Comprehensive characterization of bacterial glycoconjugate vaccines by liquid chromatography - mass spectrometry.

Bacterial pathogens can cause a broad range of infections with detrimental effects on health. Vaccine development is essential as multi-drug resistance in bacterial infections is a rising concern. Recombinantly produced proteins carrying O-antigen glycosylation are promising glycoconjugate vaccine candidates to prevent bacterial infections. However, methods for their comprehensive structural characterization are lacking. Here, we present a bottom-up approach for their site-specific characterization, detecting N-glycopeptides by nano reversed-phase liquid chromatography-mass spectrometry (RP-LC-MS). Glycopeptide analyses revealed information on partial site-occupancy and site-specific glycosylation heterogeneity and helped corroborate the polysaccharide structures and their modifications. Bottom-up analysis was complemented by intact glycoprotein analysis using nano RP-LC-MS allowing the fast visualization of the polysaccharide distribution in the intact glycoconjugate. At the glycopeptide level, the model glycoconjugates analyzed showed different repeat unit (RU) distributions that spanned from 1 to 21 RUs attached to each of the different glycosylation sites. Interestingly, the intact glycoprotein analysis displayed a RU distribution ranging from 1 to 28 RUs, showing the predominant species when the different glycopeptide distributions are combined in the intact glycoconjugate. The complete workflow based on LC-MS measurements allows detailed and comprehensive analysis of the glycosylation state of glycoconjugate vaccines.

Shrinkage versus fragmentation response in neoadjuvantly treated oesophageal adenocarcinoma: significant prognostic relevance.

AIMS: No consensus exists on the clinical value of tumour regression grading (TRG) systems for therapy effects of neoadjuvant chemoradiotherapy (nCRT) in oesophageal adenocarcinoma. Existing TRG systems lack standardization and reproducibility, and do not consider the morphological heterogeneity of tumour response. Therefore, we aim to identify morphological tumour regression patterns of oesophageal adenocarcinoma after nCRT and their association with survival. METHODS AND RESULTS: Patients with oesophageal adenocarcinoma, who underwent nCRT followed by surgery and achieved a partial response to nCRT, were identified from two Dutch upper-gastrointestinal (GI) centres (2005-18; test cohort). Resection specimens were scored for regression patterns by two independent observers according to a pre-defined three-step flowchart. The results were validated in an external cohort (2001-17). In total, 110 patients were included in the test cohort and 115 in the validation cohort. In the test cohort, two major regression patterns were identified: fragmentation (60%) and shrinkage (40%), with an excellent interobserver agreement (κ = 0.87). Here, patients with a fragmented pattern had a significantly higher pathological stage (stages III/IV: 52 versus 16%; P < 0.001), less downstaging (48 versus 91%; P < 0.001), a higher risk of recurrence [risk ratio (RR) = 2.9, 95% confidence interval (CI) = 1.5-5.6] and poorer 5-year overall survival (30 versus 80% respectively, P = 0.001). CONCLUSIONS: The validation cohort confirmed these findings, although had more advanced cases (case-stages = III/IV 91 versus 73%, P = 0.005) and a higher prevalence of fragmented-pattern cases (80 versus 60%, P = 0.002). When combining the cohorts in multivariate analysis, the pattern of response was an independent prognostic factor [hazard ratio (HR) = 1.76, 95% CI = 1.0-3.0]. In conclusion, we established an externally validated, reproducible and clinically relevant classification of tumour response.

Glycan and Protein Analysis of Glycoengineered Bacterial E. coli Vaccines by MALDI-in-Source Decay FT-ICR Mass Spectrometry.

