Liver Investigation: Testing Marker Utility in Steatohepatitis (LITMUS): Assessment & validation of imaging modality performance across the NAFLD spectrum in a prospectively recruited cohort study (the LITMUS imaging study): Study protocol

Non-alcoholic fatty liver disease (NAFLD) is the liver manifestation of the metabolic syndrome with global prevalence reaching epidemic levels. Despite the high disease burden in the population only a small proportion of those with NAFLD will develop progressive liver disease, for which there is currently no approved pharmacotherapy. Identifying those who are at risk of progressive NAFLD currently requires a liver biopsy which is problematic. Firstly, liver biopsy is invasive and therefore not appropriate for use in a condition like NAFLD that affects a large proportion of the population. Secondly, biopsy is limited by sampling and observer dependent variability which can lead to misclassification of disease severity. Non-invasive biomarkers are therefore needed to replace liver biopsy in the assessment of NAFLD. Our study addresses this unmet need. The LITMUS Imaging Study is a prospectively recruited multi-centre cohort study evaluating magnetic resonance imaging and elastography, and ultrasound elastography against liver histology as the reference standard. Imaging biomarkers and biopsy are acquired within a 100-day window. The study employs standardised processes for imaging data collection and analysis as well as a real time central monitoring and quality control process for all the data submitted for analysis. It is anticipated that the high-quality data generated from this study will underpin changes in clinical practice for the benefit of people with NAFLD. Study Registration: clinicaltrials.gov: NCT05479721.

Hepatic Unsaturated Fatty Acids Are Linked to Lower Degree of Fibrosis in Non-alcoholic Fatty Liver Disease

Background: The hepatic lipidome of patients with early stages of non-alcoholic fatty liver disease (NAFLD) has been fairly well-explored. However, studies on more progressive forms of NAFLD, i.e., liver fibrosis, are limited.

Materials and methods: Liver fatty acids were determined in cholesteryl esters (CE), phospholipids (PL), and triacylglycerols (TAG) by gas chromatography. Cross-sectional associations between fatty acids and biopsy-proven NAFLD fibrosis (n = 60) were assessed using multivariable logistic regression models. Stages of fibrosis were dichotomized into none-mild (F0–1) or significant fibrosis (F2–4). Models were adjusted for body-mass index (BMI), age and patatin-like phospholipase domain-containing protein 3 (PNPLA3 rs738409) (I148M) genotype. A secondary analysis examined whether associations from the primary analysis could be confirmed in the corresponding plasma lipid fractions.

Results: PL behenic acid (22:0) was directly associated [OR (95% CI): 1.86 (1.00, 3.45)] whereas PL docosahexaenoic acid (22:6n-3) [OR (95% CI): 0.45 (0.23, 0.89)], TAG oleic acid (18:1n-9) [OR (95% CI): 0.52 (0.28, 0.95)] and 18:1n-9 and vaccenic acid (18:1n-7) (18:1) [OR (95% CI): 0.52 (0.28, 0.96)] were inversely associated with liver fibrosis. In plasma, TAG 18:1n-9 [OR (95% CI): 0.55 (0.31, 0.99)], TAG 18:1 [OR (95% CI): 0.54 (0.30, 0.97)] and PL 22:0 [OR (95% CI): 0.46 (0.25, 0.86)] were inversely associated with liver fibrosis.

Conclusion: Higher TAG 18:1n-9 levels were linked to lower fibrosis in both liver and plasma, possibly reflecting an altered fatty acid metabolism. Whether PL 22:6n-3 has a protective role, together with a potentially adverse effect of hepatic 22:0, on liver fibrosis warrants large-scale studies.

The Combination of MR Elastography and Proton Density Fat Fraction Improves Diagnosis of Nonalcoholic Steatohepatitis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide. It is subdivided into nonalcoholic fatty liver (NAFL) and the more aggressive form, nonalcoholic steatohepatitis (NASH), which carries a higher risk of developing fibrosis and cirrhosis. There is currently no reliable non-invasive method for differentiating NASH from NAFL.

