Epha1 is a cell-surface marker for the neuromesodermal competent population.

The vertebrate body is built during embryonic development by the sequential addition of new tissue as the embryo grows at its caudal end. During this process, progenitor cells within the neuromesodermal competent (NMC) region generate the postcranial neural tube and paraxial mesoderm. Here, we have applied a genetic strategy to recover the NMC cell population from mouse embryonic tissues and have searched their transcriptome for cell-surface markers that would give access to these cells without previous genetic modifications. We found that Epha1 expression is restricted to the axial progenitor-containing areas of the mouse embryo. Epha1-positive cells isolated from the mouse tailbud generate neural and mesodermal derivatives when cultured in vitro. This observation, together with their enrichment in the Sox2+/Tbxt+ molecular phenotype, indicates a direct association between Epha1 and the NMC population. Additional analyses suggest that tailbud cells expressing low Epha1 levels might also contain notochord progenitors, and that high Epha1 expression might be associated with progenitors entering paraxial mesoderm differentiation. Epha1 could thus be a valuable cell-surface marker for labeling and recovering physiologically active axial progenitors from embryonic tissues.

Robotic versus laparoscopic gastrectomy for gastric cancer: A Western propensity score matched analysis.

BACKGROUND: Robot-assisted gastrectomy (RG) has been shown to be safe and feasible in the treatment of gastric cancer (GC). However, it is unclear whether RG is equivalent to laparoscopic gastrectomy (LG), especially in the Western world. Our objective was to compare the outcomes of RG and LG in GC patients. METHODS: We reviewed all gastric adenocarcinoma patients who underwent curative gastrectomy by minimally invasive approach in our institution from 2009 to 2022. Propensity score matching (PSM) analysis was conducted to reduce selection bias. DaVinci Si platform was used for RG. RESULTS: A total of 156 patients were eligible for inclusion (48 RG and 108 LG). Total gastrectomy was performed in 21.3% and 25% of cases in LG and RG, respectively. The frequency of stage pTNM II/III was 48.1%, and 54.2% in the LG and RG groups (p = 0.488). After PSM, 48 patients were matched in each group. LG and RG had a similar number of dissected lymph nodes (p = 0.759), operative time (p = 0.421), and hospital stay (p = 0.353). Blood loss was lower in the RG group (p = 0.042). The major postoperative complications rate was 16.7% for LG and 6.2% for RG (p = 0.109). The 30-day mortality rate was 2.1% and 0% for LG and RG, respectively (p = 1.0). There was no significant difference between the LG and RG groups for disease-free survival (79.6% vs. 61.2%, respectively; p = 0.155) and overall survival (75.9% vs. 65.7%, respectively; p = 0.422). CONCLUSION: RG had similar surgical and long-term outcomes compared to LG, with less blood loss observed in RG.

Tagging mortality in acoustic telemetry studies: Insights from a multispecies analysis.

The widespread adoption of acoustic telemetry has transformed our understanding of marine species' behavior and movement ecology. However, accurately interpreting telemetry data, especially concerning tagging mortality, is essential for drawing valid conclusions. In this study, we scrutinized tagging mortality in 223 individuals across 14 species and evaluated the impact of tagging methodologies, including capture method and size effects. Results reveal high tagging survival rates overall, attributable to the resiliency of the studied species and the rigorous animal welfare protocols followed during tagging procedures. Our results highlight the importance of tailoring array designs to the specific mobility patterns of the studied species for accurate survival assessments. This research contributes to generalizing mortality assessments and clearing the path for more precise and reliable telemetry studies in the future.

Multivisceral resection compared to standard gastrectomy for gastric adenocarcinoma: A propensity score-matching analysis.