Bacterial glycoconjugate vaccines have a major role in preventing microbial infections. Immunogenic bacterial glycans, such as O-antigen polysaccharides, can be recombinantly expressed and combined with specific carrier proteins to produce effective vaccines. O-Antigen polysaccharides are typically polydisperse, and carrier proteins can have multiple glycosylation sites. Consequently, recombinant glycoconjugate vaccines have a high structural heterogeneity, making their characterization challenging. Since development and quality control processes rely on such characterization, novel strategies are needed for faster and informative analysis. Here, we present a novel approach employing minimal sample preparation and ultrahigh-resolution mass spectrometry analysis for protein terminal sequencing and characterization of the oligosaccharide repeat units of bacterial glycoconjugate vaccines. Three glycoconjugate vaccine candidates, obtained from the bioconjugation of the O-antigen polysaccharides from E. coli serotypes O2, O6A, and O25B with the genetically detoxified exotoxin A from Pseudomonas aeruginosa, were analyzed by MALDI-in-source decay (ISD) FT-ICR MS. Protein and glycan ISD fragment ions were selectively detected using 1,5-diaminonaphtalene and a 2,5-dihydroxybenzoic acid/2-hydroxy-5-methoxybenzoic acid mixture (super-DHB) as a MALDI matrix, respectively. The analysis of protein fragments required the absence of salts in the samples, while the presence of salt was key for the detection of sodiated glycan fragments. MS/MS analysis of O-antigen ISD fragments allowed for the detection of specific repeat unit signatures. The developed strategy requires minute sample amounts, avoids the use of chemical derivatizations, and comes with minimal hands-on time allowing for fast corroboration of key structural features of bacterial glycoconjugate vaccines during early- and late-stage development.

Age-specific incidence, treatment, and survival trends in esophageal cancer: a Dutch population-based cohort study.

BACKGROUND: Data on the age-specific incidence of esophageal cancer are lacking. Our aim was to investigate the age-stratified incidence, treatment, and survival trends of esophageal cancer in the Netherlands, with a focus on adults <50 years. MATERIAL AND METHODS: Patients diagnosed with esophageal cancer were included from the nationwide Netherlands Cancer Registry (1989-2018). Follow-up data were available until 31 December 2018. Annual percentage changes of incidence were analyzed according to age group (<50, 50-74, and ≥75 years) and histology type: adenocarcinoma (EAC) and squamous cell carcinoma (ESCC). Treatment trends and relative survival rates (RSR) were estimated by age and stage grouping. RESULTS: A total 59,584 patients were included. In adults <50 years, EAC incidence tripled (mean increase per year: males 1.5%, females 3%), while the incidence of ESCC decreased (mean decrease per year: males -5.3%, females -4.3%). Patients <50 years more often presented with advanced disease stages compared to older patients and were more likely to receive multimodality treatments. Most patients <50 years with potentially curable disease were treated with neoadjuvant chemoradiotherapy followed by surgery compared to patients 50-74 and ≥75 years (74% vs. 55% vs. 15%, respectively; p < .001), and received more frequent systemic therapy once staged with palliative disease (72% vs. 54% vs. 19%, respectively; p < .001). The largest RSR improvement was seen in patients <50 years with early-stage (five years: +47%), potentially curable (five years: +22%), and palliative disease (one year: +11%). Over time, a trend of increasing survival difference was seen between patients <50 and ≥75 years with potentially curable (five-year difference: 17% to 27%) and palliative disease (one-year difference: 11% to 20%). CONCLUSION: The incidence of EAC is increasing in adults <50 years in the Netherlands. Differences in the use of multimodality treatments with curative or life-prolonging intent in different age categories may account for increasing survival gaps.

Impact of pathological tumor response after CROSS neoadjuvant chemoradiotherapy followed by surgery on long-term outcome of esophageal cancer: a population-based study.

