PhD project was to develop and validate MR-based methods that can be used to non-invasively characterize liver disease.Paper I investigated if R2* mapping, a MR-method for measuring liver iron content, can be confounded by liver fat. The results show fat does affect R2*. The conclusion was therefore that fat must be taken into account when measuring small amounts of liver iron, as a small increase in R2* could be due to either small amounts of iron or large amounts of fat.Paper II examined whether T1 mapping, which is another MR-method, can be used for staging liver fibrosis. The results of previous research have been mixed; some studies have been very promising, whereas other studies have been less promising. Unfortunately, the results in Paper II belongs to the less promising studies.Paper III focused on measuring liver function by dynamic contrast-enhanced MRI (DCEMRI) using a liver specific contrast agent, which is taken up the hepatocytes and excreted to the bile. The purpose of the paper was to extend and validate a method for estimating uptake and efflux rates of the contrast agent. The method had previously only been applied in health volunteers. Paper II showed that the method can be applied to CLD patients and that the uptake of the contrast agent is lower in patients with advanced fibrosis.Paper IV also used studied liver function with DCE-MRI in patients with primary sclerosing cholangitis (PSC). PSC is a CLD where the bile ducts are attacked by the immune system. When diagnosing PSC patients, it is common to use magnetic resonance cholangiopancreatography (MRCP), which is a method for imaging the bile ducts. Paper IV examined if there was any correlation between number and severity of the morphological changes, seen on MRCP, and measures of liver function derived using DCE-MRI. However, the results showed no such correlation. The conclusion was that the results indicates that MRCP should not be used to predict parenchymal function.Paper V developed a method for translating DCE-MRI liver function parameters from rats to humans. This translation could be of value when developing new drugs, as a tool for predicting which drugs might cause drug-induced liver injury.In summary, this thesis has shown that multimodal quantitative MR has a bright future for characterizing liver disease from a range of different aspects.
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| 4. |
- Blomdahl, Julia, 1991-
(författare)
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Non-Alcoholic Fatty Liver Disease : Insights into Alcohol Consumption, Genetics, and Proteomics
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- NAFLD (Non-Alcoholic Fatty Liver Disease) affects approximately a quarter of the global population and is closely linked to type 2 diabetes mellitus and obesity. The disease spectrum ranges from steatosis and steatohepatitis to fibrosis, cirrhosis, and hepatocellular cancer. However, accurately predicting which patients will experience a progressive disease course remains a significant challenge. The variant gene of PNPLA3 is known to be associated with NAFLD and a more progressive disease, although its precise function remains unclear. Patients with NAFLD typically consume small to moderate amounts of alcohol, with recommended thresholds set at a maximum of 210 gram per week for males and 140 grams per week in females. However, the impact of alcohol consumption on liver disease in NAFLD remains disputed, with conflicting research findings. Liver biopsy is considered the gold standard for diagnosing NAFLD. However, due to its impracticality for such a large population with the condition, various non-invasive methods have been explored for diagnosing and evaluating NAFLD. This thesis aimed to investigate the potential effects of moderate alcohol consumption on NAFLD histology, explore the potential role of variant PNPLA3 in NAFLD, and assess the use of proteomics in classifying fibrosis. In Papers I and II, moderate alcohol consumption was assessed through questionnaires, clinical interviews, and measurement of the direct alcohol biomarker phosphatidylethanol (PEth). Paper I, a cross-sectional study including 86 participants, showed an association between moderate consumption and advanced fibrosis. Moderate consumption was defined as consuming more than 66 grams of ethanol per week or a PEth-value over 50 ng/mL. Notably, individuals with both moderate alcohol consumption and a diagnosis of type 2 diabetes exhibited significantly more advanced fibrosis. Paper II was a cohort study where 82 participants were followed over 17.2 years. Similarly, participants with moderate alcohol consumption displayed significant fibrosis progression. The strongest association was observed in participants with PEth-value of 48 ng/mL or higher, or those with binge drinking. In Paper III, the potential role of variant PNPLA3 was explored, exhibiting impaired autophagic flux and reduced lipophagy in variant PNPLA3 cells. Liver biopsies of NAFLD individuals with variant PNPLA3 displayed an accumulation of lipid droplets positive for both PNPLA3 and LC3 (a common marker of the autophagosome). This suggests that PNPLA3 is part of the lipophagy process, which is impaired in the variant gene and contributes to steatosis. Paper IV examined two independent NAFLD cohorts. In the discovery cohort, 60 