A spatially resolved timeline of the human maternal-fetal interface

Beginning in the first trimester, fetally derived extravillous trophoblasts (EVTs) invade the uterus and remodel its spiral arteries, transforming them into large, dilated blood vessels. Several mechanisms have been proposed to explain how EVTs coordinate with the maternal decidua to promote a tissue microenvironment conducive to spiral artery remodelling (SAR)1-3. However, it remains a matter of debate regarding which immune and stromal cells participate in these interactions and how this evolves with respect to gestational age. Here we used a multiomics approach, combining the strengths of spatial proteomics and transcriptomics, to construct a spatiotemporal atlas of the human maternal-fetal interface in the first half of pregnancy. We used multiplexed ion beam imaging by time-of-flight and a 37-plex antibody panel to analyse around 500,000 cells and 588 arteries within intact decidua from 66 individuals between 6 and 20 weeks of gestation, integrating this dataset with co-registered transcriptomics profiles. Gestational age substantially influenced the frequency of maternal immune and stromal cells, with tolerogenic subsets expressing CD206, CD163, TIM-3, galectin-9 and IDO-1 becoming increasingly enriched and colocalized at later time points. By contrast, SAR progression preferentially correlated with EVT invasion and was transcriptionally defined by 78 gene ontology pathways exhibiting distinct monotonic and biphasic trends. Last, we developed an integrated model of SAR whereby invasion is accompanied by the upregulation of pro-angiogenic, immunoregulatory EVT programmes that promote interactions with the vascular endothelium while avoiding the activation of maternal immune cells.

Single-cell spatial proteomic imaging for human neuropathology

Neurodegenerative disorders are characterized by phenotypic changes and hallmark proteopathies. Quantifying these in archival human brain tissues remains indispensable for validating animal models and understanding disease mechanisms. We present a framework for nanometer-scale, spatial proteomics with multiplex ion beam imaging (MIBI) for capturing neuropathological features. MIBI facilitated simultaneous, quantitative imaging of 36 proteins on archival human hippocampus from individuals spanning cognitively normal to dementia. Customized analysis strategies identified cell types and proteopathies in the hippocampus across stages of Alzheimer's disease (AD) neuropathologic change. We show microglia-pathologic tau interactions in hippocampal CA1 subfield in AD dementia. Data driven, sample independent creation of spatial proteomic regions identified persistent neurons in pathologic tau neighborhoods expressing mitochondrial protein MFN2, regardless of cognitive status, suggesting a survival advantage. Our study revealed unique insights from multiplexed imaging and data-driven approaches for neuropathologic analysis and serves broadly as a methodology for spatial proteomic analysis of archival human neuropathology. TEASER: Multiplex Ion beam Imaging enables deep spatial phenotyping of human neuropathology-associated cellular and disease features.

Transition to invasive breast cancer is associated with progressive changes in the structure and composition of tumor stroma

Ductal carcinoma in situ (DCIS) is a pre-invasive lesion that is thought to be a precursor to invasive breast cancer (IBC). To understand the changes in the tumor microenvironment (TME) accompanying transition to IBC, we used multiplexed ion beam imaging by time of flight (MIBI-TOF) and a 37-plex antibody staining panel to interrogate 79 clinically annotated surgical resections using machine learning tools for cell segmentation, pixel-based clustering, and object morphometrics. Comparison of normal breast with patient-matched DCIS and IBC revealed coordinated transitions between four TME states that were delineated based on the location and function of myoepithelium, fibroblasts, and immune cells. Surprisingly, myoepithelial disruption was more advanced in DCIS patients that did not develop IBC, suggesting this process could be protective against recurrence. Taken together, this HTAN Breast PreCancer Atlas study offers insight into drivers of IBC relapse and emphasizes the importance of the TME in regulating these processes.

