Fibroblast inflammatory priming determines regenerative versus fibrotic skin repair in reindeer.

Adult mammalian skin wounds heal by forming fibrotic scars. We report that full-thickness injuries of reindeer antler skin (velvet) regenerate, whereas back skin forms fibrotic scar. Single-cell multi-omics reveal that uninjured velvet fibroblasts resemble human fetal fibroblasts, whereas back skin fibroblasts express inflammatory mediators mimicking pro-fibrotic adult human and rodent fibroblasts. Consequently, injury elicits site-specific immune responses: back skin fibroblasts amplify myeloid infiltration and maturation during repair, whereas velvet fibroblasts adopt an immunosuppressive phenotype that restricts leukocyte recruitment and hastens immune resolution. Ectopic transplantation of velvet to scar-forming back skin is initially regenerative, but progressively transitions to a fibrotic phenotype akin to the scarless fetal-to-scar-forming transition reported in humans. Skin regeneration is diminished by intensifying, or enhanced by neutralizing, these pathologic fibroblast-immune interactions. Reindeer represent a powerful comparative model for interrogating divergent wound healing outcomes, and our results nominate decoupling of fibroblast-immune interactions as a promising approach to mitigate scar.

IL-1/MyD88-Dependent G-CSF and IL-6 Secretion Mediates Postburn Anemia.

The anemia of critical illness (ACI) is a nearly universal pathophysiological consequence of burn injury and a primary reason burn patients require massive quantities of transfused blood. Inflammatory processes are expected to drive postburn ACI and prevent meaningful erythropoietic stimulation through iron or erythropoietin supplementation, but to this day no specific inflammatory pathways have been identified as a critical mechanism. In this study, we examined whether secretion of G-CSF and IL-6 mediates distinct features of postburn ACI and interrogated inflammatory mechanisms that could be responsible for their secretion. Our analysis of mouse and human skin samples identified the burn wound as a primary source of G-CSF and IL-6 secretion. We show that G-CSF and IL-6 are secreted independently through an IL-1/MyD88-dependent mechanism, and we ruled out TLR2 and TLR4 as critical receptors. Our results indicate that IL-1/MyD88-dependent G-CSF secretion plays a key role in impairing medullary erythropoiesis and IL-6 secretion plays a key role in limiting the access of erythroid cells to iron. Importantly, we found that IL-1α/ß neutralizing Abs broadly attenuated features of postburn ACI that could be attributed to G-CSF or IL-6 secretion and rescued deficits of circulating RBC counts, hemoglobin, and hematocrit caused by burn injury. We conclude that wound-based IL-1/MyD88 signaling mediates postburn ACI through induction of G-CSF and IL-6 secretion.

HoxD transcription factors define monosynaptic sensory-motor specificity in the developing spinal cord.

The specificity of monosynaptic connections between proprioceptive sensory neurons and their recipient spinal motor neurons depends on multiple factors, including motor neuron positioning and dendrite morphology, axon projection patterns of proprioceptive sensory neurons in the spinal cord, and the ligand-receptor molecules involved in cell-to-cell recognition. However, with few exceptions, the transcription factors engaged in this process are poorly characterized. Here, we show that members of the HoxD family of transcription factors play a crucial role in the specificity of monosynaptic sensory-motor connections. Mice lacking Hoxd9, Hoxd10 and Hoxd11 exhibit defects in locomotion but have no obvious defects in motor neuron positioning or dendrite morphology through the medio-lateral and rostro-caudal axes. However, we found that quadriceps motor neurons in these mice show aberrant axon development and receive inappropriate inputs from proprioceptive sensory axons innervating the obturator muscle. These genetic studies demonstrate that the HoxD transcription factors play an integral role in the synaptic specificity of monosynaptic sensory-motor connections in the developing spinal cord.

Current use of drains and management of seroma following mastectomy and axillary surgery: results of a United Kingdom national practice survey.