BACKGROUND: Multivisceral resection (MVR) in locally advanced gastric cancer (GC) is a morbid procedure. However, the precise impact of removing additional organs remains controversial. This study aimed to compare the outcomes of MVR versus standard gastrectomy (SG) in an unbiased cohort. METHODS: Patients who underwent curative-intent surgery for gastric adenocarcinoma were considered. Those submitted to SG were compared to the ones who received MVR using Propensity Score Matching (PSM) analysis. RESULTS: A total of 685 GC patients were included (621 SG and 64 MVR). Groups were distinct concerning the extent of the gastrectomy, tumor size, pTNM, R0, postoperative complications, and 90-day mortality. After PSM, 57 patients were matched in each group. All variables assigned in the score were well matched. Postoperative complication, 90-day mortality, and overall survival (OS) became similar among groups. Age >65 years old and resection of two or more organs, besides the stomach, were factors associated with 90-day mortality. R1 and not received multimodal therapy were independent prognostic factors for worse OS. CONCLUSIONS: After PSM, the difference in morbidity, mortality, and survival of MVR compared to SG was no longer statistically significant, suggesting that MVR is an acceptable therapeutic strategy to patients with advanced GC.

Preoperative chemotherapy is a better strategy than upfront surgery in cT4 gastric cancer.

BACKGROUND: Chemotherapy (CMT) followed by surgery is recommended by Western countries for advanced gastric cancer (GC). However, cT4 GC usually undergoes upfront surgery, due to symptoms. This study aimed to evaluate if preoperative CMT is a better strategy than upfront surgery in cT4 GC. METHODS: All cT4 GCs who underwent curative gastrectomy were included. Patients were divided according to their initial treatment: upfront surgery (SURG) or CMT + SURG. RESULTS: Among the 226 GC initially staged as cT4, 150 underwent SURG and 76 CMT + SURG. Groups were similar concerning age, comorbidities, American Society of Anesthesiologists, gastrectomy performed, and postoperative complications. The CMT + SURG group had less advanced pTNM. Median overall survival (OS) was 32 and 58.5 months for SURG and CMT + SURG, respectively (p = 0.04). Patients who received perioperative or adjuvant CMT had better OS compared to surgery alone (49.4 vs. 15.9 months, p < 0.001). OS was similar for those receiving preoperative and adjuvant CMT. Non-CMT, pN+, and R1 resection were independent risk factors for worse OS. CONCLUSION: Multimodal treatment associating CMT with surgery, regardless of whether the approach is pre- or postoperative, is essential to improve the survival of cT4 GC. As tolerance to adjuvant treatment is reduced, preoperative CMT is a better strategy than upfront surgery in these patients.

Gastrectomy for elderly gastric cancer patients: A propensity score-matching analysis.

BACKGROUND: Although D2-gastrectomy is the most effective treatment for resectable gastric cancer (GC), it is unclear whether elderly patients have increased risk of morbidity and worse survival. This study aimed to compare the short- and long-term outcomes of older age (OA) patients with those of less advanced age (LAA). METHODS: GC patients undergoing curative gastrectomy were retrospectively analyzed and divided into two groups: OA (>75 years) and LAA (<75 years). Propensity score-matching (PSM) analysis using seven variables was conducted to reduce selection bias. RESULTS: Among 586 patients, 494 (84.3%) were classified as LAA and 92 (15.7%) as OA. OA patients had worse clinical status, higher rates of D1-lymphadenectomy, subtotal gastrectomy, and Lauren type; higher mortality and worse survival. No difference in pathological tumor-node-metastasis (pTNM) stage was observed between groups. Preoperative chemotherapy was performed more frequently in the LAA group. After PSM (92 OA: 92 LAA), all variables included in PSM were matched, and mortality rates and survival became similar between groups. In multivariate analysis, American Society of Anaesthesiologists score III/IV was an independent factor associated with a 90-day mortality after PSM. CONCLUSION: Gastrectomy in elderly GC patients has similar outcomes compared with younger ones. Clinical status and disease stage are more important than the patient's age.

Gastric cancer with microsatellite instability displays increased thymidylate synthase expression.