Multiplexed imaging reveals an IFN-γ-driven inflammatory state in nivolumab-associated gastritis

Immune checkpoint blockade using PD-1 inhibition is an effective approach for treating a wide variety of cancer subtypes. While lower gastrointestinal (GI) side effects are more common, upper gastrointestinal adverse events are rarely reported. Here, we present a case of nivolumab-associated autoimmune gastritis. To elucidate the immunology underlying this condition, we leverage multiplexed ion beam imaging by time-of-flight (MIBI-TOF) to identify the presence and proportion of infiltrating immune cells from a single section of biopsy specimen. Using MIBI-TOF, we analyze formalin-fixed, paraffin-embedded human gastric tissue with 28 labels simultaneously. Our analyses reveal a gastritis characterized by severe mucosal injury, interferon gamma (IFN-γ)-producing gastric epithelial cells, and mixed inflammation that includes CD8 and CD4 T cell infiltrates with reduced expression of granzyme B and FOXP3, respectively. Here, we provide a comprehensive multiplexed histopathological mapping of gastric tissue, which identifies IFN-γ-producing epithelial cells as possible contributors to the nivolumab-associated gastritis.

MAUI (MBI Analysis User Interface)-An image processing pipeline for Multiplexed Mass Based Imaging

Mass Based Imaging (MBI) technologies such as Multiplexed Ion Beam Imaging by time of flight (MIBI-TOF) and Imaging Mass Cytometry (IMC) allow for the simultaneous measurement of the expression levels of 40 or more proteins in biological tissue, providing insight into cellular phenotypes and organization in situ. Imaging artifacts, resulting from the sample, assay or instrumentation complicate downstream analyses and require correction by domain experts. Here, we present MBI Analysis User Interface (MAUI), a series of graphical user interfaces that facilitate this data pre-processing, including the removal of channel crosstalk, noise and antibody aggregates. Our software streamlines these steps and accelerates processing by enabling real-time and interactive parameter tuning across multiple images.

High-dimensional Imaging technologies allow to simultaneously measure the expression levels of dozens of proteins in biological tissue, providing insight into single-cell phenotypes and organization in situ. Imaging artifacts, resulting from the sample, assay or instrumentation complicate downstream analyses and require correction by domain experts. Here, we present MAUI, a series of graphical user interfaces that facilitate this data pre-processing, including the removal of channel crosstalk, noise and antibody aggregates. MAUI accelerates and automates these steps, such that reproducible, high-quality data will be the input for subsequent stages of analysis.

Single-cell metabolic profiling of human cytotoxic T cells

Cellular metabolism regulates immune cell activation, differentiation and effector functions, but current metabolic approaches lack single-cell resolution and simultaneous characterization of cellular phenotype. In this study, we developed an approach to characterize the metabolic regulome of single cells together with their phenotypic identity. The method, termed single-cell metabolic regulome profiling (scMEP), quantifies proteins that regulate metabolic pathway activity using high-dimensional antibody-based technologies. We employed mass cytometry (cytometry by time of flight, CyTOF) to benchmark scMEP against bulk metabolic assays by reconstructing the metabolic remodeling of in vitro-activated naive and memory CD8+ T cells. We applied the approach to clinical samples and identified tissue-restricted, metabolically repressed cytotoxic T cells in human colorectal carcinoma. Combining our method with multiplexed ion beam imaging by time of flight (MIBI-TOF), we uncovered the spatial organization of metabolic programs in human tissues, which indicated exclusion of metabolically repressed immune cells from the tumor-immune boundary. Overall, our approach enables robust approximation of metabolic and functional states in individual cells.

Abstract PR05: Mapping the tumor and microenvironmental evolution underlying DCIS progression through multiplexed ion beam imaging

