Optimizing the design and geometry of T cell engaging bispecific antibodies targeting CEA in colorectal cancer

Metastatic colorectal cancer (mCRC) remains a leading cause of cancer-related deaths, with a 5-year survival rate of only 15%. T cell engaging bispecific antibodies (TCBs) represent a class of biopharmaceuticals that redirect cytotoxic T cells towards tumor cells, thereby turning immunologically "cold" tumors "hot." The carcinoembryonic antigen (CEA) is an attractive tumor-associated antigen (TAA) that is overexpressed in over 98% of CRC patients. In this study, we report the comparison of four different TCB formats employing the antibodies F4 (targeting human CEA) and 2C11 (targeting mouse CD3ε). These formats include both antibody fragment- and IgG-based constructs, with either one or two binding specificities of the respective antibodies. The 2+1 arrangement, using an anti-CEA single-chain diabody (scDbCEA) fused to an anti-CD3 single-chain variable fragment (scFvCD3), emerged as the most potent design, showing tumor killing at subnanomolar concentrations across three different CEA+ cell lines. The in vitro activity was three times greater in C57BL/6 mouse colon adenocarcinoma cells (MC38) expressing high levels of CEA compared to those expressing low levels, highlighting the impact of CEA antigen density in this assay. The optimal TCB candidate was tested in two different immunocompetent mouse models of colorectal cancer and showed tumor growth retardation. Ex vivo analysis of tumor infiltrates showed an increase in CD4+ and CD8+ T cells upon TCB treatment. This study suggests that bivalent tumor targeting, monovalent T cell targeting, and a short spatial separation are promising characteristics for CEA targeting TCBs.

A novel strategy to generate immunocytokines with activity-on-demand using small molecule inhibitors

Cytokine-based therapeutics have been shown to mediate objective responses in certain tumor entities but suffer from insufficient selectivity, causing limiting toxicity which prevents dose escalation to therapeutically active regimens. The antibody-based delivery of cytokines significantly increases the therapeutic index of the corresponding payload but still suffers from side effects associated with peak concentrations of the product in blood upon intravenous administration. Here we devise a general strategy (named "Intra-Cork") to mask systemic cytokine activity without impacting anti-cancer efficacy. Our technology features the use of antibody-cytokine fusions, capable of selective localization at the neoplastic site, in combination with pathway-selective inhibitors of the cytokine signaling, which rapidly clear from the body. This strategy, exemplified with a tumor-targeted IL12 in combination with a JAK2 inhibitor, allowed to abrogate cytokine-driven toxicity without affecting therapeutic activity in a preclinical model of cancer. This approach is readily applicable in clinical practice.

A DNA-encoded chemical library based on chiral 4-amino-proline enables stereospecific isozyme-selective protein recognition

DNA-encoded chemical libraries (DELs) consist of large chemical compound collections individually linked to DNA barcodes, facilitating pooled construction and screening. However, screening campaigns often fail if the molecular arrangement of the building blocks is not conducive to an efficient interaction with a protein target. Here we postulated that the use of rigid, compact and stereo-defined central scaffolds for DEL synthesis may facilitate the discovery of very specific ligands capable of discriminating between closely related protein targets. We synthesized a DEL comprising 3,735,936 members, featuring the four stereoisomers of 4-aminopyrrolidine-2-carboxylic acid as central scaffolds. The library was screened in comparative selections against pharmaceutically relevant targets and their closely related protein isoforms. Hit validation results revealed a strong impact of stereochemistry, with large affinity differences between stereoisomers. We identified potent isozyme-selective ligands against multiple protein targets. Some of these hits, specific to tumour-associated antigens, demonstrated tumour-selective targeting in vitro and in vivo. Collectively, constructing DELs with stereo-defined elements contributed to high library productivity and ligand selectivity.

Adapting Neutralizing Antibodies to Viral Variants by Structure-Guided Affinity Maturation Using Phage Display Technology

Neutralizing monoclonal antibodies have achieved great efficacy and safety for the treatment of numerous infectious diseases. However, their neutralization potency is often rapidly lost when the target antigen mutates. Instead of isolating new antibodies each time a pathogen variant arises, it can be attractive to adapt existing antibodies, making them active against the new variant. Potential benefits of this approach include reduced development time, cost, and regulatory burden. Here a methodology is described to rapidly evolve neutralizing antibodies of proven activity, improving their function against new pathogen variants without losing efficacy against previous ones. The reported procedure is based on structure-guided affinity maturation using combinatorial mutagenesis and phage display technology. Its use against the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is demonstrated, but it is suitable for any other pathogen. As proof of concept, the method is applied to CoV-X2, a human bispecific antibody that binds with high affinity to the early SARS-CoV-2 variants but lost neutralization potency against Delta. Antibodies emerging from the affinity maturation selection exhibit significantly improved neutralization potency against Delta and no loss of efficacy against the other viral sequences tested. These results illustrate the potential application of structure-guided affinity maturation in facilitating the rapid adaptation of neutralizing antibodies to pathogen variants.

Role of single nucleotide polymorphism rs2383206 on coronary artery disease risk among Saudi Population: a case-control study

OBJECTIVE

We aim to investigate the relationship between genetic variation and biological function on a genomic scale, focusing on identifying genes responsible for complex diseases using single nucleotide polymorphisms. Specifically, the study explores the association between the rs2383206 gene located on chromosome 9p21.3 and the development of coronary artery disease (CAD) in a specific Saudi population.