BACKGROUND: Gastric cancer (GC) with microsatellite instability (MSI) is a less aggressive disease and associated with resistance to 5-fluorouracil (5-FU)-based chemotherapy (CMT). Thymidylate synthase (TS) is inhibited by 5-FU, and another potential mediator of therapeutic resistance to 5-FU. Therefore, we aimed to analyze the association between MSI and TS expression in GC, and its impact on disease outcomes. METHODS: We retrospectively evaluated GC who underwent D2-gastrectomy. MSI and TS were analyzed by immunohistochemistry. We also investigated p53 expression, PD-L1 status, and tumor-infiltrating lymphocytes (CD4 and CD8). RESULTS: Out of 284 GC, 60 (21.1%) were MSI. Median TS-score for all cases was 16.5. TS expression was significantly higher in MSI compared to microsatellite-stable (MSS; p < 0.001). Considering both status, GC were classified in four groups: 167 (58.8%) MSS + TS-low; 57 (20.1%) MSS + TS-High; 24 (8.5%) MSI + TS-low; and 36 (12.7%) MSI + TS-high. MSI + TS-high group had less advanced pTNM stage, higher CD8+T cells levels (p < 0.001) and PD-L1 positivity (p < 0.001). Normal p53 expression was related to MSI GC (p < 0.001). Improved survival was observed in MSI + TS-high, but no survival benefit was seen with CMT. CONCLUSION: MSI GC was associated with high TS levels, which may explain therapeutic resistance to 5-FU. Additionally, MSI + TS-high showed better survival, but without improvement with CMT.

Esophagojejunostomy after total gastrectomy: A systematic review and meta-analysis comparing hand-sewn and stapled anastomosis.

This review aims to evaluate the surgical outcomes of hand-sewn esophageal anastomosis compared to mechanical anastomosis to reconstruct total gastrectomy. A systematic review and meta-analysis of comparative studies evaluating hand-sewn and stapled anastomosis were performed. A total of 12 studies were selected, comprising 1761 individuals. The results indicate that the hand-sewn and stapled esophageal anastomosis have similar surgical outcomes. Stapled anastomosis has a shorter operation time.

Value of Immunohistochemistry to Differentiate Digital Papillary Adenocarcinoma From Acral Hidradenoma With Papillary Structures.

ABSTRACT: Digital papillary adenocarcinoma is a malignant adnexal tumor with a predilection for acral sites. Hidradenoma is a benign solid and cystic sweat gland neoplasm with focal ductal and glandular differentiation and good outcomes. Hidradenomas can occur at acral sites and show papillary structures; for this reason, they are included in the differential diagnosis of digital papillary adenocarcinoma, and immunohistochemistry is a valuable tool in this scenario. We described a case of a 43-year-old man with an epithelial tumor showing papillary structures in the intermediate phalanx of the fourth finger. There was diffuse positivity for p63 and negativity for S100 protein, suggesting that this tumor was an acral hidradenoma with papillary structures.

Rehabilitation of Atrophic Maxilla With Immediate Loading of Extrasinus Zygomatic Implant.

ABSTRACT: The aim of this case series was to evaluate the long-term success rate of immediate occlusal loading of extrasinus zygomatic dental implants after a 3-year follow-up. The sample consisted of 31 patients (mean age of 64 years) with atrophic maxillae rehabilitated with 1 to 4 extrasinus zygomatic implants, placed unilaterally or bilaterally. All the patients received complete implant-supported dental prostheses with immediate loading by associating zygomatic implants with conventional implants. None of the procedures were associated with bone grafts. During the 3-year period of follow-up in the present study, all the patients attended clinical sessions and underwent radiographic exams every 6 months. In total 55 zygomatic and 69 conventional implants were placed, where 1 zygomatic and 2 conventional implants were lost, representing success rates of 98.18% and 97.20%, respectively. None of the studied patients had signs of sinusitis or changes in the maxillary sinuses. All the patients showed occlusal contact on natural antagonist teeth or implant-supported dental prostheses. Therefore, it was concluded that the use of exteriorized zygomatic implants with immediate loading represented a feasible option with high success rates for the treatment of atrophic maxilla.

