SARS-CoV-2 antigen rapid detection tests: test performance during the COVID-19 pandemic and the impact of COVID-19 vaccination.

BACKGROUND: SARS-CoV-2 antigen rapid detection tests (RDTs) emerged as point-of-care diagnostics alongside reverse transcription polymerase chain reaction (RT-qPCR) as reference. METHODS: In a prospective performance assessment from 12 November 2020 to 30 June 2023 at a single centre tertiary care hospital, the sensitivity and specificity (primary endpoints) of RDTs from three manufacturers (NADAL®, Panbio™, MEDsan®) were compared to RT-qPCR as reference standard among patients, accompanying persons and staff aged ≥ six month in large-scale, clinical screening use. Regression models were used to assess influencing factors on RDT performance (secondary endpoints). FINDINGS: Among 78,798 paired RDT/RT-qPCR results analysed, overall RDT sensitivity was 34.5% (695/2016; 95% CI 32.4-36.6%), specificity 99.6% (76,503/76,782; 95% CI 99.6-99.7%). Over the pandemic course, sensitivity decreased in line with a lower rate of individuals showing typical COVID-19 symptoms. The lasso regression model showed that a higher viral load and typical COVID-19 symptoms were directly significantly correlated with the likelihood of a positive RDT result in SARS-CoV-2 infection, whereas age, sex, vaccination status, and the Omicron VOC were not. INTERPRETATION: The decline in RDT sensitivity throughout the pandemic can primarily be attributed to the reduced prevalence of symptomatic infections among vaccinated individuals and individuals infected with Omicron VOC. RDTs remain valuable for detecting SARS-CoV-2 in symptomatic individuals and offer potential for detecting other respiratory pathogens in the post-pandemic era, underscoring their importance in infection control efforts. FUNDING: German Federal Ministry of Education and Research (BMBF), Free State of Bavaria, Bavarian State Ministry of Health and Care.

Proficiency in bariatric surgery may shorten the learning curve for minimally-invasive D2 gastrectomy.

INTRODUCTION: Evidence from Asian studies suggests that minimally-invasive gastrectomy achieves equivalent oncological but improved perioperative outcomes compared to open surgery. Oncological gastric resections are less frequent in European countries. Index procedures may play a role for the learning curve of minimally-invasive gastrectomy. The aim of our study was to evaluate if skills acquired in bariatric surgery allow a safe and oncologically adequate implementation of minimally-invasive gastrectomy in a cohort of european patients. METHODS: In this single-center retrospective study, all patients who received primary bariatric surgery between January 2015 and December 2018 and minimally-invasive surgery for gastric cancer treated from June 2019 to January 2023 were evaluated. Primary endpoints were operation time, lymph node yield and lymph node fractions. Secondary endpoints included postoperative complications and oncological outcomes. RESULTS: Learning curves for two surgeons with 350 bariatric procedures and 44 minimally-invasive gastrectomies were analyzed. For bariatric surgery, the mean operation time decreased from initially 82 ± 27 to 45 ± 21 min and 118 ± 28 to 81 ± 36 min for sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), while the complication rate remained within the international benchmark. For laparoscopic gastrectomy (n = 30), operation times decreased but then remained stable over time. Operation times for the robotic platform were longer (302 ± 60 vs. 390 ± 48 min; p < 0.001) with the learning curve remaining incomplete after 14 procedures. R0 status was achieved in 95.5% of patients; the mean number of lymph nodes retrieved was 37 ± 14 with no differences between the groups. Complete mesogastric excision was more frequently achieved during the later laparoscopic cases whereas it occurred earlier for the robotic group (p = 0.004). Perioperative morbidity was comparable to the European benchmark. Textbook outcome was achieved in 54.4% of the cases. CONCLUSION: In summary, we could demonstrate a successful skill transfer from bariatric surgery to minimally-invasive laparoscopic oncological gastric surgery enabling safe and oncologically adequate minimally-invasive D2 gastrectomy in a central European patient collective.

