"Triple-low" radiation dose bronchial artery CT angiography before bronchial artery embolisation: a feasibility study

AIM

To explore the feasibility of a "triple-low" dose (low tube voltage, low tube current, and low contrast agent volume) bronchial artery computed tomography (CT) angiography (CTA) to replace routine dose bronchial artery CTA before bronchial artery embolisation (BAE).

MATERIALS AND METHODS

CTA was obtained from 60 patients with body mass index (BMI) < 30 kg/m2 using a 256 multi-section iCT system, and they were divided into two groups: (1) group A: 100 kVp, 100 mAs, 50 ml contrast medium (CM); (2) group B: 120 kVp, automatic tube current modulation (ACTM), 80 ml CM. CT attenuation of the thoracic aorta, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated, and subjective image quality scores and traceability scores assessed. The effective radiation dose was calculated.

RESULTS

The radiation dose was reduced by 79.7% in group A compared to group B (p<0.05). The CT attenuation of the thoracic aorta was increased by approximately 13% in group A compared to group B (p<0.05). Higher image noise, lower SNR, and CNR were obtained in group A compared to group B (all p<0.05). Both subjective image quality scores and traceability scores did not differ between groups A and B (both p>0.05).

CONCLUSION

It is feasible to use the "triple-low" dose CTA protocol for patients with a body mass index (BMI) < 30 kg/m2. The radiation dose was reduced by 79.7%, and the dose of contrast medium was reduced by 37.5% to ensure the diagnostic value.

Correlation between retinal vein pulse amplitude, estimated intracranial pressure, and postural change

Spaceflight associated neuro-ocular syndrome (SANS) is common amongst astronauts on long duration space missions and is associated with signs consistent with elevated cerebrospinal fluid (CSF) pressure. Additionally, CSF pressure has been found to be elevated in a significant proportion of astronauts in whom lumbar puncture was performed after successful mission completion. We have developed a retinal photoplethysmographic technique to measure retinal vein pulsation amplitudes. This technique has enabled the development of a non-invasive CSF pressure measurement apparatus. We tested the system on healthy volunteers in the sitting and supine posture to mimic the range of tilt table extremes and estimated the induced CSF pressure change using measurements from the CSF hydrostatic indifferent point. We found a significant relationship between pulsation amplitude change and estimated CSF pressure change (p < 0.0001) across a range from 2.7 to 7.1 mmHg. The increase in pulse amplitude was highest in the sitting posture with greater estimated CSF pressure increase (p < 0.0001), in keeping with physiologically predicted CSF pressure response. This technique may be useful for non-invasive measurement of CSF pressure fluctuations during long-term space voyages.

Non-viral precision T cell receptor replacement for personalized cell therapy

T cell receptors (TCRs) enable T cells to specifically recognize mutations in cancer cells1-3. Here we developed a clinical-grade approach based on CRISPR-Cas9 non-viral precision genome-editing to simultaneously knockout the two endogenous TCR genes TRAC (which encodes TCRα) and TRBC (which encodes TCRβ). We also inserted into the TRAC locus two chains of a neoantigen-specific TCR (neoTCR) isolated from circulating T cells of patients. The neoTCRs were isolated using a personalized library of soluble predicted neoantigen-HLA capture reagents. Sixteen patients with different refractory solid cancers received up to three distinct neoTCR transgenic cell products. Each product expressed a patient-specific neoTCR and was administered in a cell-dose-escalation, first-in-human phase I clinical trial ( NCT03970382 ). One patient had grade 1 cytokine release syndrome and one patient had grade 3 encephalitis. All participants had the expected side effects from the lymphodepleting chemotherapy. Five patients had stable disease and the other eleven had disease progression as the best response on the therapy. neoTCR transgenic T cells were detected in tumour biopsy samples after infusion at frequencies higher than the native TCRs before infusion. This study demonstrates the feasibility of isolating and cloning multiple TCRs that recognize mutational neoantigens. Moreover, simultaneous knockout of the endogenous TCR and knock-in of neoTCRs using single-step, non-viral precision genome-editing are achieved. The manufacture of neoTCR engineered T cells at clinical grade, the safety of infusing up to three gene-edited neoTCR T cell products and the ability of the transgenic T cells to traffic to the tumours of patients are also demonstrated.

Neoantigen-targeted CD8+ T cell responses with PD-1 blockade therapy

Neoantigens are peptides derived from non-synonymous mutations presented by human leukocyte antigens (HLAs), which are recognized by antitumour T cells1-14. The large HLA allele diversity and limiting clinical samples have restricted the study of the landscape of neoantigen-targeted T cell responses in patients over their treatment course. Here we applied recently developed technologies15-17 to capture neoantigen-specific T cells from blood and tumours from patients with metastatic melanoma with or without response to anti-programmed death receptor 1 (PD-1) immunotherapy. We generated personalized libraries of neoantigen-HLA capture reagents to single-cell isolate the T cells and clone their T cell receptors (neoTCRs). Multiple T cells with different neoTCR sequences (T cell clonotypes) recognized a limited number of mutations in samples from seven patients with long-lasting clinical responses. These neoTCR clonotypes were recurrently detected over time in the blood and tumour. Samples from four patients with no response to anti-PD-1 also demonstrated neoantigen-specific T cell responses in the blood and tumour to a restricted number of mutations with lower TCR polyclonality and were not recurrently detected in sequential samples. Reconstitution of the neoTCRs in donor T cells using non-viral CRISPR-Cas9 gene editing demonstrated specific recognition and cytotoxicity to patient-matched melanoma cell lines. Thus, effective anti-PD-1 immunotherapy is associated with the presence of polyclonal CD8+ T cells in the tumour and blood specific for a limited number of immunodominant mutations, which are recurrently recognized over time.

A global perspective on bacterial diversity in the terrestrial deep subsurface

While recent efforts to catalogue Earth's microbial diversity have focused upon surface and marine habitats, 12-20 % of Earth's biomass is suggested to exist in the terrestrial deep subsurface, compared to ~1.8 % in the deep subseafloor. Metagenomic studies of the terrestrial deep subsurface have yielded a trove of divergent and functionally important microbiomes from a range of localities. However, a wider perspective of microbial diversity and its relationship to environmental conditions within the terrestrial deep subsurface is still required. Our meta-analysis reveals that terrestrial deep subsurface microbiota are dominated by Betaproteobacteria, Gammaproteobacteria and Firmicutes, probably as a function of the diverse metabolic strategies of these taxa. Evidence was also found for a common small consortium of prevalent Betaproteobacteria and Gammaproteobacteria operational taxonomic units across the localities. This implies a core terrestrial deep subsurface community, irrespective of aquifer lithology, depth and other variables, that may play an important role in colonizing and sustaining microbial habitats in the deep terrestrial subsurface. An in silico contamination-aware approach to analysing this dataset underscores the importance of downstream methods for assuring that robust conclusions can be reached from deep subsurface-derived sequencing data. Understanding the global panorama of microbial diversity and ecological dynamics in the deep terrestrial subsurface provides a first step towards understanding the role of microbes in global subsurface element and nutrient cycling.

Intrauterine Bigatti Shaver (IBS ® ) successful placental remnants removal, after caesarean section for a cervical pregnancy with placenta accreta

Placenta accreta located in a caesarean section scar is difficult to remove. The Intrauterine Bigatti Shaver (IBS®) has already been proven to be effective in placental remnant removal. Our case report highlights that the IBS® is also a safe method to remove placental remnants attached to a previous caesarean section scar performed for a cervical pregnancy and associated with placenta accreta.