PATIENTS AND METHODS

This case-control study was conducted between September 2013 and May 2015 at King Abdullah Medical City (KAMC) and Al-Noor Specialist Hospital targeting the Saudi Population residing in the western region of Saudi Arabia. The study enrolled 315 cases with documented CAD and 205 controls with normal coronary arteries on coronary angiography. Genomic DNA was extracted from peripheral blood samples of both groups, and genotyping of rs2383206 was performed using the tetra-primer amplification-refractory mutation system-polymerase chain reaction (ARMS-PCR) method.

RESULTS

In this study, the prevalence of the GG genotype in rs2383206 was found to be higher in patients with CAD than in controls, with an odds ratio of 1.997 [95% confidence interval (CI): 1.176-3.394, p = 0.007]. Additionally, individuals with the GG genotype who had sedentary lifestyles, hyperlipidemia, and smoked were found to be at a higher risk for developing CAD (p = 0.003, 0.009, and 0.003, respectively). The G allele also increased the risk of CAD with an odds ratio of 1.413 (95% CI: 1.099-1.817; p = 0.004).

CONCLUSIONS

In conclusion, this study demonstrated a significant association between the rs2383206 variant located on chromosome 9p21 and the development of CAD. The findings of this study provide valuable insights into the genetic susceptibility to CAD and highlight the potential of this variant as a target for future functional studies.

Generation of a novel fully human non-superagonistic anti-CD28 antibody with efficient and safe T-cell co-stimulation properties

Antibody-based therapeutics represent an important class of biopharmaceuticals in cancer immunotherapy. CD3 bispecific T-cell engagers activate cytotoxic T-cells and have shown remarkable clinical outcomes against several hematological malignancies. The absence of a costimulatory signal through CD28 typically leads to insufficient T-cell activation and early exhaustion. The combination of CD3 and CD28 targeting products offers an attractive strategy to boost T-cell activity. However, the development of CD28-targeting therapies ceased after TeGenero's Phase 1 trial in 2006 evaluating a superagonistic anti-CD28 antibody (TGN1412) resulted in severe life-threatening side effects. Here, we describe the generation of a novel fully human anti-CD28 antibody termed "E1P2" using phage display technology. E1P2 bound to human and mouse CD28 as shown by flow cytometry on primary human and mouse T-cells. Epitope mapping revealed a conformational binding epitope for E1P2 close to the apex of CD28, similar to its natural ligand and unlike the lateral epitope of TGN1412. E1P2, in contrast to TGN1412, showed no signs of in vitro superagonistic properties on human peripheral blood mononuclear cells (PBMCs) using different healthy donors. Importantly, an in vivo safety study in humanized NSG mice using E1P2, in direct comparison and contrast to TGN1412, did not cause cytokine release syndrome. In an in vitro activity assay using human PBMCs, the combination of E1P2 with CD3 bispecific antibodies enhanced tumor cell killing and T-cell proliferation. Collectively, these data demonstrate the therapeutic potential of E1P2 to improve the activity of T-cell receptor/CD3 activating constructs in targeted immunotherapeutic approaches against cancer or infectious diseases.

Generation and in vivo characterization of a novel high-affinity human antibody targeting carcinoembryonic antigen

There are no effective treatment options for most patients with metastatic colorectal cancer (mCRC). mCRC remains a leading cause of tumor-related death, with a five-year survival rate of only 15%, highlighting the urgent need for novel pharmacological products. Current standard drugs are based on cytotoxic chemotherapy, VEGF inhibitors, EGFR antibodies, and multikinase inhibitors. The antibody-based delivery of pro-inflammatory cytokines provides a promising and differentiated strategy to improve the treatment outcome for mCRC patients. Here, we describe the generation of a novel fully human monoclonal antibody (termed F4) targeting the carcinoembryonic antigen (CEA), a tumor-associated antigen overexpressed in colorectal cancer and other malignancies. The F4 antibody was selected by antibody phage display technology after two rounds of affinity maturation. F4 in single-chain variable fragment format bound to CEA in surface plasmon resonance with an affinity of 7.7 nM. Flow cytometry and immunofluorescence on human cancer specimens confirmed binding to CEA-expressing cells. F4 selectively accumulated in CEA-positive tumors, as evidenced by two orthogonal in vivo biodistribution studies. Encouraged by these results, we genetically fused murine interleukin (IL) 12 to F4 in the single-chain diabody format. F4-IL12 exhibited potent antitumor activity in two murine models of colon cancer. Treatment with F4-IL12 led to an increased density of tumor-infiltrating lymphocytes and an upregulation of interferon γ expression by tumor-homing lymphocytes. These data suggest that the F4 antibody is an attractive delivery vehicle for targeted cancer therapy.

ADIPONECTIN LEVELS IN GRAVES' DISEASE - SYSTEMATIC REVIEW AND META-ANALYSIS

Context

Graves' disease is the most prevalent cause of hyperthyroidism worldwide. Adiponectin, the most abundant adipokine, plays a significant role in a cluster of prevalent diseases connected to metabolic disorders.