PURPOSE: Up to 40% of the 56,000 women diagnosed with breast cancer each year in the UK undergo mastectomy. Seroma formation following surgery is common, may delay wound healing, and be uncomfortable or delay the start of adjuvant treatment. Multiple strategies to reduce seroma formation include surgical drains, flap fixation and external compression exist but evidence to support best practice is lacking. We aimed to survey UK breast surgeons to determine current practice to inform the feasibility of undertaking a future trial. METHODS: An online survey was developed and circulated to UK breast surgeons via professional and trainee associations and social media to explore current attitudes to drain use and management of post-operative seroma. Simple descriptive statistics were used to summarise the results. RESULTS: The majority of surgeons (82/97, 85%) reported using drains either routinely (38, 39%) or in certain circumstances (44, 45%). Other methods for reducing seroma such as flap fixation were less commonly used. Wide variation was reported in the assessment and management of post-operative seromas. Over half (47/91, 52%) of respondents felt there was some uncertainty about drain use after mastectomy and axillary surgery and two-thirds (59/91, 65%) felt that a trial evaluating the use of drains vs no drains after simple breast cancer surgery was needed. CONCLUSIONS: There is a need for a large-scale UK-based RCT to determine if, when and in whom drains are necessary following mastectomy and axillary surgery. This work will inform the design and conduct of a future trial.

Current axillary management of patients with early breast cancer and low-volume nodal disease undergoing primary surgery: results of a United Kingdom national practice survey.

PURPOSE: UK NICE guidelines recommend axillary node clearance (ANC) should be performed in all patients with biopsy-proven node-positive breast cancer having primary surgery. There is, however, increasing evidence such extensive surgery may not always be necessary. Targeted axillary dissection (TAD) may be an effective alternative in patients with low-volume nodal disease who are clinically node negative (cN0) but have abnormal nodes detected radiologically. This survey aimed to explore current management of this group to inform feasibility of a future trial. METHODS: An online survey was developed to explore current UK management of patients with low-volume axillary disease and attitudes to a future trial. The survey was distributed via breast surgery professional associations and social media from September to November 2022. One survey was completed per unit and simple descriptive statistics used to summarise the results. RESULTS: 51 UK breast units completed the survey of whom 78.5% (n = 40) reported performing ANC for all patients with biopsy-proven axillary nodal disease having primary surgery. Only 15.7% of units currently performed TAD either routinely (n = 6, 11.8%) or selectively (n = 2, 3.9%). There was significant uncertainty (83.7%, n = 36/43) about the optimal surgical management of these patients. Two-thirds (n = 27/42) of units felt an RCT comparing TAD and ANC would be feasible. CONCLUSIONS: ANC remains standard of care for patients with low-volume node-positive breast cancer having primary surgery in the UK, but considerable uncertainty exists regarding optimal management of this group. This survey suggests an RCT comparing the outcomes of TAD and ANC may be feasible.

Physical interactions between Gsx2 and Ascl1 balance progenitor expansion versus neurogenesis in the mouse lateral ganglionic eminence.

The Gsx2 homeodomain transcription factor promotes neural progenitor identity in the lateral ganglionic eminence (LGE), despite upregulating the neurogenic factor Ascl1. How this balance in maturation is maintained is unclear. Here, we show that Gsx2 and Ascl1 are co-expressed in subapical progenitors that have unique transcriptional signatures in LGE ventricular zone (VZ) cells. Moreover, whereas Ascl1 misexpression promotes neurogenesis in dorsal telencephalic progenitors, the co-expression of Gsx2 with Ascl1 inhibits neurogenesis. Using luciferase assays, we found that Gsx2 reduces the ability of Ascl1 to activate gene expression in a dose-dependent and DNA binding-independent manner. Furthermore, Gsx2 physically interacts with the basic helix-loop-helix (bHLH) domain of Ascl1, and DNA-binding assays demonstrated that this interaction interferes with the ability of Ascl1 to bind DNA. Finally, we modified a proximity ligation assay for tissue sections and found that Ascl1-Gsx2 interactions are enriched within LGE VZ progenitors, whereas Ascl1-Tcf3 (E-protein) interactions predominate in the subventricular zone. Thus, Gsx2 contributes to the balance between progenitor maintenance and neurogenesis by physically interacting with Ascl1, interfering with its DNA binding and limiting neurogenesis within LGE progenitors.

