Abstract 2051: Perfusable 3D angiogenesis in a high-throughput microfluidic culture platform

The transition from 2D to 3D cell culture is a first step towards more physiologically relevant in vitro cancer models. To adequately capture the complex tissue architectures observed in vivo, 3D microfluidic techniques incorporate and achieve long-term gradient stability, continuous perfusion and patterning of cancer cell layers as stratified co-cultures. We used a standardized high-throughput (n=40) microfluidic 3D tissue culture platform called the OrganoPlate® to generate precisely controlled gradients, without pumps, ideal for growing blood vessels and inducing controlled 3D angiogenic sprouting. The blood vessel is grown against an extracellular matrix (ECM) gel with cancer cells and is subsequently exposed to pro- and antiangiogenic compounds to direct sprouting towards 3D cancer cell clusters. Utilizing high-content confocal time-lapse imaging and analysis, angiogenic potential was measured in various cancer models. The exposed vasculature shows many of the important hallmarks of cancer angiogenesis found in vivo, including tip cells induction and migration and stalk cells formation. Importantly, the stalk cells develop a perfusable lumen that is connected to the parental vessel as demonstrated with perfusion of high-molecular-weight (150KD) fitc-dextran through microvascular structures. This model will be used as an in vitro cancer screening platform to unravel the important drivers in angiogenesis and vasculogenesis and the mechanism of action of antiangiogenic compounds. By combining this culture platform with mural cells, cell-cell interactions can be studied. In parallel, we will combine this 3D cancer angiogenesis platform with our current Tumor-on-a-Chip models to create tissue models with integrated vasculature.

Citation Format: K M. Bircsak, V van Duinen, S J. Trietsch, A J. van Zonneveld, T Hankemeier, A Saleh, P Vulto. Perfusable 3D angiogenesis in a high-throughput microfluidic culture platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2051.

Percutaneous Closure of Left Atrial Appendage significantly affects Lipidome Metabolism

Patients with non-valvular atrial fibrillation (AF) and a high risk for oral anticoagulation can be treated by percutaneous implantation of left atrial appendage occlusion devices (LAAC) to reduce the risk of cardio-embolic stroke. This study evaluates whether LAAC may influence lipid metabolism, which has never been investigated before. Patients with successful LAAC were included consecutively. Venous peripheral blood samples of patients were collected immediately before (T0, baseline) and 6 months after (T1, mid-term) LAAC. A targeted metabolomics approach based on electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS/MS) and MS/MS measurements was performed. A total of 34 lipids revealed a significant change from baseline to mid-term follow-up after successful LAAC. Subgroup analysis revealed confounding influence by gender, age, diabetes mellitus type II, body mass index, left ventricular ejection fraction, creatinine and NT-proBNP. After multivariable adjustment within logistic regression models, these 34 lipids were still significantly altered after LAAC. Successful percutaneous LAAC may affect lipid metabolism and thereby may potentially affect pro-atherogenic and cardio-toxic effects.

Trace Element Determination and Cardioprotection of Terminalia pallida Fruit Ethanolic Extract in Isoproterenol Induced Myocardial Infarcted Rats by ICP-MS

The trace elements and minerals in Terminalia pallida fruit ethanolic extract (TpFE) were determined by the instrument inductively coupled plasma-mass spectrometry (ICP-MS), and the cardioprotection of TpFE against isoproterenol (ISO)-administered rats was studied. Rats were pretreated with TpFE (100, 300, and 500 mg/kg bw) for 30 days, with concurrent administration of ISO (85 mg/kg bw) for two consecutive days. The levels of trace elements and minerals in TpFE were below the permitted limits of World Health Organization standards. ISO administration significantly increased the heart weight and cardiac marker enzymes in serum, xanthine oxidase, sodium, and calcium in the heart, whereas significantly decreased body weight, reduced glutathione, glutathione-S-transferase, superoxide dismutase, and potassium in the heart. Oral pretreatment of TpFE significantly prevented the ISO-induced alterations. This is the first report that revealed the determination of trace elements and mineral nutrients of TpFE by ICP-MS which plays a principal role in the herbal drug discovery for the treatment of cardiovascular diseases.