A bioinspired scaffold for rapid oxygenation of cell encapsulation systems

Inadequate oxygenation is a major challenge in cell encapsulation, a therapy which holds potential to treat many diseases including type I diabetes. In such systems, cellular oxygen (O2) delivery is limited to slow passive diffusion from transplantation sites through the poorly O2-soluble encapsulating matrix, usually a hydrogel. This constrains the maximum permitted distance between the encapsulated cells and host site to within a few hundred micrometers to ensure cellular function. Inspired by the natural gas-phase tracheal O2 delivery system of insects, we present herein the design of a biomimetic scaffold featuring internal continuous air channels endowed with 10,000-fold higher O2 diffusivity than hydrogels. We incorporate the scaffold into a bulk hydrogel containing cells, which facilitates rapid O2 transport through the whole system to cells several millimeters away from the device-host boundary. A computational model, validated by in vitro analysis, predicts that cells and islets maintain high viability even in a thick (6.6 mm) device. Finally, the therapeutic potential of the device is demonstrated through the correction of diabetes in immunocompetent mice using rat islets for over 6 months.

Abstract 2177: Tumor neoantigen profiling with validated patient-specific TCR characterization to improve neoepitope prediction

PACT Pharma has developed an ultra-sensitive approach to validate predicted neoantigens and the cognate T cell receptors (neoTCRs) from tumor specific somatic mutations by capturing neoantigen-specific T cells from peripheral blood. This process is used in clinical trials (NCT03970382) of personalized neoTCR-T therapy for persons with solid cancers.

Using the state of the art prediction pipeline and screening process, more than one hundred twenty neoantigens were predicted from 5 type of solid cancers that were validated by characterizing cognate T cells and their close to 200 unique TCRs captured from the blood of the same individual. These validated neoepitopes of 8 to 11 amino acids represent broad HLA class I coverage with &gt;30 alleles to date. Our analysis revealed that mutations can occur in all positions within the epitopes. Epitope immunogenicity is potentially affected by different mechanisms including mutation position, agretopicity, as well as HLA interacting positions and/or by interactions between mutated residues and its cognate TCRs. It was observed that these validated neoepitopes comprise broad ranges of predicted HLA binding affinities, stability, and neoantigen expression levels. The analysis presented here offers insights to enable machine learning to advance rules for epitope selection and prioritization that may be important for immunological approaches to address a broad range of diseases, including cancer.

Citation Format: Zheng Pan, Olivier Dalmas, Songming Peng, Kyle Jacoby, Barbara Sennino, Yan Ma, Chad Smith, Amin Momin, Allison Xu, Katharine Heeringa, Jonathan Johnston, Duo An, Boi Quach, William Lu, Diana Nguyen, Andrew Conroy, Bhamini Purandare, Eva Huang, Eric Stawiski, Alex Franzusoff, Stefanie Mandl. Tumor neoantigen profiling with validated patient-specific TCR characterization to improve neoepitope prediction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2177.

Complete genome sequence and genetic organization of a Garlic virus D infecting garlic (Allium sativum) from northern India

The present paper describes first full genome sequence of the Garlic virus D (GarV-D) from northern India with a genome size of 8425 bp long ssRNA. The infected leaves and bulbs of garlic variety Yamuna Safed (G-282) plants suspected for GarV-D infection were collected with the aim to identify contagion virus during March, 2018. The total RNA was extracted from the pooled garlic plants using TRIzol reagent and sequenced using an Illumina HiSeq 2000 platform. BLASTn search in the NCBI database identified contagion as GarV-D (MK518067). It shared 83.63-85.83% nucleotide sequence identities with other (GarV-D) isolates from Argentina (KF550407, KF555653, KR819505) and 83.15% with isolates from China (MF795136, MF363012). Keywords: Allium sativum; Allexivirus; Garlic virus D; India.

Dynamic DNA material with emergent locomotion behavior powered by artificial metabolism

Metabolism is a key process that makes life alive-the combination of anabolism and catabolism sustains life by a continuous flux of matter and energy. In other words, the materials comprising life are synthesized, assembled, dissipated, and decomposed autonomously in a controlled, hierarchical manner using biological processes. Although some biological approaches for creating dynamic materials have been reported, the construction of such materials by mimicking metabolism from scratch based on bioengineering has not yet been achieved. Various chemical approaches, especially dissipative assemblies, allow the construction of dynamic materials in a synthetic fashion, analogous to part of metabolism. Inspired by these approaches, here, we report a bottom-up construction of dynamic biomaterials powered by artificial metabolism, representing a combination of irreversible biosynthesis and dissipative assembly processes. An emergent locomotion behavior resembling a slime mold was programmed with this material by using an abstract design model similar to mechanical systems. Dynamic properties, such as autonomous pattern generation and continuous polarized regeneration, enabled locomotion along the designated tracks against a constant flow. Furthermore, an emergent racing behavior of two locomotive bodies was achieved by expanding the program. Other applications, including pathogen detection and hybrid nanomaterials, illustrated further potential use of this material. Dynamic biomaterials powered by artificial metabolism could provide a previously unexplored route to realize "artificial" biological systems with regenerating and self-sustaining characteristics.

Abstract NG11: Landscape analysis of neoepitope-specific T-cell responses to immunotherapy

