MFGE8 in exosomes derived from mesenchymal stem cells prevents esophageal stricture after endoscopic submucosal dissection in pigs.

BACKGROUND: Endoscopic submucosal dissection (ESD) is the current standard treatment for early-stage esophageal neoplasms. However, the postoperative esophageal stricture after extensive mucosal dissection remains a severe challenge with limited effective treatments available. In this study, we introduced a chitosan/gelatin (ChGel) sponge encapsulating the adipose mesenchymal stem cells (ADMSCs)-derived exosomes (ChGelMSC-Exo) for the prevention of esophageal stenosis after ESD in a porcine model. RESULTS: Pigs were randomly assigned into (1) ChGelMSC-Exo treatment group, (2) ChGelPBS group, and (3) the controls. Exosome treatments were applied immediately on the day after ESD as well as on day 7. Exosome components crucial for wound healing were investigated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and small RNA sequencing. ChGelMSC-Exo treatment significantly reduced mucosal contraction on day 21, with less fiber accumulation and inflammatory infiltration, and enhanced angiogenesis when compared with the control and ChGelPBS groups. The anti-fibrotic effects following MSC-Exo treatment were further found to be associated with the anti-inflammatory M2 polarization of the resident macrophages, especially within the M2b subset characterized by the reduced TGFß1 secretion, which sufficiently inhibited inflammation and prevented the activation of myofibroblast with less collagen production at the early stage after ESD. Moreover, the abundant expression of exosomal MFGE8 was identified to be involved in the transition of the M2b-macrophage subset through the activation of MFGE8/STAT3/Arg1 axis. CONCLUSIONS: Our study demonstrates that exosomal MFGE8 significantly promotes the polarization of the M2b-macrophage subset, consequently reducing collagen deposition. These findings suggest a promising potential for MSC-Exo therapy in preventing the development of esophageal stricture after near-circumferential ESD.

Intracerebral hirudin injection alleviates cognitive impairment and oxidative stress and promotes hippocampal neurogenesis in rats subjected to cerebral ischemia.

Cerebral ischemia starts with cerebral blood flow interruption that causes severely limited oxygen and glucose supply, eliciting a cascade of pathological events, such as excitotoxicity, oxidative stress, calcium dysregulation, and inflammatory response, which could ultimately result in neuronal death. Hirudin has beneficial effects in ischemic stroke and possesses antioxidant and anti-inflammatory properties. Therefore, we investigated the biological functions of hirudin and its related mechanisms in cerebral ischemia. The ischemia-like conditions were induced by transient middle cerebral artery occlusion (MCAO). To investigate hirudin roles, intracerebroventricular injection of 10 U hirudin was given to the rats. Cognitive and motor functions were examined by beam walking and Morris water maze tests. 2,3,5-triphenyl tetrazolium chloride-stained brain sections were used to measure infarct volume. Oxidative stress was determined by assessment of oxidative stress markers. The proliferated cells were labeled by BrdU and Nestin double staining. Western blotting was performed to measure protein levels. Hirudin administration improved cognitive and motor deficits post-ischemia. Hirudin reduced brain infarction and neurological damage in MCAO-subjected rats. Hirudin alleviated oxidative stress and enhanced neurogenesis in ischemic rats. Hirudin facilitated the promotion of phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and serine-threonine kinase. In sum, hirudin alleviates cognitive deficits by attenuating oxidative stress and promoting hippocampal neurogenesis through the regulation of ERK1/2 and serine-threonine kinase in MCAO-subjected rats.

Nanoparticle-assembled bioadhesive coacervate coating with prolonged gastrointestinal retention for inflammatory bowel disease therapy.