Additional over-the-scope-clip closure can shorten endoscopic vacuum therapy for postoperative upper gastrointestinal leakage.

Background and study aims Endoscopic vacuum therapy (EVT) has become the most effective therapeutic option for upper gastrointestinal leakage. Despite its efficiency, this treatment can necessitate a long hospitalization. The aim of this study was to evaluate whether additional use of an over-the-scope-clips (OTSC) closure after successful EVT can shorten leakage therapy. Patients and methods All patients treated with EVT for leakages in the upper gastrointestinal tract at our center from 2012 to 2022 were divided into two propensity matched cohorts (EVT+OTSC vs. EVT only). The EVT+OTSC patients received OSTC application at the end of successful EVT directly after removal of the last sponge. The primary endpoint was the time interval from leakage diagnosis until discharge. Secondary endpoints included EVT efficacy, complications, and nutritional status at discharge. Results A total of 84 matched patients were analyzed. EVT efficacy was 100% in both groups. The time interval from leakage until discharge was significantly shorter in the EVT+OTSC vs. EVT group (33 [19-48] vs. 46 days [29-77] P = 0.004). No patient in the EVT+OTSC group required additional procedures for leakage management, whereas five (12%) in the EVT group needed additional stent placement ( P = 0.021). More patients could be discharged on sufficient oral nutrition in the EVT+OTSC group (98% vs. 60%; P < 0.001). Conclusions The addition of OTSCs after successful EVT is safe and has the potential to shorten leakage therapy, enabling earlier discharge along with better functional outcomes.

Surgical options in retrosternal oesophageal reconstruction.

BACKGROUND: Retrosternal oesophageal reconstructions with collar anastomoses can become necessary when the stomach is either unavailable for oesophageal replacement, or orthotopic reconstruction is deemed impractical. Our aim was to analyse our results regarding technical approaches and outcomes. MATERIALS AND METHODS: All patients undergoing primary and secondary oesophageal retrosternal reconstructions with collar anastomoses at our centre (2019-2023) were retrospectively analysed and individual surgical reconstruction options were presented. RESULTS: Overall, twelve patients received primary (n = 5; 42.7%) or secondary (n = 7; 58.3%) reconstructions; ten with colonic interposition and two with gastric pull-up. Male/female ratio was 4:8; median age 66 years (30-87). Charlson-Comorbidity-Score (CCS) was 5 (1-7); 8/12 patients (67%) had ASA-classification score ≥ 3. We observed no conduit necrosis, but one patient (8.3%) with a leakage of the oesophago-colonostomy which was successfully treated by endoscopic vacuum therapy. Four patients (33.3%) acquired nosocomial pneumonia. Additional drainages for pleural fluid collections were necessary in three patients (25%). Overall comprehensive-complication-index (CCI) was 26.2 (0-44.9). Length-of-stay (LOS) was 22 days median (15-40). There was no 90-days mortality. Overall, CCI during the follow-up (FU) period at median 26 months (16-50) was 33.7 (0-100). 10 out of 12 patients were on sufficient oral nutrition at 12 months FU. CONCLUSION: Primary and secondary oesophageal retrosternal reconstructions encompass diverse entities and typically requires tailored decision-making. These procedures, though rare, are feasible with acceptable complication rates and positive functional outcomes when performed in experienced hands.

Perioperative Enhanced Recovery Concepts Significantly Improve Postoperative Outcome in Patients with Crohn`s Disease.

