Neutrophils direct preexisting matrix to initiate repair in damaged tissues.

Internal organs heal injuries with new connective tissue, but the cellular and molecular events of this process remain obscure. By tagging extracellular matrix around the mesothelium lining in mouse peritoneum, liver and cecum, here we show that preexisting matrix was transferred across organs into wounds in various injury models. Using proteomics, genetic lineage-tracing and selective injury in juxtaposed organs, we found that the tissue of origin for the transferred matrix likely dictated the scarring or regeneration of the healing tissue. Single-cell RNA sequencing and genetic and chemical screens indicated that the preexisting matrix was transferred by neutrophils dependent on the HSF-integrin AM/B2-kindlin3 cascade. Pharmacologic inhibition of this axis prevented matrix transfer and the formation of peritoneal adhesions. Matrix transfer was thus an early event of wound repair and provides a therapeutic window to dampen scaring across a range of conditions.

Annexin A1 based inflammation resolving mediators and nanomedicines for inflammatory bowel disease therapy.

Inflammatory bowel diseases (IBD) such as Crohn's Disease (CD) and Ulcerative Colitis (UC) are chronic, progressive, and relapsing disorders of the gastrointestinal tract (GIT), characterised by intestinal epithelial injury and inflammation. Current research shows that in addition to traditional anti-inflammatory therapy, resolution of inflammation and repair of the epithelial barrier are key biological requirements in combating IBD. Resolution mediators include endogenous lipids that are generated during inflammation, e.g., lipoxins, resolvins, protectins, maresins; and proteins such as Annexin A1 (ANXA1). Nanoparticles can specifically deliver these potent inflammation resolving mediators in a spatiotemporal manner to IBD lesions, effectively resolve inflammation, and promote a return to homoeostasis with minimal collateral damage. We discuss these exciting and timely concepts in this review.

The splicing-regulatory lncRNA NTRAS sustains vascular integrity.

Vascular integrity is essential for organ homeostasis to prevent edema formation and infiltration of inflammatory cells. Long non-coding RNAs (lncRNAs) are important regulators of gene expression and often expressed in a cell type-specific manner. By screening for endothelial-enriched lncRNAs, we identified the undescribed lncRNA NTRAS to control endothelial cell functions. Silencing of NTRAS induces endothelial cell dysfunction in vitro and increases vascular permeability and lethality in mice. Biochemical analysis revealed that NTRAS, through its CA-dinucleotide repeat motif, sequesters the splicing regulator hnRNPL to control alternative splicing of tight junction protein 1 (TJP1; also named zona occludens 1, ZO-1) pre-mRNA. Deletion of the hnRNPL binding motif in mice (Ntras∆CA/∆CA ) significantly repressed TJP1 exon 20 usage, favoring expression of the TJP1α- isoform, which augments permeability of the endothelial monolayer. Ntras∆CA/∆CA mice further showed reduced retinal vessel growth and increased vascular permeability and myocarditis. In summary, this study demonstrates that NTRAS is an essential gatekeeper of vascular integrity.

Development of an image-based Random Forest classifier for prediction of surgery duration of laparoscopic sigmoid resections.

PURPOSE: Sigmoid diverticulitis is a disease with a high socioeconomic burden, accounting for a high number of left-sided colonic resections worldwide. Modern surgical scheduling relies on accurate prediction of operation times to enhance patient care and optimize healthcare resources. This study aims to develop a predictive model for surgery duration in laparoscopic sigmoid resections, based on preoperative CT biometric and demographic patient data. METHODS: This retrospective single-center cohort study included 85 patients who underwent laparoscopic sigmoid resection for diverticular disease. Potentially relevant procedure-specific anatomical parameters recommended by a surgical expert were measured in preoperative CT imaging. After random split into training and test set (75% / 25%) multiclass logistic regression was performed and a Random Forest classifier was trained on CT imaging parameters, patient age, and sex in the training cohort to predict categorized surgery duration. The models were evaluated in the test cohort using established performance metrics including receiver operating characteristics area under the curve (AUROC). RESULTS: The Random Forest model achieved a good average AUROC of 0.78. It allowed a very good prediction of long (AUROC = 0.89; specificity 0.71; sensitivity 1.0) and short (AUROC = 0.81; specificity 0.77; sensitivity 0.56) procedures. It clearly outperformed the multiclass logistic regression model (AUROC: average = 0.33; short = 0.31; long = 0.22). CONCLUSION: A Random Forest classifier trained on demographic and CT imaging biometric patient data could predict procedure duration outliers of laparoscopic sigmoid resections. Pending validation in a multicenter study, this approach could potentially improve procedure scheduling in visceral surgery and be scaled to other procedures.