Objective

Although the association between adiponectin and Graves' disease has been studied, the existing data is inconsistent. Therefore, we conducted this systematic review and meta-analysis to evaluate the relationship between adiponectin levels and Graves' disease.

Methods

We performed a systematic electronic search on PubMed, EMBASE, Scopus and Cochrane Library using predefined keywords. We used the NHLBI quality assessment tools to assess the included studies.

Results

There were 11 studies involving 781 subjects included in our qualitative synthesis, while 6 studies were included in our quantitative synthesis. We observed significantly increased adiponectin levels in Graves' disease patients compared to controls (MD 2.983 [95% CI 0.138-5.828]) and hypothyroidism patients (MD 3.389 [95% CI 1.332-5.446]). Nevertheless, no significant MD was observed when comparing Graves' disease patients with and without Graves' ophthalmopathy (MD -27.124 [95% CI -88.893 - 34.645]).

Conclusions

Adiponectin levels were significantly higher in patients with Graves' disease compared to controls and hypothyroidism patients. However, patients with and without Graves' ophthalmopathy did not present a significant mean difference in adiponectin levels.

Fibroblast Activation Protein Triggers Release of Drug Payload from Non-internalizing Small Molecule Drug Conjugates in Solid Tumors

PURPOSE

Small molecule drug conjugates (SMDC) are modular anticancer prodrugs that include a tumor-targeting small organic ligand, a cleavable linker, and a potent cytotoxic agent. Most of the SMDC products that have been developed for clinical applications target internalizing tumor-associated antigens on the surface of tumor cells. We have recently described a novel non-internalizing small organic ligand (named OncoFAP) of fibroblast activation protein (FAP), a tumor-associated antigen highly expressed in the stroma of most solid human malignancies.

EXPERIMENTAL DESIGN

In this article, we describe a new series of OncoFAP-Drug derivatives based on monomethyl auristatin E (MMAE; a potent cytotoxic tubulin poison) and dipeptide linkers that are selectively cleaved by FAP in the tumor microenvironment.

RESULTS

The tumor-targeting potential of OncoFAP was confirmed in patients with cancer using nuclear medicine procedures. We used mass spectrometry methodologies to quantify the amount of prodrug delivered to tumors and normal organs, as well as the efficiency of the drug release process. Linkers previously exploited for anticancer drug conjugates were used as benchmark. We identified OncoFAP-Gly-Pro-MMAE as the best performing SMDC, which has now been prioritized for further clinical development. OncoFAP-Gly-Pro-MMAE selectively delivered more than 10% injected dose per gram of MMAE to FAP-positive tumors, with a tumor-to-kidney ratio of 16:1 at 24 hours post-injection.

CONCLUSIONS

The FAP-specific drug conjugates described in this article promise to be efficacious for the targeting of human malignancies. The extracellular release of potent anticancer payloads mediates durable complete remission in difficult-to-treat animal models of cancer.

Selection of a PD-1 blocking antibody from a novel fully human phage display library

Programmed cell death protein 1 (PD-1) is an immunoregulatory target which is recognized by different monoclonal antibodies, approved for the therapy of multiple types of cancer. Different anti-PD-1 antibodies display different therapeutic properties and there is a pharmaceutical interest to generate and characterize novel anti-PD-1 antibodies. We screened multiple human antibody phage display libraries to target novel epitopes on the PD-1 surface and we discovered a unique and previously undescribed binding specificity (termed D12) from a new antibody library (termed AMG). The library featured antibody fragments in single-chain fragment variable (scFv) format, based on the IGHV3-23*03 (VH ) and IGKV1-39*01 (Vκ) genes. The D12 antibody was characterized by surface plasmon resonance (SPR), cross-reacted with the Cynomolgus monkey antigen and bound to primary human T cells, as shown by flow cytometry. The antibody blocked the PD-1/PD-L1 interaction in vitro with an EC50 value which was comparable to the one of nivolumab, a clinically approved antibody. The fine details of the interaction between D12 and PD-1 were elucidated by x-ray crystallography of the complex at a 3.5 Å resolution, revealing an unprecedented conformational change at the N-terminus of PD-1 following D12 binding, as well as partial overlap with the binding site for the cognate PD-L1 and PD-L2 ligands which prevents their binding. The results of the study suggest that the expansion of antibody library repertoires may facilitate the discovery of novel binding specificities with unique properties that hold promises for the modulation of PD-1 activity in vitro and in vivo.

A Dimeric FAP-Targeting Small-Molecule Radioconjugate with High and Prolonged Tumor Uptake