BACKGROUND AND AIMS: Despite recent advancements in medical and surgical techniques in patients suffering from Crohn`s Disease (CD), postoperative morbidity remains relevant due to a long-standing, non-curable disease burden. As demonstrated for oncological patients, perioperative enhanced recovery concepts provide great potential to improve postoperative outcome. However, robust evidence about the effect of perioperative enhanced recovery concepts in the specific cohort of CD patients is lacking. METHODS: In a prospective single-center study, all patients receiving ileocecal resection due to CD between 2020 and 2023 were included. A specific perioperative enhanced recovery concept (ERC) was implemented and patients were divided into two groups (before and after implementation). The primary outcome focused on postoperative complications as measured by the Comprehensive Complication Index (CCI), secondary endpoints were severe complications, length of hospital stay, and rates of re-admission. RESULTS: 83 patients were analyzed of which 33 patients participated in the enhanced recovery program (postERC). While patient characteristics were comparable between both groups, ERC resulted in significantly decreased rates of overall and severe postoperative complications (CCI: 21.4 versus 8.4, p=0.0036; Clavien Dindo >2: 38% versus 3.1%, p=0.0002). Additionally, postERC-patients were earlier ready for discharge (6.5 days versus 5 days, p=0.001) and rates of re-admission were significantly lower (20% versus 3.1%, p=0.03). In a multivariate analysis, the recovery concept was identified as independent factor to reduce severe postoperative complications (p=0.019). CONCLUSION: A specific perioperative enhanced recovery concept significantly improves the postoperative outcome of patients suffering from Crohn`s Disease.

Positive resection margins in Crohn's disease are a relevant risk factor for postoperative disease recurrence.

Postoperative disease recurrence in Crohn's disease represents a relevant issue despite recent advancements in surgical and medical therapies. Additional criteria are necessary to improve the identification of patients at risk and to enable selective therapeutic approaches. The role of resection margins on disease recurrence remains unclear and general recommendations are lacking. A single-center retrospective analysis was performed including all patients who received ileocecal resection due to Crohn's disease. Resection margins were analyzed by two independent pathologists and defined by histopathological criteria based on previous consensus reports. 158 patients were included for analysis with a median follow up of 35 months. While postoperative morbidity was not affected, positive resection margins resulted in significantly increased rates of severe endoscopic recurrence at 6 months (2.0% versus 15.6%, p = 0.02) and overall (4.2% versus 19.6%, p = 0.001), which resulted in significantly increased numbers of surgical recurrence (0% versus 4.5%, p = 0.04). Additionally, positive margins were identified as independent risk factor for severe endoscopic disease recurrence in a multivariate analysis. Based on that, positive margins represent an independent risk factor for postoperative endoscopic and surgical disease recurrence. Prospective studies are required to determine whether extended resection or postoperative medical prophylaxis is beneficial for patients with positive resection margins.

Role of Rabenosyn-5 and Rab5b in host cell cytosol uptake reveals conservation of endosomal transport in malaria parasites.

Vesicular trafficking, including secretion and endocytosis, plays fundamental roles in the unique biology of Plasmodium falciparum blood-stage parasites. Endocytosis of host cell cytosol (HCC) provides nutrients and room for parasite growth and is critical for the action of antimalarial drugs and parasite drug resistance. Previous work showed that PfVPS45 functions in endosomal transport of HCC to the parasite's food vacuole, raising the possibility that malaria parasites possess a canonical endolysosomal system. However, the seeming absence of VPS45-typical functional interactors such as rabenosyn 5 (Rbsn5) and the repurposing of Rab5 isoforms and other endolysosomal proteins for secretion in apicomplexans question this idea. Here, we identified a parasite Rbsn5-like protein and show that it functions with VPS45 in the endosomal transport of HCC. We also show that PfRab5b but not PfRab5a is involved in the same process. Inactivation of PfRbsn5L resulted in PI3P and PfRab5b decorated HCC-filled vesicles, typical for endosomal compartments. Overall, this indicates that despite the low sequence conservation of PfRbsn5L and the unusual N-terminal modification of PfRab5b, principles of endosomal transport in malaria parasite are similar to that of model organisms. Using a conditional double protein inactivation system, we further provide evidence that the PfKelch13 compartment, an unusual apicomplexa-specific endocytosis structure at the parasite plasma membrane, is connected upstream of the Rbsn5L/VPS45/Rab5b-dependent endosomal route. Altogether, this work indicates that HCC uptake consists of a highly parasite-specific part that feeds endocytosed material into an endosomal system containing more canonical elements, leading to the delivery of HCC to the food vacuole.