The mesenteric entry site as a potential weak point in gastrointestinal anastomoses - findings from an ex-vivo biomechanical analysis.

PURPOSE: Gastrointestinal disorders frequently necessitate surgery involving intestinal resection and anastomosis formation, potentially leading to severe complications like anastomotic leakage (AL) which is associated with increased morbidity, mortality, and adverse oncologic outcomes. While extensive research has explored the biology of anastomotic healing, there is limited understanding of the biomechanical properties of gastrointestinal anastomoses, which was aimed to be unraveled in this study. METHODS: An ex-vivo model was developed for the biomechanical analysis of 32 handsewn porcine end-to-end anastomoses, using interrupted and continuous suture techniques subjected to different flow models. While multiple cameras captured different angles of the anastomosis, comprehensive data recording of pressure, time, and temperature was performed simultaneously. Special focus was laid on monitoring time, location and pressure of anastomotic leakage (LP) and bursting pressures (BP) depending on suture techniques and flow models. RESULTS: Significant differences in LP, BP, and time intervals were observed based on the flow model but not on the suture techniques applied. Interestingly, anastomoses at the insertion site of the mesentery exhibited significantly higher rates of leakage and bursting compared to other sections of the anastomosis. CONCLUSION: The developed ex-vivo model facilitated comparable, reproducible, and user-independent biomechanical analyses. Assessing biomechanical properties of anastomoses offers an advantage in identifying technical weak points to refine surgical techniques, potentially reducing complications like AL. The results indicate that mesenteric insertion serves as a potential weak spot for AL, warranting further investigations and refinements in surgical techniques to optimize outcomes in this critical area of anastomotic procedures.

Robust classification using average correlations as features (ACF).

MOTIVATION: In single-cell transcriptomics and other omics technologies, large fractions of missing values commonly occur. Researchers often either consider only those features that were measured for each instance of their dataset, thereby accepting severe loss of information, or use imputation which can lead to erroneous results. Pairwise metrics allow for imputation-free classification with minimal loss of data. RESULTS: Using pairwise correlations as metric, state-of-the-art approaches to classification would include the K-nearest-neighbor- (KNN) and distribution-based-classification-classifier. Our novel method, termed average correlations as features (ACF), significantly outperforms those approaches by training tunable machine learning models on inter-class and intra-class correlations. Our approach is characterized in simulation studies and its classification performance is demonstrated on real-world datasets from single-cell RNA sequencing and bottom-up proteomics. Furthermore, we demonstrate that variants of our method offer superior flexibility and performance over KNN classifiers and can be used in conjunction with other machine learning methods. In summary, ACF is a flexible method that enables missing value tolerant classification with minimal loss of data.

A nationwide population-based study on the clinical and economic burden of anastomotic leakage in colorectal surgery.

AIM: Anastomotic leakage (AL) is one of the most dreaded complications in colorectal surgery. In 2013, the International Classification of Diseases code K91.83 for AL was introduced in Germany, allowing nationwide analysis of AL rates and associated parameters. The aim of this population-based study was to investigate the current incidence, risk factors, mortality, clinical management, and associated costs of AL in colorectal surgery. METHODS: A data query was performed based on diagnosis-related group data of all hospital cases of inpatients undergoing colon or sphincter-preserving rectal resections between 2013 and 2018 in Germany. RESULTS: A total number of 690,690 inpatient cases were included in this study. AL rates were 6.7% for colon resections and 9.2% for rectal resections in 2018. Regarding the treatment of AL, the application of endoluminal vacuum therapy increased during the studied period, while rates of relaparotomy, abdominal vacuum therapy, and terminal enterostomy remained stable. AL was associated with significantly increased in-house mortality (7.11% vs. 20.11% for colon resections and 3.52% vs. 11.33% for rectal resections in 2018) and higher socioeconomic costs (mean hospital reimbursement volume per case: 14,877€ (no AL) vs. 37,521€ (AL) for colon resections and 14,602€ (no AL) vs. 30,606€ (AL) for rectal resections in 2018). CONCLUSIONS: During the studied time period, AL rates did not decrease, and associated mortality remained at a high level. Our study provides updated population-based data on the clinical and economic burden of AL in Germany. Focused research in the field of AL is still urgently necessary to develop targeted strategies to prevent AL, improve patient care, and decrease socioeconomic costs.

