John Devar

Purpose: The microbiome is increasingly recognised as a contributor to pancreatic ductal adenocarcinoma (PDAC) pathogenesis, presenting opportunities for biomarker discovery and therapeutic intervention. Characterising microbial signatures associated with PDAC could improve early detection to improve survival outcomes. Experimental Design: While previous studies on the PDAC microbiome have focused primarily on faecal samples, this study employed 16S rRNA gene amplicon sequencing to profile the bacteriome across 226 biospecimens ( n = 111 PDAC, n = 115 control) collected from the mouth, stomach, duodenum, bile and pancreas. We assessed alpha and beta diversity, taxonomic composition, relative abundance and prevalence of bacterial communities across these upper gastrointestinal tract sites. Results: Microbial diversity was significantly higher in the PDAC cohort, particularly in the stomach, duodenum and bile, with the latter showing unexpectedly high richness. While five dominant phyla (Pseudomonadota, Bacillota, Actinomycetota, Bacteroidota and Fusobacteriota) were shared between cohorts, the PDAC cohort harboured a greater number of unique low‐abundance taxa and displayed distinct site‐specific microbial profiles compared with control samples. Notable microbial shifts included enrichment of Pseudomonas , Acinetobacter , Geobacillus and Corynebacterium , genera previously implicated in inflammation, immune modulation and tumour persistence. Microbial clustering was strongly influenced by anatomical site and moderately by ethnicity, suggesting complex host–microbiome interactions in PDAC. Conclusions: This study demonstrates distinct, site‐specific microbial variation in PDAC and supports an association for the microbiome in PDAC development and progression, warranting further mechanistic investigation.

Background: Gall bladder cancer (GBC) is the most common biliary tract malignancy and is often diagnosed at advanced stages, partly due to the absence of reliable biomarkers and limited understanding of its biology in African populations. This study aimed to characterize the metabolomic and lipoprotein profiles of GBC patients of Black African ancestry. Methods: NMR spectroscopy was used to profile the serum samples. Group comparisons used Wilcoxon tests, correlations used Spearman’s rank test, unsupervised analysis was carried out using the KODAMA algorithm, partial least squares modeling estimated free cholesterol (FC) to cholesterol ester (CE) ratios, while multivariate logistic regression evaluated independent predictors. Results: GBC patients showed altered ethanol levels and dysregulated lipoproteins, including increased IDL-C, IDL-TG, and LDL-TG, and decreased HDL-C, HDL-P, and medium HDL-P. Total and conjugated bilirubin strongly correlated with lipoproteins. Unsupervised analysis revealed a GBC subgroup with abnormal lipoprotein profiles and elevated FC/CE ratios, suggesting cholestasis-related LpX formation. Elevated asparagine, reduced ethanol, and an inflammatory metabolic signature characterized the GBC fingerprint. Ethanol and bilirubin emerged as independent predictors of GBC. Conclusions: GBC patients exhibit distinct metabolomic and lipoprotein alterations that may underlie disease progression and serve as potential biomarkers. These findings enhance understanding of GBC pathophysiology in African populations and may inform future diagnostic strategies.

Background Gall bladder cancer (GBC) is the most prevalent cancer of the biliary tract with a poor prognosis. Most of the patients are diagnosed at an advanced stage. This is due to a lack of reliable biomarkers and an understanding of the tumour biology in our patient population. This study aims to demonstrate the metabolomic and lipoprotein profiles associated with GBC patients of African ancestry. Methods: An untargeted metabolomics analysis was conducted on serum obtained from consenting individuals (41 GBC and 29 Benign Biliary Pathology (BBP)). Statisti-cal analysis was conducted in R (v 4.3.2), and Wilcoxon tests were used to compare the groups. Spearman’s rank test was used for correlation analyses. Unsupervised analysis of the groups was carried out using the KODAMA algorithm. Results: GBC patients showed a significant alteration of the metabolite ethanol as well as lipoproteins such as IDL-C, IDL-TG, LDL-TG, compared to BBP patients. In contrast, decreased levels of HDL-C, HDL-P, medium HDL-P were observed in GBC patients. Both Total and conjugated bilirubin levels showed a strong correlation with lipopro-teins. Furthermore, the altered free cholesterol to cholesterol ester ratio was demon-strated to be linked to abnormal lipid metabolism. Conclusion: This study demonstrated alterations in key lipoproteins and metabolites in the patient population. These alterations may play a role in disease progression and potentially serve as novel biomarkers for the disease.

Background: Acute pancreatitis (AP) can be life-threatening with unpredictable severity. Despite advances in management, its pathogenesis remains unclear. This study investigated metabolites and lipoprotein profiles in AP patients of African descent to understand the underlying pathophysiological conditions so as to inform prognosis and management. Methods: Serum samples were collected from 9 healthy controls (HCs) and 30 AP patients (8 with mild AP, 14 with moderately severe AP, and 8 with severe AP) on days 1, 3, 5, and 7 post epigastric pain and subjected to nuclear magnetic resonance (NMR) spectroscopy. Wilcoxon and Kruskal–Wallis rank-sum tests compared numerical covariates. Lipoprotein characterization was performed using the Liposcale test, and Spearman’s rank test assessed data correlations. The p-values < 0.05 indicated significance. Results: Thirty-eight metabolic signals and information on lipoprotein subclasses were identified from the NMR spectra. The severity of AP correlated with increased levels of 3-hydroxybutyrate and acetoacetate and decreased levels of ascorbate. Distinct metabolic phenotypes were identified and characterized by unique inflammatory and lipoprotein profiles. High-density lipoprotein cholesterol (HDL-C) decreased across all the metabolic phenotypes of AP when compared with the HC, while elevated immediate density lipoprotein cholesterol (IDL-C) and very low-density lipoprotein cholesterol (VLDL-C) levels were observed. Time-dependent changes in metabolites were indicative of responsiveness to therapy. Conclusions: Our findings indicate that dysregulated metabolites and lipoproteins can be used to differentiate AP disease state and severity. Furthermore, integrating clinical parameters with data on metabolic and lipoprotein perturbations can contribute to a better understanding of the complex pathophysiology of AP.