A key challenge for the effective treatment of gastrointestinal diseases including inflammatory bowel disease is to develop an orally administered drug delivery system capable of prolonged retention in the gastrointestinal tract. Herein we report a bioadhesive liquid coacervate based on hydrogen bonding-driven nanoparticle assembly. Free from electrostatic interactions, our fluid nanoparticle-assembled coacervate demonstrates significant pH- and salt-independent structural stability and forms a physically adhesive coating on a large surface area of intestinal tract with an extended residence time of more than 2 days to mediate the sustained release of preloaded water-soluble small molecule drugs in vivo. The orally administered drug-laden nanoparticle-assembled coacervate significantly mitigates the symptoms of inflammatory bowel disease, restores the diversity of gut microbiota, reduces systemic drug exposure, and improves the therapeutic efficacy in a rat acute colitis model compared with the oral administration of the same amount of drug in solution form. We suggest that the nanoparticle-assembled coacervate provides a promising drug delivery platform for management and treatment of numerous gastrointestinal diseases where controlled drug release with extended residence time is desired.

Ultrafast self-gelling powder mediates robust wet adhesion to promote healing of gastrointestinal perforations.

Achieving strong adhesion of bioadhesives on wet tissues remains a challenge and an acute clinical demand because of the interfering interfacial water and limited adhesive-tissue interactions. Here we report a self-gelling and adhesive polyethyleneimine and polyacrylic acid (PEI/PAA) powder, which can absorb interfacial water to form a physically cross-linked hydrogel in situ within 2 seconds due to strong physical interactions between the polymers. Furthermore, the physically cross-linked polymers can diffuse into the substrate polymeric network to enhance wet adhesion. Superficial deposition of PEI/PAA powder can effectively seal damaged porcine stomach and intestine despite excessive mechanical challenges and tissue surface irregularities. We further demonstrate PEI/PAA powder as an effective sealant to enhance the treatment outcomes of gastric perforation in a rat model. The strong wet adhesion, excellent cytocompatibility, adaptability to fit complex sites, and easy synthesis of PEI/PAA powder make it a promising bioadhesive for numerous biomedical applications.

Endoscopy-assisted magnetic navigation of biohybrid soft microrobots with rapid endoluminal delivery and imaging.

High-precision delivery of microrobots at the whole-body scale is of considerable importance for efforts toward targeted therapeutic intervention. However, vision-based control of microrobots, to deep and narrow spaces inside the body, remains a challenge. Here, we report a soft and resilient magnetic cell microrobot with high biocompatibility that can interface with the human body and adapt to the complex surroundings while navigating inside the body. We achieve time-efficient delivery of soft microrobots using an integrated platform called endoscopy-assisted magnetic actuation with dual imaging system (EMADIS). EMADIS enables rapid deployment across multiple organ/tissue barriers at the whole-body scale and high-precision delivery of soft and biohybrid microrobots in real time to tiny regions with depth up to meter scale through natural orifice, which are commonly inaccessible and even invisible by conventional endoscope and medical robots. The precise delivery of magnetic stem cell spheroid microrobots (MSCSMs) by the EMADIS transesophageal into the bile duct with a total distance of about 100 centimeters can be completed within 8 minutes. The integration strategy offers a full clinical imaging technique-based therapeutic/intervention system, which broadens the accessibility of hitherto hard-to-access regions, by means of soft microrobots.

CYP1A2 suppresses hepatocellular carcinoma through antagonizing HGF/MET signaling.