Hyperpolarized Solution-State NMR Spectroscopy with Optically Polarized Crystals.

Nuclear spin hyperpolarization provides a promising route to overcome the challenges imposed by the limited sensitivity of nuclear magnetic resonance. Here we demonstrate that dissolution of spin-polarized pentacene-doped naphthalene crystals enables transfer of polarization to target molecules via intermolecular cross-relaxation at room temperature and moderate magnetic fields (1.45 T). This makes it possible to exploit the high spin polarization of optically polarized crystals, while mitigating the challenges of its transfer to external nuclei. With this method, we inject the highly polarized mixture into a benchtop NMR spectrometer and observe the polarization dynamics for target 1H nuclei. Although the spectra are radiation damped due to the high naphthalene magnetization, we describe a procedure to process the data to obtain more conventional NMR spectra and extract the target nuclei polarization. With the entire process occurring on a time scale of 1 min, we observe NMR signals enhanced by factors between -200 and -1730 at 1.45 T for a range of small molecules.

Retrospective study of prognosis of patients with multiple colorectal carcinomas: synchronous versus metachronous makes the difference.

PURPOSE: Little is known about difference between synchronous colorectal cancer (SCRC) and metachronous colorectal cancer (MCRC) despite the relevance for this selected patient group. The aim of this retrospective review was to analyze patients with SCRC and MCRC. METHODS: All patients who underwent surgery for SCRC and MCRC between 1982 and 2019 were included in this retrospective analysis of our tertiary referral center. Clinical, histological, and molecular genetic characteristics were analyzed. The primary endpoint was cause-specific survival, evaluated by the Kaplan-Meier method. Secondary endpoints were recurrence-free survival and the identification of prognostic factors. RESULTS: Overall, 3714 patients were included in this analysis. Of those, 3506 (94.4%) had a primary unifocal colorectal cancer (PCRC), 103 (2.7%) had SCRC, and 105 (2.8%) had MCRC. SCRC occurred more frequently in elderly (p=0.009) and in male patients (p=0.027). There were no differences concerning tumor stages or grading. Patients with SCRC did not show altered recurrence or survival rates, as compared to unifocal tumors. However, MCRC had a lower rate of recurrence, compared to PCRC (24% vs. 41%, p=0.002) and a lower rate of cause-specific death (13% vs. 37%, p<0.001). Five-year cause-specific survival rates were 63±1% for PCRC, 62±6% for SCRC (p=0.588), and 88±4% for MCRC (p<0.001). Multivariable analysis revealed that MCRC were an independent favorable prognostic parameter regarding case-specific survival. CONCLUSION: Patients with SCRC seem to not have a worse prognosis compared to patients with PCRC. Noteworthy, patients with MCRC showed better survival rates in this retrospective analysis.

Crohn's disease: a population-based study of surgery in the age of biological therapy.

PURPOSE: Despite primary conservative therapy for Crohn's disease, a considerable proportion of patients ultimately needs to undergo surgery. Presumably, due to the increased use of biologics, the number of surgeries might have decreased. This study aimed to delineate current case numbers and trends in surgery in the era of biological therapy for Crohn's disease. METHODS: Nationwide standardized hospital discharge data (diagnosis-related groups statistics) from 2010 to 2017 were used. All patients who were admitted as inpatient Crohn's disease cases in Germany were included. Time-related development of admission numbers, rate of surgery, morbidity, and mortality of inpatient Crohn's disease cases were analyzed. RESULTS: A total number of 201,165 Crohn's disease cases were included. Within the analyzed time period, the total number of hospital admissions increased by 10.6% (n = 23,301 vs. 26,069). While gender and age distribution remained comparable, patients with comorbidities such as stenosis formation (2010: 10.1%, 2017: 13.4%) or malnutrition (2010: 0.8%, 2017: 3.2%) were increasingly admitted. The total number of all analyzed operations for Crohn's disease increased by 7.5% (2010: n = 1567; 2017: n = 1694). On average, 6.8 ± 0.2% of all inpatient patients received ileocolonic resections. Procedures have increasingly been performed minimally invasive (2010: n = 353; 2017: n = 687). The number of postoperative complications remained low. CONCLUSION: Despite the development of novel immunotherapeutics, the number of patients requiring surgery for Crohn's disease remains stable. Interestingly, patients have been increasingly hospitalized with stenosis and malnutrition. The trend towards more minimally invasive operations has not relevantly changed the rate of overall complications.