BACKGROUND: With increasing interest in organ-preserving strategies for potentially curable esophageal cancer, real-world data is needed to understand the impact of pathological tumor response after neoadjuvant chemoradiotherapy (CRT) on patient outcome. The objective of this study is to assess the association between pathological tumor response following CROSS neoadjuvant CRT and long-term overall survival (OS) in a nationwide cohort. MATERIAL AND METHODS: All patients diagnosed in the Netherlands with potentially curable esophageal cancer between 2009 and 2017, and treated with neoadjuvant CRT followed by esophagectomy were included. Through record linkage with the nationwide Dutch Pathology Registry (PALGA), pathological data were obtained. The primary outcome was pathological tumor response based on ypTNM, classified into pathological complete response (ypT0N0) and incomplete responders (ypT0N+, ypT+N0, and ypT+N+). Multivariable logistic and Cox regression models were used to identify predictors of pathological complete response (pCR) and survival. RESULTS: A total of 4946 patients were included. Overall, 24% achieved pCR, with 19% in adenocarcinoma and 42% in squamous cell carcinoma. Patients with pCR had a better estimated 5-year OS compared to incomplete responders (62% vs. 38%, p< .001). Of the patients with incomplete response, ypT+N+ patients (32% of total population) had the lowest estimated 5-year OS rate, followed by ypT0N+ and ypT+ N0 (22%, 47%, and 49%, respectively, p< .001). Adenocarcinoma, well to moderate differentiation, cT3-4, cN+, signet ring cell differentiation and lymph node yield (≥15) were associated with lower likelihood of pCR. CONCLUSION: In this population-based study, pathological tumor response based on the ypTNM-stage was associated with different prognostic subgroups. A quarter of patients achieved ypT0N0 with favorable long-term survival, while one-third had an ypT+N+ response with very poor survival. The association between pathological tumor response and long-term survival could help in more accurate assessments of individual prognosis and treatment decisions.

Salvage endoscopic resection after definitive chemoradiotherapy for esophageal cancer: a Western experience.

BACKGROUND AND AIMS: Definitive chemoradiotherapy (CRT) is increasingly used as a nonsurgical treatment for esophageal cancer. In Japanese studies, salvage endoscopic resection (ER) has emerged as a promising strategy for local failure after definitive CRT. We aimed to evaluate the safety and efficacy of salvage ER in a Western setting. METHODS: Gastroenterologists from Europe and the United States were invited to submit their experience with salvage endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) after definitive CRT. Participating gastroenterologists completed an anonymized database, including patient demographics, clinicopathologic variables, and follow-up on survival and recurrence. RESULTS: Gastroenterologists from 10 endoscopic units in 6 European countries submitted information on 25 patients. A total of 35 salvage ER procedures were performed, of which 69% were ESD and 31% EMR. Most patients had squamous cell carcinoma (64%) of the middle or lower esophagus (68%) staged as cT2-3 (68%) and cN+ (52%) before definitive CRT. The median time from end of definitive CRT to ER was 22 months (interquartile range, 6-47). The en-bloc resection rate was 92% for ESD and 46% for EMR. During a median of 24 months (interquartile range, 12-59) of follow-up after salvage ER, 52% developed a recurrence (11 locoregional, 2 distant). The 5-year recurrence-free survival, overall survival, and disease-specific survival were 36%, 52%, and 79%, respectively. No major intra- or postprocedural adverse events, such as bleeding or perforation, were reported. CONCLUSIONS: In carefully selected esophageal cancer patients, salvage ER is technically feasible after definitive CRT. Further prospective research is recommended to validate the safety and effectivity of salvage ER for the management of local failure.

Predicting lymph node metastases with endoscopic resection in cT2N0M0 oesophageal cancer: A systematic review and meta-analysis.