In infectious disease, polyclonal T cell responses against immunodominant epitopes drive successful immune responses. In cancer, neoepitopes (neoE) derived from non-synonymous mutations, similarly to the immunodominant epitopes in viral infections, are potentially highly immunogenic because the T cells recognizing these antigens are not subjected to the mechanisms of tolerance. Indeed, early studies support that neoE derived from non-synonymous mutations are the primary target of T cell responses induced by immune checkpoint blockade therapy and have been successfully targeted by adoptively transferred T cell therapies (ACT) in multiple cancer histologies. However, there is limited knowledge on the immunodominance and evolution of neoE's, or the clonality of the T cell responses against these neoE. Furthermore, little is known regarding the correlation between the presence and expansion of neoE-specific T cells and the clinical response to immunotherapy in patients. To characterize the neoE-specific T cell responses induced after immunotherapy, we collected peripheral blood mononuclear cells (PBMCs) over time (longitudinally) and established expanded tumor infiltrating lymphocyte cultures (TILs) and autologous tumor cell lines from the patient's tumor biopsies. We performed whole exome and RNA sequencing of the tumor and normal tissue controls for the computational prediction and ranking of patient-specific neoEs. We then generated a library of capture reagents consisting of the patient HLA class I molecules loaded with predicted neoE (Peng et al. AACR 2019) and isolated neoE-specific T cells from the patients' PBMC or TIL samples. Once isolated, the paired neoE-specific TCR alpha and beta chains (neoTCR) were obtained by single cell sequencing. For functional characterization of the neoTCRs, healthy donor primary human T cells were modified to express the neoTCR using CRISPR-based, non-viral precision genome engineering by replacing the endogenous TCR with the respective neoTCR (Jacoby et al., AACR 2019, Sennino et al., AACR 2019). These gene-edited T cells were then used in co-culture experiments with the patient autologous cell lines. We analyzed T cell responses in three patients (PT1, PT2, and PT3) with metastatic melanoma receiving immunotherapy. PT1 had a fast and durable anti-tumor response to anti-PD-1 therapy. Sequencing identified 2556 somatic coding mutations. A library of 243 neoE-specific pMHC capture reagents across 3 HLA types, HLA-A*03:01, A*24:01, and C*12:03 was generated and used for screening of PBMCs or TILs derived from multiple longitudinal time points. Several hundred neoE-specific T cells were isolated. Importantly, this neoE-specific T cell response was comprised of 17 different neoE-specific T cells clones targeting only 5 different HLA-neoE complexes supporting the immunodominance hypothesis. On the other hand, PT2 and PT3 showed marginal responses to immunotherapy. Patient two progressed after being treated with anti-PD1. This patient had 24 somatic coding mutations. Seventeen neoE-HLA reagents across 3 HLAs, B*35:03, C*12:03, and C*08:01 were generated and used to capture neoE-specific T cells from TILs and PBMCs. While 14 different TCRs targeting 7 HLA-neoE complexes were identified from expanded TILs, no neoE-reactive T cells were captured from the peripheral blood. PT3 presented with progressive disease after being treated with local TVEC. This patient had 61 somatic coding mutations; 78 neoE-specific pHLA capture reagents covering HLA-A*02:01, A*03:01, B*07:02, C*05:01, and C*07:02 were generated and used to screen for neoE-specific T cells in the patient's TIL and PBMCs. In contrast to PT2, 2 different neoTCRs targeting the same HLA-neoE complexes were isolated from PBMCs, but none from TILs. To further characterize the T cell responses from patients that responded or did not respond to immunotherapy, we generated 18 separate T cell products, each expressing a different neoTCR isolated from PT1, PT2 and PT3. For PT1, we characterized 14 different neoTCRs specific for neoE's in the mutated IL8, PUM1 and TPP2 genes. All 14 T cell products displayed specific cytotoxicity against the matched autologous melanoma cell line established from a biopsy of patient one (50-75% tumor growth inhibition compared to melanoma cell line growth in co-culture with a mismatched control TCR, 96 hour assay using a product to target ratio (P:T) of 1:1, p &lt; 0.000001 for each comparison). No cytotoxic effect against an unmatched human melanoma cell line was observed. Furthermore, neoE TCR T cells upregulated 4-1BB and OX-40, secreted IFNγ, IL-2, TNFα, and IL6, and induced T cell proliferation and degranulation. Again, no unspecific T cell activation was observed when T cells were co-cultured with unmatched targets. Interestingly, precision genome engineered T cell products expressing neoTCRs identified from patients that did not respond to therapy (PT2 and PT3), also potently killed autologous tumor cells. Four neoTCRs were studied (2 TCR for PT2 and 2 TCRs for PT3), and three of them showed specific cytotoxicity against the matched autologous melanoma cell line (50-100% tumor growth inhibition compared to melanoma cell line growth in co-culture with a mismatched control TCR, 96 hour assay using P:T 5:1, p &lt; 0.05 for each comparison). Additionally, upon co-culture with the matched melanoma cell line, but not against an unmatched melanoma cell line control, neoE TCR T cells upregulated 4-1BB and OX-40, secreted IFNγ, IL-2, TNFα, and IL6, and induced T cell proliferation and degranulation. These data demonstrate that even patients that did not respond to immunotherapy harbor neoTCRs that, when expressed in ‘fresh' T cells, are able to kill the autologous tumor cell lines. Using newly developed techniques to isolate and capture neoE-specific single T cells, as well as non-viral gene editing, we isolated and characterized neoE-specific T cells that can recognize the cancer cells and induce an anti-tumor response. We also studied the neoE immunodominance and TCR clonality over time of the natural T cell repertoire that induce anti-tumor responses to ICB therapy. Our results show that in a patient with a good response to anti-PD-1, there is a polyclonal response that targets a limited number of neoE-HLA complexes (2% of the neoE tested in the case of patient one) highlighting the immunodominance of these epitopes. Interestingly, different T cell clonotypes targeting the same mutations evolve over time, suggesting functional differences amongst the TCRs. In addition, our results demonstrate that even patients that did not respond to these therapies harbor neoE-specific T cells, as we were able to isolate neoE-specific T cells that recognized and killed patient-derived cancer cells. This suggests that even in patients that do not respond to immunotherapy, neoE-specific TCRs can be isolated and could be potentially used for personalized ACT. Finally, our results also show how non-viral precision genome engineering can successfully redirect T cells to neoE-expressing tumors, enabling the personalized ACT.

Citation Format: Cristina Puig-Saus, Barbara Sennino, Bhamini Purandare, Duo An, Boi Quach, Songming Peng, Huiming Xia, Sidi Zhao, Zheng Pan, Yan Ma, Justin Saco, Sameeha Jilani, Christine Shieh, Katharine Heeringa, Olivier Dalmas, Robert Moot, Diana Nguyen, William Lu, Kyle Jacoby, Andrew Conroy, Jasreet Hundal, Malachi Griffith, Stefanie Mandl, Alex Franzusoff, Antoni Ribas. Landscape analysis of neoepitope-specific T-cell responses to immunotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr NG11.

Abstract 3253: A high-throughput platform to produce neoE-HLA libraries for capturing neoE-specific T cells from the peripheral blood of patients with solid tumors

A critical step in the development of personalized neoTCR-T cell therapies is operational selection of tumor-exclusive neoantigen peptide targets (neoepitopes or neoE) presented by each person's own HLA proteins (neoE-HLA targets). We have developed a high-throughput, automated process for the cloning, expression and purification of soluble proteins comprising neoE peptide with beta2m and the HLA heavy chain fused into a single polypeptide (neoE-HLA proteins).

Of the 13 thousand HLA alleles in the human population, with 6 HLA alleles expressed in each person, our HLA catalog enables rapid production of neoE-HLA protein candidate libraries, representing &gt;4 of 6 HLAs for ≥95% of all patients, regardless of ethnicity. We apply our proprietary bioinformatics pipeline to predict and prioritize tumor-exclusive neoE-HLA candidates for each patient. We then generate neoE-HLA libraries in single production runs for up to several hundred neoE-HLA candidates per patient. These soluble neoE-HLA proteins are then assembled into barcoded snare multimers. These barcoded snare libraries are used to interrogate matched PBMCs from that patient to capture rare (&gt;1 per 106) to abundant antigen-experienced CD8 T cells which specifically bind the cognate neoE-HLA tumor targets, using the imPACT Isolation Technology®.

This platform is capable of producing barcoded snares predicted to represent high affinity (≤500 nM) and low affinity (&gt;500nM) neoE binding to their cognate HLAs. These capabilities permit deep and broad interrogation of the tumor-targeted neoE-specific T cell repertoire in the blood of patients with solid cancers. Data shown here demonstrate that &gt;85% of patients with different cancer types, indeed, harbor a surprising repertoire of tumor-targeted neoE-specific T cells. These antigen-experienced T cells reveal the pre-existing immune response to each person's cancer, and how that repertoire evolves in longitudinal analyses of patients that respond/do not respond to their cancer therapies.

In summary, PACTs proprietary neoE-HLA prediction pipeline and the proprietary high-throughput neoE-HLA protein production platform enables the discovery of tumor-targeted, neoE-specific T cells from patients. We leverage the neoTCRs cloned from these captured T cells to engineer fresh T cells from the patient into a full dose of tumor-targeted personalized neoTCR-T cells (NeoTCR-P1 T cell therapy). This fully personalized NeoTCR-P1 cell therapy is manufactured in fully enclosed, automatable systems for each individual patient with solid tumors. These breakthrough technologies support the on-going Phase 1 clinical trial of personalized engineered autologous NeoTCR-P1 T cell therapies for patients with six different solid tumor types (NCT03970382).