Innovative approaches for induction of gastrointestinal anastomotic healing: an update on experimental and clinical aspects.

PURPOSE: In most cases, traditional techniques to perform an anastomosis following gastrointestinal resections lead to successful healing. However, despite focused research in the field, in certain high-risk situations leakage rates remain almost unchanged. Here, additional techniques may help the surgeon to protect the anastomosis and prevent leakage. We give an overview of some of the latest developments on experimental and clinical techniques for induction of anastomotic healing. METHODS: We performed a review of the current literature on approaches to improve anastomotic healing. RESULTS: Many promising approaches with a high clinical potential are in the developmental pipeline. Highly experimental approaches like inhibition of matrix metalloproteinases, stem cell therapy, hyperbaric oxygen therapy, induction of the hypoxic adaptive response, and the administration of growth factors are still in the preclinical phase. Other more clinical developments aim to strengthen the anastomotic suture line mechanically while shielding it from the influence of the microbiome. Among them are gluing, seaming the staple line, attachment of laminar biomaterials, and temporary intraluminal tubes. In addition, individualized bowel preparation, selectively reducing certain detrimental microbial populations could become the next stage of bowel preparation. Compression anastomoses are evolving as an equivalent technique additional to established hand-sewn and stapled anastomoses. Fluorescence angiography and flexible endoscopy could complement intraoperative quality control additionally to the air leak tests. Virtual ileostomy is a concept to prepare the bowel for the easy formation of a stoma in case of leakage. CONCLUSION: A variety of promising diagnostic and prophylactic measures that may support the surgeon in identifying high-risk anastomoses and support them according to their potential deficits is currently in development.

Radiologic predictors for failure of non-operative management of complicated diverticulitis: a single-centre cohort study.

PURPOSE: Modern non-operative management of diverticulitis consists of a complex therapeutic regimen and is successful in most cases even of complicated diverticulitis. Still, a certain proportion of patients requires urgent surgery due to failure of the conservative approach. This study aims to identify predictors for failure of conservative treatment of complicated diverticulitis with the need for subsequent urgent resection during the acute episode. METHODS: A single-centre retrospective cohort study was performed at our tertiary centre including cases of acute complicated diverticulitis (characterized by localized abscess formation and/or pericolic air) between 2007 and 2019 that were treated guideline-conform by multimodal conservative treatment. Radiologic characteristics of disease in CT scans upon admission were analysed by uni- and multivariable logistic regression to determine predictors for resection within 30 days after onset of the conservative therapy approach. RESULTS: A total of 669 cases of acute diverticulitis were identified, of which 141 patients met the inclusion criteria. Overall, 13% (n = 19) of patients were operated within 30 days despite initial conservative management. Multivariable logistic regression identified length of inflamed bowel greater than 7 cm (p < 0.011) and abscess formations >1 cm (p < 0.001) as significant risk factors for failure of conservative treatment. CONCLUSION: Patients with length of inflamed bowel >7 cm or abscess formation >1 cm have increased risk for failure of conservative treatment of acute episodes of diverticulitis with contained perforations with subsequent need for urgent surgery. Therefore, conservative treatment of those patients should be monitored with special caution.

Annexin A1 Expression Capacity as a Determinant for Disease Severity in Crohn's Disease.