PURPOSE

To investigate the ability of magnetic resonance imaging (MRI)-based imaging biomarkers to diagnose NASH and moderate fibrosis as well as assess their repeatability.

STUDY TYPE

Prospective.

SUBJECTS

Sixty-eight participants (41% women) with biopsy-proven NAFLD (53 NASH and 15 NAFL). Thirty participants underwent a second MRI in order to assess repeatability.

FIELD STRENGTH/SEQUENCE

3.0 T; MR elastography (MRE) (a spin-echo echo-planar imaging [SE-EPI] sequence with motion-encoding gradients), MR proton density fat fraction (PDFF) and R2* mapping (a multi-echo three-dimensional gradient-echo sequence), T1 mapping (a single-point saturation-recovery technique), and diffusion-weighted imaging (SE-EPI sequence).

ASSESSMENT

Quantitative MRI measurements were obtained and assessed alone and in combination with biochemical markers (cytokeratin-18 [CK18] M30, alanine transaminase [ALT], and aspartate transaminase [AST]) using logistic regression models. Models that could differentiate between NASH and NAFL and between moderate to advanced fibrosis (F2-4) and no or mild fibrosis (F0-1), based on the histopathological results, were identified.

STATISTICAL TESTS

Independent samples t-test, Pearson's chi-squared test, area under the receiver operating characteristic curve (AUROC), Spearman's correlation, intra-individual coefficient of variation, and intraclass correlation coefficient (ICC). Statistical significance was set at P < 0.05.

RESULTS

There was a significant difference between the NASH and NAFL groups with liver stiffness assessed with MRE, CK18 M30, and ALT, with an AUROC of 0.74, 0.76, and 0.70, respectively. Both MRE and PDFF contributed significantly to a bivariate model for diagnosing NASH (AUROC = 0.84). MRE could significantly differentiate between F2-4 and F0-1 (AUROC = 0.74). A model combining MRE with AST improved the diagnosis of F2-4 (AUROC = 0.83). The ICC for repeatability was 0.94 and 0.99 for MRE and PDFF, respectively.

DATA CONCLUSION

MRE can potentially diagnose NASH and differentiate between fibrosis stages. Combining MRE with PDFF improves the diagnosis of NASH.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Randomised clinical trial: semaglutide versus placebo reduced liver steatosis but not liver stiffness in subjects with non-alcoholic fatty liver disease assessed by magnetic resonance imaging

BACKGROUND

Glucagon-like peptide-1 receptor agonists may be a treatment option in patients with non-alcoholic fatty liver disease (NAFLD).

AIMS

To investigate the effects of semaglutide on liver stiffness and liver fat in subjects with NAFLD using non-invasive magnetic resonance imaging (MRI) methods.

METHODS

This randomised, double-blind, placebo-controlled trial enrolled subjects with liver stiffness 2.50-4.63 kPa by magnetic resonance elastography (MRE) and liver steatosis ≥10% by MRI proton density fat fraction (MRI-PDFF). The primary endpoint was change from baseline to week 48 in liver stiffness assessed by MRE.

RESULTS

Sixty-seven subjects were randomised to once-daily subcutaneous semaglutide 0.4 mg (n = 34) or placebo (n = 33). Change from baseline in liver stiffness was not significantly different between semaglutide and placebo at week 48 (estimated treatment ratio 0.96 (95% CI 0.89, 1.03; P = 0.2798); significant differences in liver stiffness were not observed at weeks 24 or 72. Reductions in liver steatosis were significantly greater with semaglutide (estimated treatment ratios: 0.70 [0.59, 0.84], P = 0.0002; 0.47 [0.36, 0.60], P < 0.0001; and 0.50 [0.39, 0.66], P < 0.0001) and more subjects achieved a ≥ 30% reduction in liver fat content with semaglutide at weeks 24, 48 and 72, (all P < 0.001). Decreases in liver enzymes, body weight and HbA_1c were also observed with semaglutide.

