Patient Acceptance of Routine Serial Postoperative Endoscopy Following Low Anterior Resection (LAR) and Its Ability to Detect Biomarkers in Anastomotic Lavage Fluid.

BACKGROUND: Various reports have now established that postoperative endoscopy to examine and intervene in the process of anastomotic healing is both feasible and safe. Here we present our preliminary experience with serial postoperative endoscopy to determine its feasibility, patient acceptance and the ability to obtain and the utility of perianastomotic material for molecular analysis. METHODS: Patients undergoing LAR with ileostomy for rectal cancer were recruited for study to undergo routine serial endoscopic surveillance (SES) at three time points during the course of LAR: intraoperatively, before discharge (postoperative day 3-7) and at follow-up (postoperative day 10-28). At each endoscopy, images were captured, anastomotic tissues were lavaged and lavage fluid was retrieved. Fluid samples were analyzed using proteomics, zymography, ELISA and bacteria via 16S rRNA gene amplicon sequencing and culture of collagenolytic strains. RESULTS: SES is feasible and acceptable to this limited set of patients following LAR. Biologic analysis of perianastomotic fluids was able to detect the presence of proteins, microbiota and inflammatory mediators previously identified at anastomotic sites in animals with pathologic healing. CONCLUSION: SES can be implemented in patients undergoing LAR with a high degree of patient compliance and capture of biologic information and imaging. Application of this approach has the potential to uncover, for the first time, the natural history of normal versus pathologic anastomotic healing in patients undergoing anastomotic surgery.

Media from macrophages co-incubated with Enterococcus faecalis induces epithelial cell monolayer reassembly and altered cell morphology.

Signal exchange between intestinal epithelial cells, microbes and local immune cells is an important mechanism of intestinal homeostasis. Given that intestinal macrophages are in close proximity to both the intestinal epithelium and the microbiota, their pathologic interactions may result in epithelial damage. The present study demonstrates that co-incubation of murine macrophages with E. faecalis strains producing gelatinase (GelE) and serine protease (SprE) leads to resultant condition media (CM) capable of inducing reassembly of primary colonic epithelial cell monolayers. Following the conditioned media (CM) exposure, some epithelial cells are shed whereas adherent cells are observed to undergo dissolution of cell-cell junctions and morphologic transformation with actin cytoskeleton reorganization resulting in flattened and elongated shapes. These cells exhibit marked filamentous filopodia and lamellipodia formation. Cellular reorganization is not observed when epithelial monolayers are exposed to: CM from macrophages co-incubated with E. faecalis GelE/SprE-deficient mutants, CM from macrophages alone, or E. faecalis (GelE/SprE) alone. Flow cytometry analysis reveals increased expression of CD24 and CD44 in cells treated with macrophage/E. faecalis CM. This finding in combination with the appearance colony formation in matrigel demonstrate that the cells treated with macrophage/E. faecalis CM contain a higher proportion progenitor cells compared to untreated control. Taken together, these findings provide evidence for a triangulated molecular dialogue between E. faecalis, macrophages and colonic epithelial cells, which may have important implications for conditions in the gut that involve inflammation, injury or tumorigenesis.

Critical role of microbiota within cecal crypts on the regenerative capacity of the intestinal epithelium following surgical stress.

Cecal crypts represent a unique niche that are normally occupied by the commensal microbiota. Due to their density and close proximity to stem cells, microbiota within cecal crypts may modulate epithelial regeneration. Here we demonstrate that surgical stress, a process that invariably involves a short period of starvation, antibiotic exposure, and tissue injury, results in cecal crypt evacuation of their microbiota. Crypts devoid of their microbiota display pathophysiological features characterized by abnormal stem cell activation as judged by leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) staining, expansion of the proliferative zone toward the tips of the crypts, and an increase in apoptosis. In addition, crypts devoid of their microbiota display loss of their regenerative capacity as assessed by their ability to form organoids ex vivo. When a four-member human pathogen community isolated from the stool of a critically ill patient is introduced into the cecum of mice with empty crypts, crypts become occupied by the pathogens and further disruption of crypt homeostasis is observed. Fecal microbiota transplantation restores the cecal crypts' microbiota, normalizes homeostasis within crypts, and reestablishes crypt regenerative capacity. Taken together, these findings define an emerging role for the microbiota within cecal crypts to maintain epithelial cell homeostasis in a manner that may enhance recovery in response to the physiological stress imposed by the process of surgery. NEW & NOTEWORTHY: This study provides novel insight into the process by which surgical injury places the intestinal epithelium at risk for colonization by pathogenic microbes and impairment of its regenerative capacity via loss of its microbiota. We show that fecal transplant restores crypt homeostasis in association with repopulation of the microbiota within cecal crypts.