Serum biomarkers in periprosthetic joint infections

OBJECTIVES

The diagnosis of periprosthetic joint infection (PJI) is difficult and requires a battery of tests and clinical findings. The purpose of this review is to summarize all current evidence for common and new serum biomarkers utilized in the diagnosis of PJI.

METHODS

We searched two literature databases, using terms that encompass all hip and knee arthroplasty procedures, as well as PJI and statistical terms reflecting diagnostic parameters. The findings are summarized as a narrative review.

RESULTS

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were the two most commonly published serum biomarkers. Most evidence did not identify other serum biomarkers that are clearly superior to ESR and CRP. Other serum biomarkers have not demonstrated superior sensitivity and have failed to replace CRP and ESR as first-line screening tests. D-dimer appears to be a promising biomarker, but more research is necessary. Factors that influence serum biomarkers include temporal trends, stage of revision, and implant-related factors (metallosis).

CONCLUSION

Our review helped to identify factors that can influence serum biomarkers' level changes; the recognition of such factors can help improve their diagnostic utility. As such, we cannot rely on ESR and CRP alone for the diagnosis of PJI prior to second-stage reimplantation, or in metal-on-metal or corrosion cases. The future of serum biomarkers will likely shift towards using genomics and proteomics to identify proteins transcribed via messenger RNA in response to infection and sepsis.Cite this article:Bone Joint Res 2018;7:85-93.

Comparison of adjunctive azithromycin and amoxicillin/metronidazole for patients with chronic periodontitis: preliminary randomized control trial

BACKGROUND

There are insufficient guidelines for the use of adjunctive systemic antibiotics for patients with periodontal disease. The aim of this study was to compare clinical outcomes for patients with moderate-advanced chronic periodontitis treated with: scaling and root planing (SRP), SRP with amoxicillin and metronidazole (A+M), SRP with Azithromycin (Az).

METHODS

Thirty-seven non-smokers with generalized moderate to advanced chronic periodontitis were divided into three treatment groups: SRP, A+M and Az. Patients received the medications after the last SRP session and were reviewed three months later. Changes in clinical parameters were compared between the groups. Separate analyses were executed for: 'all sites', 'molar sites', 'sites with different PPD severities' and 'number of sites with shallow, moderate and deep PPD'.

RESULTS

The three groups exhibited improvements in most clinical parameters. At three months, A+M showed a higher reduction in PPD compared to Az in the 'all sites analysis'. Molars exhibited better reduction in BOP and PPD with A+M than SRP. Pocket depth of the 4-6 mm category reduced more in the A+M than SRP. A+M experienced a higher increase in the number of sites with PPD 1-3 mm than Az.

CONCLUSIONS

Adjunctive systemic antibiotics in the initial phase of treatment may result in improved clinical outcomes.

Impact of portal vein infiltration and type of venous reconstruction in surgery for borderline resectable pancreatic cancer

BACKGROUND

The International Study Group of Pancreatic Surgery (ISGPS) recommends operative exploration and resection of pancreatic cancers in the presence of reconstructable mesentericoportal axis involvement. However, there is no consensus on the ideal method of vascular reconstruction. The effect of depth of tumour invasion of the vessel wall on outcome is also unknown.

METHODS

This was a retrospective cohort study of pancreaticoduodenectomy with vein resection for T3 adenocarcinoma of the head of the pancreas across nine centres. Outcome measures were overall survival based on the impact of the depth of tumour infiltration of the vessel wall, and morbidity, in-hospital mortality and overall survival between types of venous reconstruction: primary closure, end-to-end anastomosis and interposition graft.

RESULTS

A total of 229 patients underwent portal vein resection; 129 (56·3 per cent) underwent primary closure, 64 (27·9 per cent) had an end-to-end anastomosis and 36 (15·7 per cent) an interposition graft. There was no difference in overall morbidity (26 (20·2 per cent), 14 (22 per cent) and 9 (25 per cent) respectively; P = 0·817) or in-hospital mortality (6 (4·7 per cent), 2 (3 per cent) and 2 (6 per cent); P = 0·826) between the three groups. One hundred and six patients (47·5 per cent) had histological evidence of vein involvement; 59 (26·5 per cent) had superficial invasion (tunica adventitia) and 47 (21·1 per cent) had deep invasion (tunica media or intima). Median survival was 18·8 months for patients who had primary closure, 27·6 months for those with an end-to-end anastomosis and 13·0 months among patients with an interposition graft. There was no significant difference in median survival between patients with superficial, deep or no histological vein involvement (20·8, 21·3 and 13·3 months respectively; P = 0·111). Venous tumour infiltration was not associated with decreased overall survival on multivariable analysis.