INTRODUCTION: Crohn's disease (CD) is characterized by relapsing intestinal inflammation. The anti-inflammatory protein annexin A1 (ANXA1) has been linked to inflammatory processes in the gut. OBJECTIVE: To examine ANXA1 expression patterns in the inflamed intestine of patients with CD and associate ANXA1 expression capacity with disease characteristics. METHODS: Surgical specimens of patients with CD operated between 2003 and 2015 were examined. Immunohistochemistry and immunofluorescence were performed to delineate ANXA1 expression. Those with pronounced ANXA1 expression were included in further analysis by qPCR. ANXA1 mRNA expression ratio of the inflamed to non-inflamed tissue was determined and defined as expression capacity of the tissue. Depending on their expression capacity, patients were divided into 2 groups (ANXA1-low vs. ANXA1-high), which were associated with clinical characteristics. RESULTS: Immunohistochemical ANXA1 expression was localized in inflamed regions of the intestine. In immunofluorescence, ANXA1 costained with myeloperoxidase as neutrophil marker, CD4 and CD8 as T cell marker but not CD20 as B cell marker or CD68 as macrophage marker. In qPCR, ANXA1 mRNA expression was upregulated by 20-fold in inflamed to noninflamed tissues. Patients with higher intrinsic ANXA1 expression capacity had significantly less severity of inflammation. Furthermore, the ANXA1-high group had significantly more locally restricted disease (p = 0.0070), more stricturating disease (p = 0.0037), and was less frequently treated by preoperative steroid therapy (p = 0.030). CONCLUSIONS: ANXA1 expression was strongly associated with intestinal inflammation and expressed in T cells and neutrophils of the CD tissues. Patients with higher intrinsic ANXA1 expression capacity of the inflamed tissue presented milder inflammatory changes and indolent clinical course.

Meta-analysis and single-center experience on the protective effect of negative suction drains on wound healing after stoma reversal.

BACKGROUND: Compromised wound healing following stoma reversal is a frequent problem. The use of negative suction drainage for reduction of complications remains controversial. METHODS: The patient database of our center was reviewed for patients with ileostomy reversal between 2007 and 2017. Risk factors for wound complications were analyzed using multivariate regression analysis. Systematic review and meta-analysis was performed. Ultimately, results of this study were integrated into meta-analysis to assess the effect of drainage placement on wound healing. RESULTS: In our institutional analysis, a total of 406 patients with ileostomy reversal were included (n = 240 (59.1%) with drainage vs. n = 166 (40.8%) without drainage). In multivariate analysis, body mass index (BMI) was a risk factor for wound complications (odds ratio (95% CI) 1.06 (1.02-1.12)). Patients with drainage needed significantly fewer interventions than those without drainage (17.1% vs. 28.9%, p = 0.005). Placement of drainage significantly reduced the risk of wound complications even in the group with elevated BMI (odds ratio (95% CI) 0.462 (0.28-0.76), p = 0.003). Meta-analysis identified 6 studies with a total of 1180 patients eligible for further analysis (2 prospectively randomized trials; 4 retrospective cohort studies). Overall analysis revealed a significantly beneficial effect of wound drainage following ileostomy reversal (RR (95% CI) 0.47 (0.34, 0.66); p < 0.0001). CONCLUSION: In our institutional analysis as well as meta-analysis, the use of subcutaneous suction drains was beneficial for prevention of wound healing complications following ostomy reversal. Drainage placement is especially valuable in high-risk situations such as in obese patients.

The immunologic changes during different phases of intestinal anastomotic healing.

Intestinal anatomosis is a complex and multicellular process that involving three overlapped phases: exudative phase, proliferative phase, and reparative phase. Undisturbed anastomotic healings are crucial for the recovery of patients after operations but unsuccessful healings are linked with a considerable mortality. This time, we concentrate on the immunologic changes during different phases of intestinal anastomotic healing and select several major immune cells and cytokines of each phase to get a better understanding of these immunologic changes in different phases, which will be significant for more precise therapy strategies in anastomoses.

Robust and Accurate Electric Field Sensing with Solid State Spin Ensembles.