A Photoswitchable Ligand Targeting the ß1 -Adrenoceptor Enables Light-Control of the Cardiac Rhythm.

Catecholamine-triggered ß-adrenoceptor (ß-AR) signaling is essential for the correct functioning of the heart. Although both ß1 - and ß2 -AR subtypes are expressed in cardiomyocytes, drugs selectively targeting ß1 -AR have proven this receptor as the main target for the therapeutic effects of beta blockers in the heart. Here, we report a new strategy for the light-control of ß1 -AR activation by means of photoswitchable drugs with a high level of ß1 -/ß2 -AR selectivity. All reported molecules allow for an efficient real-time optical control of receptor function in vitro. Moreover, using confocal microscopy we demonstrate that the binding of our best hit, pAzo-2, can be reversibly photocontrolled. Strikingly, pAzo-2 also enables a dynamic cardiac rhythm management on living zebrafish larvae using light, thus highlighting the therapeutic and research potential of the developed photoswitches. Overall, this work provides the first proof of precise control of the therapeutic target ß1 -AR in native environments using light.

Prognostic implications of tumor-infiltrating lymphocytes in association with programmed cell death ligand 1 expression in remnant gastric cancer.

Objective: Remnant gastric cancer (RGC) is usually associated with a worse prognosis. As they are less common and very heterogeneous tumors, new prognostic and reliable determinants are required to predict patients' clinical course for RGC. This study aimed to investigate the tumor-infiltrating lymphocytes (TILs) and programmed cell death ligand 1 (PD-L1) status as prognostic biomarkers in a cohort of patients with RGC to develop an immune-related score. Methods: Patients with gastric cancer (GC) who underwent curative intent gastrectomy were retrospectively investigated. RGC resections with histological diagnosis of gastric adenocarcinoma were enrolled in the study. The risk score based on immune parameters was developed using binary logistic regression analysis. RGCs were divided into high-risk (HR), intermediate-risk (IR), and low-risk (LR) groups based on their immune score. The markers (CD3+, CD4+/CD8+ T cells and PD-L1) were selected for their potential prognostic, therapeutic value, and evaluated by immunohistochemistry (IHC). Results: A total of 42 patients with RGC were enrolled in the study. The score based on immune parameters exhibited an accuracy of 79% [the area under the receiver operating characteristic curve (AUC)=0.79, 95% confidence interval (95% CI), 0.63-0.94, P=0.002], and the population was divided into 3 prognostic groups: 10 (23.8%) patients were classified as LR, 15 (35.7%) as IR, and 17 (40.5%) as HR groups. There were no differences in clinicopathological and surgical characteristics between the three groups. In survival analysis, HR and IR groups had worse disease-free survival and overall survival rates compared to the LR group. In the multivariate analysis, lymph node metastasis and the immune score risk groups were independent factors related to worse survival. Conclusions: A scoring system with immune-related markers was able to distinguish prognostic groups of RGC associated with survival. Accordingly, tumor-infiltrating immune lymphocytes and PD-L1 status may serve as a potential prognostic biomarker for patients with RGC.

D2 Lymphadenectomy According to the Arterial Variations in Gastric and Hepatic Irrigation.