Citation Format: Olivier Dalmas, Zheng Pan, Christine Shieh, Allison Xu, Jason Kwa, Katharine Heeringa, Yan Ma, John Collins, Duo An, Songming Peng, Alex Franzusoff. A high-throughput platform to produce neoE-HLA libraries for capturing neoE-specific T cells from the peripheral blood of patients with solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3253.

[Non-suicidal self-injury and exposure to suicidal behaviors among Chinese adolescents: a longitudinal study]

Objective: Non-suicidal self-injury (NSSI) in adolescents appeared prevalent and multifactorial. This study was to examine the associations between exposure to suicidal behaviors and NSSI in the Chinese adolescents. Methods: Participants included for analyses were 5 154 adolescent students who participated in the baseline survey in 2015 and the first follow-up survey in 2016 of the Shandong Adolescent Behavior and Health Cohort, but with no history of NSSI at the baseline survey. A self-administered structured questionnaire was used to collect data on demographics, behavioral and emotional problems, lifetime and last-year NSSI. Data on the history of exposure to suicide attempt or death of a family member, friend, or close acquaintance were also collected. Multivariate logistic regression methods were used to examine the associations between exposure to suicidal behaviors and NSSI. Results: In the baseline survey, mean age of the 5 154 participants was (14.49±1.48) years, with 48.5% of the participants as girls. Of the participants, 9.0% reported having been exposed to suicidal behaviors, including 6.0% reported to suicide attempt, 4.9% to suicide death, 7.3% to suicidal behaviors of friends/close acquaintances, and 3.1% to suicidal behaviors of relatives. The prevalence rates of NSSI in the last year were significantly higher in adolescents who had been exposed to suicidal behaviors than those who had not (P<0.05). Results from the multivariate logistic regressions showed that exposure to suicide death (OR=1.91, 95%CI: 1.22-3.01) or to suicidal behaviors of relatives (OR=1.79, 95%CI: 1.02-3.12) were both significantly associated with the increased risk of NSSI. Conclusions: Experiences related to exposure to suicide-death or suicidal behaviors of relatives were associated with increased risk of NSSI in adolescents. After the suicide events, psychological counseling and health education programs set for high-risk groups were helpful in promoting physical and mental health and preventing the attempt of self-injury in teenagers.

An Atmosphere-Breathing Refillable Biphasic Device for Cell Replacement Therapy

Cell replacement therapy is emerging as a promising treatment platform for many endocrine disorders and hormone deficiency diseases. The survival of cells within delivery devices is, however, often limited due to low oxygen levels in common transplantation sites. Additionally, replacing implanted devices at the end of the graft lifetime is often unfeasible and, where possible, generally requires invasive surgical procedures. Here, the design and testing of a modular transcutaneous biphasic (BP) cell delivery device that provides enhanced and unlimited oxygen supply by direct contact with the atmosphere is presented. Critically, the cell delivery unit is demountable from the fixed components of the device, allowing for surgery-free refilling of the therapeutic cells. Mass transfer studies show significantly improved performance of the BP device in comparison to subcutaneous controls. The device is also tested for islet encapsulation in an immunocompetent diabetes rodent model. Robust cell survival and diabetes correction is observed following a rat-to-mouse xenograft. Lastly, nonsurgical cell refilling is demonstrated in dogs. These studies show the feasibility of this novel device for cell replacement therapies.

Zwitterionically modified alginates mitigate cellular overgrowth for cell encapsulation

Foreign body reaction (FBR) to implanted biomaterials and medical devices is common and can compromise the function of implants or cause complications. For example, in cell encapsulation, cellular overgrowth (CO) and fibrosis around the cellular constructs can reduce the mass transfer of oxygen, nutrients and metabolic wastes, undermining cell function and leading to transplant failure. Therefore, materials that mitigate FBR or CO will have broad applications in biomedicine. Here we report a group of zwitterionic, sulfobetaine (SB) and carboxybetaine (CB) modifications of alginates that reproducibly mitigate the CO of implanted alginate microcapsules in mice, dogs and pigs. Using the modified alginates (SB-alginates), we also demonstrate improved outcome of islet encapsulation in a chemically-induced diabetic mouse model. These zwitterion-modified alginates may contribute to the development of cell encapsulation therapies for type 1 diabetes and other hormone-deficient diseases.

Engineering transferrable microvascular meshes for subcutaneous islet transplantation

The success of engineered cell or tissue implants is dependent on vascular regeneration to meet adequate metabolic requirements. However, development of a broadly applicable strategy for stable and functional vascularization has remained challenging. We report here highly organized and resilient microvascular meshes fabricated through a controllable anchored self-assembly method. The microvascular meshes are scalable to centimeters, almost free of defects and transferrable to diverse substrates, ready for transplantation. They promote formation of functional blood vessels, with a density as high as ~220 vessels mm-2, in the poorly vascularized subcutaneous space of SCID-Beige mice. We further demonstrate the feasibility of fabricating microvascular meshes from human induced pluripotent stem cell-derived endothelial cells, opening a way to engineer patient-specific microvasculature. As a proof-of-concept for type 1 diabetes treatment, we combine microvascular meshes and subcutaneously transplanted rat islets and achieve correction of chemically induced diabetes in SCID-Beige mice for 3 months.

P343Comparison of Focal Impulse and Rotor Modulation Ablation (FIRM) only versus second-generation cyroballoon ablation in patients with paroxysmal atrial fibrillation

Background

Rotors have been postulated to be a major driver of atrial fibrillation (AF). Initial studies demonstrated, that focal impulse and rotor modulation (FIRM) might be an effective therapy for the treatment of paroxysmal AF (PAF). However, data about FIRM-guided ablation strategies without PVI is sparse.

Objective

To compare the safety and efficacy of FIRM-guided catheter ablation (without PVI; FIRM arm) and second generation cryoballoon (CB2, CB2 arm) based PVI in patients with paroxysmal atrial fibrillation (PAF) and de-novo catheter ablation of AF.

Methods

In this retrospective single-center study patients with PAF undergoing de-novo ablation of PAF between February 2016 and January 2017 were enrolled. Patients treated with FIRM-guided AF ablation as a standalone therapy without PVI were included and compared with patients undergoing CB2 based PVI. All patients in the FIRM arm were part of the randomized multicenter FIRMAP AF trial (results of this trial will be presented at this meeting). In patients undergoing FIRM-guided ablation, 3D electroanatomical mapping of both atria was performed. Rotor mapping using FIRM technology was conducted in spontaneous or induced AF. The procedural endpoint was the elimination of all rotors and focal impulses; no PVI was performed in those patients. In the CB2 arm, CB based PVI with the procedural endpoint of isolation of all veins was performed. Procedural data and arrhythmia-free survival after 12 months were compared.

Results

FIRM-guided and CB2 based AF ablation was performed in 22 and 86 patients, respectively. Follow up was completed in 20 and 79 patients LA diameter differed between groups. Otherwise, baseline characteristics did not differ between the FIRM group (mean age 60±11 years, 59.1% males) and the CB2 group (mean age 62±13, 62.4% male).

Arrhythmia-free survival including a 90-day blanking period was 25.0% (15/20) in the FIRM group and 86.1% (11/79) in the CB2 PVI group (p=0.000; Figure 1). Procedure duration was significantly longer in the FIRM group (152 [120; 176] minutes) compared to the CB2 PVI group (122 [110; 145] minutes) (p=0.031), whereas radiation dose was lower in the FIRM group (1266 [1027; 2281] cGy·cm2 vs. 3020 [1677; 4215] cGy·cm2). Adverse events (groin complications) occurred in 1 patient (1.2%) in the CB2 PVI group and 5 patients (22.7%) in the FIRM group.