Imaging procedures based on small-molecule radioconjugates targeting fibroblast activation protein (FAP) have recently emerged as a powerful tool for the diagnosis of a wide variety of tumors. However, the therapeutic potential of radiolabeled FAP-targeting agents is limited by their short residence time in neoplastic lesions. In this work, we present the development and in vivo characterization of BiOncoFAP, a new dimeric FAP-binding motif with an extended tumor residence time and favorable tumor-to-organ ratio. Methods: The binding properties of BiOncoFAP and its monovalent OncoFAP analog were assayed against recombinant human FAP. Preclinical experiments with ¹⁷⁷Lu-OncoFAP-DOTAGA (¹⁷⁷Lu-OncoFAP) and ¹⁷⁷Lu-BiOncoFAP-DOTAGA (¹⁷⁷Lu-BiOncoFAP) were performed on mice bearing FAP-positive HT-1080 tumors. Results: OncoFAP and BiOncoFAP displayed comparable subnanomolar dissociation constants toward recombinant human FAP in solution, but the bivalent BiOncoFAP bound more avidly to the target immobilized on solid supports. In a comparative biodistribution study, ¹⁷⁷Lu-BiOncoFAP exhibited a more stable and prolonged tumor uptake than ¹⁷⁷Lu-OncoFAP (∼20 vs. ∼4 percentage injected dose/g, respectively, at 24 h after injection). Notably, ¹⁷⁷Lu-BiOncoFAP showed favorable tumor-to-organ ratios with low kidney uptake. Both ¹⁷⁷Lu-OncoFAP and ¹⁷⁷Lu-BiOncoFAP displayed potent antitumor efficacy when administered at therapeutic doses to tumor-bearing mice. Conclusion: ¹⁷⁷Lu-BiOncoFAP is a promising candidate for radioligand therapy of cancer, with favorable in vivo tumor-to-organ ratios, a long tumor residence time, and potent anticancer efficacy.

Generation and in vivo validation of an IL-12 fusion protein based on a novel anti-human FAP monoclonal antibody

BACKGROUND

In this study, we describe the generation of a fully human monoclonal antibody (named '7NP2') targeting human fibroblast activation protein (FAP), an antigen expressed in the microenvironment of different types of solid neoplasms.

METHODS

7NP2 was isolated from a synthetic antibody phage display library and was improved by one round of mutagenesis-based affinity maturation. The tumor recognition properties of the antibody were validated by immunofluorescence procedures performed on cancer biopsies from human patients. A fusion protein consisting of the 7NP2 antibody linked to interleukin (IL)-12 was generated and the anticancer activity of the murine surrogate product (named mIL12-7NP2) was evaluated in mouse models. Furthermore, the safety of the fully human product (named IL12-7NP2) was evaluated in Cynomolgus monkeys.

RESULTS

Biodistribution analysis in tumor-bearing mice confirmed the ability of the product to selectively localize to solid tumors while sparing healthy organs. Encouraged by these results, therapy studies were conducted in vivo, showing a potent antitumor activity in immunocompetent and immunodeficient mouse models of cancer, both as single agent and in combination with immune checkpoint inhibitors. The fully human product was tolerated when administered to non-human primates.

CONCLUSIONS

The results obtained in this work provided a rationale for future clinical translation activities using IL12-7NP2.

Abstract LB535: A novel IL12-based immunocytokine targeting fibroblast activation protein (FAP) for the treatment of cancer

Immunocytokines, which consist of the fusion of cytokines to tumor targeting antibodies, represent a novel class of biopharmaceuticals that have great potential for cancer treatment. The use of these products improves the efficacy of the delivered drug by reducing related side effects and significantly enhances the therapeutic index of the payload. Over the past years, nuclear medicine studies have validated the Fibroblast Activation Protein (FAP) as a pantumoral antigen, with more than 28 different cancer types successfully imaged in patients. Since FAP is mostly undetectable in healthy organs, it has been considered as an attractive target for both imaging and therapeutic applications. For this reason, here we describe the generation of a novel fully human monoclonal antibody targeting FAP. The antibody was isolated from a synthetic antibody phage display library and its tumor recognition properties were validated by immunofluorescence performed on a commercial tissue microarray as well as on freshly frozen colon cancer biopsies from human patients. An ex vivo biodistribution analysis in mice confirmed the ability of anti-FAP in IgG1 format to selectively localize to solid tumors while sparing healthy organs. Furthermore, Pharmacokinetics (PK) studies in Cynomolgus Monkey showed no sink effects at early time points and a slow clearance from bloodstream as expected for IgG1 antibodies. Encouraged by these results, an antibody cytokine fusion (mIL12-FAP) based on the novel anti-FAP antibody was generated and characterized in vitro and in vivo, showing activation of the immune system both in immunocompetent and immunodeficient mouse models bearing FAP-positive tumors. mIL12-FAP exhibited strong anticancer activity in mice bearing CT26-FAP colon carcinomas which could be boosted by the combination with immune checkpoint inhibitors, leading to durable cancer eradication. The targeted delivery of mIL12 to the tumor microenvironment increased the infiltrate of tumor-specific lymphocytes and Natural Killer (NK) cells as compared to the control group without apparent evidence of toxicity.

Citation Format: Lisa Nadal, Frederik Peissert, Abdullah Elsayed, Chiara Libbra, Dario Neri, Roberto De Luca. A novel IL12-based immunocytokine targeting fibroblast activation protein (FAP) for the treatment of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB535.