Background: Acute pancreatitis (AP) is a common clinical disease with varying severity. The Revised Atlanta Classification (RAC) categorises AP into mild, moderately severe, and severe (MAP, MSAP and SAP) respectively. Despite the availability of different scoring systems to triage patients, these are not always suitable for predicting the course and outcome of certain patients during admission. In this study, untargeted metabolomics was used to identify metabolic parameters that can potentially be used as prognostic markers for stratifying the risk profiles of patients for improved management and treatment. Methods: Serum isolated from blood samples collected from 30 AP patients (8 MAP, 14 MSAP, and 8 SAP) and 9 healthy control (HC) individuals was analysed using ¹ H nuclear magnetic resonance (NMR) spectroscopy. Wilcoxon and Kruskal–Walli’s rank-sum tests were used to compare differences in numerical covariates. A liposcale test was used for lipoprotein characterization and the Spearman rank test was conducted for correlation of the data. P-values < 0.05 were considered significant. Results: Elevated levels of lactate, (rho = 0.67; p-value < 0.001, FDR = 0.001), 3-hydroxybutyrate (rho = 0.46; p-value < 0.003, FDR = 0.013), acetoacetate (rho = 0.63; p-value < 0.001, FDR < 0.001) and lipid alpha-CH2 (rho = 0.45; p-value = 0.004, FDR = 0.013) were associated with AP severity as was decreased levels of ascorbate (rho = 0.46; p-value < 0.003, FDR = 0.013), methanol (rho = 0.46; p-value < 0.003, FDR = 0.013), glutamine (rho = -0.55; p-value < 0.001, FDR = 0.002), ethanol (rho = 0.64; p-value < 0.001, FDR< 0.001), protein-NH (rho= -0.75; p-value < 0.001, FDR<0.001) among others. HDL-C decreased while IDL-C and VLDL-C increased across all the AP metabolic phenotypes compared to the HC. Conclusion: Dysregulated metabolites and lipids can potentially add to the understanding of the pathophysiological conditions of AP and can aid in the early prognosis and stratification of patients for specialist care.

Acute pancreatitis (AP) is an inflammatory disease, which presents with epigastric pain and is clinically diagnosed by amylase and lipase three times the upper limit of normal. The 2012 Atlanta classification stratifies the severity of AP as one of three risk categories namely, mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP). Challenges in stratifying AP upon diagnosis suggest that a better understanding of the underlying complex pathophysiology may be beneficial. To identify the role of the chemokine receptor 8 (CCR8), expressed by T-helper type-2 Lymphocytes and peritoneal macrophages, and its possible association to Interleukin (IL)-6 and AP stratification. This study was a prospective case-control study. A total of 40 patients were recruited from the Chris Hani Baragwanath Academic Hospital and the Charlotte Maxeke Johannesburg Academic Hospital. Bioassays were performed on 29 patients (14 MAP, 11 MSAP, and 4 SAP) and 6 healthy controls as part of a preliminary study. A total of 12 mL of blood samples were collected at Day (D) 1, 3, 5, and 7 post epigastric pain. Using multiplex immunoassay panels, real-time polymerase chain reaction (qRT-PCR) arrays, and multicolour flow cytometry analysis, immune response-related proteins, genes, and cells were profiled respectively. GraphPad Prism™ software and fold change (FC) analysis was used to determine differences between the groups. PP = 0.001 and P = 0.013 respectively, in a multiplex assay. When a FC of 2 was applied to identify differentially expressed genes using RT² Profiler, CCR8 was shown to increase steadily with disease severity from MAP (1.33), MSAP (38.28) to SAP (1172.45) median FC. Further verification studies using RT-PCR showed fold change increases of CCR8 in MSAP and SAP ranging from 1000 to 1000000 times when represented as Log₁₀, compared to healthy control respectively at D3. The findings also showed differing lymphocyte and monocyte cell frequency between the groups. With monocyte population frequency as high as 70% in MSAP at D3. The higher levels of CCR8 and IL-6 in the severe patients and immune cell differences compared to MAP and controls provide an avenue for exploring AP stratification to improve management.

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest human malignancies with a dismal prognosis. During PDAC progression, the immune response is affected as cancer cells evade detection and elimination. Recently, there have been advances in the treatment of PDAC using immunotherapy, although a lot more work is yet to be done. In this review, we discuss these advances, challenges and potentials. We focus on existing and potential immune targets for PDAC, drugs used to target them, and some clinical trials conducted so far with them. Finally, novel targets in the tumour microenvironment such as stromal cells and other potential future areas to explore including bacterial therapy and the use of neoantigens in immunotherapy are highlighted.