Transcriptomic analysis of intestine following administration of a transglutaminase 2 inhibitor to prevent gluten-induced intestinal damage in celiac disease.

Transglutaminase 2 (TG2) plays a pivotal role in the pathogenesis of celiac disease (CeD) by deamidating dietary gluten peptides, which facilitates antigenic presentation and a strong anti-gluten T cell response. Here, we elucidate the molecular mechanisms underlying the efficacy of the TG2 inhibitor ZED1227 by performing transcriptional analysis of duodenal biopsies from individuals with CeD on a long-term gluten-free diet before and after a 6-week gluten challenge combined with 100 mg per day ZED1227 or placebo. At the transcriptome level, orally administered ZED1227 effectively prevented gluten-induced intestinal damage and inflammation, providing molecular-level evidence that TG2 inhibition is an effective strategy for treating CeD. ZED1227 treatment preserved transcriptome signatures associated with mucosal morphology, inflammation, cell differentiation and nutrient absorption to the level of the gluten-free diet group. Nearly half of the gluten-induced gene expression changes in CeD were associated with the epithelial interferon-γ response. Moreover, data suggest that deamidated gluten-induced adaptive immunity is a sufficient step to set the stage for CeD pathogenesis. Our results, with the limited sample size, also suggest that individuals with CeD might benefit from an HLA-DQ2/HLA-DQ8 stratification based on gene doses to maximally eliminate the interferon-γ-induced mucosal damage triggered by gluten.

How Future Pharmacologic Therapies for Celiac Disease Will Complement the Gluten-Free Diet.

The only proven treatment for celiac disease is adherence to a strict, lifelong, gluten-free diet. However, complete dietary gluten avoidance is challenging and a substantial number of patients do not respond fully, clinically, or histologically, despite their best efforts. As celiac disease is common and its central pathophysiology is well elucidated, it has become attractive for drug development to address the limitations of dietary treatment. Most efforts address nonresponsive celiac disease, defined as continued symptoms and/or signs of disease activity despite a gluten-free diet, and the more severe forms of refractory celiac disease, types I and II. An increasing spectrum of therapeutic approaches target defined mechanisms in celiac disease pathogenesis and some have advanced to current phase 2 and 3 clinical studies. We discuss these approaches in terms of potential efficiency, practicability, safety, and need, as defined by patients, regulatory authorities, health care providers, and payors.

Short-term reduction of dietary gluten improves metabolic-dysfunction associated steatotic liver disease: A randomised, controlled proof-of-concept study.

BACKGROUND: The current management of metabolic dysfunction-associated steatotic liver disease (MASLD) relies on lifestyle intervention. Prior studies have shown that nutritional wheat amylase trypsin inhibitors (ATI) activate toll-like receptor 4 on intestinal myeloid cells to enhance intestinal and extra-intestinal inflammation, including the promotion of murine MASLD, insulin resistance and liver fibrosis. AIMS: We aimed to assess the impact of ATI (gluten)-free diet in liver as well as metabolic parameters of biopsy-proven MASLD patients. METHODS: We performed a 6-week, proof-of-concept 1:1 randomised controlled trial of an ATI-free diet. The controls followed a balanced diet recommended by the German Nutrition Society. We assessed changes in controlled attenuation parameter (CAP), body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR). Patient-reported outcomes were assessed by the CLDQ-NASH questionnaire. Forty-five patients were consecutively enrolled (21 in the intervention arm and 24 in the control arm). RESULTS: Three patients from each arm discontinued the study. In the ATI-free diet group, a significant decrease in BMI (p = 0.018), CAP (p = 0.018) and HOMA-IR (p = 0.042) was observed at 6 weeks. The mean difference in CAP between the two arms at week 6 was 30.5 dB/m (p = 0.039), with a delta significantly higher in the ATI-free diet group (p = 0.043). Only an ATI-free diet could achieve a significant improvement in CLDQ-NASH domains (p value for total scoring: 0.013). CONCLUSIONS: A short-term ATI-free diet leads to significant improvements in liver and metabolic parameters, as well as patient-reported outcomes with good tolerability. A larger follow-up study is justified to corroborate these findings. CLINICAL TRIAL NUMBER: NCT04066400.

Effects of Short-Term Gluten-Free Diet on Cardiovascular Biomarkers and Quality of Life in Healthy Individuals: A Prospective Interventional Study.

INTRODUCTION: The exposome concept includes nutrition as it significantly influences human health, impacting the onset and progression of diseases. Gluten-containing wheat products are an essential source of energy for the world's population. However, a rising number of non-celiac healthy individuals tend to reduce or completely avoid gluten-containing cereals for health reasons. AIM AND METHODS: This prospective interventional human study aimed to investigate whether short-term gluten avoidance improves cardiovascular endpoints and quality of life (QoL) in healthy volunteers. A cohort of 27 participants followed a strict gluten-free diet (GFD) for four weeks. Endothelial function measured by flow-mediated vasodilation (FMD), blood testing, plasma proteomics (Olink®) and QoL as measured by the World Health Organisation Quality-of-Life (WHOQOL) survey were investigated. RESULTS: GFD resulted in decreased leucocyte count and C-reactive protein levels along with a trend of reduced inflammation biomarkers determined by plasma proteomics. A positive trend indicated improvement in FMD, whereas other cardiovascular endpoints remained unchanged. In addition, no improvement in QoL was observed. CONCLUSION: In healthy individuals, a short-term GFD demonstrated anti-inflammatory effects but did not result in overall cardiovascular improvement or enhanced quality of life.