Abstract LB527: A novel dimeric small molecule-radio conjugate targeting fibroblast activation protein with high and prolonged tumor uptake

Imaging procedures based on small molecule-radio conjugates targeting Fibroblast Activation Protein (FAP) are taking the spotlight in clinical practice for the diagnosis of a wide variety of cancer lesions. However, therapeutic applications of FAP-targeting radioligand therapeutics are limited by their short residence time in tumor lesions. We have recently described the discovery of OncoFAP, a novel ultra-high affinity ligand of FAP which has been already validated for PET imaging applications in more than twenty patients with solid tumors. In this abstract, we describe the development and in vivo characterization of BiOncoFAP, a dimeric FAP targeting small molecule based on OncoFAP. In particular, OncoFAP and BiOncoFAP displayed a superimposable affinity for recombinant human FAP (KD = 970 pM and 993 pM, respectively, measured by Fluorescence Polarization). Moreover, the two ligands exhibited a clear selectivity for the target, without significantly interacting with a wide panel of non-target proteins. BiOncoFAP was coupled to a DOTAGA chelator, suitable for radiolabeling with [177Lu]Lu for therapeutic applications. Cold [natLu]Lu-BiOncoFAP-DOTAGA showed an excellent stability in both mouse and human serum, with half-life longer than 5 days, supporting in vivo investigations. In a head-to-head in vivo biodistribution comparative study against [177Lu]Lu-OncoFAP-DOTAGA, [177Lu]Lu-BiOncoFAP-DOTAGA exhibited a more stable and prolonged residence time in FAP-positive tumors implanted in immunodeficient mice (~20% ID/g and ~200-to-1 tumor-to-blood ratio, 24 h after systemic administration). Notably, [177Lu]Lu-BiOncoFAP-DOTAGA did not significantly accumulate in healthy organs, thus showing an outstanding tumor-to-organ ratio (e.g., 12-to-1 tumor-to-kidney and 34-to-1 tumor-to-liver ratio, at the 24 h time point). These findings heighten BiOncoFAP as promising candidate for the development of anti-cancer radioligand therapeutics towards FAP-expressing tumor lesions.

Citation Format: Samuele Cazzamalli, Andrea Galbiati, Aureliano Zana, Matilde Bocci, Jacopo Millul, Jacqueline Mock, Abdullah Elsayed, Dario Neri. A novel dimeric small molecule-radio conjugate targeting fibroblast activation protein with high and prolonged tumor uptake [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB527.

Abstract LB522: Fibroblast activation protein triggers the release of drug payload from non-internalizing small molecule-drug conjugates in solid tumors

Small Molecule-Drug Conjugates (SMDCs) are modular anti-cancer pro-drugs that include a tumor-targeting small ligand, a cleavable linker and a potent cytotoxic agent. SMDC products that have been developed for clinical applications are targeting internalizing tumor-associated antigens expressed on the surface of tumor cells. We have recently developed a novel non-internalizing small organic ligand (named OncoFAP) of Fibroblast Activation Protein (FAP), a tumor-associated antigen highly expressed in the stroma of most of solid human malignancies. The tumor targeting performance of OncoFAP has been validated by nuclear medicine studies in patients with various solid tumors. In a previous study, we showed that OncoFAP can be used to produce non-internalizing SMDCs that are effective and well tolerated. Here, we describe a new series of OncoFAP-Drug derivatives based on the MMAE tubulin poison and dipeptide linkers that are selectively cleaved by FAP in the tumor microenvironment. We benchmarked the new SMDCs against OncoFAP-MMAE conjugates displaying linker modules which are widely used in approved and clinical stage Antibody-Drug Conjugates, including structures cleaved by Cathepsin B and by reducing agents. We selected OncoFAP-GlyPro-MMAE as the most efficacious and safe SMDC for further clinical development after quantitatively analyzing the biodistribution of MMAE released by OncoFAP-MMAE conjugates. OncoFAP-GlyPro-MMAE selectively delivers high amounts of MMAE at the site of disease, with a tumor-to-kidney ratio of 7-to-1 and of 16-to-1 at 6- and 24-hours post-injection, respectively. Our molecules based on the OncoFAP tumor-targeting ligand and FAP-cleavable linkers promise to be safe and effective against most of human malignancies.

Citation Format: Aureliano Zana, Andrea Galbiati, Ettore Gilardoni, Jacopo Millul, Theo Sturm, Riccardo Stucchi, Matilde Bocci, Abdullah Elsayed, Lisa Nadal, Martina Cirillo, Dario Neri, Samuele Cazzamalli. Fibroblast activation protein triggers the release of drug payload from non-internalizing small molecule-drug conjugates in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB522.

Flow vorticity relationships with right ventricular geometry in adult tetralogy of Fallot

Background

Repaired tetralogy of Fallot adults (rToF) undergo right ventricular (RV) remodeling, in part due to volume overload of residual pulmonary regurgitation volume (PRV). Time-resolved phase-contrast cardiac magnetic resonance imaging (4D Flow MRI) enables the qualitative and quantitative measurement of altered blood flow patterns, including vorticity. Cardiac atlases allow for complex three-dimensional heart shapes to be expressed as morphometric scores. Those scores show the extent of geometrical shift and can help explore uncharted relationships between vorticity and architecture.

Purpose

We aimed to quantify vorticity, incorporating deep learning to enhance 4D Flow data, and correlate this with global cardiac parameters and morphometric scores.

Methods

12 Adult rToF patients and 10 age-matched controls underwent 4D flow MRI and cine imaging. RV interventricular vorticity was calculated for outflow and inflow tracts. EDV, ESV and SV were computed from cines which were also used to build three-dimensional shape models.