participants with biopsy-proven NAFLD were included, while 59 participants were included in the validation cohort. The study evaluated 266 proteins and found that a biomarker model combining ACE2, HGF, and IGFBP-7 distinguished between different fibrosis stages (F0–1 and F2–4) in both cohorts. In summary, measuring phosphatidylethanol is advisable in NAFLD patient evaluations. Elevated PEth-levels (≥48 ng/mL) or alcohol consumption exceeding 66 grams per week should warrant advice to abstain from alcohol. PNPLA3 is implicated in NAFLD pathophysiology, potentially through impaired lipophagy. While its clinical application remains uncertain, genetic profiling for NAFLD risk assessment may become part of future non-invasive approaches. Additionally, proteomics holds promise for non-invasive NAFLD assessment, with the combination of ACE2, HGF, and IGFBP-7 identifying significant fibrosis in two separate cohorts.
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| 5. |
- Nasr, Patrik, 1987-
(författare)
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Non-Alcoholic Fatty Liver Disease : Aspects on Diagnosis and Long-term Prognosis
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease affecting approximately 25% of the global population and is commonly recognized as the hepatic manifestation of the metabolic syndrome. The histological spectrum of NAFLD ranges from isolated steatosis to non-alcoholic steatohepatitis (NASH), with risk of developing fibrosis and subsequent cirrhosis and hepatocellular carcinoma. The gold standard for diagnosing NAFLD is liver biopsy. However, because of its invasive nature, several non-invasive methods have been developed and validated in evaluating fat and fibrosis in patients with NAFLD.Liver fat content can be assessed using various methods. The conventional histopathological method consists of a visual semiquantitative approach in which the pathologist uses a four-point scale: grade 0 corresponds to fat deposition in <5% of hepatocytes and grade 1−3 (which is needed for the diagnosis of NAFLD) corresponds to ≥5%. An alternate approach is to quantitatively assess steatosis using stereological point counting (SPC) – which rely on liver biopsy. However, in vivo proton magnetic resonance spectroscopy (1H-MRS) is a reliable noninvasive method that can be used to quantitatively assess total hepatic lipid content, or proton density fat fraction (PDFF).In Paper I we compared the conventional semiquantitative histological method (grade 0-3) with SPC and 1H-MRS. We found a strong positive correlation between 1H-MRS and SPC, whereas the correlations between 1H-MRS or SPC and histopathological grading were substantially weaker. Using the widely used cut-off value of PDFF ≥5%, all participants were found to have steatosis (specificity 100%, sensitivity 53%). Reducing the cut-off value to 3% maintained 100% specificity while increasing sensitivity to 79%.In Paper IV we evaluated quantitative steatosis, by SPC, in 106 biopsy-proven NAFLD patients during a 20-year follow-up. SPC was independently associated with an increased risk of all-cause mortality and development of T2DM. Moreover, in the 59 patients with sequential biopsies (approximately 10 years apart), a reduction of quantitative hepatic steatosis decreased the all-time risk of developing T2DM.NASH is commonly seen as a histological feature portending a worse prognosis in NAFLD. Interestingly, no dual biopsy study has ever shown that NASH predicts fibrosis progression. Yet, NASH is seen as a surrogate marker in pharmaceutical trials – were resolution in NASH is equivalent to future resolution of fibrosis.In Paper II we conducted a long-term follow-up study (20 years) in a large cohort of biopsy-proven NAFLD patients (n=646), in a collaboration with Karolinska Institute. We could not ascertain that NASH had any effect on all-cause, or disease-specific mortality. However, higher stages of fibrosis predicted all-cause and disease specific mortality. In Paper III, we present 129 biopsy-proven NAFLD patients, in which we had prospective, longitudinal data. They were included between 1988 and 1993. All patients alive, were re-invited 2003-2005 and 2013-2015. Dual biopsies were present in 68 patients, and three consecutive biopsies were available in 33 patients. Results showed that NAFLD is a highly heterogeneous disease, with 9.3% developing end-stage liver disease and 16% progressing to advanced stages of fibrosis without any clinically significant baseline data predicting disease progression. In summary, when using 1H-MRS as a diagnostic method for NAFLD, the diagnostic cut-off should be reduced from 5% to 3%. Furthermore, quantitative amount of hepatic steatosis could be used to stratify patients with NAFLD related to future risk of developing T2DM. Moreover, we have shown that NASH does not predict future all-cause or disease-specific mortality nor end-stage liver disease, therefore a different surrogate marker should be used in clinical trials when assessing NAFLD improvement, so to not imbue false reliance in new therapies. Lastly, we have shown that NAFLD has a more dismal prognosis than previously reported, and that it is unexpectedly difficult to predict fibrosis progression in individual NAFLD patients, emphasizing the need for robust non-invasive biomarkers suitable to monitor large number of patients.