Figure 1. Kaplan-Meier-survival curve dem

Conclusion

De novo ablation of PAF using a FIRM-guided AF ablation only (without PVI) is associated with poor arrhythmia-free survival after 12 months compared to CB2 PVI. These results underline the importance of PVI as the first-line approach in catheter ablation of AF.

Abstract 4042: Longitudinal monitoring of neoepitope-specific T cell repertoires in patient blood following cancer immunotherapy

T cells targeting neoepitopes derived from mutations exclusive to the tumor are one of the main drivers of cancer immunotherapy efficacy. Tracking these neoepitope-specific T cells during cancer immunotherapy has been hampered by the impracticality of repeated sampling from the tumor, and by the low frequency of neoepitope-specific T cells in peripheral blood. An ultra-sensitive and high-throughput technology (imPACT) has been developed for the identification and isolation of neoepitope-specific T cells from peripheral blood. Subjects with colorectal cancer, endometrial adenocarcinoma, nasopharyngeal carcinoma and other solid tumors were treated with AB122 (anti-PD-1 antibody) as part of an ongoing dose-escalation clinical trial. Pre-treatment blood samples were analyzed to identify the basal repertoire of neoepitope-specific T cells. Evolution of this repertoire during AB122 treatment was monitored to enable immune phenotyping and correlation with clinical outcomes. In addition, transcriptional profile changes were monitored at the single-cell level for each neoepitope-specific T cell. These data will enable us to analyze T cells targeting neoepitopes and identify driver mutations that correlate with and may be responsible for therapeutic benefit. More broadly, this platform technology promises to significantly advance our understanding of T cell-mediated mechanisms of cancer immunotherapy.

Citation Format: Songming Peng, Benjamin Yuen, Joanne Tan, Fangfang Yin, Robert Bao, Zheng Pan, Olivier Dalmas, Duo An, Boi Quach, Michael Yi, Michael Bethune, Stefanie Mandl, Matt Walters, Juan Jaen, Alex Franzusoff. Longitudinal monitoring of neoepitope-specific T cell repertoires in patient blood following cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4042.

Abstract 1435: An ultra-sensitive and high-throughput technology (imPACT) for the identification and isolation of intrinsic and emergent neoepitope-specific T cells from the peripheral blood and TILs of cancer patients

T cells capable of targeting neoepitopes (neoE) from tumor-specific mutations hold the potential to uniquely recognize and kill tumor cells. However, most cancer patients fail to mount a sufficient intrinsic T cell immune response to translate into clinical benefit. PACT Pharma has developed an ultra-sensitive and high-throughput technology (imPACT) for identifying and isolating neoE-specific T cells from peripheral blood. Whole exome sequencing of tumors and computational prediction identify patient-specific neoepitopes resulting from tumor-specific mutations. We then interrogate patient blood for neoE-specific T cells using human leukocyte antigen (HLA) protein-based reagents comprising a spectrum of human HLAs, thus enabling the evaluation of &gt;99% of all individuals with cancer. We have identified and isolated neoE-specific T cells from the peripheral blood of &gt;80% treatment-naive patients with bladder and colorectal cancers, melanoma and other solid tumors. Primary human T cells engineered with T cell receptor sequences (TCRs) cloned from the imPACT-isolated T cells gain the ability to kill cognate neoE-presenting tumor cells, thereby also confirming the specificity of the isolated TCR sequences to bind to the neoE target. This approach is also amenable to the longitudinal analysis of patients undergoing treatment for their cancers, to characterize the neoE-specific T cell populations likely to confer clinical benefit. In summary, the imPACT technology efficiently discovers potentially meaningful intrinsic neoE-specific TCRs from patients, enabling the development of personalized neoTCR-T cell therapies for the eradication of solid tumors.

Citation Format: Songming Peng, Boi Quach, Duo An, Salemiz Sandoval, Robert Bao, Zheng Pan, Michael Bethune, Olivier Dalmas, Michael Yi, Corey Meadows, Katherine Heeringa, Linlin Guo, Benjamin yuen, John Sorfleet, Kyle Jacoby, Robert Moot, William Lu, Diana Nguyen, Barbara Sennino, Andrew Conroy, Bhamini Purandare, Adam Litterman, Stefanie Mandl, Alex Franzusoff. An ultra-sensitive and high-throughput technology (imPACT) for the identification and isolation of intrinsic and emergent neoepitope-specific T cells from the peripheral blood and TILs of cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1435.

Physical confinement induces malignant transformation in mammary epithelial cells

The physical microenvironment of tumor cells plays an important role in cancer initiation and progression. Here, we present evidence that confinement - a new physical parameter that is apart from matrix stiffness - can also induce malignant transformation in mammary epithelial cells. We discovered that MCF10A cells, a benign mammary cell line that forms growth-arrested polarized acini in Matrigel, transforms into cancer-like cells within the same Matrigel material following confinement in alginate shell hydrogel microcapsules. The confined cells exhibited a range of tumor-like behaviors, including uncontrolled cellular proliferation and invasion. Additionally, 4-6 weeks after transplantation into the mammary fad pads of immunocompromised mice, the confined cells formed large palpable masses that exhibited histological features similar to that of carcinomas. Taken together, our findings suggest that physical confinement represents a previously unrecognized mechanism for malignancy induction in mammary epithelial cells and also provide a new, microcapsule-based, high throughput model system for testing new breast cancer therapeutics.

Toll-like receptors TLR2 and TLR4 block the replication of pancreatic β cells in diet-induced obesity

Consumption of a high-energy Western diet triggers mild adaptive β cell proliferation to compensate for peripheral insulin resistance; however, the underlying molecular mechanism remains unclear. In the present study we show that the toll-like receptors TLR2 and TLR4 inhibited the diet-induced replication of β cells in mice and humans. The combined, but not the individual, loss of TLR2 and TLR4 increased the replication of β cells, but not that of α cells, leading to enlarged β cell area and hyperinsulinemia in diet-induced obesity. Loss of TLR2 and TLR4 increased the nuclear abundance of the cell cycle regulators cyclin D2 and Cdk4 in a manner dependent on the signaling mediator Erk. These data reveal a regulatory mechanism controlling the proliferation of β cells in diet-induced obesity and suggest that selective targeting of the TLR2/TLR4 pathways may reverse β cell failure in patients with diabetes.

Cortical thinning in epilepsy patients with postictal generalized electroencephalography suppression

BACKGROUND AND PURPOSE

The aim was to investigate the brain microstructural abnormalities in epilepsy patients with postictal generalized electroencephalographic suppression (PGES) using a cortical surface-based analysis.

METHODS

According to the video-electroencephalography records of epilepsy patients with generalized convulsive seizures, 30 patients with PGES (PGES+) and 21 patients without PGES (PGES-) were recruited. High-resolution T1-weighted images were acquired from each patient and 30 matched healthy control subjects. Cortical thickness was compared amongst the three groups using FreeSurfer software.

RESULTS

Patients with PGES showed reduced cortical thickness in the right paracentral lobule, inferior parietal lobule, supramarginal gyrus and middle temporal lobe compared with patients without PGES. In relation to healthy control subjects, the PGES+ group presented reduced cortical thickness in the right superior parietal lobule and supramarginal gyrus, whilst the PGES- group presented reduced cortical thickness in the left precuneus, precentral gyrus, lateral occipital gyrus, parahippocampal gyrus, superior parietal lobule and right caudal middle frontal gyrus.