Electron spins in solids constitute remarkable quantum sensors. Individual defect centers in diamond were used to detect individual nuclear spins with a nanometer scale resolution, and ensemble magnetometers rival SQUID and vapor cell magnetometers when taking into account room-temperature operation and size. NV center spins can also detect electric field vectors, despite their weak coupling to electric fields. Here, we employ ensembles of NV center spins to measure macroscopic AC electric fields with high precision. We utilize low strain, 12C enriched diamond to achieve the maximum sensitivity and tailor the spin Hamiltonian via the proper magnetic field adjustment to map out the AC electric field strength and polarization and arrive at refined electric field coupling constants. For high-precision measurements, we combine classical lock-in detection with aspects from quantum phase estimation for the effective suppression of technical noise. Eventually, this enables t-1/2 uncertainty scaling of the electric field strength over extended averaging periods, enabling us to reach a precision down to 10-7 V/µm for an AC electric field with a frequency of 2 kHz and an amplitude of 0.012 V/ µm.

Mastering the scales: a survey on the benefits of multiscale computing software.

In the last few decades, multiscale modelling has emerged as one of the dominant modelling paradigms in many areas of science and engineering. Its rise to dominance is primarily driven by advancements in computing power and the need to model systems of increasing complexity. The multiscale modelling paradigm is now accompanied by a vibrant ecosystem of multiscale computing software (MCS) which promises to address many challenges in the development of multiscale applications. In this paper, we define the common steps in the multiscale application development process and investigate to what degree a set of 21 representative MCS tools enhance each development step. We observe several gaps in the features provided by MCS tools, especially for application deployment and the preparation and management of production runs. In addition, we find that many MCS tools are tailored to a particular multiscale computing pattern, even though they are otherwise application agnostic. We conclude that the gaps we identify are characteristic of a field that is still maturing and features that enhance the deployment and production steps of multiscale application development are desirable for the long-term success of MCS in its application fields. This article is part of the theme issue 'Multiscale modelling, simulation and computing: from the desktop to the exascale'.

Assessing the scales in numerical weather and climate predictions: will exascale be the rescue?

We discuss scientific features and computational performance of kilometre-scale global weather and climate simulations, considering the Icosahedral Non-hydrostatic (ICON) model and the Integrated Forecast System (IFS). Scalability measurements and a performance modelling approach are used to derive performance estimates for these models on upcoming exascale supercomputers. This is complemented by preliminary analyses of the model data that illustrate the importance of high-resolution models to gain improvements in the accuracy of convective processes, a better understanding of physics dynamics interactions and poorly resolved or parametrized processes, such as gravity waves, convection and boundary layer. This article is part of the theme issue 'Multiscale modelling, simulation and computing: from the desktop to the exascale'.

Cutting Edge: IL-36 Receptor Promotes Resolution of Intestinal Damage.

IL-1 family members are central mediators of host defense. In this article, we show that the novel IL-1 family member IL-36γ was expressed during experimental colitis and human inflammatory bowel disease. Germ-free mice failed to induce IL-36γ in response to dextran sodium sulfate (DSS)-induced damage, suggesting that gut microbiota are involved in its induction. Surprisingly, IL-36R-deficient (Il1rl2(-/-)) mice exhibited defective recovery following DSS-induced damage and impaired closure of colonic mucosal biopsy wounds, which coincided with impaired neutrophil accumulation in the wound bed. Failure of Il1rl2(-/-) mice to recover from DSS-induced damage was associated with a profound reduction in IL-22 expression, particularly by colonic neutrophils. Defective recovery of Il1rl2(-/-) mice could be rescued by an aryl hydrocarbon receptor agonist, which was sufficient to restore IL-22 expression and promote full recovery from DSS-induced damage. These findings implicate the IL-36/IL-36R axis in the resolution of intestinal mucosal wounds.

Protecting a Diamond Quantum Memory by Charge State Control.

In recent years, solid-state spin systems have emerged as promising candidates for quantum information processing. Prominent examples are the nitrogen-vacancy (NV) center in diamond, phosphorus dopants in silicon (Si:P), rare-earth ions in solids, and VSi-centers in silicon-carbide. The Si:P system has demonstrated that its nuclear spins can yield exceedingly long spin coherence times by eliminating the electron spin of the dopant. For NV centers, however, a proper charge state for storage of nuclear spin qubit coherence has not been identified yet. Here, we identify and characterize the positively charged NV center as an electron-spin-less and optically inactive state by utilizing the nuclear spin qubit as a probe. We control the electronic charge and spin utilizing nanometer scale gate electrodes. We achieve a lengthening of the nuclear spin coherence times by a factor of 4. Surprisingly, the new charge state allows switching of the optical response of single nodes facilitating full individual addressability.