Cross talk between LAM cells and fibroblasts may influence alveolar epithelial cell behavior in lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a female-specific cystic lung disease in which tuberous sclerosis complex 2 (TSC2)-deficient LAM cells, LAM-associated fibroblasts (LAFs), and other cell types infiltrate the lungs. LAM lesions can be associated with type II alveolar epithelial (AT2) cells. We hypothesized that the behavior of AT2 cells in LAM is influenced locally by LAFs. We tested this hypothesis in the patient samples and in vitro. In human LAM lung, nodular AT2 cells show enhanced proliferation when compared with parenchymal AT2 cells, demonstrated by increased Ki67 expression. Furthermore, nodular AT2 cells express proteins associated with epithelial activation in other disease states including matrix metalloproteinase 7, and fibroblast growth factor 7 (FGF7). In vitro, LAF-conditioned medium is mitogenic and positively chemotactic for epithelial cells, increases the rate of epithelial repair, and protects against apoptosis. In vitro, LAM patient-derived TSC2 null cells cocultured with LAFs upregulate LAF expression of the epithelial chemokine and mitogen FGF7, a potential mediator of fibroblast-epithelial cross talk, in a mechanistic target of rapamycin (mTOR)-dependent manner. In a novel in vitro model of LAM, ex vivo cultured LAM lung-derived microtissues promote both epithelial migration and adhesion. Our findings suggest that AT2 cells in LAM display a proliferative, activated phenotype and fibroblast accumulation following LAM cell infiltration into the parenchyma contributes to this change in AT2 cell behavior. Fibroblast-derived FGF7 may contribute to the cross talk between LAFs and hyperplastic epithelium in vivo, but does not appear to be the main driver of the effects of LAFs on epithelial cells in vitro.

Combinatorial Transcriptional Profiling of Mouse and Human Enteric Neurons Identifies Shared and Disparate Subtypes In Situ.

BACKGROUND & AIMS: The enteric nervous system (ENS) coordinates essential intestinal functions through the concerted action of diverse enteric neurons (ENs). However, integrated molecular knowledge of EN subtypes is lacking. To compare human and mouse ENs, we transcriptionally profiled healthy ENS from adult humans and mice. We aimed to identify transcripts marking discrete neuron subtypes and visualize conserved EN subtypes for humans and mice in multiple bowel regions. METHODS: Human myenteric ganglia and adjacent smooth muscle were isolated by laser-capture microdissection for RNA sequencing. Ganglia-specific transcriptional profiles were identified by computationally subtracting muscle gene signatures. Nuclei from mouse myenteric neurons were isolated and subjected to single-nucleus RNA sequencing, totaling more than 4 billion reads and 25,208 neurons. Neuronal subtypes were defined using mouse single-nucleus RNA sequencing data. Comparative informatics between human and mouse data sets identified shared EN subtype markers, which were visualized in situ using hybridization chain reaction. RESULTS: Several EN subtypes in the duodenum, ileum, and colon are conserved between humans and mice based on orthologous gene expression. However, some EN subtype-specific genes from mice are expressed in completely distinct morphologically defined subtypes in humans. In mice, we identified several neuronal subtypes that stably express gene modules across all intestinal segments, with graded, regional expression of 1 or more marker genes. CONCLUSIONS: Our combined transcriptional profiling of human myenteric ganglia and mouse EN provides a rich foundation for developing novel intestinal therapeutics. There is congruency among some EN subtypes, but we note multiple species differences that should be carefully considered when relating findings from mouse ENS research to human gastrointestinal studies.

Maturation of heart valve cell populations during postnatal remodeling.

Heart valve cells mediate extracellular matrix (ECM) remodeling during postnatal valve leaflet stratification, but phenotypic and transcriptional diversity of valve cells in development is largely unknown. Single cell analysis of mouse heart valve cells was used to evaluate cell heterogeneity during postnatal ECM remodeling and leaflet morphogenesis. The transcriptomic analysis of single cells from postnatal day (P)7 and P30 murine aortic (AoV) and mitral (MV) heart valves uncovered distinct subsets of melanocytes, immune and endothelial cells present at P7 and P30. By contrast, interstitial cell populations are different from P7 to P30. P7 valve leaflets exhibit two distinct collagen- and glycosaminoglycan-expressing interstitial cell clusters, and prevalent ECM gene expression. At P30, four interstitial cell clusters are apparent with leaflet specificity and differential expression of complement factors, ECM proteins and osteogenic genes. This initial transcriptomic analysis of postnatal heart valves at single cell resolution demonstrates that subpopulations of endothelial and immune cells are relatively constant throughout postnatal development, but interstitial cell subpopulations undergo changes in gene expression and cellular functions in primordial and mature valves.