CONCLUSIONS

Patients with PGES exhibited characteristic brain microstructural abnormalities, corroborating the PGES mechanisms at the brain level. The right-sided predominance of the detected PGES-related cortical thinning was the same as that of sudden unexpected death in epilepsy (SUDEP) cases and patients at high risk for SUDEP, implying that PGES and SUDEP may share a common abnormal brain substrate that is involved in the pathophysiology of these conditions.

Cu(II)/Proline-Catalyzed Reductive Coupling of Sulfuryl Chloride and P(O)-H for P-S-C Bond Formation

A considerably improved method for the Cu-catalyzed coupling of sulfuryl chloride with P(O)-H was described. Using commercially available l-proline as the ligand decreased the precatalyst loading, broadened the substrate scope and greatly promoted the efficiency of the coupling reaction. Moreover, gram-scale preparation, easy-to handle and recyclable catalyst featured this transformation.

Control of microbial sulfide production by limiting sulfate dispersal in a water-injected oil field

Oil production by water injection often involves the use of makeup water to replace produced oil. Sulfate in makeup water is reduced by sulfate-reducing bacteria to sulfide, a process referred to as souring. In the MHGC field souring was caused by using makeup water with 4mM (384ppm) sulfate. Mixing with sulfate-free produced water gave injection water with 0.8mM sulfate. This was amended with nitrate to limit souring and was then distributed fieldwide. The start-up of an enhanced-oil-recovery pilot caused all sulfate-containing makeup water to be used for dissolution of polymer, which was then injected into a limited region of the field. Produced water from this pilot contained 10% of the injected sulfate concentration as sulfide, but was free of sulfate. Its use as makeup water in the main water plant of the field caused injection water sulfate to drop to zero. This in turn strongly decreased produced sulfide concentrations throughout the field and allowed a decreased injection of nitrate. The decreased injection of sulfate and nitrate caused major changes in the microbial community of produced waters. Limiting sulfate dispersal into a reservoir, which acts as a sulfate-removing biofilter, is thus a powerful method to decrease souring.

Disrupted intrinsic and remote functional connectivity in heterotopia-related epilepsy

OBJECTIVES

Several neuroimaging studies have examined neural interactions in patients with periventricular nodular heterotopia (PNH). However, features of the underlying functional network remain poorly understood. In this study, we examined alterations in the local (regional) and remote (interregional) cerebral networks in this disorder.

METHODS

Twenty-eight subjects all having suffered from PNH with epilepsy, as well as 28 age- and sex- matched healthy controls, were enrolled in this study. Amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) were calculated to detect regional neural function and functional network integration, respectively.

RESULTS

Compared with healthy controls, patients with PNH-related epilepsy showed decreased ALFF in the ventromedial prefrontal cortex (vmPFC) and precuneus areas. ALFF values in both areas were negative correlated with epilepsy duration (P < .05, Bonferroni-corrected). Furthermore, patients with PNH-related epilepsy had increased remote interregional FC mainly in bilateral prefrontal and parietal cortices, supramarginal gyrus, dorsal cingulate gyrus, and right insula; lower FC was found in posterior brain regions including bilateral parahippocampal gyrus and inferior temporal gyrus.

CONCLUSIONS

Focal spontaneous hypofunction, as assessed by ALFF, correlates with epilepsy duration in patients with PNH-related epilepsy. Abnormalities existed both within the default-mode network and then across the whole brain, demonstrating that intrinsic brain dysfunction may be related to specific network interactions. Our findings provide novel understanding of the connectivity-based pathophysiological mechanisms of PNH.

Scalable Production and Cryostorage of Organoids Using Core-Shell Decoupled Hydrogel Capsules

Organoids, organ-mimicking multicellular structures derived from pluripotent stem cells or organ progenitors, have recently emerged as an important system for both studies of stem cell biology and development of potential therapeutics; however, a large-scale culture of organoids and cryopreservation for whole organoids, a prerequisite for their industrial and clinical applications, has remained a challenge. Current organoid culture systems relying on embedding the stem or progenitor cells in bulk extracellular matrix (ECM) hydrogels (e.g., Matrigel™) have limited surface area for mass transfer and are not suitable for large-scale productions. Here, we demonstrate a capsule-based, scalable organoid production and cryopreservation platform. The capsules have a core-shell structure where the core consists of Matrigel™ that supports the growth of organoids, and the alginate shell form robust spherical capsules, enabling suspension culture in stirred bioreactors. Compared with conventional, bulk ECM hydrogels, the capsules, which could be produced continuously by a two-fluidic electrostatic co-spraying method, provided better mass transfer through both diffusion and convection. The core-shell structure of the capsules also leads to better cell recovery after cryopreservation of organoids probably through prevention of intracellular ice formation.

Perilesional and contralateral white matter evolution and integrity in patients with periventricular nodular heterotopia and epilepsy: a longitudinal diffusion tensor imaging study

BACKGROUND AND PURPOSE

This study aimed to assess the evolution of perinodular and contralateral white matter abnormalities in patients with periventricular nodular heterotopia (PNH) and epilepsy.

METHODS

Diffusion tensor imaging (DTI) (64 directions) and 3 T structural magnetic resonance imaging were performed in 29 PNH patients (mean age 27.3 years), and 16 patients underwent a second scan (average time between the two scans 1.1 years). Fractional anisotropy and mean diffusivity were measured within the perilesional and contralateral white matter.

RESULTS

Longitudinal analysis showed that white matter located 10 mm from the focal nodule displayed characteristics intermediate to tissue 5 mm away, and normal-appearing white matter (NAWM) also established evolution profiles of perinodular white matter in different cortical lobes. Compared to 29 age- and sex-matched healthy controls, significant decreased fractional anisotropy and elevated mean diffusivity values were observed in regions 5 and 10 mm from nodules (P < 0.01), whilst DTI metrics of the remaining NAWM did not differ significantly from controls. Additionally, normal DTI metrics were shown in the contralateral region in patients with unilateral PNH.

CONCLUSIONS

Periventricular nodular heterotopia is associated with microstructural abnormalities within the perilesional white matter and the extent decreases with increasing distance from the nodule. In the homologous contralateral region, white matter diffusion metrics were unchanged in unilateral PNH. These findings have clinical implications with respect to the medical and surgical interventions of PNH-related epilepsy.

Effect of viral suppression on hepatic venous pressure gradient in hepatitis C with cirrhosis and portal hypertension

Portal hypertension is a predictor of liver-related clinical events and mortality in patients with hepatitis C and cirrhosis. The effect of interferon-free hepatitis C treatment on portal pressure is unknown. Fifty patients with Child-Pugh-Turcotte (CPT) A and B cirrhosis and portal hypertension (hepatic venous pressure gradient [HVPG] >6 mm Hg) were randomized to receive 48 weeks of open-label sofosbuvir plus ribavirin at Day 1 or after a 24-week observation period. The primary endpoint was sustained virologic response 12 weeks after therapy (SVR12) in patients who received ≥1 dose of treatment. Secondary endpoints included changes in HVPG, laboratory parameters, and MELD and CPT scores. A subset of patients was followed 48 weeks posttreatment to determine late changes in HVPG. SVR12 occurred in 72% of patients (33/46). In the 37 patients with paired HVPG measurements at baseline and the end of treatment, mean HVPG decreased by -1.0 (SD 3.97) mm Hg. Nine patients (24%) had ≥20% decreases in HVPG during treatment. Among 39 patients with pretreatment HVPG ≥12 mm Hg, 27 (69%) achieved SVR12. Four of the 33 (12%) patients with baseline HVPG ≥12 mm Hg had HVPG <12 mm Hg at the end of treatment. Of nine patients with pretreatment HVPG ≥12 mm Hg who achieved SVR12 and completed 48 weeks of follow-up, eight (89%) had a ≥20% reduction in HVPG, and three reduced their pressure to <12 mm Hg. Patients with chronic HCV and compensated or decompensated cirrhosis who achieve SVR can have clinically meaningful reductions in HVPG at long-term follow-up. (EudraCT 2012-002457-29).