Modeling Acinetobacter baumannii wound infections: The critical role of iron.

BACKGROUND: Acinetobacter baumannii has emerged as an increasingly important and successful opportunistic human pathogen due to its ability to withstand harsh environmental conditions, its characteristic virulence factors, and quick adaptability to stress. METHODS: We developed a clinically relevant murine model of A. baumannii traumatic wound infection to determine the effect of local wound environment on A. baumannii virulence. Mice underwent rectus muscle crush injury combined with ischemia created by epigastric vessel ligation, followed by A. baumannii inoculation. Reiterative experiments were performed using (1) a mutant deficient in the production of the siderophore acinetobactin, or (2) iron supplementation of the wound milieu. Mice were euthanized 7 days later, and rectus muscle analyzed for signs of clinical infection, HIF1α accumulation, bacterial abundance, and colony morphotype. To determine the effect of wound milieu on bacterial virulence, Galleria mellonella infection model was used. RESULTS: The combination of rectus muscle injury with ischemia and A. baumannii inoculation resulted in 100% incidence of clinical wound infection that was significantly higher compared with other groups (n = 15/group, p < 0.0001). The highest level of wound infection was accompanied by the highest level of A. baumannii colonization (p < 0.0001) and the highest degree of HIF1α accumulation (p < 0.05). A. baumannii strains isolated from injured/ischemic muscle with clinical infection displayed a rough morphotype and a higher degree of virulence as judged by G. mellonella killing assay as compared with smooth morphotype colonies isolated from injured muscle without clinical infection (100% vs. 60%, n = 30 Log-Rank test, p = 0.0422). Iron supplementation prevented wound infection (n = 30, p < 0.0001) and decreased HIF1α (p = 0.039643). Similar results of decrease in wound infection and HIF1α were obtained when A. baumannii wild type was replaced with its derivative mutant [INCREMENT]BasD deficient in acinetobactin production. CONCLUSION: The ability of A. baumannii to cause infections in traumatized wound relies on its ability to scavenge iron and can be prevented by iron supplementation to the wound milieu.

Morphine Promotes Colonization of Anastomotic Tissues with Collagenase - Producing Enterococcus faecalis and Causes Leak.

BACKGROUND: Despite ever more powerful antibiotics, newer surgical techniques, and enhanced recovery programs, anastomotic leaks remain a clear and present danger to patients. Previous work from our laboratory suggests that anastomotic leakage may be caused by Enterococcus faecalis strains that express a high collagenase phenotype (i.e., collagenolytic). Yet the mechanisms by which the practice of surgery shifts or selects for collagenolytic phenotypes to colonize anastomotic tissues remain unknown. METHODS: Here, we hypothesized that morphine, an analgesic agent universally used in gastrointestinal surgery, promotes tissue colonization with collagenolytic E. faecalis and causes anastomotic leak. To test this, rats were administered morphine in a chronic release form as would occur during routine surgery or vehicle. Rats were observed for 6 days and then underwent exploratory laparotomy for anastomotic inspection and tissue harvest for microbial analysis. These results provide further rationale to enhanced recovery after surgery (i.e., ERAS) programs that suggest limiting or avoiding the use of opioids in gastrointestinal surgery. RESULTS: Results demonstrated that compared to placebo-treated rats, morphine-treated rats demonstrated markedly impaired anastomotic healing and gross leaks that correlated with the presence of high collagenase-producing E. faecalis adherent to anastomotic tissues. To determine the direct role of morphine on this response, various isolates of E. faecalis from the rats were exposed to morphine and their collagenase activity and adherence capacity determined in vitro. Morphine increased both the adhesiveness and collagenase production of four strains of E. faecalis harvested from anastomotic tissues, two that were low collagenase producers at baseline, and two that were high collagenase producers at baseline. CONCLUSION: These results provide further rationale to enhanced recovery after surgery (i.e., ERAS) programs that suggest limiting or avoiding the use of opioids in gastrointestinal surgery.