The biventricular models were projected onto an atlas generated from 95 rToF patients, and twenty-one principal component analysis shape modes were correlated with cardiac metrics and vorticity to identify global shape variations. Association between biventricular shape and vorticity was further analysed using multivariate multiple regression models.

Results

Strong correlation was found between PRV and the right ventricular outflow tract (RVOT) vorticity. PRV and RVOT vorticity both correlated with the same 3 shape modes (r=−0.55, −0.50 and 0.6 (p<0.05) respectively for PR and r=0.63, −0.82 and 0.60 (p<0.05) respectively for vorticity) i.e., the RV dilates with an increase in basal bulging, apical bulging and tricuspid annulus tilting with more severe regurgitation, as well as a smaller LV, and a paradoxical movement of the septum (Figure 1). However, RV vorticity correlated with 2 modes that did not correlate with PRV, (r=−0.62, −0.69, p<0.05). With higher vorticity the RV was longer, increased tilting of the tricuspid annulus and an increased basal bulge around the tricuspid area. The multivariate analysis model demonstrated that higher vorticity was associated with displacement of the pulmonary valve and change in the RVOT length and direction. A septal displacement towards the left ventricle was observed and increased apical flatness of the RV (Figure 1). Qualitatively, vorticity in rToF group was more heterogeneous than controls (Figure 2).

Conclusions

Vorticity is a novel marker based on the influence of blood motion providing new insight into early diagnosis and prognosis of cardiac disease. This is the first study to examine the relationships between vorticity and regional RV shape changes in rToF. Mode associations with vorticity were different to associations with PRV. More longitudinal studies are required for standardization of change in vorticity with the disease process.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The New Zealand heart foundation Mode variations and morphometric modelVorticity visualization and analysis

A DNA-Encoded Chemical Library Based on Peptide Macrocycles

The synthesis and characterization of a novel DNA-encoded library of macrocyclic peptide derivatives are described; the macrocycles are based on three sets of proteinogenic and non-proteinogenic amino acid building blocks and featuring the use of copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction for ring closure. The library (termed YO-DEL) which contains 1 254 838 compounds, was encoded with DNA in single-stranded format and was screened against target proteins of interest using affinity capture procedures and photocrosslinking. YO-DEL selections yielded specific binders against serum albumins, carbonic anhydrases and NKp46, a marker of activated Natural Killer cells.

Bioprocess enhancement of feather degradation using alkaliphilic microbial mixture

1. The main aim of this work is to develop a robust method to generate a microbial mixture which can successfully degrade poultry feathers to overcome environmental problems. 2. Four different alkaliphilic microbes were isolated and shown to degrade poultry feathers. 3. Two of the isolates were phylogenetically identified as Lysinibacillus and the others were identified as Nocardiopsis and Micrococcus. 4. The best microbial co-culture for white and black feather degradation was optimised for pH, temperature and relative population of the isolates to achieve almost 96% of degradation compared with a maximum of 31% when applying each isolate individually. 5. The maximum activity of keratinase was estimated to be 1.5 U/ml after 3 d for white feathers and 0.6 U/ml after 4 d for black feathers in a basal medium containing feather as the main carbon source. Additionally, non-denaturing polyacrylamide gel electrophoresis showed 4 and 3 protease activity bands for white and black feather, respectively. 6. This study provides a robust method to develop potential new mixtures of microorganisms that are able to degrade both white and black feathers by applying a Central Composite Design.

Oral delivery of insulin using a lipoamino acid nanocarrier system

Lipoamino acid nanocarriers based on the interactions between L-arginine and oleic acid were formulated with the aid of Tween 80 and explored as a novel carrier for the oral administration of insulin. The interaction between oleic acid and L-arginine was confirmed by FTIR, DSC/TGA, viscosity and surface tension measurements. The pharmacological activity of orally administered insulin-loaded nanocarriers (10, 25 and 50 IU/kg) was evaluated in healthy rabbits. Insulin loaded in lipoamino acid nanocarriers was therapeutically active as demonstrated by the remarkable reduction in blood glucose levels after oral administration of the preparation. A blood glucose lowering of 80% was achieved 4 h after administration of the oral insulin preparation. In addition, insulin-loaded nanocarriers decreased glycemia in a dose dependent manner, with the maximum effect noticed with 50 IU/kg. Moreover, a significant effect observed 1 h after administration suggested that these nanocarriers could be considered as a fast-acting preparation. These results clearly show that these lipoamino acid nanocarriers hold promising potential for oral delivery of insulin.