Phase-Selective Syntheses of Cobalt Telluride Nanofleeces for Efficient Oxygen Evolution Catalysts

Cobalt-based nanomaterials have been intensively explored as promising noble-metal-free oxygen evolution reaction (OER) electrocatalysts. Herein, we report phase-selective syntheses of novel hierarchical CoTe₂ and CoTe nanofleeces for efficient OER catalysts. The CoTe₂ nanofleeces exhibited excellent electrocatalytic activity and stablity for OER in alkaline media. The CoTe₂ catalyst exhibited superior OER activity compared to the CoTe catalyst, which is comparable to the state-of-the-art RuO₂ catalyst. Density functional theory calculations showed that the binding strength and lateral interaction of the reaction intermediates on CoTe₂ and CoTe are essential for determining the overpotential required under different conditions. This study provides valuable insights for the rational design of noble-metal-free OER catalysts with high performance and low cost by use of Co-based chalcogenides.

High-water-content and resilient PEG-containing hydrogels with low fibrotic response

Hydrogels such as those based on polyethylene glycol (PEG) are broadly used in biomedicine where high water contents, robust mechanical properties such as resilience and favorable interactions with the body are often simultaneously desirable. However, the mechanical properties of conventional hydrogels often degrade rapidly after swelling or with increasing water content, limiting their potential in many applications. Here we describe a new class of PEG-containing hydrogels that remain highly resilient after maximum swelling. We achieved the hydrogels by incorporating reversible "dual" hydrogen bonding into highly coiled, elastic PEG networks. These hydrogels, due to their high water content and high mechanical resilience, can form highly permeable, yet durable and easy-to-handle cell delivery devices without any additional structural support. In addition, optimization of chemical composition resulted in hydrogels with superior bio-inertness, inducing much less fibrosis upon subcutaneous implantation in mice than a polyhydroxyethylmethacrylate (PHEMA) hydrogel control.

STATEMENT OF SIGNIFICANCE

Hydrogels such as polyethylene glycol (PEG)-based ones are broadly used in the biomedical world. Examples include wound dressings, tissue scaffolds, medical implants, biosensors and drug or cell delivery devices. In many of these applications, robust mechanical property, high water content (or facile mass transfer) and favorable interactions with the body are often simultaneously desirable. However, the mechanical property of hydrogels often degrades rapidly after swelling or with increasing water content. Here we report a new class of PEG-based hydrogels that simultaneously possess high water content, high mechanical resilience and low fibrotic response upon subcutaneous implantation in mice. These hydrogels may therefore find broad applications in biomedicine.

Mass production of shaped particles through vortex ring freezing

A vortex ring is a torus-shaped fluidic vortex. During its formation, the fluid experiences a rich variety of intriguing geometrical intermediates from spherical to toroidal. Here we show that these constantly changing intermediates can be 'frozen' at controlled time points into particles with various unusual and unprecedented shapes. These novel vortex ring-derived particles, are mass-produced by employing a simple and inexpensive electrospraying technique, with their sizes well controlled from hundreds of microns to millimetres. Guided further by theoretical analyses and a laminar multiphase fluid flow simulation, we show that this freezing approach is applicable to a broad range of materials from organic polysaccharides to inorganic nanoparticles. We demonstrate the unique advantages of these vortex ring-derived particles in several applications including cell encapsulation, three-dimensional cell culture, and cell-free protein production. Moreover, compartmentalization and ordered-structures composed of these novel particles are all achieved, creating opportunities to engineer more sophisticated hierarchical materials.

GS-9857 in patients with chronic hepatitis C virus genotype 1-4 infection: a randomized, double-blind, dose-ranging phase 1 study

GS-9857, an inhibitor of the hepatitis C virus (HCV) nonstructural protein (NS) 3/4A, demonstrates potent activity against HCV genotypes 1-6 and improved coverage against commonly encountered NS3 resistance-associated variants (RAVs). In this study, the safety, tolerability, antiviral activity and pharmacokinetics (PK) of GS-9857 were evaluated in patients with chronic HCV genotype 1-4 infection. Patients with genotype 1-4 infection received placebo or once-daily GS-9857 at doses ranging from 50 to 300 mg for 3 days under fasting conditions. GS-9857 was well tolerated; all reported adverse events (AEs) were mild or moderate in severity. Diarrhoea and headache were the most commonly reported AEs. Grade 3 or 4 laboratory abnormalities were observed in 17% of patients receiving GS-9857; there were no Grade 3 or 4 abnormalities in alanine aminotransferase, aspartate aminotransferase or alkaline phosphatase levels. GS-9857 demonstrated potent antiviral activity in patients with chronic HCV infection, achieving mean and median maximum reductions in HCV RNA of ≥3 log10 IU/mL following administration of a 100-mg dose in patients with HCV genotype 1a, 1b, 2, 3 or 4 infection. The antiviral activity of GS-9857 was unaffected by the presence of pretreatment NS3 RAVs. In patients with genotype 1-4 infection, GS-9857 exhibited linear PK and was associated with a median half-life of 29-42 h, supporting once-daily dosing. Thus, the tolerability, efficacy and pharmacokinetic profile of GS-9857 support its further evaluation for treatment of patients with chronic HCV infection.

DNA Microgels as a Platform for Cell-Free Protein Expression and Display

Protein expression and selection is an essential process in the modification of biological products. Expressed proteins are selected based on desired traits (phenotypes) from diverse gene libraries (genotypes), whose size may be limited due to the difficulties inherent in diverse cell preparation. In addition, not all genes can be expressed in cells, and linking genotype with phenotype further presents a great challenge in protein engineering. We present a DNA gel-based platform that demonstrates the versatility of two DNA microgel formats to address fundamental challenges of protein engineering, including high protein yield, isolation of gene sets, and protein display. We utilize microgels to show successful protein production and capture of a model protein, green fluorescent protein (GFP), which is further used to demonstrate a successful gene enrichment through fluorescence-activated cell sorting (FACS) of a mixed population of microgels containing the GFP gene. Through psoralen cross-linking of the hydrogels, we have synthesized DNA microgels capable of surviving denaturing conditions while still possessing the ability to produce protein. Lastly, we demonstrate a method of producing extremely high local gene concentrations of up to 32 000 gene repeats in hydrogels 1 to 2 μm in diameter. These DNA gels can serve as a novel cell-free platform for integrated protein expression and display, which can be applied toward more powerful, scalable protein engineering and cell-free synthetic biology with no physiological boundaries and limitations.