The Rhesus Macaque Serves As a Model for Human Lateral Branch Nephrogenesis.

BACKGROUND: Most nephrons are added in late gestation. Truncated extrauterine nephrogenesis in premature infants results in fewer nephrons and significantly increased risk for CKD in adulthood. To overcome the ethical and technical difficulties associated with studies of late-gestation human fetal kidney development, third-trimester rhesus macaques served as a model to understand lateral branch nephrogenesis (LBN) at the molecular level. METHODS: Immunostaining and 3D rendering assessed morphology. Single-cell (sc) and single-nucleus (sn) RNA-Seq were performed on four cortically enriched fetal rhesus kidneys of 129-131 days gestational age (GA). An integrative bioinformatics strategy was applied across single-cell modalities, species, and time. RNAScope validation studies were performed on human archival tissue. RESULTS: Third-trimester rhesus kidney undergoes human-like LBN. scRNA-Seq of 23,608 cells revealed 37 transcriptionally distinct cell populations, including naïve nephron progenitor cells (NPCs), with the prior noted marker genes CITED1, MEOX1, and EYA1 (c25). These same populations and markers were reflected in snRNA-Seq of 5972 nuclei. Late-gestation rhesus NPC markers resembled late-gestation murine NPC, whereas early second-trimester human NPC markers aligned to midgestation murine NPCs. New, age-specific rhesus NPCs (SHISA8) and ureteric buds (POU3F4 and TWIST) predicted markers were verified in late-gestation human archival samples. CONCLUSIONS: Rhesus macaque is the first model of bona fide LBN, enabling molecular studies of late gestation, human-like nephrogenesis. These molecular findings support the hypothesis that aging nephron progenitors have a distinct molecular signature and align to their earlier human counterparts, with unique markers highlighting LBN-specific progenitor maturation.

Kidney Single-cell Transcriptomes Predict Spatial Corticomedullary Gene Expression and Tissue Osmolality Gradients.

BACKGROUND: Single-cell transcriptomes from dissociated tissues provide insights into cell types and their gene expression and may harbor additional information on spatial position and the local microenvironment. The kidney's cells are embedded into a gradient of increasing tissue osmolality from the cortex to the medulla, which may alter their transcriptomes and provide cues for spatial reconstruction. METHODS: Single-cell or single-nuclei mRNA sequencing of dissociated mouse kidneys and of dissected cortex, outer, and inner medulla, to represent the corticomedullary axis, was performed. Computational approaches predicted the spatial ordering of cells along the corticomedullary axis and quantitated expression levels of osmo-responsive genes. In situ hybridization validated computational predictions of spatial gene-expression patterns. The strategy was used to compare single-cell transcriptomes from wild-type mice to those of mice with a collecting duct-specific knockout of the transcription factor grainyhead-like 2 (Grhl2CD-/-), which display reduced renal medullary osmolality. RESULTS: Single-cell transcriptomics from dissociated kidneys provided sufficient information to approximately reconstruct the spatial position of kidney tubule cells and to predict corticomedullary gene expression. Spatial gene expression in the kidney changes gradually and osmo-responsive genes follow the physiologic corticomedullary gradient of tissue osmolality. Single-nuclei transcriptomes from Grhl2CD-/- mice indicated a flattened expression gradient of osmo-responsive genes compared with control mice, consistent with their physiologic phenotype. CONCLUSIONS: Single-cell transcriptomics from dissociated kidneys facilitated the prediction of spatial gene expression along the corticomedullary axis and quantitation of osmotically regulated genes, allowing the prediction of a physiologic phenotype.

Patient-Reported Outcome Measures for Post-mastectomy Breast Reconstruction: A Systematic Review of Development and Measurement Properties.