[Robotic rectal surgery]. / Robotische Rektumchirurgie.

Colorectal cancer is one of the most frequent cancerous diseases in industrial nations, whereby tumors of the rectum constitute approximately 30-40% of all colorectal cancers. In addition to the implementation and establishment of novel neoadjuvant concepts for the treatment of rectal cancer, there has been a continuous evolution of surgical techniques in recent years towards minimally invasive surgery. In this respect robot-assisted surgery has become more and more popular despite seemingly weak evidence regarding clinical benefits and the not to be ignored economic aspects; however, recently published high-quality studies provide new evidence showing advantages for a robotic resection in patients suffering from rectal cancer. Thus, the progressive implementation of robotic surgical systems is increasingly attaining a scientific foundation.

[Watch and Wait for Rectal Cancer]. / Surveillance bei Watch-and-Wait nach neoadjuvanter Therapie beim Rektumkarzinom.

About one third of all colorectal carcinomas (CRC) are localised in the rectum. As part of a multimodal therapy concept, neoadjuvant therapy achieves downstaging of the tumour in 50-60% of cases and a so-called complete clinical response (cCR), defined as clinically (and radiologically) undetectable residual tumour after completion of neoadjuvant therapy, in 10-30% of cases.In view of the perioperative morbidity and mortality associated with radical rectal resection, including the occurrence of a symptom complex known as low anterior resection syndrome (LARS) and the need for deviation, at least temporarily, the question of the risk-benefit balance of organ resection in the presence of cCR has been raised. In this context, the therapeutic concept of a "watch-and-wait" approach with omission of immediate organ resection and inclusion in a structured surveillance regime, has emerged.For a safe, oncological implementation of this option, it is necessary to develop standards in the definition of a suitable patient clientele and the implementation of the concept. In addition to the initial correct selection of the patient group that is suitable for a primarily non-surgical procedure, the inherent goal is the early and sufficient detection of tumour recurrence (so-called local regrowth) during the "watch-and-wait" phase (surveillance).In this context, in this paper we address the questions of: 1. the optimal timing of initial re-staging, 2. the criteria for assessing the clinical response and selecting the appropriate patient clientele, 3. the rhythm and design of the surveillance protocol.

Safety, Efficacy and Outcome of Rotational Thrombectomy assisted Endovascular Revascularisation of the Superior Mesenteric Artery in Acute Thromboembolic Mesenteric Ischaemia.

