QS-21 shows in vitro hemolytic effect and causes side effects in vivo. New saponin adjuvant formulations with better toxicity profiles are needed. This study aims to evaluate the safety and tolerability of QS-21 and the improved saponin adjuvants (ISCOM, ISCOMATRIX and Matrix-M^™) from vaccine trials. A systematic literature search was conducted from MEDLINE, EMBASE, Cochrane library and Clinicaltrials.gov. We selected for the meta-analysis randomized controlled trials (RCTs) of vaccines adjuvanted with QS-21, ISCOM, ISCOMATRIX or Matrix-M^™, which included a placebo control group and reported safety outcomes. Pooled risk ratios (RRs) and their 95% confidence intervals (CIs) were calculated using a random-effects model. Jadad scale was used to assess the study quality. Nine RCTs were eligible for the meta-analysis: six trials on QS-21-adjuvanted vaccines and three trials on ISCOMATRIX-adjuvanted, with 907 patients in total. There were no studies on ISCOM or Matrix-M^™ adjuvanted vaccines matching the inclusion criteria. Meta-analysis identified an increased risk for diarrhea in patients receiving QS21-adjuvanted vaccines (RR 2.55, 95% CI 1.04–6.24). No increase in the incidence of the reported systemic AEs was observed for ISCOMATRIX-adjuvanted vaccines. QS-21- and ISCOMATRIX-adjuvanted vaccines caused a significantly higher incidence of injection site pain (RR 4.11, 95% CI 1.10–15.35 and RR 2.55, 95% CI 1.41–4.59, respectively). ISCOMATRIX-adjuvanted vaccines also increased the incidence of injection site swelling (RR 3.43, 95% CI 1.08–10.97). Our findings suggest that vaccines adjuvanted with either QS-21 or ISCOMATRIX posed no specific safety concern. Furthermore, our results indicate that the use of ISCOMATRIX enables a better systemic tolerability profile when compared to the use of QS-21. However, no better local tolerance was observed for ISCOMATRIX-adjuvanted vaccines in immunized non-healthy subjects. This meta-analysis is limited by the relatively small number of individuals recruited in the included trials, especially in the control groups.

Our knowledge of complex pathological mechanisms underlying organ fibrosis is predominantly derived from animal studies. However, relevance of animal models for human disease is limited; therefore, an ex vivo model of human precision-cut tissue slices (PCTS) might become an indispensable tool in fibrosis research and drug development by bridging the animal–human translational gap. This study, presented as two parts, provides comprehensive characterization of the dynamic transcriptional changes in PCTS during culture by RNA sequencing. Part I investigates the differences in culture-induced responses in murine and human PCTS derived from healthy liver, kidney and gut. Part II delineates the molecular processes in cultured human PCTS generated from diseased liver, kidney and ileum. We demonstrated that culture was associated with extensive transcriptional changes and impacted PCTS in a universal way across the organs and two species by triggering an inflammatory response and fibrosis-related extracellular matrix (ECM) remodelling. All PCTS shared mRNA upregulation of IL-11 and ECM-degrading enzymes MMP3 and MMP10. Slice preparation and culturing activated numerous pathways across all PCTS, especially those involved in inflammation (IL-6, IL-8 and HMGB1 signalling) and tissue remodelling (osteoarthritis pathway and integrin signalling). Despite the converging effects of culture, PCTS display species-, organ- and pathology-specific differences in the regulation of genes and canonical pathways. The underlying pathology in human diseased PCTS endures and influences biological processes like cytokine release. Our study reinforces the use of PCTS as an ex vivo fibrosis model and supports future studies towards its validation as a preclinical tool for drug development.

Animal models are a valuable tool in preclinical research. However, limited predictivity of human biological responses in the conventional models has stimulated the search for reliable preclinical tools that show translational robustness. Here, we used precision-cut kidney slices (PCKS) as a model of renal fibrosis and investigated its predictive capacity for screening the effects of anti-fibrotics. Murine and human PCKS were exposed to TGFβ or PDGF pathway inhibitors with established anti-fibrotic efficacy. For each treatment modality, we evaluated whether it affected: (1) culture-induced collagen type I gene expression and interstitial accumulation; (2) expression of markers of TGFβ and PDGF signaling; and (3) expression of inflammatory markers. We summarized the outcomes of published in vivo animal and human studies testing the three inhibitors in renal fibrosis, and drew a parallel to the PCKS data. We showed that the responses of murine PCKS to anti-fibrotics highly corresponded with the known in vivo responses observed in various animal models of renal fibrosis. Moreover, our results suggested that human PCKS can be used to predict drug efficacy in clinical trials. In conclusion, our study demonstrated that the PCKS model is a powerful predictive tool for ex vivo screening of putative drugs for renal fibrosis.