BACKGROUND: Breast reconstruction (BR) is performed to improve outcomes for patients undergoing mastectomy. A recently developed core outcome set for BR includes six patient-reported outcomes that should be measured and reported in all future studies. It is vital that any instrument used to measure these outcomes as part of a core measurement set be robustly developed and validated so data are reliable and accurate. The aim of this systematic review is to evaluate the development and measurement properties of existing BR patient-reported outcome measures (PROMs) to inform instrument selection for future studies. METHODS: A PRISMA-compliant systematic review of development and validation studies of BR PROMs was conducted to assess their measurement properties. PROMs with adequate content validity were assessed using three steps: (1) the methodological quality of each identified study was assessed using the COSMIN Risk of Bias checklist; (2) criteria were applied for assessing good measurement properties; and (3) evidence was summarized and the quality of evidence assessed using a modified GRADE approach. RESULTS: Fourteen articles reported the development and measurement properties of six PROMs. Of these, only three (BREAST-Q, BRECON-31, and EORTC QLQ-BRECON-23) were considered to have adequate content validity and proceeded to full evaluation. This showed that all three PROMs had been robustly developed and validated and demonstrated adequate quality. CONCLUSIONS: BREAST-Q, BRECON-31, and EORTC QLQ-BRECON-23 have been well-developed and demonstrate adequate measurement properties. Work with key stakeholders is now needed to generate consensus regarding which PROM should be recommended for inclusion in a core measurement set.

Breast Angiosarcoma Surveillance Study: UK national audit of management and outcomes of angiosarcoma of the breast and chest wall.

BACKGROUND: Breast angiosarcomas are rare tumours of vascular origin. Secondary angiosarcoma occurs following radiotherapy for breast cancer. Angiosarcomas have high recurrence and poor survival rates. This is concerning owing to the increasing use of adjuvant radiotherapy for the treatment of invasive breast cancer and ductal cancer in situ (DCIS), which could explain the rising incidence of angiosarcoma. Outcome data are limited and provide a poor evidence base for treatment. This paper presents a national, trainee-led, retrospective, multicentre study of a large angiosarcoma cohort. METHODS: Data for patients with a diagnosis of breast/chest wall angiosarcoma between 2000 and 2015 were collected retrospectively from 15 centres. RESULTS: The cohort included 183 patients with 34 primary and 149 secondary angiosarcomas. Median latency from breast cancer to secondary angiosarcoma was 6 years. Only 78.9 per cent of patients were discussed at a sarcoma multidisciplinary team meeting. Rates of recurrence were high with 14 of 28 (50 per cent ) recurrences in patients with primary and 80 of 124 (64.5 per cent ) in those with secondary angiosarcoma at 5 years. Many patients had multiple recurrences: total of 94 recurrences in 162 patients (58.0 per cent). Median survival was 5 (range 0-16) years for patients with primary and 5 (0-15) years for those with secondary angiosarcoma. Development of secondary angiosarcoma had a negative impact on predicted breast cancer survival, with a median 10-year PREDICT prognostic rate of 69.6 per cent, compared with 54.0 per cent in the observed cohort. CONCLUSION: A detrimental impact of secondary angiosarcoma on breast cancer survival has been demonstrated. Although not statistically significant, almost all excess deaths were attributable to angiosarcoma. The increased use of adjuvant radiotherapy to treat low-risk breast cancer and DCIS is a cause for concern and warrants further study.

Innovations for the future of breast surgery.

BACKGROUND: Future innovations in science and technology with an impact on multimodal breast cancer management from a surgical perspective are discussed in this narrative review. The work was undertaken in response to the Commission on the Future of Surgery project initiated by the Royal College of Surgeons of England. METHODS: Expert opinion was sought around themes of surgical de-escalation, reduction in treatment morbidities, and improving the accuracy of breast-conserving surgery in terms of margin status. There was emphasis on how the primacy of surgical excision in an era of oncoplastic and reconstructive surgery is increasingly being challenged, with more effective systemic therapies that target residual disease burden, and permit response-adapted approaches to both breast and axillary surgery. RESULTS: Technologies for intraoperative margin assessment can potentially half re-excision rates after breast-conserving surgery, and sentinel lymph node biopsy will become a therapeutic procedure for many patients with node-positive disease treated either with surgery or chemotherapy as the primary modality. Genomic profiling of tumours can aid in the selection of patients for neoadjuvant and adjuvant therapies as well as prevention strategies. Molecular subtypes are predictive of response to induction therapies and reductive approaches to surgery in the breast or axilla. CONCLUSION: Treatments are increasingly being tailored and based on improved understanding of tumour biology and relevant biomarkers to determine absolute benefit and permit delivery of cost-effective healthcare. Patient involvement is crucial for breast cancer studies to ensure relevance and outcome measures that are objective, meaningful, and patient-centred.