Ductal Carcinoma in Situ (DCIS) is a pre-invasive lesion that accounts for nearly 20% of new breast cancer diagnoses. Of these cases, about half will progress to invasive breast cancer (IBC) within ten years. However, because diagnostic criteria for delineating low risk lesions from those likely to progress to IBC have not been identified, many patients are receiving unnecessary chemotherapy and surgery that can result in therapy-related morbidity and death. With this in mind, we used Multiplexed Ion Beam Imaging by time of flight (MIBI-TOF) and RNA-seq laser-capture microdissection (SMART-3SEQ) to construct a comprehensive spatial atlas describing the structure, function, and cellular composition of DCIS. MIBI-TOF and SMART-3SEQ were used to compare lesions from patients that later developed IBC with those from age- and history matched DCIS controls without recurrence. Using a 37-marker staining panel to interrogate 137 lesions, we identified 30 distinct cell populations of the epithelial, stromal, and immune lineages that were arranged in recurrent cellular microenvironments specific for DCIS or invasive disease. We observe a coordinated shift in the immune and stromal compartments as invasive disease arises, including an expansion of immune cell diversity and transition to reactive stromal phenotypes in synchronous DCIS + IBC, which was distinct from the macrophage-dominant microenvironment of recurrent IBC. Single-cell segmentation using a deep learning model was combined with pixel-level coexpression analysis to determine how thickness, continuity, and phenotype of ductal myoepithelium changes as tumors progress from a pre-invasive state. These data were incorporated into a comprehensive model which was subsequently used to identify a subset of features that correlate with disease-free survival following DCIS tumor resection. Taken together, these features represent important prognostic metrics that can be used to separate pre-invasive from indolent DCIS tumors, and allow for tailored therapy that improves patient outcomes and quality of life in this disease.

Citation Format: Tyler Risom, Belen Rivero, Candace Liu, Alex Baranski, Siri Strand, Noah Greenwald, Erin McCaffrey, Sushama Varma, Leeat Keren, Sucheta Srivastava, Chunfang Zhu, Sujay Vennam, Shelley Hwang, Graham Colditz, Sean Bendall, Robert West, Michael Angelo. Mapping the tumor and microenvironmental evolution underlying DCIS progression through multiplexed ion beam imaging [abstract]. In: Proceedings of the AACR Virtual Special Conference on Tumor Heterogeneity: From Single Cells to Clinical Impact; 2020 Sep 17-18. Philadelphia (PA): AACR; Cancer Res 2020;80(21 Suppl):Abstract nr PR05.

Cyclic voltammetric detection in capillary electrophoresis with application to metal ions

Fast cyclic voltammetry (CV) was evaluated over sweep rates of 20-1000 V/s at Au disk electrodes (25 and 10 μm) for end-capillary detection in capillary electrophoresis with metal ions as test analytes; some studies were also done with 25-μm Pt disk electrodes. The waveform applied to the electrode consisted of a preconcentration period (55-330 ms) followed by cyclic voltammetry (2-100 ms). Maximum signal-to-noise was obtained with the integrated CV current as the analytical signal, and this was linearly proportional to sweep rate; maximum response was obtained at sweep rates of >100 V/s for 10-μm electrodes and >200 V/s for 25-μm electrodes; sweep rates of >400 V/s caused peak tailing due to trapping of the analyte at the electrode. With this CV detection approach, comigrating analytes could be identified and determined. Reproducibilities for six analytes over the range 1.0 × 10(-)(7)-1.0 × 10(-)(5) mol/L were 2%-5%, and calibration curves were linear, with response factors in the range of 2%-6%. Detection limits (2 × peak-to-peak baseline noise) were in the range of 5 × 10(-)(9)-4 × 10(-)(8) mol/L, which are 1-2 orders of magnitude better than results obtained previously with square-wave pulsed amperometric detection of metal ions.

Clinical aspects of small-bowel transplantation

AIM

To update clinical aspects of small-bowel transplantation.

METHODS

Critical review of the literature.

RESULTS

The two major functions of the small bowel are absorption of food and protection of the body against ingested pathogens. The highly developed immune system of the bowel, necessary for the latter function, prevented successful small-bowel transplantation during the 1960s and 1970s by provoking early and severe rejection of the graft. The introduction of cyclosporin in the 1980s enabled small-bowel transplantation with a moderate success rate. Further improvement of immunosuppressive regimens, especially the introduction of tacrolimus and aggressive surveillance for and treatment of infections, has resulted in a slow but steady improvement of transplant results during the past decade. At this moment, however, long-term parenteral nutrition is still the first-line treatment of the short-bowel syndrome world-wide because of the excellent results with regard to patient survival.

CONCLUSION

Although results of small-bowel transplantation are steadily improving, especially due to better immunosuppressive regimens, long-term parenteral nutrition is still the first-line treatment of short-bowel syndrome.