Our understanding of gut functioning and pathophysiology has grown considerably in the past decades, and advancing technologies enable us to deepen this understanding. Single-cell RNA sequencing (scRNA-seq) has opened a new realm of cellular diversity and transcriptional variation in the human gut at a high, single-cell resolution. ScRNA-seq has pushed the science of the digestive system forward by characterizing the function of distinct cell types within complex intestinal cellular environments, by illuminating the heterogeneity within specific cell populations and by identifying novel cell types in the human gut that could contribute to a variety of intestinal diseases. In this review, we highlight recent discoveries made with scRNA-seq that significantly advance our understanding of the human gut both in health and across the spectrum of gut diseases, including inflammatory bowel disease, colorectal carcinoma and celiac disease.

Background and aims Primary sclerosing cholangitis (PSC) is an inflammatory disorder of the bile ducts, often accompanied by inflammatory bowel disease (PSC-IBD). Substantial differences in clinical presentation are observed between PSC-IBD and ulcerative colitis (UC). In this study we aim to find distinct pathomechanisms for PSC-IBD using single-cell mRNA sequencing. Methods Forty-seven colonic mucosal biopsies of PSC-IBD (n=24), UC (n=18) (where possible matched inflamed (I) non-inflamed (NI)), and non-IBD subjects (n=5) were collected and dissociated. Library preparation and processing for sequencing was followed by differential abundance, differential expression, and cell-cell-interaction analyses. Stainings for DUOX2 and HLA-DR were applied on tissue sections. Results In total, 71,798 cells comprised 54 distinct cell types, including a new cell type: the DUOX2+ enterocyte, mainly present in inflamed colon and acting as antigen presenting cells (HLA-DR+). Stem cells exhibited increased abundances in PSC-NI but not in UC-NI. Additionally, we found distinct gene expression profiles in PSC and UC which were related to inflammation: while mainly inflammatory monocytes were activated in PSC inflammation, and inflammatory fibroblasts were activated in UC inflammation. Conclusion Our study found a new cell type, the DUOX2+ enterocyte that is primarily present in inflamed conditions, and based on their expression profile, potentially perform antigen presentation. Moreover, we highlight that PSC-IBD, but not UC, is characterized by the activation of inflammatory HLA-DRB1+ monocytes, which are likely involved in the activation of CD4+ T cells. Notably, we observed an increased abundance of stem cells in non-inflamed PSC-IBD, possibly linked to the elevated risk of colorectal cancer in PSC-IBD. What is known on the subject?Inflammatory Bowel Disease (IBD) presents in 60–80% of primary sclerosis cholangitis (PSC) patients, termed PSC-IBD. However, the clinical presentation is distinct: patients have 10 times increased risk of colorectal carcinoma as compared to ulcerative colitis (UC) patients, and the conventional IBD treatment regimen is not always effective. The underlying genetic predisposition is also different from general IBD, where PSC-IBD shows a very strong risk association in the HLA-DRB1 region, generally a hallmark of auto-immune disease. What this study adds This study uncovers that PSC-IBD has more autoimmune and UC more inflammatory characteristics. This is supported by the interaction between inflammatory monocytes and CD4+/CD8+ T cells through HLA-DR in PSC-IBD. PSC-IBD patients have pronounced increased activity of inflammatory monocytes, not seen in UC. We find increased stem cell abundance in PSC-IBD. In addition, we show cellular-molecular mechanisms potentially driving the increased risk of carcinoma in PSC-IBD patients offering valuable foundations for targeted therapeutic strategies. In addition, we determined the new DUOX2+ enterocyte. How this research might affect research, practice, or policy This study uncovers that PSC-IBD has more autoimmune characteristics whereas UC is an immune mediated inflammatory disease. This is supported by the specific interaction between inflammatory monocytes and CD4+/CD8+ T cells through HLA-DR in PSC-IBD, while in UC DUOX2+ enterocytes and inflammatory monocytes communicate with innate immune cells, Tregs and CD4+ T cells. Our findings may form new treatment targets for PSC-IBD and IBD in general.

Ulcerative colitis (UC) is a chronic, relapsing inflammatory disease of the gastrointestinal tract. When conventional therapy fails, patients need biologics such as vedolizumab (VDZ) to manage the disease. While VDZ has shown a compelling efficacy in UC, the rate of primary non-response amounts up to 50%. To uncover cellular and molecular cues that coordinate VDZ (non-)response, we performed single-cell transcriptomics and high-dimensional immunoprofiling of gut mucosal and peripheral blood cells obtained from 25 UC patients before and 14 weeks after the initiation of VDZ therapy. We show that VDZ non-response is not driven by integrins beyond the VDZ-targeted α4β7 that may carry on the influx of leukocytes to the inflamed gut mucosa. Instead, non-response is marked by a distinct cellular signature of highly abundant innate immune cells, which is clearly detectable before the start of VDZ treatment. We furthermore highlight the aberrant functional state of inflammatory monocytes and regulatory T cells in non-responders, which together with inflammatory fibroblasts form a rewired cell-to-cell communication network. This prospective longitudinal study reveals that mucosal inflammatory mechanisms are fundamentally different between responders and non-responders to VDZ, which provides deeper insights and new opportunities for improvement of UC treatment.