PURPOSE: To evaluate the efficacy and safety of percutaneous rotational thrombectomy-assisted endovascular revascularization of acute thromboembolic superior mesenteric artery occlusions in acute mesenteric ischemia. MATERIALS AND METHODS: Fifteen cases of percutaneous rotational thrombectomy- assisted (Rotarex S, BD, USA) revascularization were retrospectively analyzed. The etiology was embolic in 40 % of cases and thrombotic in 60 %. A "Thrombectomy in Visceral Ischemia" (TIVI) 5-point score determined vessel patency at presentation, after percutaneous rotational thrombectomy, and after adjunctive technologies. TIVI 3 indicated nearly complete revascularization (minimal residual side branch thrombus). TIVI 4 indicated complete revascularization. Technical success was defined as successful device application and a final TIVI score of 3/4 after adjunctive technologies. Safety and outcome were also analyzed. RESULTS: Device application via femoral access was feasible in 100 % of cases and improved flow in 86.7 % of cases (1â€Š× TIVI 0→1, 11â€Š× TIVI 0→2, 1â€Š× TIVI 1→2). There was no change in 13.3 % of cases (2â€Š× TIVI 2→2). Additional devices resulted in further flow improvement in 93.3 % of cases (8â€Š× TIVI 3, 6â€Š× TIVI 4). One recanalization failed (TIVI 2→2→2). After adjunctive technologies (10â€Š× manual aspiration, 11â€Š× angioplasty, 9â€Š× stenting), the technical success rate was 93.3 %. The mean procedure time was 40.5(±â€Š14) minutes for embolism and 72.1(±â€Š20) minutes for thrombosis. There was one device-related major complication (catheter tip fracture) resulting in a device-related safety rate of 93.3 %. The overall major complication rate was 20 %. Surgical exploration (13 ×), bowel resection (9 ×) and Fogarty embolectomy/bypass (3 ×) were also performed. The 30-day mortality rate was 40 %. CONCLUSION: Percutaneous rotational thrombectomy is an effective adjunct for rapid endovascular recanalization of acute thromboembolic superior mesenteric artery occlusions with an acceptable rate of major procedural complications. KEY POINTS: · Percutaneous rotational thrombectomy-assisted superior mesenteric artery revascularization in acute occlusive mesenteric ischemia is feasible and effective.. · Percutaneous rotational thrombectomy facilitates rapid flow restoration in native and stented superior mesenteric artery segments.. · Brachial access should be considered in the case of steep take-off angles of the superior mesenteric artery..

[Structured implementation of fast-track pathways to enhance recovery after elective colorectal resection : First results from five German hospitals]. / Strukturierte Fast-track-Implementierung zur beschleunigten Genesung nach elektiven kolorektalen Resektionen : Erste Erfahrungen 5 deutscher Kliniken.

BACKGROUND: Multimodal optimized perioperative management (mPOM, fast-track, enhanced recovery after surgery, ERAS) leads to a significantly accelerated recovery of patients with elective colorectal resections. Nevertheless, fast-track surgery has not yet become established in everyday clinical practice in Germany. We present the results of a structured fast-track implementation in five German hospitals. METHODS: Prospective data collection in the context of a 13-month structured fast-track implementation. All patients ≥ 18 years undergoing elective colorectal resection and who gave informed consent were included. After 3 months of preparation (pre-FAST), fast-track treatment was initiated and continued for 10 months (FAST). Outcome criteria were adherence to internationally recommended fast-track elements, postoperative complications, functional recovery, and postoperative hospital stay. RESULTS: Data from 192 pre-FAST and 529 FAST patients were analyzed. Age, sex, patient risk, location, and type of disease were not different between both groups. The FAST patients were more likely to have undergone minimally invasive surgery (82% vs. 69%). Fast-track adherence increased from 52% (35-65%) under traditional treatment to 83% (65-96%) under fast-track treatment (p < 0.01). The duration until the end of infusion treatment, removal of the bladder catheter, first bowel movement, oral solid food, regaining autonomy, suitability for discharge and postoperative length of stay were significantly lower in the FAST group. Complications, reoperations, and readmission rates did not differ. CONCLUSION: Fast-track adherence rates > 75% can also be achieved in German hospitals through structured fast-track implementation and the recovery of patients can be significantly accelerated.

The Kelch13 compartment contains highly divergent vesicle trafficking proteins in malaria parasites.