BACKGROUND: Despite modern imaging modalities, staging of clinically staged T2N0M0 (cT2N0M0) oesophageal cancer is suboptimal, often leading to overtreatment. Endoscopic resection - the first-line therapy for early localised tumours - could be used to improve staging and to attain predictors of nodal upstaging enabling more stage-guided treatment decisions. OBJECTIVE: A systematic literature review and a meta-analysis were conducted to assess the prevalence and the pathological risk factors of lymph node metastases in cT2N0M0 oesophageal cancer. METHODS: Databases of PUBMED, EMBASE and Cochrane were searched for literature. The primary outcome was lymph node metastases determined after primary surgical resection. RESULTS: Nine studies with a total of 1650 cT2N0M0 patients were included. The prevalence of lymph node metastases was 43% (95% confidence interval: 35-50%) with heterogeneity being high across studies (I2 = 0.86, p < 0.001). Factors potentially attainable by endoscopic resection and having a significant association with lymph node metastases were invasion depth, differentiation grade, tumour size, depth of invasion in the muscularis propria and lymphovascular invasion. CONCLUSIONS: Clinical lymph node staging is inaccurate in almost half of cT2N0M0 oesophageal cancer. Endoscopic resection is a promising diagnostic modality that might even be a valid alternative to surgery in selected patients without high-risk features, but further evidence is warranted.

Barrett oesophagus.

Barrett oesophagus (BE), the only known histological precursor of oesophageal adenocarcinoma (EAC), is a condition in which the squamous epithelium of the oesophagus is replaced by columnar epithelium as an adaptive response to gastro-oesophageal reflux. EAC has one of the fastest rising incidences of cancers in Western countries and has a dismal prognosis. BE is usually detected during endoscopic examination, and diagnosis is confirmed by the histological presence of intestinal metaplasia. Advances in genomics and transcriptomics have improved our understanding of the pathogenesis and malignant progression of intestinal metaplasia. As the majority of EAC cases are diagnosed in individuals without a known history of BE, screening for BE could potentially decrease disease-related mortality. Owing to the pre-malignant nature of BE, endoscopic surveillance of patients with BE is imperative for early detection and treatment of dysplasia to prevent further progression to invasive EAC. Developments in endoscopic therapy have resulted in a major shift in the treatment of patients with BE who have dysplasia or early EAC, from surgical resection to endoscopic resection and ablation. In addition to symptom control by optimization of lifestyle and pharmacological therapy with proton pump inhibitors, chemopreventive strategies based on NSAIDs and statins are currently being investigated for BE management.

Cause or effect of arteriogenesis: compositional alterations of microparticles from CAD patients undergoing external counterpulsation therapy.

UNLABELLED: Recently, a clinical study on patients with stable coronary artery disease (CAD) showed that external counterpulsation therapy (ECP) at high (300 mmHg) but not at low inflation pressure (80 mmHg) promoted coronary collateral growth, most likely due to shear stress-induced arteriogenesis. The exact molecular mechanisms behind shear stress-induced arteriogenesis are still obscure. We therefore characterized plasma levels of circulating microparticles (MPs) from these CAD patients because of their ambivalent nature as a known cardiovascular risk factor and as a promoter of neovascularization in the case of platelet-derived MPs. MPs positive for Annexin V and CD31CD41 were increased, albeit statistically significant (P<0.05, vs. baseline) only in patients receiving high inflation pressure ECP as determined by flow cytometry. MPs positive for CD62E, CD146, and CD14 were unaffected. In high, but not in low, inflation pressure treatment, change of CD31CD41 was inversely correlated to the change in collateral flow index (CFI), a measure for collateral growth. MPs from the high inflation pressure group had a more sustained pro-angiogenic effect than the ones from the low inflation pressure group, with the exception of one patient showing also an increased CFI after treatment. A total of 1005 proteins were identified by a label-free proteomics approach from MPs of three patients of each group applying stringent acceptance criteria. Based on semi-quantitative protein abundance measurements, MPs after ECP therapy contained more cellular proteins and increased CD31, corroborating the increase in MPs. Furthermore, we show that MP-associated factors of the innate immune system were decreased, many membrane-associated signaling proteins, and the known arteriogenesis stimulating protein transforming growth factor beta-1 were increased after ECP therapy. In conclusion, our data show that ECP therapy increases platelet-derived MPs in patients with CAD and that the change in protein cargo of MPs is likely in favor of a pro angiogenic/arteriogenic property. TRIAL REGISTRATION: ClinicalTrials.gov NCT00414297.