CONCLUSIONS

The change in liver stiffness in subjects with NAFLD was not significantly different between semaglutide and placebo. However, semaglutide significantly reduced liver steatosis compared with placebo which, together with improvements in liver enzymes and metabolic parameters, suggests a positive impact on disease activity and metabolic profile. ClinicalTrials.gov identifier: NCT03357380.

MO621AGE-RELATED PATTERNS OF KIDNEY PARENCHIMAL VOLUME IN T1D, T2D AND DIFFERENT TREATMENT GROUPS OF T2D: A CROSS-SECTIONAL STUDY OF 35,703 UK BIOBANK PARTICIPANTS

Background and Aims

Kidney parenchymal volume (KPV) presents a natural variation with respect to sex, age, and body size, and is also affected by diseases such as diabetes. The UK Biobank (UKBB) is a large-scale study including clinical and MRI data. The current project investigated the association between KPV and age in UKBB participants without diabetes and with diabetes type 1 (T1D), and type 2 (T2D). In addition, the effect of different treatments for T2D on KPV was investigated.

Method

KPV was estimated in 35,703 UKBB participants (52% women, age = 45-82 years) with a deep-learning-based segmentation of both kidneys (Dice = 0.956, error &lt; 4%). The cohort was classified into Control, T1D and T2D subjects using an algorithm developed on UKBB clinical data (Eastwood et al 2016). Individuals with T2D were further divided into groups related to treatment: Lifestyle (no pharmaceuticals, i.e. light treatment, mean disease duration of 6.2 years), Metformin (metformin as the only pharmaceutical, i.e. intermediate treatment, mean disease duration of 8.3 years), and Other (more potent treatment, combination of pharmaceuticals, mean disease duration of 14.1 years). KPV was studied as a function of age in the different groups, divided according to sex. The statistical difference in mean KPV between groups was tested. For each group, the association between KPV and age was assessed by linear regression. Comparison of line slopes was conducted to investigate whether age-related patterns in KPV differed statistically between groups.

Results

The moving average curve of KPV vs age, in controls and subjects with T1D and T2D, is shown in Fig 1A (with a 15-year sliding window). The corresponding curve for different T2D treatment groups is depicted in Fig 1B. Fig 2A-D presents results for the comparison of KPV and regression line slope between the subject groups. According to Fig 1A and 2A, KPV is usually higher in subjects with T1D and T2D than in controls. As shown in Fig 1B and 2B, T2D subjects with longer disease duration and on pharmaceutical treatment (Metformin or Other) are generally more prone to large KPV than subjects with adapted lifestyle as treatment. The decreasing KPV pattern with age is faster in T2D subjects than controls but not significantly different between T1D subjects and controls (Fig 1A and 2C). Women in group Other also show a pattern of steeper age-related decline in KPV compared to remaining women with T2D treatment (Fig 1B and 2D).

Conclusion

Compared to controls, T1D subjects show enlarged KPV similar to that of T2D subjects, which is in line with previous literature. Subjects with T2D show a pattern of steeper age-related decline in KPV compared to controls. Female T2D subjects with longer disease duration, usually on a more potent treatment (beyond adaption of lifestyle and metformin as the only pharmaceutical), are more prone to enlarged KPV and exhibit a pattern of steeper age-related decline in KPV. This may be due to hyperfiltration caused by diabetes, resulting in increased kidney size. The normal loss of glomeruli with age could be accelerated by diabetes, leading to a greater loss in KPV per year in diabetics. Steeper KPV decline patterns in disease could also be caused by selection bias where old subjects with large KPV and related complications are less likely to participate in the study.