This article describes how future innovations in science and technology influence the management of breast cancer from a surgical perspective. This work was undertaken in response to the Commission on the Future of Surgery project initiated by the Royal College of Surgeons of England.

The NeST (Neoadjuvant systemic therapy in breast cancer) study: National Practice Questionnaire of United Kingdom multi-disciplinary decision making.

BACKGROUND: Neoadjuvant systemic therapy (NST) is increasingly used in the treatment of breast cancer, yet it is clear that there is significant geographical variation in its use in the UK. This study aimed to examine stated practice across UK breast units, in terms of indications for use, radiological monitoring, pathological reporting of treatment response, and post-treatment surgical management. METHODS: Multidisciplinary teams (MDTs) from all UK breast units were invited to participate in the NeST study. A detailed questionnaire assessing current stated practice was distributed to all participating units in December 2017 and data collated securely usingREDCap. Descriptive statistics were calculated for each questionnaire item. RESULTS: Thirty-nine MDTs from a diverse range of hospitals responded. All MDTs routinely offered neoadjuvant chemotherapy (NACT) to a median of 10% (range 5-60%) of patients. Neoadjuvant endocrine therapy (NET) was offered to a median of 4% (range 0-25%) of patients by 66% of MDTs. The principal indication given for use of neoadjuvant therapy was for surgical downstaging. There was no consensus on methods of radiological monitoring of response, and a wide variety of pathological reporting systems were used to assess tumour response. Twenty-five percent of centres reported resecting the original tumour footprint, irrespective of clinical/radiological response. Radiologically negative axillae at diagnosis routinely had post-NACT or post-NET sentinel lymph node biopsy (SLNB) in 73.0 and 84% of centres respectively, whereas 16% performed SLNB pre-NACT. Positive axillae at diagnosis would receive axillary node clearance at 60% of centres, regardless of response to NACT. DISCUSSION: There is wide variation in the stated use of neoadjuvant systemic therapy across the UK, with general low usage of NET. Surgical downstaging remains the most common indication of the use of NAC, although not all centres leverage the benefits of NAC for de-escalating surgery to the breast and/or axilla. There is a need for agreed multidisciplinary guidance for optimising selection and management of patients for NST. These findings will be corroborated in phase II of the NeST study which is a national collaborative prospective audit of NST utilisation and clinical outcomes.

Single-Cell Transcriptomic Analysis Identifies a Unique Pulmonary Lymphangioleiomyomatosis Cell.

Rationale: Lymphangioleiomyomatosis (LAM) is a metastatic neoplasm of reproductive-age women associated with mutations in tuberous sclerosis complex genes. LAM causes cystic remodeling of the lung and progressive respiratory failure. The sources and cellular characteristics of LAM cells underlying disease pathogenesis remain elusive.Objectives: Identification and characterization of LAM cells in human lung and uterus using a single-cell approach.Methods: Single-cell and single-nuclei RNA sequencing on LAM (n = 4) and control (n = 7) lungs, immunofluorescence confocal microscopy, ELISA, and aptamer proteomics were used to identify and validate LAMCORE cells and secreted biomarkers, predict cellular origins, and define molecular and cellular networks in LAM.Measurements and Main Results: A unique cell type termed LAMCORE was identified, which was distinct from, but closely related to, lung mesenchymal cells. LAMCORE cells expressing signature genes included known LAM markers such as PMEL, FIGF, CTSK, and MLANA and novel biomarkers validated by aptamer screening, ELISA, and immunofluorescence microscopy. LAM cells in lung and uterus are morphologically indistinguishable and share similar gene expression profiles and biallelic TSC2 mutations, supporting a potential uterine origin for the LAMCORE cell. Effects of LAM on resident pulmonary cell types indicated recruitment and activation of lymphatic endothelial cells.Conclusions: A unique population of LAMCORE cells was identified in lung and uterus of patients with LAM, sharing close transcriptomic identity. LAM cell selective markers, secreted biomarkers, and the predicted cellular molecular features provide new insights into the signaling and transcriptional programs that may serve as diagnostic markers and therapeutic targets to influence the pathogenesis of LAM.