Rationale: Hyperactivation of HGF/MET signaling pathway is a critical driver in liver tumorigenesis. Cytochrome P450 1A2 (CYP1A2) was significantly down-regulated in hepatocellular carcinoma (HCC). However, little is explored about its tumor suppressive role in HCC. In this study, we examined the functional mechanisms and clinical implication of CYP1A2 in HCC. Methods: The clinical impact of CYP1A2 was evaluated in HCC patients in Hong Kong cohort. The biological functions of CYP1A2 were investigated in vitro and in vivo. A series of biochemical experiments including Western blot assay, immunohistochemistry, quantitative reverse transcription-polymerase chain reaction, and Co-immunoprecipitation assay were conducted. Results: CYP1A2 expression was prominently silenced in HCC tumor tissues and the high expression of CYP1A2 was significantly correlated with lower AFP level, less vascular invasion, and better tumor-free survival in local cohort of HCC patients. The overexpression of CYP1A2 inhibited HCC cell viability and clonogenicity, reduced cell migration and invasion abilities in vitro, and suppressed tumorigenicity in vivo, whereas CYP1A2 knockdown exhibited the opposite effects. CYP1A2 significantly hindered HGF/MET signaling and Matrix metalloproteinases (MMPs) expression in HCC cells. Mechanically, CYP1A2 decreased HGF level and diminished HIF-1α expression, both of which are recognized as key regulators of MET activation. As the transcriptional activator of MET, HIF-1α was identified as a binding partner of CYP1A2. Direct binding of CYP1A2 with HIF-1α induced ubiquitin-mediated degradation of HIF-1α, inhibiting HIF-1α-mediated transcriptions. Conclusions: In conclusion, our results have identified CYP1A2 as a novel antagonist of HGF/MET signaling, and CYP1A2 may serve as an independent new biomarker for the prognosis of HCC patients.

Bioadhesive hydrogels demonstrating pH-independent and ultrafast gelation promote gastric ulcer healing in pigs.

Hydrogels are soft materials used in an array of biomedical applications. However, the in situ formation of hydrogels at target sites, particularly in dynamic in vivo environments, usually requires a prolonged gelation time and results in poor adhesion. These limitations cause considerable loss of both hydrogel mass and encapsulated therapeutic cargoes, thereby compromising treatment outcomes. Here, we report the development of a hydrogel based on thiourea-catechol reaction to enhance the bioadhesion. Compared with classical bioadhesive hydrogels, our hydrogels show enhanced mechanical properties, exceedingly short curing time, and pH-independent gelation with a much lower oxidant concentration. We further report the robust adhesion of our hydrogels to acidic gastric tissues and easy delivery to the porcine stomach via endoscopy. The delivered hydrogels adhered to ulcer sites in vivo for at least 48 hours. Hydrogel treatment of gastric ulcers in rodent and porcine models accelerated ulcer healing by suppressing inflammation and promoting re-epithelization and angiogenesis. The improved retention of proregenerative growth factors and reduced exposure to external catabolic factors after hydrogel application may contribute to the observed therapeutic outcomes. Our findings reveal a promising biomaterial-based approach for treating gastrointestinal diseases.

A robotic flexible endoscope with shared autonomy: a study of mockup cholecystectomy.

BACKGROUND: Endoscope is the eye of surgeon in minimally invasive surgery (MIS). Prevailing handheld endoscopes are manually steered, which can cause endoscope-instrument fencing. Robotic endoscopes can reduce the fatigue but could not reduce collisions. Handheld endoscopes with a flexible bending tip can reduce the shaft pivoting and collisions. However, its steering is challenging. In this paper, we present a robotic flexible endoscope with auto-tracking function and compare it with the conventional rigid endoscopes. METHODS: A robotic flexible endoscope (RFE) with shared autonomy is developed. The RFE could either track the instruments automatically or be controlled by a foot pedal. A mockup cholecystectomy was designed to evaluate the performance. Five surgeons were invited to perform the mockup cholecystectomy in an abdominal cavity phantom with a manual rigid endoscope (MRE), a robotic rigid endoscope (RRE), and the RFE. Space occupation, time consumption, and questionnaires based on the NASA task load index were adopted to evaluate the performances and compare the three endoscope systems. An ex vivo experiment was conducted to demonstrate the feasibility of using the RFE in a biological tissue environment. RESULTS: All surgeons completed the mockup cholecystectomy with the RFE independently. Failure occurred in the cases involving the RRE and the MRE. Inside the body cavity, the space occupied when using the RFE is 17.28% and 23.95% (p < 0.05) of that when using the MRE and the RRE, respectively. Outside the body cavity, the space occupied when using the RFE is 14.60% and 15.53% (p < 0.05) of that by using MRE and RRE. Time consumed in the operations with MRE, RRE, and RFE are 28.3 s, 93.2 s and 34.8 s, respectively. Questionnaires reveal that the performance of the RFE is the best among the three endoscope systems. CONCLUSIONS: The RFE provides a wider field of view (FOV) and occupies less space than rigid endoscopes.