CONCLUSION

In this study, there was no difference in morbidity between the three modes of venous reconstruction, and overall survival was similar regardless of tumour infiltration of the vein.

Validation and development of MTH1 inhibitors for treatment of cancer

BACKGROUND

Previously, we showed cancer cells rely on the MTH1 protein to prevent incorporation of otherwise deadly oxidised nucleotides into DNA and we developed MTH1 inhibitors which selectively kill cancer cells. Recently, several new and potent inhibitors of MTH1 were demonstrated to be non-toxic to cancer cells, challenging the utility of MTH1 inhibition as a target for cancer treatment.

MATERIAL AND METHODS

Human cancer cell lines were exposed in vitro to MTH1 inhibitors or depleted of MTH1 by siRNA or shRNA. 8-oxodG was measured by immunostaining and modified comet assay. Thermal Proteome profiling, proteomics, cellular thermal shift assays, kinase and CEREP panel were used for target engagement, mode of action and selectivity investigations of MTH1 inhibitors. Effect of MTH1 inhibition on tumour growth was explored in BRAF V600E-mutated malignant melanoma patient derived xenograft and human colon cancer SW480 and HCT116 xenograft models.

RESULTS

Here, we demonstrate that recently described MTH1 inhibitors, which fail to kill cancer cells, also fail to introduce the toxic oxidized nucleotides into DNA. We also describe a new MTH1 inhibitor TH1579, (Karonudib), an analogue of TH588, which is a potent, selective MTH1 inhibitor with good oral availability and demonstrates excellent pharmacokinetic and anti-cancer properties in vivo.

CONCLUSION

We demonstrate that in order to kill cancer cells MTH1 inhibitors must also introduce oxidized nucleotides into DNA. Furthermore, we describe TH1579 as a best-in-class MTH1 inhibitor, which we expect to be useful in order to further validate the MTH1 inhibitor concept.

Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170  TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.

Medical undergraduates' contributions to publication output of world's top universities in 2013

BACKGROUND

Medical undergraduates' (UGs) involvement in research activities is thought to be mutually beneficial to students, their mentors and the scholarly productivity of their universities. However, most evidence in favor of such assumption relies on subjective measures such as the self-reported gains in skills or knowledge rather than robust objective estimates for assessing impact.

AIM

We aimed to objectively track and describe publications with UG co-authors-their proportion to the total publication output of world's top universities, their characteristics and their potential impact on biomedical literature.

METHODS

We contacted the corresponding authors of the 2013's Medline-indexed publications affiliated to world's top 10 universities to investigate if any of their co-authors was an UG. Articles with UG co-authors were further assessed to determine, along with other variables: the type of study design, field of the article, publishing journal and its impact factor (IF), and number of received citations.

RESULTS

Out of 25 152 publications, 2537 articles (10.1%) contained at least one UG co-author who was the first author in 635 papers (25%). Articles with UG co-authors were published in 1114 journals with a median IF of 3.661. Most UGs' co-authored publications (82.7%, n = 2098) were cited at least once within 1 year, for a median of three citations per article.

CONCLUSION

UGs contributed to one in every 10 publications affiliated to top universities. Their papers were published in journals with good IFs and received a fair number of citations, which would reflect the relatively good quality and impact of these articles.

Early postoperative tissue harmonic sonography of the thyroid gland

Purpose: Fundamental gray-scale imaging (FGI) is known to be unuseful for thyroid imaging in the early postoperative setting. Thus, we evaluated the feasability of tissue harmonic imaging (THI) early after thyroid resection.

Material and Methods: FGI and THI of the neck were perfomed in 48 consecutive patients 4 days after surgery. The examiner was blinded to patient diagnoses and types of surgery. FGI and THI examinations were stored on videotape and reviewed offline by two different readers who rated the quality of delineation of the organ borders and presence or absence of focal lesions. The results were compared to neck US performed 12 weeks after surgery.