Single-Cell Profiling of AKI in a Murine Model Reveals Novel Transcriptional Signatures, Profibrotic Phenotype, and Epithelial-to-Stromal Crosstalk.

BACKGROUND: Current management of AKI, a potentially fatal disorder that can also initiate or exacerbate CKD, is merely supportive. Therefore, deeper understanding of the molecular pathways perturbed in AKI is needed to identify targets with potential to lead to improved treatment. METHODS: We performed single-cell RNA sequencing (scRNA-seq) with the clinically relevant unilateral ischemia-reperfusion murine model of AKI at days 1, 2, 4, 7, 11, and 14 after AKI onset. Using real-time quantitative PCR, immunofluorescence, Western blotting, and both chromogenic and single-molecule in situ hybridizations, we validated AKI signatures in multiple experiments. RESULTS: Our findings show the time course of changing gene expression patterns for multiple AKI stages and all renal cell types. We observed elevated expression of crucial injury response factors-including kidney injury molecule-1 (Kim1), lipocalin 2 (Lcn2), and keratin 8 (Krt8)-and of several novel genes (Ahnak, Sh3bgrl3, and Col18a1) not previously examined in kidney pathologies. AKI induced proximal tubule dedifferentiation, with a pronounced nephrogenic signature represented by Sox4 and Cd24a. Moreover, AKI caused the formation of "mixed-identity cells" (expressing markers of different renal cell types) that are normally seen only during early kidney development. The injured tubules acquired a proinflammatory and profibrotic phenotype; moreover, AKI dramatically modified ligand-receptor crosstalk, with potential pathologic epithelial-to-stromal interactions. Advancing age in AKI onset was associated with maladaptive response and kidney fibrosis. CONCLUSIONS: The scRNA-seq, comprehensive, cell-specific profiles provide a valuable resource for examining molecular pathways that are perturbed in AKI. The results fully define AKI-associated dedifferentiation programs, potential pathologic ligand-receptor crosstalk, novel genes, and the improved injury response in younger mice, and highlight potential targets of kidney injury.

Psychrophilic proteases dramatically reduce single-cell RNA-seq artifacts: a molecular atlas of kidney development.

Single-cell RNA-seq is a powerful technique. Nevertheless, there are important limitations, including the technical challenges of breaking down an organ or tissue into a single-cell suspension. Invariably, this has required enzymatic incubation at 37°C, which can be expected to result in artifactual changes in gene expression patterns. Here, we describe a dissociation method that uses a protease with high activity in the cold, purified from a psychrophilic microorganism. The entire procedure is carried out at 6°C or colder, at which temperature mammalian transcriptional machinery is largely inactive, thereby effectively 'freezing in' the in vivo gene expression patterns. To test this method, we carried out RNA-seq on 20,424 single cells from postnatal day 1 mouse kidneys, comparing the results of the psychrophilic protease method with procedures using 37°C incubation. We show that the cold protease method provides a great reduction in gene expression artifacts. In addition, the results produce a single-cell resolution gene expression atlas of the newborn mouse kidney, an interesting time in development when mature nephrons are present yet nephrogenesis remains extremely active.

Therapeutic mammaplasty is a safe and effective alternative to mastectomy with or without immediate breast reconstruction.

BACKGROUND: Therapeutic mammaplasty (TM) may be an alternative to mastectomy, but few well designed studies have evaluated the success of this approach or compared the short-term outcomes of TM with mastectomy with or without immediate breast reconstruction (IBR). Data from the national iBRA-2 and TeaM studies were combined to compare the safety and short-term outcomes of TM and mastectomy with or without IBR. METHODS: The subgroup of patients in the TeaM study who underwent TM to avoid mastectomy were identified, and data on demographics, complications, oncology and adjuvant treatment were compared with those of patients undergoing mastectomy with or without IBR in the iBRA-2 study. The primary outcome was the percentage of successful breast-conserving procedures in the TM group. Secondary outcomes included postoperative complications and time to adjuvant therapy. RESULTS: A total of 2916 patients (TM 376; mastectomy 1532; mastectomy and IBR 1008) were included in the analysis. Patients undergoing TM were more likely to be obese and to have undergone bilateral surgery than those having IBR. However, patients undergoing mastectomy with or without IBR were more likely to experience complications than the TM group (TM: 79, 21·0 per cent; mastectomy: 570, 37·2 per cent; mastectomy and IBR: 359, 35·6 per cent; P < 0·001). Breast conservation was possible in 87·0 per cent of patients who had TM, and TM did not delay adjuvant treatment. CONCLUSION: TM may allow high-risk patients who would not be candidates for IBR to avoid mastectomy safely. Further work is needed to explore the comparative patient-reported and cosmetic outcomes of the different approaches, and to establish long-term oncological safety.