Vascular dysfunction and arterial hypertension in experimental celiac disease are mediated by gut-derived inflammation and oxidative stress.

AIMS: We examined the cardiovascular effects of celiac disease (CeD) in a humanized mouse model, with a focus on vascular inflammation, endothelial dysfunction, and oxidative stress. METHODS AND RESULTS: NOD.DQ8 mice genetically predisposed to CeD were subjected to a diet regime and oral gavage to induce the disease (gluten group vs. control). We tested vascular function, confirmed disease indicators, and evaluated inflammation and oxidative stress in various tissues. Plasma proteome profiling was also performed. CeD markers were confirmed in the gluten group, indicating increased blood pressure and impaired vascular relaxation. Pro-inflammatory genes were upregulated in this group, with increased CD11b+ myeloid cell infiltration and oxidative stress parameters observed in aortic and heart tissue. However, heart function remained unaffected. Plasma proteomics suggested the cytokine interleukin-17A (IL-17A) as a link between gut and vascular inflammation. Cardiovascular complications were reversed by adopting a gluten-free diet. CONCLUSION: Our study sheds light in the heightened cardiovascular risk associated with active CeD, revealing a gut-to-cardiovascular inflammatory axis potentially mediated by immune cell infiltration and IL-17A. These findings augment our understanding of the link between CeD and cardiovascular disease providing clinically relevant insight into the underlying mechanism. Furthermore, our discovery that cardiovascular complications can be reversed by a gluten-free diet underscores a critical role for dietary interventions in mitigating cardiovascular risks associated with CeD.

The fibroblast hormone Endotrophin is a biomarker of mortality in chronic diseases.

Fibrosis, driven by fibroblast activities, is an important contributor to morbidity and mortality in most chronic diseases. Endotrophin, a signaling molecule derived from processing of type VI collagen by highly activated fibroblasts, is involved in fibrotic tissue remodeling. Circulating levels of endotrophin have been associated with an increased risk of mortality in multiple chronic diseases. We conducted a systematic literature review collecting evidence from original papers published between 2012 and January 2023 that reported associations between circulating endotrophin (PROC6) and mortality. Cohorts with data available to the study authors were included in an Individual Patient Data (IPD) meta-analysis that evaluated the association of PROC6 with mortality (PROSPERO registration number: CRD42023340215) after adjustment for age, sex and BMI, where available. In the IPD meta-analysis including sixteen cohorts of patients with different non-communicable chronic diseases (NCCDs) (N = 15,205) the estimated summary hazard ratio for 3-years all-cause mortality was 2.10 (95 % CI 1.75-2.52) for a 2-fold increase in PROC6, with some heterogeneity observed between the studies (I2=70 %). This meta-analysis is the first study documenting that fibroblast activities, as quantified by circulating endotrophin, are independently associated with mortality across a broad range of NCCDs. This indicates that, irrespective of disease, interstitial tissue remodeling, and consequently fibroblast activities, has a central role in adverse clinical outcomes, and should be considered with urgency from drug developers as a target to treat.

An unbiased ranking of murine dietary models based on their proximity to human metabolic dysfunction-associated steatotic liver disease (MASLD).

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease, encompasses steatosis and metabolic dysfunction-associated steatohepatitis (MASH), leading to cirrhosis and hepatocellular carcinoma. Preclinical MASLD research is mainly performed in rodents; however, the model that best recapitulates human disease is yet to be defined. We conducted a wide-ranging retrospective review (metabolic phenotype, liver histopathology, transcriptome benchmarked against humans) of murine models (mostly male) and ranked them using an unbiased MASLD 'human proximity score' to define their metabolic relevance and ability to induce MASH-fibrosis. Here, we show that Western diets align closely with human MASH; high cholesterol content, extended study duration and/or genetic manipulation of disease-promoting pathways are required to intensify liver damage and accelerate significant (F2+) fibrosis development. Choline-deficient models rapidly induce MASH-fibrosis while showing relatively poor translatability. Our ranking of commonly used MASLD models, based on their proximity to human MASLD, helps with the selection of appropriate in vivo models to accelerate preclinical research.

Macrophages and platelets in liver fibrosis and hepatocellular carcinoma.

During fibrosis, (myo)fibroblasts deposit large amounts of extracellular matrix proteins, thereby replacing healthy functional tissue. In liver fibrosis, this leads to the loss of hepatocyte function, portal hypertension, variceal bleeding, and increased susceptibility to infection. At an early stage, liver fibrosis is a dynamic and reversible process, however, from the cirrhotic stage, there is significant progression to hepatocellular carcinoma. Both liver-resident macrophages (Kupffer cells) and monocyte-derived macrophages are important drivers of fibrosis progression, but can also induce its regression once triggers of chronic inflammation are eliminated. In liver cancer, they are attracted to the tumor site to become tumor-associated macrophages (TAMs) polarized towards a M2- anti-inflammatory/tumor-promoting phenotype. Besides their role in thrombosis and hemostasis, platelets can also stimulate fibrosis and tumor development by secreting profibrogenic factors and regulating the innate immune response, e.g., by interacting with monocytes and macrophages. Here, we review recent literature on the role of macrophages and platelets and their interplay in liver fibrosis and hepatocellular carcinoma.