HEROIC: a 5-year observational cohort study aimed at identifying novel factors that drive diabetic kidney disease: rationale and study protocol

INTRODUCTION

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease worldwide and a major cause of premature mortality in diabetes mellitus (DM). While improvements in care have reduced the incidence of kidney disease among those with DM, the increasing prevalence of DM means that the number of patients worldwide with DKD is increasing. Improved understanding of the biology of DKD and identification of novel therapeutic targets may lead to new treatments. A major challenge to progress has been the heterogeneity of the DKD phenotype and renal progression. To investigate the heterogeneity of DKD we have set up The East and North London Diabetes Cohort (HEROIC) Study, a secondary care-based, multiethnic observational study of patients with biopsy-proven DKD. Our primary objective is to identify histological features of DKD associated with kidney endpoints in a cohort of patients diagnosed with type 1 and type 2 DM, proteinuria and kidney impairment.

METHODS AND ANALYSIS

HEROIC is a longitudinal observational study that aims to recruit 500 patients with DKD at high-risk of renal and cardiovascular events. Demographic, clinical and laboratory data will be collected and assessed annually for 5 years. Renal biopsy tissue will be collected and archived at recruitment. Blood and urine samples will be collected at baseline and during annual follow-up visits. Measured glomerular filtration rate (GFR), echocardiography, retinal optical coherence tomography angiography and kidney and cardiac MRI will be performed at baseline and twice more during follow-up. The study is 90% powered to detect an association between key histological and imaging parameters and a composite of death, renal replacement therapy or a 30% decline in estimated GFR.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Bloomsbury Research Ethics Committee (REC 18-LO-1921). Any patient identifiable data will be stored on a password-protected National Health Services N3 network with full audit trail. Anonymised imaging data will be stored in a ISO27001-certificated data warehouse.Results will be reported through peer-reviewed manuscripts and conferences and disseminated to participants, patients and the public using web-based and social media engagement tools as well as through public events.

Drug-induced myocardial dysfunction - recommendations for assessment in clinical and pre-clinical studies

Introduction: Drug-induced myocardial dysfunction is an important safety concern during drug development. Oncology compounds can cause myocardial dysfunction, leading to decreased left ventricular ejection fraction and heart failure via several mechanisms. Cardiovascular imaging has a major role in the early detection and monitoring of cardiotoxicity. Echocardiography is the method of choice because of its widespread availability, low cost, and absence of radiation exposure. Cardiac magnetic resonance imaging can provide better reliability, reproducibility, and accuracy in the detection of drug-induced myocardial dysfunction. In addition, it enables assessment of myocardial edema, fibrosis, and necrosis. Cardiac serologic biomarkers such as troponins and B-type natriuretic peptides are used in combination with imaging during drug development. This article provides a general overview of each imaging modality and practical guidance for early detection and monitoring of cardiotoxicity.Areas covered: Cardiovascular imaging modalities and cardiac biomarkers for monitoring of cardiac function and early detection of drug-induced myocardial dysfunction in drug development.Expert opinion: Some new drugs especially in the oncology field, can cause myocardial dysfunction. Depending on the strength of pre-clinical or clinical data, CV imaging modalities and cardiac biomarkers play an important role in the early detection and mitigation plans for such drugs during their development.

Consensus-based technical recommendations for clinical translation of renal T1 and T2 mapping MRI

To develop technical recommendations on the acquisition and post-processing of renal longitudinal (T1) and transverse (T2) relaxation time mapping. A multidisciplinary panel consisting of 18 experts in the field of renal T1 and T2 mapping participated in a consensus project, which was initiated by the European Cooperation in Science and Technology Action PARENCHIMA CA16103. Consensus recommendations were formulated using a two-step modified Delphi method. The first survey consisted of 56 items on T1 mapping, of which 4 reached the pre-defined consensus threshold of 75% or higher. The second survey was expanded to include both T1 and T2 mapping, and consisted of 54 items of which 32 reached consensus. Recommendations based were formulated on hardware, patient preparation, acquisition, analysis and reporting. Consensus-based technical recommendations for renal T1 and T2 mapping were formulated. However, there was considerable lack of consensus for renal T1 and particularly renal T2 mapping, to some extent surprising considering the long history of relaxometry in MRI, highlighting key knowledge gaps that require further work. This paper should be regarded as a first step in a long-term evidence-based iterative process towards ever increasing harmonization of scan protocols across sites, to ultimately facilitate clinical implementation.