ANTECEDENTES: La mamoplastia terapéutica (therapeutic mammaplasty, TM) puede ser una alternativa a la mastectomía, pero hay pocos estudios bien diseñados que hayan evaluado el éxito de esta estrategia o hayan comparado los resultados a corto plazo de la TM con la mastectomía con o sin (+/-) reconstrucción mamaria inmediata (immediate breast reconstruction, IBR). Para comparar la seguridad y los resultados a corto plazo de la TM y la mastectomía +/- IBR se combinaron los datos de los estudios nacionales iBRA-2 y TeaM. MÉTODOS: En el estudio TeaM se identificó el subgrupo de pacientes al que se realizó una TM para evitar la mastectomía y se compararon los datos demográficos, las complicaciones, los resultados oncológicos y el tratamiento adyuvante con las pacientes sometidas a mastectomía +/- IBR del estudio iBRA-2. La variable principal fue el porcentaje de éxito de la cirugía conservadora de mama en el grupo TM. Las variables secundarias fueron las complicaciones postoperatorias y el intervalo de tiempo hasta el inicio del tratamiento adyuvante. RESULTADOS: Se incluyeron en el análisis 2.916 pacientes (TM n = 376; mastectomía n = 1.532; IBR n = 1.008). La TM era más frecuente en pacientes obesas o en las sometidas a cirugía bilateral en comparación con las pacientes con IBR. Sin embargo, las pacientes sometidas a una mastectomía +/- IBR tenían más probabilidades de desarrollar complicaciones que las del grupo TM (TM n = 79, 21,0%; mastectomía n = 570, 37,2%; mastectomía y IBR n = 359, 35,6%; P < 0,001). La conservación de la mama fue posible en el 87% de las pacientes con TM y el procedimiento no retrasó el inicio del tratamiento adyuvante. CONCLUSIÓN: La TM puede permitir que pacientes de alto riesgo que no serían candidatas a IBR eviten la mastectomía de una forma segura. Se necesitan más trabajos para comparar los resultados percibidos por las pacientes y los estéticos de las diferentes estrategias terapéuticas y establecer la seguridad oncológica a largo plazo.

A systematic review and in-depth analysis of outcome reporting in early phase studies of colorectal cancer surgical innovation.

AIM: Early phase studies are essential to evaluate new technologies prior to randomized evaluation. Evaluation is limited, however, by inconsistent measurement and reporting of outcomes. This study examines outcome reporting in studies of innovative colorectal cancer surgery. METHODS: Systematic searches identified studies of invasive procedures treating primary colorectal adenocarcinoma. Included were a random sample of studies which authors reported as 'new' or 'modified'. Outcomes were extracted verbatim and categorized using an existing framework of 32 domains relevant to early phase studies. Outcomes were classified as 'measured' (where there was an explicit statement to that effect or evidence that data collection had occurred) or 'mentioned but not measured' (where outcomes were discussed but data collection was not evident). Patterns of identified outcomes are described. RESULTS: Of 8373 records, 816 were potentially eligible. Full-text review of a random sample of 218 studies identified 51 for inclusion of which 34 (66%) were 'new' and 17 (33%) were 'modified'. Some 2073 outcomes were identified, and all mapped to domains. 'Anticipated disadvantages' were most frequently identified [660 (32%) outcomes identified across 50 (98%) studies]. No domain was represented in all studies. Under half (944, 46%) of outcomes were 'measured'. 'Surgeon's/operator's experience of the innovation' was more frequently 'mentioned but not measured' [207 (18%) outcomes across 46 (90%) studies] than 'measured' [17 (2%) outcomes, 11 (22%) studies]. CONCLUSION: There is outcome reporting heterogeneity in studies of early phase colorectal cancer surgery. The adoption of core outcome sets may help to resolve these inconsistencies and enable efficient evaluation of surgical innovations.