BACKGROUND: D2 lymphadenectomy for gastric cancer is technically demanding and requires clearance of the lymph node stations along the main arteries that irrigate the stomach and the liver. As gastric and hepatic irrigation have a different pattern from the classic branching of the celiac trunk in approximately 25% of patients, acquaintance with these variations and knowledge on how to adequately perform the lymphadenectomy in different anatomic settings is of utmost importance for surgeons who manage gastric cancer.1 METHODS: This video demonstrates, step-by-step, how to perform D2 lymphadenectomy in accordance with gastric and hepatic irrigation. Illustrations of the arterial variation correlate with the corresponding computed tomography image and operative management of the lymph node stations. DISCUSSION: D2 lymphadenectomy is the standard of care in advanced gastric cancer.2 It implies clearing the lymph node stations along the celiac trunk, left gastric artery, and common and proper hepatic arteries. However, the celiac trunk and hepatic irrigation are highly variable and surgeons must be aware of how to properly and safely address the lymph node stations in all scenarios. Vessel anatomical variations increase the risk of vascular injuries and its complications, such as bleeding, necrosis, liver function impairment, liver necrosis, and conversion to open surgery.3-5 Additionally, the lymphadenectomy cannot be compromised if a variation is found.6 Preoperative knowledge of the gastric blood supply also shortens the surgical duration.7 CONCLUSIONS: The present video demonstrates how to recognize the most common variations found during D2 gastrectomy, and provides strategies to adequately approach them.

Donor cell engineering with GSK3 inhibitor-loaded nanoparticles enhances engraftment after in utero transplantation.

Host cell competition is a major barrier to engraftment after in utero hematopoietic cell transplantation (IUHCT). Here we describe a cell-engineering strategy using glycogen synthase kinase-3 (GSK3) inhibitor-loaded nanoparticles conjugated to the surface of donor hematopoietic cells to enhance their proliferation kinetics and ability to compete against their fetal host equivalents. With this approach, we achieved remarkable levels of stable, long-term hematopoietic engraftment for up to 24 weeks post-IUHCT. We also show that the salutary effects of the nanoparticle-released GSK3 inhibitor are specific to donor progenitor/stem cells and achieved by a pseudoautocrine mechanism. These results establish that IUHCT of hematopoietic cells decorated with GSK3 inhibitor-loaded nanoparticles can produce therapeutic levels of long-term engraftment and could therefore allow single-step prenatal treatment of congenital hematological disorders.

Clinical feasibility and impact of fully automated multiparametric PET imaging using direct Patlak reconstruction: evaluation of 103 dynamic whole-body 18F-FDG PET/CT scans.

PURPOSE: Functional imaging by standard whole-body (WB) 18F-flurodeoxyglucose (FDG) positron emission tomography (PET) is an integrated part of disease diagnostics. Recently, a clinical dynamic whole-body (D-WB) FDG PET/CT scanning protocols has been developed allowing for quantitative imaging of tissue metabolic rate of FDG (MRFDG). It was the purpose of this retrospective study to evaluate whether MRFDG imaging is feasible in a clinical setting and whether it improves lesion detectability. METHODS: One hundred nine patients representing a broad range of referral indications for FDG PET/CT were invited to undergo a D-WB FDG PET/CT scan. Two sets of images were produced: parametric images and standard static SUV images. Both sets of images were reviewed visually, and 310 individual lesions were quantitatively analysed using the target-to-background (TBR) and contrast-to-noise (CNR) metrics. RESULTS: One hundred three out of 109 patients completed the D-WB FDG PET/CT scan. There was no difference in the number of pathological lesions identified visually on the MRFDG and the SUV images, whereas MRFDG images yielded 4 fewer false positives than the SUV images. Quantitatively, MRFDG TBR was significantly higher than SUV TBR in 299/310 lesions, and better MRFDG CNR was found to facilitate the challenging reading of lesions with low SUV TBR. CONCLUSION: D-WB FDG PET/CT is feasible in a clinical setting and produces MRFDG images of good visual quality and superior lesion contrast. In addition, MRFDG images complement the standard SUV images providing better quantification and enhanced image reading. However, although MRFDG also reduced the number of false-positive findings, no additional malignant lesions were identified. The technique therefore appears to be best suited for select patient groups or possibly treatment response evaluation.

Epstein-Barr Virus Positive Gastric Cancer: A Distinct Subtype Candidate for Immunotherapy.