Mesenchymal stem cells promote healing of nonsteroidal anti-inflammatory drug-related peptic ulcer through paracrine actions in pigs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most important causes of peptic ulcer disease in high-income countries. Proton pump inhibitors are the current standard treatment; however, safety and long-term adverse effects of using these drugs are attracting more and more concerns in recent years. Using a porcine model of NSAID-related gastric ulcer, we herein show that adipose-derived mesenchymal stem cells (ADMSCs) delivered by endoscopic submucosal injection promoted ulcer healing with less inflammatory infiltration and enhanced reepithelization and neovascularization at day 7 and day 21 when compared with the controls (saline injection). However, only few engrafted ADMSCs showed myofibroblast and epithelial cell phenotype in vivo, suggesting the ulcer healing process might be much less dependent on the stem cell transdifferentiation. Further experiment with submucosal injection of MSC-derived secretome revealed a therapeutic efficacy comparable to that of stem cell transplantation. Profiling analysis showed up-regulation of genes associated with inflammation, granulation formation, and extracellular matrix remodeling at day 7 after injection of MSC-derived secretome. In addition, the extracellular signal-regulated kinase/mitogen-activated protein kinase and the phosphoinositide-3-kinase/protein kinase B pathways were activated after injection of ADMSCs or MSC-derived secretome. Both signaling pathways were involved in mediating the major events critical to gastric ulcer healing, including cell survival, migration, and angiogenesis. Our data suggest that endoscopic submucosal injection of ADMSCs serves as a promising approach to promote healing of NSAID-related peptic ulcer, and the paracrine effectors released from stem cells play a crucial role in this process.

Secretome from hypoxia-conditioned adipose-derived mesenchymal stem cells promotes the healing of gastric mucosal injury in a rodent model.

Studies have indicated that the definitive engraftment and transdifferentiation potential of stem cells do not seem crucial for its property of tissue repair. Our previous study showed that transplantation of adipose-derived mesenchymal stem cells (ADMSCs) enhanced the healing of sutured gastric perforation. This study aimed to investigate the paracrine role of ADMSCs in the experimental gastric mucosal injury. Normoxia-conditioned medium (Nor CM) and hypoxia (HPO) CM were obtained after culturing ADMSCs in 20% O2 and 5% O2 for 48h. Cell migration, proliferation, viability, and angiogenesis in vitro were significantly enhanced upon incubation with CM, especially the HPO CM. Experiments in vivo using a rodent model of gastric ulcer demonstrated that HPO CM treatment significantly accelerated wound healing by suppressing inflammation and promoting neovascularization and re-epithelization. Meanwhile, the infusion of HPO CM activated the COX2-PGE2 axis both in vitro and in vivo. And the upregulation of COX2 was further dependent on the activation of ErK1/2-MAPK pathway. In addition, vascular endothelial growth factor, tissue inhibitors of metalloproteinases-1, and chemokine (C-C motif) ligand 20 (CCL-20) were analyzed as being highly abundant factors secreted by ADMSCs under hypoxic condition. Notably, the blockade of CCL-20 abrogated the HPO CM-induced COX2 signaling in the primary gastric mucosal epithelial cells, while incubation with recombinant CCL-20 increased the expression of COX2. In conclusion, the secretome from hypoxia-conditioned ADMSCs facilitates the repair of gastric mucosal injury through the enhancement of angiogenesis and re-epithelization, as well as the activation of COX2-PGE2 axis with a paracrine activity involving CCL-20 factor.