Capillary electrophoresis of some tetracycline antibiotics coupled with reductive fast cyclic voltammetric detection

The separation and quantitative performance parameters for tetracycline, chlortetracycline and oxytetracycline antibiotics were investigated by capillary zone electrophoresis coupled with fast cyclic voltammetric detection. Optimization of pH and complexation with a boric acid-sodium tetraborate buffer provided good resolution of all compounds. Detection by electrochemical reduction using fast on-line cyclic voltammetric detection with a Hg-film-microm electrode gave detection limits (2 x peak-to-peak baseline noise) of 7 x 10(-7) mol/l for tetracycline and chlortetracycline, and 1.5 x 10(-6) mol/l for oxytetracycline. The influence of electrode material, potential range and scan rate was examined and discussed. Optimal electrochemical detection was obtained at a Hg-film electrode with a waveform that consisted of an initial constant potential of -0.6 V for 200 ms followed by a cyclic voltammetry (CV) scan at 300 V/s from - 0.6 V to a vertex potential of 1.7 V. The analytical signal was obtained by plotting the integrated values of the CV current from each applied waveform as a function of time. The calibration plot (peak areas) for each separated peak was found to be linear over three-orders of magnitude.

Effect of sialoadenectomy and epidermal growth factor administration on liver regeneration after partial hepatectomy

Epidermal growth factor (EGF), a mitogen in vitro for hepatocytes, produces in various cell lines changes similar to those observed very rapidly in hepatocytes after partial hepatectomy (PH). These changes include ion movements, membrane hyperpolarization and proto-oncogene expression. A stimulatory effect of EGF on liver regeneration can therefore tentatively be associated with the events occurring within the first 3 hours after a PH, sometimes referred to as the "priming phase." To assess this hypothesis, we examined in Wistar rats the effect of EGF deprivation produced by sialoadenectomy (SX) performed before or after a PH of 70%. SX at the time of PH significantly decreased the 3H-thymidine uptake in the DNA 24 hours later (147 +/- 14 DPM per microgram of DNA, mean +/- SE) compared with a simple PH (322 +/- 16; P < .01), but also compared with results obtained when PH is combined with a sham sialoadenectomy (SSX) or in rats pair-fed with the sialoadenectomized rats. This incomplete inhibition was confirmed by a decreased rise in thymidine kinase (TK) activity and by reduced proliferating cell nuclear antigen (PCNA) labeling and mitotic indices 30 hours after PH. By contrast, SX did not inhibit the early expression of c-jun and c-fos, or of c-myc, 30 or 120 minutes after PH, respectively. A reduction of DNA synthesis was also obtained when SX was performed 3 hours after PH (127 +/- 15 DPM per microgram of DNA vs. 350 +/- 21 in SSX; P < .001) but not when SX was delayed until the 6th or the 17th hour after PH. It was sufficient to administer EGF (40 microg) from the third to the ninth hour to correct the reduction of [3H]thymidine uptake in rats sialoadenectomized before PH. These results indicate that the diminished EGF availability following SX decreases or at least delays liver regeneration, and that the effect of EGF on liver regeneration does not seem related to the early changes of proto-oncogene expression, but rather to events occuring later, at the time of reported internalization and binding of EGF to its nuclear receptors.

Technical problems in shipped hepatic allografts: the UCL experience

Due to developments in surgical techniques and organ preservation, the shipping of renal and extrarenal organs is becoming increasingly more frequent. During the period from 1 January 1991 to 31 December 1992, 39 of 180 (21%) implanted liver allografts were shipped to our center by local harvesting teams. The fact that each of nine livers (23.1%) presented with minor and major (vascular and parenchymatous) problems stresses the need for better surgical training and standardization in procurement techniques. The introduction of a liver allograft feedback report could be an easy way to perform quality control.