BACKGROUND: Epstein-Barr virus (EBV) positive gastric cancer (GC) has been described as a distinct molecular subtype of the disease, especially associated with gastric carcinoma with lymphoid stroma (GCLS). The possibility that EBV associated GC (EBVaGC) had better prognosis and may be susceptible to immunotherapy has increased the interest in this subtype. However, immune checkpoint and survival of EBVaGC are still controversial, especially with regard to GCLS and conventional gastric adenocarcinoma (CGA). This study aimed to evaluate the clinicopathological characteristics, immunohistochemical profiles and prognosis of EBVaGC according to the histological type GCLS and CGA. METHODS: we retrospectively evaluated a series of EBVaGC who underwent gastrectomy with D2-lymphadenectomy. Biomarkers and tumor-infiltrating cells were evaluated by immunohistochemistry. PD-L1 was evaluated using a combined positive score (CPS). RESULTS: From a total of 30 EBVaGC, 14 (46.7%) were identified as GCLS and 16 (53.3%) as CGA (9 Intestinal, 6 diffuse, 1 undetermined). There were no significant differences in age, sex, and pTNM between GCLS and CGA. CPS-positivity and high-CD8+ was significantly higher in GCLS compared with CGA (P = 0.007 and P = 0.005, respectively). Diffuse EBVaGC had worse survival than intestinal type (P = 0.020). There was no difference in survival between GCLS and intestinal CGA (P = 0.260). In multivariate analysis, CPS and pN status were related with survival in EBVaGC. CONCLUSIONS: CGLS was associated with a predominance of CD8+ cell infiltration and PD-L1 expression. CPS and lymph node metastasis were independent factors associated with prognosis in EBVaGC. These results suggest that specifically EBV-positive GCLS may be prime candidates for PD-1 directed therapy.

Cytotoxic T-lymphocyte-associated protein 4 in gastric cancer: Prognosis and association with PD-L1 expression.

BACKGROUND: Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is one of the most studied immune checkpoint in gastric cancer (GC). However, the prognostic role of CTLA-4 expression in GC is poorly described. This study aimed to evaluate CTLA-4 expression in GC and its impact on survival, including patients treated with standard platinum-based chemotherapy (CMT), and association with PD-L1 expression. METHODS: All GC patients who underwent D2-gastrectomy were investigated retrospectively. Tumor samples were examined for CTLA-4 and PD-L1 by immunohistochemistry. Tumor-infiltrating inflammatory cells, including CD4 + and CD8 + , were also examined. RESULTS: Among the 284 GC patients included, 159 (56%) were CTLA-4 positive and the remaining 125 (44%) were classified as negative. CTLA-4 positive GC was associated with increased inflammatory cell infiltration (p < 0.001), high CD8 + T cells (p = 0.016) and PD-L1 expression (p = 0.026). Considering GC referred for treatment, CTLA-4 negative patients who received CMT had a significant improvement in disease-free survival compared to untreated CLTA-4 negative (p = 0.028). In multivariate analysis, GC positive for both CTLA-4 and PD-L1 had a prognostic impact on survival. CONCLUSION: CTLA-4 positive was associated with PD-L1 expression and a high tumor-infiltrating CD8 + T cells. Accordingly, positivity for both CTLA-4 and PD-L1 was an independent factor associated to better survival in GC patients.

Augmented reality with HoloLens in parotid surgery: how to assess and to improve accuracy.