Initial energy supplementation in critically ill patients receiving enteral nutrition: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND OBJECTIVES: Here we systematically reviewed and quantitatively analyzed randomized controlled trials (RCTs) to compare the important initial outcomes of critically ill adults receiving low- and highenergy enteral nutrition. METHODS AND STUDY DESIGN: RCTs comparing low- and high-energy supplementation in critically ill adults receiving enteral nutrition admitted to the intensive care unit for an expected stay of >48 h were included. Abstracts submitted to major scientific meetings were included and the primary endpoint was mortality. The risk ratio (RR) and weighted mean difference (WMD) with 95% confidence intervals (CIs) were the effect measures. RESULTS: Eleven RCTs (3,212 patients) were included. The groups did not differ significantly in mortality (RR, 0.94; 95% CI, 0.80-1.11; p=0.47), infections morbidity (RR 1.09; 95% CI 0.95-1.26; p=0.23), pneumonia morbidity (RR 1.04; 95% CI 0.88-1.23; p=0.68), hospital length of stay (WMD -0.27; 95% CI -3.21 to 3.76; p=0.88), intensive care unit length of stay (WMD -0.32; 95% CI, -1.81 to 1.16; p=0.46), mechanical ventilation days (WMD -0.30; 95% CI-1.42 to 0.82; p=0.60). The incidence of gastrointestinal intolerance was significantly lower in the low-energy group (RR 0.79; 95% CI 0.65-0.97; p<0.05). CONCLUSIONS: The initial administration of low- versus high-energy supplements did not impact clinical outcomes except for gastrointestinal intolerance in non-malnourished critically ill patients receiving enteral nutrition. The initial administration of highrather than low-energy may benefit these patients by reducing infections, but this effect might actually be attributable to the concomitant high protein intake.

Laparoscopic Versus Open Colorectal Resection Within Fast Track Programs: An Update Meta-Analysis Based on Randomized Controlled Trials.

The objective of the study was to assess the safety and efficacy of laparoscopic colorectal surgery by comparing open operation within fast track (FT) programs. The Cochrane Library, PubMed, Embase and Chinese Biological Medicine Database were searched to identify all available randomized controlled trials (RCTs) comparing laparoscopic with open colorectal resection within FT programs. A total of seven RCTs were finally included, enrolling 714 patients with colorectal cancer: 373 patients underwent laparoscopic surgery and FT programs (laparoscopic/FT group) and 341 patients received open operation and FT programs (open/FT group). Postoperative hospital stay (weighted mean difference (WMD): 0.66; 95% CI: 0.27 - 1.04; P < 0.05), total hospital stay (WMD: 1.46; 95% CI: 0.40 - 2.51; P < 0.05) and overall complications (RR: 1.31; 95% CI: 1.12 - 1.54; P < 0.05) were significantly lower in laparoscopic/FT group than in open/FT group. However, no statistically significant differences on mortality (risk ratio (RR): 2.26; 95% CI: 0.62 - 8.22; P = 0.21), overall surgical complications (RR: 1.19; 95% CI: 0.94 - 1.51; P = 0.15) and readmission rates (RR: 1.33; 95% CI: 0.79 - 2.22; P = 0.28) were found between both groups. The laparoscopic colorectal surgery combined with FT programs shows high-level evidence on shortening postoperative and total hospital stay, reducing overall complications without compromising patients' safety.

Fast-track programs versus traditional care in hepatectomy: a meta-analysis of randomized controlled trials.

BACKGROUND/AIMS: The role of fast-track programs in hepatectomy is unclear. This meta-analysis aimed to evaluate the efficacy and safety of fast-track programs versus traditional care. METHODS: We searched Pubmed, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar for relevant randomized controlled trials (RCTs) comparing fast-track with traditional care in hepatectomy. Length of hospital stay, time to first flatus, postoperative complications, operating time, and intraoperative blood loss were assessed. Meta-analyses were performed using RevMan 5.2 software. RESULTS: Four original RCTs with 372 patients were included: 187 in the fast-track and 185 in the traditional care group. Fast-track patients had shorter hospital stay (WMD -2.32; 95% CI, -3.54 to -1.11; p < 0.001) and time to first flatus (WMD -0.99; 95% CI, -1.15 to -0.84; p < 0.001), and less postoperative complications (RR 0.66; 95% CI, 0.47 to 0.93; p < 0.05). However, there was significant heterogeneity between the studies regarding hospital stay (I(2) = 88%; p < 0.001). Operating time and intraoperative blood loss were not different. CONCLUSIONS: Patients in fast-track programs had less time to first flatus and postoperative complications compared to traditional care. Fast-track programs may reduce the length of hospital stay. Larger, higher quality prospective RCTs are necessary to draw more robust conclusions.