Consensus-based technical recommendations for clinical translation of renal T1 and T2 mapping MRI

To develop technical recommendations on the acquisition and post-processing of renal longitudinal (T1) and transverse (T2) relaxation time mapping. A multidisciplinary panel consisting of 18 experts in the field of renal T1 and T2 mapping participated in a consensus project, which was initiated by the European Cooperation in Science and Technology Action PARENCHIMA CA16103. Consensus recommendations were formulated using a two-step modified Delphi method. The first survey consisted of 56 items on T1 mapping, of which 4 reached the pre-defined consensus threshold of 75% or higher. The second survey was expanded to include both T1 and T2 mapping, and consisted of 54 items of which 32 reached consensus. Recommendations based were formulated on hardware, patient preparation, acquisition, analysis and reporting. Consensus-based technical recommendations for renal T1 and T2 mapping were formulated. However, there was considerable lack of consensus for renal T1 and particularly renal T2 mapping, to some extent surprising considering the long history of relaxometry in MRI, highlighting key knowledge gaps that require further work. This paper should be regarded as a first step in a long-term evidence-based iterative process towards ever increasing harmonization of scan protocols across sites, to ultimately facilitate clinical implementation.

Evaluation of carotid plaque inflammation in patients with active rheumatoid arthritis using (18)F-fluorodeoxyglucose PET-CT and MRI: a pilot study

BACKGROUND

Rheumatoid arthritis is associated with a 50% increased risk in cardiovascular mortality. Inflammation is thought to accelerate atherosclerosis and might also lead to an inflammatory rupture-prone plaque phenotype. We tested the hypothesis that patients with active rheumatoid arthritis also have carotid plaque inflammation and that plaque inflammation correlates with clinical and serological markers of inflammation.

METHODS

Patients with active rheumatoid arthritis, defined as the Disease Activity Score in 28 joints (DAS28) score of more than 3·2, were recruited to a single centre study in the UK. Patients with carotid plaque on ultrasound underwent carotid MRI followed by (18)F-fluorodeoxyglucose ((18)F-FDG) PET-CT. Scans were co-registered and analysed by a physicist, masked to clinical information. The maximum standardised uptake values (SUV(max)) were measured in the plaque area. The association of SUV with DAS28, C-reactive protein, and CD4+CD28- T-cell frequency was tested with non-parametric statistics. Ethics approval and informed consent were obtained.

FINDINGS

Scans were done in 13 patients, nine of whom were women. Median age was 60 years (IQR 57-65), disease duration was 11 years (6-25), and DAS28 score was 4·52 (4·32-5·13). None had a history or symptoms of clinical cardiovascular disease or took statins. All plaques caused less than 70% stenosis, and tracer uptake in plaque was seen on PET in all 13 patients. Median SUV(max) was 2·18 (IQR 2·00-2·65), and all cases had an SUV(max) greater than 1·6 (the threshold for defining carotid plaque inflammation). There was a significant association with SUV(max) and C-reactive protein (r=0·58, p=0·04) and quartiles of CD4+CD28- T-cell frequency (p=0·045), but not with low-density lipoprotein concentrations (r=-0·49, p=0·09) or DAS28 score (r=0·38, p=0·20). No association was found with age (r=0·13, p=0·69) or sex (p=0·64).

INTERPRETATION

In this small pilot study, plaque inflammation was seen in all patients and correlated with C-reactive protein. Whether this finding represents simultaneous joint and plaque inflammation, which might improve on treatment of joint disease, remains to be determined. CD4+CD28- T-cells are known to predict cardiovascular events in patients with angina. Their association with plaque inflammation in this study suggests a possible role in cardiovascular risk prediction in rheumatoid arthritis. Larger studies are warranted to investigate these findings further.

FUNDING

North West England MRC Clinical Pharmacology and Therapeutics Clinical Research Fellowship, National Institute for Health Research, AstraZeneca-University of Manchester Strategic Alliance Fund.