PURPOSE: Augmented reality improves planning and execution of surgical procedures. The aim of this study was to evaluate the feasibility of a 3D augmented reality hologram in live parotic surgery. Another goal was to develop an accuracy measuring instrument and to determine the accuracy of the system. METHODS: We created a software to build and manually align 2D and 3D augmented reality models generated from MRI data onto the patient during surgery using the HoloLens® 1 (Microsoft Corporation, Redmond, USA). To assess the accuracy of the system, we developed a specific measuring tool applying a standard electromagnetic navigation device (Fiagon GmbH, Hennigsdorf, Germany). RESULTS: The accuracy of our system was measured during real surgical procedures. Training of the experimenters and the use of fiducial markers significantly reduced the accuracy of holographic system (p = 0.0166 and p = 0.0132). Precision of the developed measuring system was very high with a mean error of the basic system of 1.3 mm. Feedback evaluation demonstrated 86% of participants agreed or strongly agreed that the HoloLens will play a role in surgical education. Furthermore, 80% of participants agreed or strongly agreed that the HoloLens is feasible to be introduced in clinical routine and will play a role within surgery in the future. CONCLUSION: The use of fiducial markers and repeated training reduces the positional error between the hologram and the real structures. The developed measuring device under the use of the Fiagon navigation system is suitable to measure accuracies of holographic augmented reality images of the HoloLens.

PGL I expression in live bacteria allows activation of a CD206/PPARγ cross-talk that may contribute to successful Mycobacterium leprae colonization of peripheral nerves.

Mycobacterium leprae, an obligate intracellular bacillus, infects Schwann cells (SCs), leading to peripheral nerve damage, the most severe leprosy symptom. In the present study, we revisited the involvement of phenolic glycolipid I (PGL I), an abundant, private, surface M. leprae molecule, in M. leprae-SC interaction by using a recombinant strain of M. bovis BCG engineered to express this glycolipid. We demonstrate that PGL I is essential for bacterial adhesion and SC internalization. We also show that live mycobacterium-producing PGL I induces the expression of the endocytic mannose receptor (MR/CD206) in infected cells in a peroxisome proliferator-activated receptor gamma (PPARγ)-dependent manner. Of note, blocking mannose recognition decreased bacterial entry and survival, pointing to a role for this alternative recognition pathway in bacterial pathogenesis in the nerve. Moreover, an active crosstalk between CD206 and the nuclear receptor PPARγ was detected that led to the induction of lipid droplets (LDs) formation and prostaglandin E2 (PGE2), previously described as fundamental players in bacterial pathogenesis. Finally, this pathway was shown to induce IL-8 secretion. Altogether, our study provides evidence that the entry of live M. leprae through PGL I recognition modulates the SC phenotype, favoring intracellular bacterial persistence with the concomitant secretion of inflammatory mediators that may ultimately be involved in neuroinflammation.

In Utero Transplantation of Expanded Autologous Amniotic Fluid Stem Cells Results in Long-Term Hematopoietic Engraftment.

In utero transplantation (IUT) of hematopoietic stem cells (HSCs) has been proposed as a strategy for the prenatal treatment of congenital hematological diseases. However, levels of long-term hematopoietic engraftment achieved in experimental IUT to date are subtherapeutic, likely due to host fetal HSCs outcompeting their bone marrow (BM)-derived donor equivalents for space in the hematopoietic compartment. In the present study, we demonstrate that amniotic fluid stem cells (AFSCs; c-Kit+/Lin-) have hematopoietic characteristics and, thanks to their fetal origin, favorable proliferation kinetics in vitro and in vivo, which are maintained when the cells are expanded. IUT of autologous/congenic freshly isolated or cultured AFSCs resulted in stable multilineage hematopoietic engraftment, far higher to that achieved with BM-HSCs. Intravascular IUT of allogenic AFSCs was not successful as recently reported after intraperitoneal IUT. Herein, we demonstrated that this likely due to a failure of timely homing of donor cells to the host fetal thymus resulted in lack of tolerance induction and rejection. This study reveals that intravascular IUT leads to a remarkable hematopoietic engraftment of AFSCs in the setting of autologous/congenic IUT, and confirms the requirement for induction of central tolerance for allogenic IUT to be successful. Autologous, gene-engineered, and in vitro expanded AFSCs could be used as a stem cell/gene therapy platform for the in utero treatment of inherited disorders of hematopoiesis. Stem Cells 2019;37:1176-1188.