Preformed antibody and complement rebound after plasma exchange: analysis of immunoglobulin isotypes and effect of splenectomy

Splenectomy (Sx) has been proposed to attenuate post-PE (plasma exchange) rebound of isoagglutinins and xenogenic (XG) antibody (Ab) in both ABO-incompatible allografts and discordant xenografts. This study analyses the qualitative nature and kinetics of serum immunoglobulins as well as complement resynthesis after PE in sham-operated (PE) and splenectomized (PE+Sx) syngeneic LOU/C rats; non-PE sham-operated or splenectomized animals were used as controls. PE was performed in unanesthetized, unheparinized rats. Immunoglobulin isotypes and subclasses (IgM, IgG1, IgG2 alpha, IgG2b) of total circulating Ab were measured pre-PE and up to 21 days post-PE, using ELISA (enzyme-linked immunosorbent assay) and specific mouse antirat monoclonal Ab. Antiguinea-pig (GP) XG Ab (IgM, IgG2a) serum levels were measured using cellular ELISA with cultured GP endothelial cells as targets. Sx alone significantly reduced XG IgM serum levels (p < 0.0001). Maximal rebound of total and XG IgM was observed on day 3 post-PE, reaching 674% and 187% of the pre-PE levels, respectively; these overshoots were entirely suppressed by Sx (p < 0.005 for total IgM; p < 0.0001 for XG IgM). Total IgG2a, IgG2b and IgG1 as well as XG IgG2a serum levels did not show significant overshoot post-PE. The activity of the complement classical pathway (mean +/- SD), assessed by CH50, was decreased at 51 +/- 19% of basal value 15 minutes after PE, and had returned to baseline level by day 2 post-PE with or without Sx.

IN CONCLUSION

(1) Six alone significantly reduced XG IgM serum levels; (2) early post-PE Ab rebound was mainly observed for IgM; (3) both total and XG IgM rebound was inhibited by Sx. This suggests that Sx probably removes a significant proportion of IgM producing cells undergoing post-PE stimulation. These data provide a rationale for combining PE with Sx in ABO-incompatible and discordant XG transplantation.

Technical problems in shipped hepatic allografts: the UCL experience

Due to developments in surgical techniques and organ preservation, the shipping of renal and extrarenal organs is becoming increasingly more frequent. During the period from 1 January 1991 to 31 December 1992, 39 of 180 (21%) implanted liver allografts were shipped to our center by local harvesting teams. The fact that each of nine livers (23.1%) presented with minor and major (vascular and parenchymatous) problems stresses the need for better surgical training and standardization in procurement techniques. The introduction of a liver allograft feedback report could be an easy way to perform quality control.

In vivo IgM depletion by anti-mu monoclonal antibody therapy. The role of IgM in hyperacute vascular rejection of discordant xenografts

Xenoreactive natural antibodies (XNA) and complement activation are thought to be the 2 main factors responsible for the hyperacute vascular rejection (HVR) of discordant xenografts. The aim of this work was to study the role of IgM XNA in the HVR of guinea pig to rat cardiac xenografts, a discordant model. Adult LOU/C rats were depleted of circulating IgM and therefore of IgM XNA using an anti-mu mAb (mouse anti-rat IgM mAb 7 [MARM-7]). Rats were injected with 10 mg and 5 mg of MARM-7 at days -3 and -1, respectively, and guinea pig cardiac xenografts were performed on day 0. Control animals were injected on the same days with 10 mg and 5 mg of anti-alpha mAb (MARA-1) or equivalent volumes of PBS. Xenografts were performed on day 0. Guinea pig cardiac xenograft survival time was significantly prolonged in IgM-depleted animals (62 min, P < 0.01) compared with controls using PBS (18 min) or MARA-1 mAb (12 min). This prolongation was not due to a decrease in the complement activity in IgM-depleted rats, since no significant variation of the C1q, C4, C3, and C5 complement hemolytic activity was observed between control and treated animals before HVR. Prolongation of the xenograft survival time in the MARM-7-treated group was correlated with an undetectable serum level of IgM and IgM XNA and a lack of IgM XNA deposits on the rejected xenograft vascular endothelium. Contrarily, both IgM-depleted and control animals showed C3 deposits on the rejected xenograft vascular endothelium and myocardium, as well as diffuse deposits of IgG2a XNA. Although HVR was not abrogated by the depletion of IgM XNA, our data indicate that IgM is implicated in the HVR and that the anti-mu approach is a potential therapeutic treatment for discordant xenografts. Finally, we suggest that other factors such as IgM-independent activation of complement might be one of the mechanisms responsible for the pathogenesis of HVR in the guinea pig to rat xenograft model.