Results: Delineation of the thyroid remnants in THI/FGI was rated to be excellent in 22/2, good in 11/9, poor in 3/16 and not visible at all in 4/13 patients. The correlation between THI-volumetry and control-volumetry was very high (r=0.81; p<0.0001). THI but not FGI depicted presence or absence of solid thyroid nodules with 100% accuracy.

Conclusion: THI is a feasible method for thyroid US in the early postoperative setting. It permits volumetry of the residual thyroid tissue and accurately depicts nodules within the thyroid remnant.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Outcome after pancreaticoduodenectomy for T3 adenocarcinoma: A multivariable analysis from the UK Vascular Resection for Pancreatic Cancer Study Group

BACKGROUND

Most resectable pancreatic cancers are classified as T3, including those involving the porto-mesenteric vein. Survival and perioperative morbidity for venous resection have been found to be comparable to standard resection. We investigate factors associated with short and long term outcomes in pancreaticoduodenectomy with (PDVR) and without (PD) venous resection exclusively for T3 adenocarcinoma of the head of the pancreas.

METHODS

This is a UK multicenter retrospective cohort study assessing outcomes in patients undergoing PD and PDVR. All consecutive patients with T3 only adenocarcinoma of the head of the pancreas undergoing surgery between December 1998 and June 2011 were included. Multivariable logistic and proportional hazards regression analyses were performed to determine the association between the surgical groups and in-hospital mortality (IHM) and overall survival (OS).

RESULTS

1070 patients were included of whom 840 (78.5%) had PD and 230 (21.5%) had PDVR. Factors independently associated with IHM were a high creatinine (aHR 1.14, p = 0.02), post-operative bleeding (aHR 2.86, p = 0.04) and a re-laparotomy (aHR 8.42, p = 0.0001). For OS, multivariable analyses identified R1 resection margin status (aHR 1.22, p = 0.01), N1 nodal status (aHR 1.92, p = 0.0001), perineural invasion (aHR 1.37, p = 0.002), tumour size >20mm (aHR 0.63, p = 0.0001) and a relaparotomy (aHR 1.84, p = 0.0001) to be independently associated with overall mortality.

CONCLUSION

This study on T3 adenocarcinoma of the head of the pancreas suggests that IHM is strongly associated with perioperative complications whilst OS is affected by histological parameters. Detailed pre-operative disease evaluation and advances in oncological treatment have the potential to improve OS.

Audit of preoperative localisation of tumor with tattoo for patients undergoing laparoscopic colorectal surgery

BACKGROUND

Preoperative localisation of tumour is an essential requirement in laparoscopic colorectal surgery. Since the introduction of laparoscopic colorectal resections in NGH in February 2010, the difficulties of tumour localisation at the time of surgery without tattoo have been highlighted. Furthermore, endoscopic documentation of site of tattoo with respect to the tumour can be inconsistent and at times misleading or difficult to interpret. Tattooing guidelines should be simple to follow and consistent for all lesions irrespective of the location of the tumour. The recommendations were to place at least three spots of tattoo one mucosal fold distal to the lesion and clearly document site of tattoo with respect to tumour in the endoscopy report.

METHOD

We identified 100 patients undergoing elective laparoscopic colorectal cancer resections over a two-year period. Data were collected regarding presence of tattoo preoperatively as documented in the colonoscopy report and subsequently the visibility of the tattoo at time of laparoscopy and its accuracy in relation to the tumour. Abdominoperineal resections and emergency colorectal operations were excluded.

RESULTS

Only 59% of the patients had a visible and accurate tattoo. In 17% of the patients, the tattoo was not visible at all, although it was documented in the endoscopy report that it had been administered. In 4% of patients, it was visible but inaccurately placed. In 20% of the patients, there were no tattoos at all, necessitating on table endoscopy and intraoperative specimen analysis to confirm that the tumour/lesion was within the resection specimen.

DISCUSSION

Preoperative tumour localisation is extremely important to correctly identify the site of tumour or lesion at laparoscopy. A standardised departmental protocol should be implemented by all endoscopists to place three spots of tattoo one mucosal fold distal to any significant lesions found. Failure to tattoo lesions/cancers preoperatively can lead to intraoperative delays and potential harm to patients from on-table endoscopy.