Single amino acid changes in the parasite protein Kelch13 (K13) result in reduced susceptibility of P. falciparum parasites to artemisinin and its derivatives (ART). Recent work indicated that K13 and other proteins co-localising with K13 (K13 compartment proteins) are involved in the endocytic uptake of host cell cytosol (HCCU) and that a reduction in HCCU results in reduced susceptibility to ART. HCCU is critical for parasite survival but is poorly understood, with the K13 compartment proteins among the few proteins so far functionally linked to this process. Here we further defined the composition of the K13 compartment by analysing more hits from a previous BioID, showing that MyoF and MCA2 as well as Kelch13 interaction candidate (KIC) 11 and 12 are found at this site. Functional analyses, tests for ART susceptibility as well as comparisons of structural similarities using AlphaFold2 predictions of these and previously identified proteins showed that vesicle trafficking and endocytosis domains were frequent in proteins involved in resistance or endocytosis (or both), comprising one group of K13 compartment proteins. While this strengthened the link of the K13 compartment to endocytosis, many proteins of this group showed unusual domain combinations and large parasite-specific regions, indicating a high level of taxon-specific adaptation of this process. Another group of K13 compartment proteins did not influence endocytosis or ART susceptibility and lacked detectable vesicle trafficking domains. We here identified the first protein of this group that is important for asexual blood stage development and showed that it likely is involved in invasion. Overall, this work identified novel proteins functioning in endocytosis and at the K13 compartment. Together with comparisons of structural predictions it provides a repertoire of functional domains at the K13 compartment that indicate a high level of adaption of endocytosis in malaria parasites.

Human organoids are superior to cell culture models for intestinal barrier research.

Loss of intestinal epithelial barrier function is a hallmark in digestive tract inflammation. The detailed mechanisms remain unclear due to the lack of suitable cell-based models in barrier research. Here we performed a detailed functional characterization of human intestinal organoid cultures under different conditions with the aim to suggest an optimized ex-vivo model to further analyse inflammation-induced intestinal epithelial barrier dysfunction. Differentiated Caco2 cells as a traditional model for intestinal epithelial barrier research displayed mature barrier functions which were reduced after challenge with cytomix (TNFα, IFN-γ, IL-1ß) to mimic inflammatory conditions. Human intestinal organoids grown in culture medium were highly proliferative, displayed high levels of LGR5 with overall low rates of intercellular adhesion and immature barrier function resembling conditions usually found in intestinal crypts. WNT-depletion resulted in the differentiation of intestinal organoids with reduced LGR5 levels and upregulation of markers representing the presence of all cell types present along the crypt-villus axis. This was paralleled by barrier maturation with junctional proteins regularly distributed at the cell borders. Application of cytomix in immature human intestinal organoid cultures resulted in reduced barrier function that was accompanied with cell fragmentation, cell death and overall loss of junctional proteins, demonstrating a high susceptibility of the organoid culture to inflammatory stimuli. In differentiated organoid cultures, cytomix induced a hierarchical sequence of changes beginning with loss of cell adhesion, redistribution of junctional proteins from the cell border, protein degradation which was accompanied by loss of epithelial barrier function. Cell viability was observed to decrease with time but was preserved when initial barrier changes were evident. In summary, differentiated intestinal organoid cultures represent an optimized human ex-vivo model which allows a comprehensive reflection to the situation observed in patients with intestinal inflammation. Our data suggest a hierarchical sequence of inflammation-induced intestinal barrier dysfunction starting with loss of intercellular adhesion, followed by redistribution and loss of junctional proteins resulting in reduced barrier function with consecutive epithelial death.

Endothelial barrier dysfunction in systemic inflammation is mediated by soluble VE-cadherin interfering VE-PTP signaling.

Breakdown of endothelial barrier integrity determines organ dysfunction and outcome of patients with sepsis. Increased levels of soluble vascular endothelial (VE)-cadherin fragments (sVE-cadherin) have previously been linked with inflammation-induced loss of endothelial barrier function. We provide evidence for a causative role of sVE-cadherin to induce loss of endothelial barrier function. In patients with sepsis, sVE-cadherin levels were associated with organ dysfunction and the need for volume resuscitation. Similarly, LPS-induced systemic inflammation in rats with microvascular dysfunction was paralleled by augmented sVE-cadherin levels. Newly generated recombinant human sVE-cadherin (extracellular domains EC1-5) induced loss of endothelial barrier function in both human microvascular endothelial cells in vitro and in rat mesenteric microvessels in vivo and reduced microcirculatory flow. sVE-cadherinEC1-5 disturbed VE-cadherin-mediated adhesion and perturbed VE-protein tyrosine phosphatase (VE-PTP)/VE-cadherin interaction resulting in RhoGEF1-mediated RhoA activation. VE-PTP inhibitor AKB9778 and Rho-kinase inhibitor Y27632 blunted all sVE-cadherinEC1-5-induced effects, which uncovers a pathophysiological role of sVE-cadherin via dysbalanced VE-PTP/RhoA signaling.