64 USING PORCINE GRANULOSA CELLS AS FEEDERS FOR PORCINE AND BOVINE TROPHECTODERM CELL CULTURE

The trophectoderm cells, arising from the outer side of the blastomere in the blastocyst stage, are the first differentiated embryonic cells with specific potential as stem cells. The physiology of trophectoderm cells has been studied; however, their functions still remain unclear, because the lack of definitive information of cell lineages. Here, we aimed to establish in culture different feeder-dependent trophectoderm cell lines from 9-day, preimplantation, in vitro-produced porcine and bovine embryos. We used 2 different feeders: porcine granulosa cells (PGC) and mouse embryonic fibroblasts (MEF). Both cells were mitotically inactivated by mitomycin-C and then cultured with a density of 5 × 104 mL–1 on 0.1% (wt/vol) gelatin coated 4-well dishes in DMEM-199 medium supplemented with 10% (vol/vol) fetal bovine serum (FBS), nonessential amino acids (NEAA), β-mercaptoethanol and nucleosides (Talbot et al. 2000 Biol. Reprod. 62, 235–247). Trophectoderm cells were observed by light microscopy and characterised by reverse transcription-PCR using specific primers for both species. Different feeders and trophectoderm cells growth rates were compared after trypsinization using a hemocytometer. Data were analysed using 1-way ANOVA. In results, trophectoderm cells display epithelial characteristics, cuboidal morphology and express mRNA of homebox protein CDX2, cytokeratin 8 (KRT8) and interferon (IFN) gamma or tau for porcine or bovine cells, respectively. Moreover, oestrogen receptor (ESR1) and progesterone receptor (PGR) were expressed in trophectoderm cells of both species. Porcine granulosa cells were highly proliferative with doubling time of 24 h when compared to MEF (P ≤ 0.5), easy to recover and provided a reasonable source of steroids, 17β-oestradiol (E2; 31.21 ± 3.1 ng mL–1) and progesterone (P4; 6.36 ± 0.4 ng mL–1). Moreover, trophectoderm cell colonies of both species that cultured on PGC grew faster, with a doubling time of 48 h when compared to those cultured on MEF (P ≤ 0.5). We speculate that the continuous supplement of steroids and other cytokines during the co-culture of trophoblasts with granulosa cells might help the trophectoderm cells growth more than that of MEF. Further investigations are required in this regard. In conclusion, porcine granulosa cells can be good alternative feeders to culture porcine and bovine trophectoderm. This research was supported by MKE (Grant # 10033839-2011-13) and IPET.

Effect of epidural dexmedetomidine on intraoperative awareness and post-operative pain after one-lung ventilation

BACKGROUND

During combined general and regional anaesthesia, it is difficult to use autonomic signs to assess whether wakefulness is suppressed adequately. We compared the effects of a dexmedetomidine-bupivacaine mixture with plain bupivacaine for thoracic epidural anaesthesia on intraoperative awareness and analgesic benefits, when combined with superficial isoflurane anaesthesia (<0.05 maximum alveolar concentration) in patients undergoing thoracic surgery with one-lung ventilation (OLV).

METHODS

Fifty adult male patients were randomly assigned to receive either epidural dexmedetomidine 1 microg/kg with bupivacaine 0.5% (group D) or bupivacaine 0.5% alone (group B) after induction of general anaesthesia. Gasometric, haemodynamic and bispectral index values were recorded. Post-operative verbal rating score for pain and observer's assessment of alertness/sedation scale were determined by a blinded observer.

RESULTS

Dexmedetomidine reduced the use of supplementary fentanyl during surgery. Patients in group B consumed more analgesics and had higher pain scores after operation than patients of group D. The level of sedation was similar between the two groups in the ICU. Two patients (8%) in group B reported possible intraoperative awareness. There was a limited decrease in PaO2 at OLV in group D compared with group B (P<0.05).

CONCLUSION

In thoracic surgery with OLV, the use of epidural dexmedetomidine decreases the anaesthetic requirements significantly, prevents awareness during anaesthesia and improves intraoperative oxygenation and post-operative analgesia.

Ascorbic acid combined with ibuprofen in hypoxic ischemic encephalopathy: a randomized controlled trial

OBJECTIVE

Free oxygen radicals and proinflammatory cytokines are important causes for brain injury in neonates with hypoxic ischemic encephalopathy (HIE). Our objectives were to test the hypothesis that a combination of antioxidants (ascorbic acid) and anti-inflammatory agents (ibuprofen) can ameliorate the brain injury in HIE and improve neurodevelopmental outcomes when given to term infants immediately after birth.

STUDY DESIGN

In a prospective, randomized, double-blinded controlled trial, 60 asphyxiated term infants were assigned to one of two groups, intervention and control. The intervention group (n=30) received intravenous ascorbic acid and oral ibuprofen for 3 days; and the control group (n=30) received similar volumes of a placebo. We measured a panel of cytokines at enrollment and administered the treatment drugs within 2 h after birth. Neurological evaluations and developmental screenings were performed for all survivors at 6 months of age.

RESULT

The Intervention and Control groups did not differ in the severity of HIE at enrollment, the concentrations of IL-1 beta and IL-6, the incidence of mortality (37 vs 33%), the incidence of neurological abnormalities at hospital discharge (47 vs 55%) and the incidence of developmental delay at 6 months of age (32 vs 40%), respectively. None of the observed complications were related to intervention. Serum interleukin (IL)-1 beta and IL-6 concentrations correlated positively with the severity of HIE at birth (P<0.01), whereas only serum IL-6 correlated with neurodevelopmental outcome at 6 months (P<0.001).

CONCLUSION

Early administration of ascorbic acid and ibuprofen did not affect outcomes in infants with perinatal asphyxia. This study does not explain whether our intervention was not effective in blocking free radicals and inflammatory cytokines, if the dosing and route of administration were inadequate, or if other mediators existed that could have a more powerful role in brain injury during hypoxia-ischemia.