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| 6. |
- Akbari, Camilla, et al.
(författare)
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Long-term major adverse liver outcomes in 1,260 patients with non-cirrhotic NAFLD
- 2024
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Ingår i: JHEP Reports. - : Elsevier. - 2589-5559. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- Background & AimsLong-term studies of the prognosis of NAFLD are scarce. Here, we investigated the risk of major adverse liver outcomes (MALO) in a large cohort of patients with NAFLD.MethodsWe conducted a cohort study with data from Swedish university hospitals. Patients (n = 1,260) with NAFLD without cirrhosis were diagnosed through biopsy or radiology, and had fibrosis estimated through vibration-controlled transient elastography, biopsy, or FIB-4 score between 1974 and 2020 and followed up through 2020. Each patient was matched on age, sex, and municipality with up to 10 reference individuals from the general population (n = 12,529). MALO were ascertained from Swedish national registers. The rate of events was estimated by Cox regression.ResultsMALO occurred in 111 (8.8%, incidence rate = 5.9/1,000 person-years) patients with NAFLD and 197 (1.6%, incidence rate = 1.0/1,000 person-years) reference individuals during a median follow up of 13 years. The rate of MALO was higher in patients with NAFLD (hazard ratio = 6.6; 95% CI = 5.2–8.5). The risk of MALO was highly associated with the stage of fibrosis at diagnosis. In the biopsy subcohort (72% of total sample), there was no difference in risk between patients with and without non-alcoholic steatohepatitis. The 20-year cumulative incidences of MALO were 2% for the reference population, 3% for patients with F0, and 35% for F3. Prognostic information from biopsy was comparable to FIB-4 (C-indices around 0.73 vs. 0.72 at 10 years).ConclusionsThis study provides updated information on the natural history of NAFLD, showing a high rate of progression to cirrhosis in F3 and a similar prognostic capacity of non-invasive tests to liver biopsy.Impact and implicationsSeveral implications for clinical care and future research may be noted based on these results. First, the risk estimates for cirrhosis development are important when communicating risk to patients and deciding on clinical monitoring and treatment. Estimates can also be used in updated health-economic evaluations, and for regulatory agencies. Second, our results again highlight the low predictive information obtained from ascertaining NASHstatus by histology and call for more objective means by which to define NASH. Such methods may include artificial intelligence-supported digital pathology. We highlight that NASH is most likely the causal factor for fibrosis progression in NAFLD, but the subjective definition makes the prognostic value of a histological NASH diagnosis of limited value. Third, the finding that prognostic information from biopsy and the very simple Fibrosis-4 score were comparable is important as it may lead to fewer biopsies and further move the field towards non-invasive means by which to define fibrosis and, importantly, use non-invasive tests as outcomes in clinical trials. However, all modalities had modest discriminatory capacity and new risk stratification systems are needed in NAFLD. Repeated measures of non-invasive scores may be a potential solution.
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