Nationwide volume-outcome relationship concerning in-hospital mortality and failure-to-rescue in surgery of sigmoid diverticulitis.

PURPOSE: A correlation between the hospital volume and outcome is described for multiple entities of oncological surgery. To date, this has not been analyzed for the surgical treatment of sigmoid diverticulitis. The aim of this study was to explore the impact of the annual caseload per hospital of colon resection on the postoperative incidence of complications, failure to rescue, and mortality in patients with diverticulitis. METHODS: Patients receiving colorectal resection independent from the diagnosis from 2012 to 2017 were selected from a German nationwide administrative dataset. The hospitals were grouped into five equal caseload quintiles (Q1-Q5 in ascending caseload order). The outcome analysis was focused on patients receiving surgery for sigmoid diverticulitis. RESULTS: In total, 662,706 left-sided colon resections were recorded between 2012 and 2017. Of these, 156,462 resections were performed due to sigmoid diverticulitis and were included in the analysis. The overall in-house mortality rate was 3.5%, ranging from 3.8% in Q1 (mean of 9.5 procedures per year) to 3.1% in Q5 (mean 62.8 procedures per year; p < 0.001). Q5 hospitals revealed a risk-adjusted odds ratio of 0.85 (95% CI 0.78-0.94; p < 0.001) for in-hospital mortality compared to Q1 during multivariable logistic regression analysis. High-volume centers showed overall lower complication rates, whereas the failure-to-rescue did not differ significantly. CONCLUSION: Surgical treatment of sigmoid diverticulitis in high-volume colorectal centers shows lower postoperative mortality rates and fewer postoperative complications.

Inhibition of Soluble Stem Cell Factor Promotes Intestinal Mucosal Repair.

BACKGROUND: Incidences of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, are escalating worldwide and can be considered a global public health problem. Given that the gold standard approach to IBD therapeutics focuses on reducing the severity of symptoms, there is an urgent unmet need to develop alternative therapies that halt not only inflammatory processes but also promote mucosal repair. Previous studies have identified increased stem cell factor (SCF) expression in inflamed intestinal mucosal tissues. However, the role that SCF plays in mediating intestinal inflammation and repair has not been explored. METHODS: Changes in the expression of SCF were evaluated in the colonic tissue of healthy mice and during dextran sodium sulfate (DSS)-induced colitis. Furthermore, mucosal wound healing and colitis severity were analyzed in mice subjected to either mechanical biopsy or DSS treatment, respectively, following intestinal epithelial cell-specific deletion of SCF or anti-SCF antibody administration. RESULTS: We report robust expression of SCF by intestinal epithelial cells during intestinal homeostasis with a switch to immune cell-produced SCF during colitis. Data from mice with intestinal epithelial cell-specific deletion of SCF highlight the importance of immune cell-produced SCF in driving the pathogenesis of colitis. Importantly, antibody-mediated neutralization of total SCF or the specific SCF248 isoform decreased immune cell infiltration and enhanced mucosal wound repair following biopsy-induced colonic injury or DSS-induced colitis. CONCLUSIONS: These data demonstrate that SCF functions as a pro-inflammatory mediator in mucosal tissues and that specific neutralization of SCF248 could be a viable therapeutic option to reduce intestinal inflammation and promote mucosal wound repair in individuals with IBD.

Our investigation demonstrates that blocking cleavable SCF248 isoform by administration of specific stem cell factor antibodies enhances healing of the intestinal mucosa and restores critical barrier function, suggesting an alternative therapeutic option to treat individuals with active IBD.