Magnetic hydroxyapatite nanoworms for magnetic resonance diagnosis of acute hepatic injury

Inorganic non-metallic biomaterials, including the silicon frustule of a unicellular diatom, the carbonate shell of a mollusk and the calcium skeleton of the vertebrate, which are the main constituent part of an organism, serve as the supportive and protective components of soft tissue. Among them, hydroxyapatite, which primarily makes up the enamel and bone, is widely used in tissue engineering. Recently, the inorganic nonmetallic biomaterials, especially the applications of hydroxyapatites have attracted great attention. Herein, we report a novel synthesis method of magnetic functionalized hydroxyapatite nanocomposites. By simply tuning the ratios of reactants, a series of hydroxyapatite-Fe3O4 worm-shaped nanocomposites (HAP-ION nanoworms) are obtained. In addition, layer-by-layer surface modifications with chitosan (CH) and sodium alginate (SA) were employed to improve the solubility and biocompatibility, and low cytotoxicity and no hemolysis were observed. With the increase of iron oxide nanocrystals, the magnetic properties of the magnetic assembled nanoworms were enhanced, which resulted in better performance of magnetic resonance (MR) imaging. Owing to the intravenous injection of HAP-ION nanoworms, the contrast to noise ratio (CNR) of hepatic MR imaging in vivo was enhanced obviously, which should be beneficial for hepatic injury grading and further therapeutic treatment.

Engraftment of human induced pluripotent stem cell-derived hepatocytes in immunocompetent mice via 3D co-aggregation and encapsulation

Cellular therapies for liver diseases and in vitro models for drug testing both require functional human hepatocytes (Hum-H), which have unfortunately been limited due to the paucity of donor liver tissues. Human pluripotent stem cells (hPSCs) represent a promising and potentially unlimited cell source to derive Hum-H. However, the hepatic functions of these hPSC-derived cells to date are not fully comparable to adult Hum-H and are more similar to fetal ones. In addition, it has been challenging to obtain functional hepatic engraftment of these cells with prior studies having been done in immunocompromised animals. In this report, we demonstrated successful engraftment of human induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells (iPS-H) in immunocompetent mice by pre-engineering 3D cell co-aggregates with stromal cells (SCs) followed by encapsulation in recently developed biocompatible hydrogel capsules. Notably, upon transplantation, human albumin and α1-antitrypsin (A1AT) in mouse sera secreted by encapsulated iPS-H/SCs aggregates reached a level comparable to the primary Hum-H/SCs control. Further immunohistochemistry of human albumin in retrieved cell aggregates confirmed the survival and function of iPS-H. This proof-of-concept study provides a simple yet robust approach to improve the engraftment of iPS-H, and may be applicable to many stem cell-based therapies.

Designing compartmentalized hydrogel microparticles for cell encapsulation and scalable 3D cell culture

Compartmentalized hydrogel microparticles with high production rate, uniform size and shape, and tunable ECM support were developed for various scalable 3D cell culture applications.

Developing robust, hydrogel-based, nanofiber-enabled encapsulation devices (NEEDs) for cell therapies

Cell encapsulation holds enormous potential to treat a number of hormone deficient diseases and endocrine disorders. We report a simple and universal approach to fabricate robust, hydrogel-based, nanofiber-enabled encapsulation devices (NEEDs) with macroscopic dimensions. In this design, we take advantage of the well-known capillary action that holds wetting liquid in porous media. By impregnating the highly porous electrospun nanofiber membranes of pre-made tubular or planar devices with hydrogel precursor solutions and subsequent crosslinking, we obtained various nanofiber-enabled hydrogel devices. This approach is broadly applicable and does not alter the water content or the intrinsic chemistry of the hydrogels. The devices retained the properties of both the hydrogel (e.g. the biocompatibility) and the nanofibers (e.g. the mechanical robustness). The facile mass transfer was confirmed by encapsulation and culture of different types of cells. Additional compartmentalization of the devices enabled paracrine cell co-cultures in single implantable devices. Lastly, we provided a proof-of-concept study on potential therapeutic applications of the devices by encapsulating and delivering rat pancreatic islets into chemically-induced diabetic mice. The diabetes was corrected for the duration of the experiment (8 weeks) before the implants were retrieved. The retrieved devices showed minimal fibrosis and as expected, live and functional islets were observed within the devices. This study suggests that the design concept of NEEDs may potentially help to overcome some of the challenges in the cell encapsulation field and therefore contribute to the development of cell therapies in future.

DNA materials: bridging nanotechnology and biotechnology

CONSPECTUS: In recent decades, DNA has taken on an assortment of diverse roles, not only as the central genetic molecule in biological systems but also as a generic material for nanoscale engineering. DNA possesses many exceptional properties, including its biological function, biocompatibility, molecular recognition ability, and nanoscale controllability. Taking advantage of these unique attributes, a variety of DNA materials have been created with properties derived both from the biological functions and from the structural characteristics of DNA molecules. These novel DNA materials provide a natural bridge between nanotechnology and biotechnology, leading to far-ranging real-world applications. In this Account, we describe our work on the design and construction of DNA materials. Based on the role of DNA in the construction, we categorize DNA materials into two classes: substrate and linker. As a substrate, DNA interfaces with enzymes in biochemical reactions, making use of molecular biology's "enzymatic toolkit". For example, employing DNA as a substrate, we utilized enzymatic ligation to prepare the first bulk hydrogel made entirely of DNA. Using this DNA hydrogel as a structural scaffold, we created a protein-producing DNA hydrogel via linking plasmid DNA onto the hydrogel matrix through enzymatic ligation. Furthermore, to fully make use of the advantages of both DNA materials and polymerase chain reaction (PCR), we prepared thermostable branched DNA that could remain intact even under denaturing conditions, allowing for their use as modular primers for PCR. Moreover, via enzymatic polymerization, we have recently constructed a physical DNA hydrogel with unique internal structure and mechanical properties. As a linker, we have used DNA to interface with other functional moieties, including gold nanoparticles, clay minerals, proteins, and lipids, allowing for hybrid materials with unique properties for desired applications. For example, we recently designed a DNA-protein conjugate as a universal adapter for protein detection. We further demonstrate a diverse assortment of applications for these DNA materials including diagnostics, protein production, controlled drug release systems, the exploration of life evolution, and plasmonics. Although DNA has shown great potential as both substrate and linker in the construction of DNA materials, it is still in the initial stages of becoming a well-established and widely used material. Important challenges include the ease of design and fabrication, scaling-up, and minimizing cost. We envision that DNA materials will continue to bridge the gap between nanotechnology and biotechnology and will ultimately be employed for many real-world applications.

Nanofibrous microposts and microwells of controlled shapes and their hybridization with hydrogels for cell encapsulation

A simple, robust, and cost-effective method is developed to fabricate nanofibrous micropatterns particularly microposts and microwells of controlled shapes. The key to this method is the use of an easily micropatternable and intrinsically conductive metal alloy as a template to collect electrospun fibers. The micropatterned alloy allows conformal fiber deposition with high fidelity on its topographical features and in situ formation of diverse, free-standing micropatterned nanofibrous membranes. Interestingly, these membranes can serve as structural frames to form robust hydrogel micropatterns that may otherwise be fragile on their own. These hybrid micropatterns represent a new platform for cell encapsulation where the nanofiber frames enhance the mechanical integrity of hydrogel and the micropatterns provide additional surface area for mass transfer and cell loading.

PEGylated upconverting luminescent hollow nanospheres for drug delivery and in vivo imaging

Upconversion luminescent hollow Y2 O3 :Yb(3+) /Er(3+) nanospheres can be synthesized by an etching-free process, which hold promising potential for applications such as drug delivery, angiography, and high-contrast cellular as well as tissue imaging, with no damage from radiation or toxicity.