Hyperinfection Strongyloidiasis: An Anticipated Outbreak in Kidney Transplant Recipients in Kuwait

BACKGROUND

Hyperinfection strongyloidiasis is a potentially fatal syndrome associated with conditions of depressed host cellular immunity. A high degree of suspicion is required to detect cases early and thereby avoid a fatal outcome.

PATIENTS AND METHODS

Three consecutive cadaveric kidney transplant recipients died within 2 months from hyperinfections with strongyloides. All members of the transplant team were involved in a campaign to localize the source of infection, identify and treat affected patients, and provide adequate prophylaxis to other transplant recipients. We reviewed cadaveric donor files and screened 61 hospital personnel, 27 hospital inpatients, and the 87 hospital outpatients transplanted in a year's time before that event for a possible source. The screening test included analysis of fresh stool samples on 3 consecutive days for strongyloides larvae. The anti-helminthic drug albendazol was administered to all patients during screening. They were followed for possible development of the disease during the infectivity period.

RESULTS

The first 2 recipients received their kidneys from 1 cadaveric donor, while the third received it from a different donor. Both donors came from areas endemic for strongyloidiasis. The 3 recipients were on tacrolimus-based immunosuppression. The twin recipient of the second kidney was on cyclosporine and did not manifest a disease. All stool samples taken for screening were negative for the infective larvae. None of the other recipients developed the disease.

CONCLUSIONS

Cadaveric donors were the possible source for this outbreak. Cyclosporine probably has a protective effect against strongyloides. In our setting, screening of cadaveric donors for strongyloides is mandatory before accepting them for donation, and oral prophylaxis is required for all recipients.

[Aprotinin in cardiac surgery in patients with platelet anti-aggregant treatment]

A large number of coronary patients referred for coronary bypass surgery receive platelet anti-aggregant therapy which has the disadvantage of increasing per and postoperative haemorrhage. The aim of this study was to assess the effects of aprotinin in 60 patients under platelet antiaggregant therapy (aspirin 250 mg/day) for over 30 days before surgery for coronary bypass grafting. The clinical (age, weight, diagnosis, bypass time, number of grafts) and biological features (preoperative haemoglobin concentration, platelet count and fibrinogen levels) were identical in a group treated by aprotinin (Group A, n = 30) and a control group (Group B, n = 30). The aprotinin treatment protocol was an intravenous injection of 2 million KIU (kallikrein inhibitory units) before starting the cardiopulmonary bypass and 2 million KIU in the filling liquid of the bypass circuit. A significant reduction in blood loss was observed in Group A with respect to Group B (370 +/- 154 ml versus 651 +/- 323 ml at day 1, p < 0.01). The haemoglobin concentration was higher in Group A than in Group B (11.9 +/- 1.6 g/100 ml versus 10.3 +/- 1.4 g/100 ml, p < 0.001) and fewer patients required blood transfusion (Group A: 16% versus Group B: 43%, p = 0.04). In conclusion, high doses of aprotinin given to patients on aspirin therapy undergoing coronary bypass surgery, significantly reduce postoperative blood loss and the number of patients transfused.

Characterization of enteroadherent-aggregative Escherichia coli, a putative agent of diarrheal disease

Escherichia coli that exhibit the aggregative pattern of adherence to HEp-2 cells (enteroadherent-aggregative E. coli [EA-AggEC]) have been epidemiologically incriminated as a cause of diarrhea. We undertook a preliminary microbiological and pathogenetic characterization of 42 isolates of this putative pathogen. The strains were negative by tests with DNA probes for enteropathogenic, enterotoxigenic, enteroinvasive, and enterohemorrhagic E. coli and, by serotype, did not fit these categories. Thirty-nine of 42 strains had a 55-65-megadalton plasmid; many shared DNA homology. With one representative strain, plasmid transfer was accompanied by transfer of smooth lipopolysaccharide, fimbriae expression, and the aggregative property. EA-AggEC caused characteristic lesions in rabbit and rat ileal loops. The intestinal lesions and (Shiga-like) limb paralysis and death in rabbits inoculated with live organisms suggest toxin involvement; assays for Shiga-like toxins were negative. These preliminary results support the contention that EA-AggEC may represent a distinct category of diarrheagenic E. coli.

Involucrin expression in cervical intraepithelial neoplasia: a critical evaluation

Involucrin is a keratinocyte envelope protein precursor which is synthesized at an early stage of differentiation in normal squamous epithelium. Recent studies suggest that this protein may be a marker for neoplastic epithelium. To address this issue, we analyzed involucrin expression in 105 biopsies containing 119 areas of normal, condylomatous, and neoplastic epithelium. Overall, 88, 75, and 55% of condylomata, well-differentiated CIN, and poorly differentiated CIN (carcinoma in situ) contained positive staining for involucrin. Excluding lesions with severe inflammation, 100, 88, and 55% of these lesions, respectively, were positive. Staining patterns in neoplastic lesions differed from those in the normal epithelium and condylomata; the staining in CIN tended to be focal, and intensity of staining varied widely from cell to cell in all layers of the epithelium. In high grade CIN, staining correlated with increases in cell size and cytoplasmic differentiation. These studies suggest that involucrin will not differentiate between lesions of low versus high risk for progressing to invasive carcinoma. However, the patterns of involucrin expression confirm the marked differences in patterns of cellular differentiation between classical condylomata and CIN.