Does long intestinal tube splinting aggravate intestinal adhesions?

OBJECTIVE: Long intestinal tube splinting (LITS) is useful for clinically reducing the recurrence of adhesive small bowel obstruction (ASBO). However, a controversy exists whether LITS aggravates intestinal adhesions. This study evaluated the postoperative effects of LITS relative to simple enterolysis on intestinal adhesions in an experimental porcine model. METHODS: A porcine model (n = 24) of dense intestinal adhesion was established by abrading the ileal wall with sterile P240 sandpaper. Enterolysis was performed on postoperative day 14. Animals were randomly divided into a group that underwent enterolysis only (control; n = 12) and those who underwent LITS as well as enterolysis (LITS; n = 12). The long intestinal tube was removed on post-LITS day 14, after abdominal radiography. All animals were euthanized on postenterolysis day 28 for assessment of intestinal adhesions using a semiquantitative macroscopic grading scale, hematoxylin-eosin histology, and hydroxyproline assay. RESULTS: Prior to enterolysis, the experimentally induced intestinal adhesions of the two groups were similar in extent and severity. On postenterolysis day 28 the LITS and control groups were comparable with regard to adhesion loop length (p = .440), macroscopic adhesion severity (p = .820), serosal fibrosis grading (p = .450), and hydroxyproline content of the adhesion ileal segment (p = .630). CONCLUSION: Placement of the long intestinal tube did not aggravate intestinal adhesions over that of simple enterolysis in this intestinal adhesion porcine model.

Essential amino acid enriched high-protein enteral nutrition modulates insulin-like growth factor-1 system function in a rat model of trauma-hemorrhagic shock.

BACKGROUND: Nutrition support for critically ill patients supplemented with additional modular protein may promote skeletal muscle protein anabolism in addition to counteracting acute nitrogen loss. The present study was designed to investigate whether the essential amino acid (EAA) enriched high-protein enteral nutrition (EN) modulates the insulin-like growth factor-1 (IGF-1) system and activates the mammalian target of rapamycin (mTOR) anabolic signaling pathway in a trauma-hemorrhagic shock (T-HS) rat model. METHODOLOGY/PRINCIPAL FINDINGS: Male Sprague-Dawley rats (n = 90, 278.18 ± 0.94 g) were randomly assigned to 5 groups: (1) normal control, (2) pair-fed, (3) T-HS, (4) T-HS and standard EN, and (5) T-HS and EAA enriched high-protein EN. Six animals from each group were harvested on days 2, 4, and 6 for serum, gastrocnemius, soleus, and extensor digitorum longus sample collection. T-HS significantly reduced muscle mass. Nutrition support maintained muscle mass, especially the EAA enriched high-protein EN. Meanwhile, a pronounced derangement in IGF-1-IGFBPs axis as well as impaired mTOR transduction was observed in the T-HS group. Compared with animals receiving standard EN, those receiving EAA enriched high-protein EN presented 18% higher serum free IGF-1 levels following 3 days of nutrition support and 22% higher after 5 days. These changes were consistent with the concomitant elevation in serum insulin and reduction in corticosterone levels. In addition, phosphorylations of downstream anabolic signaling effectors - including protein kinase B, mTOR, and ribosomal protein S6 kinase1 - increased significantly in rats receiving EAA enriched high-protein EN. CONCLUSION/SIGNIFICANCE: Our findings firstly demonstrate the beneficial effect of EAA enriched high-protein EN on the metabolic modulation of skeletal muscle protein anabolism by regulating the IGF-1 system and downstream anabolic signaling transduction.