Mature tertiary lymphoid structures are key niches of tumour-specific immune responses in pancreatic ductal adenocarcinomas.

OBJECTIVE: To better understand the immune microenvironment of pancreatic ductal adenocarcinomas (PDACs), here we explored the relevance of T and B cell compartmentalisation into tertiary lymphoid structures (TLSs) for the generation of local antitumour immunity. DESIGN: We characterised the functional states and spatial organisation of PDAC-infiltrating T and B cells using single-cell RNA sequencing (scRNA-seq), flow cytometry, multicolour immunofluorescence, gene expression profiling of microdissected TLSs, as well as in vitro assays. In addition, we performed a pan-cancer analysis of tumour-infiltrating T cells using scRNA-seq and sc T cell receptor sequencing datasets from eight cancer types. To evaluate the clinical relevance of our findings, we used PDAC bulk RNA-seq data from The Cancer Genome Atlas and the PRINCE chemoimmunotherapy trial. RESULTS: We found that a subset of PDACs harbours fully developed TLSs where B cells proliferate and differentiate into plasma cells. These mature TLSs also support T cell activity and are enriched with tumour-reactive T cells. Importantly, we showed that chronically activated, tumour-reactive T cells exposed to fibroblast-derived TGF-ß may act as TLS organisers by producing the B cell chemoattractant CXCL13. Identification of highly similar subsets of clonally expanded CXCL13 + tumour-infiltrating T cells across multiple cancer types further indicated a conserved link between tumour-antigen recognition and the allocation of B cells within sheltered hubs in the tumour microenvironment. Finally, we showed that the expression of a gene signature reflecting mature TLSs was enriched in pretreatment biopsies from PDAC patients with longer survival after receiving different chemoimmunotherapy regimens. CONCLUSION: We provided a framework for understanding the biological role of PDAC-associated TLSs and revealed their potential to guide the selection of patients for future immunotherapy trials.

WHAT FACTORS CONTRIBUTE TO DELAYED GASTRIC EMPTYING AFTER DUODENOPANCREATECTOMY WITH PILORIC PRESERVATION?

BACKGROUND: The delay in gastric emptying is the second most frequent complication after duodenopancreatectomy with pyloric preservation, that increases hospitalization time and hospital costs. AIM: To identify factors that contribute to the appearance the delay in this surgical procedure. METHOD: Ninety-five patients were submitted to duodenopancreatectomy with pyloric preservation. After retrospective analysis of the medical records, it was observed that 60 had prolonged hospitalization due to complications. Thus, univariate and multivariate logistic regression were used to analyze predictors of delayed gastric emptying. RESULTS: Delay was present in 65% (n=39) and pancreatic fistula in 38.3% (n=23). Univariate analysis revealed that the presence of pancreatic complications (pancreatic fistula, p=0.01), other intracavitary complications with the appearance of abdominal collections (p=0.03) and hypoalbuminemia (p=0.06) were responsible, also confirmed by the multivariate analysis. In those who presented delay without a determined cause, it was observed that high levels of total bilirubin (p=0.01) and direct bilirubin (p=0.01) could be related to it. CONCLUSION: The delay in gastric emptying in patients undergoing duodenopancreatectomy with pyloric preservation is due to intracavitary complications.

What factors contribute to delayed gastric emptying after duodenopancreatectomy with piloric preservation? / Que fatores contribuem para retardo do esvaziamento gástrico após duodenopancreatectomia com preservação pilórica?

ABSTRACT Background: The delay in gastric emptying is the second most frequent complication after duodenopancreatectomy with pyloric preservation, that increases hospitalization time and hospital costs. Aim: To identify factors that contribute to the appearance the delay in this surgical procedure. Method: Ninety-five patients were submitted to duodenopancreatectomy with pyloric preservation. After retrospective analysis of the medical records, it was observed that 60 had prolonged hospitalization due to complications. Thus, univariate and multivariate logistic regression were used to analyze predictors of delayed gastric emptying. Results: Delay was present in 65% (n=39) and pancreatic fistula in 38.3% (n=23). Univariate analysis revealed that the presence of pancreatic complications (pancreatic fistula, p=0.01), other intracavitary complications with the appearance of abdominal collections (p=0.03) and hypoalbuminemia (p=0.06) were responsible, also confirmed by the multivariate analysis. In those who presented delay without a determined cause, it was observed that high levels of total bilirubin (p=0.01) and direct bilirubin (p=0.01) could be related to it. Conclusion: The delay in gastric emptying in patients undergoing duodenopancreatectomy with pyloric preservation is due to intracavitary complications.

RESUMO Racional: O retardo do esvaziamento gástrico é a segunda complicação mais frequente após a realização da duodenopancreatectomia com preservação pilórica, aumentando o tempo de internação e custos hospitalares. Objetivo: Identificar fatores que contribuem para o aparecimento desse retardo nesse procedimento cirúrgico. Método: Noventa e cinco doentes foram submetidos à duodenopancreatectomia com preservação pilórica. Após análise retrospectiva dos prontuários observou-se que 60 apresentaram internação prolongada por complicações. Assim, utilizou-se a regressão logística uni e multivariada para análise de fatores preditores do retardo. Resultados: O retardo esteve presente em 65% (n=39) e a fístula pancreática em 38,3% (n=23). A análise univariada revelou que a presença de complicações pancreáticas (fístula pancreática, p=0,01), outras complicações intracavitárias com aparecimento de coleções abdominais (p=0,03) e hipoalbuminemia (p=0,06) foram os responsáveis, resultados estes também confirmados pela análise mutilvariada. Naqueles que apresentaram retardo sem causa determinada, observou-se que níveis elevados de bilirrubina total (p=0,01) e bilirrubina direta (p=0,01) poderiam estar relacionados a ele. Conclusão: O retardo do esvaziamento gástrico nos pacientes submetidos à duodenopancreatectomia com preservação pilórica é decorrente de complicações intracavitárias.

Increased survival of free fat grafts with platelet-rich plasma in rabbits.

BACKGROUND: Numerous applications of autogenous platelet-rich plasma (PRP) have been studied so far; however, its property of enhancing the survival of free fat grafts has not been defined yet. In the literature, many reports are anecdotal and few include controls to definitely determine the role played by PRP in these grafts. OBJECTIVE: PRP was investigated to study its effect in free fat grafts' survival in a rabbit model. MATERIAL AND METHOD: A total of 30 New Zealand male rabbits aged 6 months received 0.8 g fat tissue (harvested by scissors dissection from the scapular area of the own animal) in the ears and were randomised into two groups. Group 1 (PRP group) was given the combination of 0.8 g of free fat graft and 1 ml of PRP. Group 2 (control group) received 0.8 g of free fat graft and 1 ml of saline solution. The rabbits were followed up for a period of 6 months after the procedure and then euthanised. The grafted tissue was stained with haematoxylin-eosin and submitted to microscopical evaluation. Graft histopathology was investigated for adipocyte viability, number of blood vessels and the presence of necrosis and fibrosis. All data were statistically analysed by the differences between the study groups. RESULTS: Three major effects of the addition of PRP in the free fat graft were observed. Group 1 showed a significantly higher fat survival weight as compared with the control group (P<0.05). Histopathological investigations revealed that the number of viable adipocytes and blood vessels was higher in group 1, and still, a larger number of necrotic areas and fibrosis were detected between group 2 (P<0.05). CONCLUSION: Application of autogenous PRP can enhance free fat graft survival in rabbits.