Collagen degradation and MMP9 activation by Enterococcus faecalis contribute to intestinal anastomotic leak.

Even under the most expert care, a properly constructed intestinal anastomosis can fail to heal, resulting in leakage of its contents, peritonitis, and sepsis. The cause of anastomotic leak remains unknown, and its incidence has not changed in decades. We demonstrate that the commensal bacterium Enterococcus faecalis contributes to the pathogenesis of anastomotic leak through its capacity to degrade collagen and to activate tissue matrix metalloproteinase 9 (MMP9) in host intestinal tissues. We demonstrate in rats that leaking anastomotic tissues were colonized by E. faecalis strains that showed an increased collagen-degrading activity and also an increased ability to activate host MMP9, both of which contributed to anastomotic leakage. We demonstrate that the E. faecalis genes gelE and sprE were required for E. faecalis-mediated MMP9 activation. Either elimination of E. faecalis strains through direct topical antibiotics applied to rat intestinal tissues or pharmacological suppression of intestinal MMP9 activation prevented anastomotic leak in rats. In contrast, the standard recommended intravenous antibiotics used in patients undergoing colorectal surgery did not eliminate E. faecalis at anastomotic tissues nor did they prevent leak in our rat model. Finally, we show in humans undergoing colon surgery and treated with the standard recommended intravenous antibiotics that their anastomotic tissues still contained E. faecalis and other bacterial strains with collagen-degrading/MMP9-activating activity. We suggest that intestinal microbes with the capacity to produce collagenases and to activate host metalloproteinase MMP9 may break down collagen in the intestinal tissue contributing to anastomotic leak.

Phosphate-containing polyethylene glycol polymers prevent lethal sepsis by multidrug-resistant pathogens.

Antibiotic resistance among highly pathogenic strains of bacteria and fungi is a growing concern in the face of the ability to sustain life during critical illness with advancing medical interventions. The longer patients remain critically ill, the more likely they are to become colonized by multidrug-resistant (MDR) pathogens. The human gastrointestinal tract is the primary site of colonization of many MDR pathogens and is a major source of life-threatening infections due to these microorganisms. Eradication measures to sterilize the gut are difficult if not impossible and carry the risk of further antibiotic resistance. Here, we present a strategy to contain rather than eliminate MDR pathogens by using an agent that interferes with the ability of colonizing pathogens to express virulence in response to host-derived and local environmental factors. The antivirulence agent is a phosphorylated triblock high-molecular-weight polymer (here termed Pi-PEG 15-20) that exploits the known properties of phosphate (Pi) and polyethylene glycol 15-20 (PEG 15-20) to suppress microbial virulence and protect the integrity of the intestinal epithelium. The compound is nonmicrobiocidal and appears to be highly effective when tested both in vitro and in vivo. Structure functional analyses suggest that the hydrophobic bis-aromatic moiety at the polymer center is of particular importance to the biological function of Pi-PEG 15-20, beyond its phosphate content. Animal studies demonstrate that Pi-PEG prevents mortality in mice inoculated with multiple highly virulent pathogenic organisms from hospitalized patients in association with preservation of the core microbiome.

Emergence of the P2 phenotype in Pseudomonas aeruginosa PAO1 strains involves various mutations in mexT or mexF.

We recently demonstrated that Pseudomonas aeruginosa PAO1 undergoes a pronounced phenotypic change when introduced into the intestines of rats during surgical injury. Recovered strains displayed a specific phenotype (termed the P2 phenotype) characterized by altered pyocyanin production, high collagenase activity, high swarming motility, low resistance to chloramphenicol, and increased killing of Caenorhabditis elegans compared to the inoculating strain (termed the P1 phenotype). The aims of this study were to characterize the differences between the P. aeruginosa P1 and P2 phenotypes in quorum sensing and competitiveness. We then determined the presence of the P2 phenotype among PAO1 strains from various laboratories. Results demonstrated that P2 cells display accelerated growth during early exponential phase and early activation of quorum-sensing systems and overcome the growth of P1 cells in a mixed population. Among eight PAO1 strains obtained from different laboratories, four exhibited the P2 phenotype. Of 27 mutants analyzed from the P. aeruginosa MPAO1 transposon library, 25 displayed P2 phenotypes. The P2 phenotype in both cases correlated with a lack of expression of mexE or mexF due to mutations in mexT and mexF genes. In summary, strains possessing the P2 phenotype are distributed among PAO1 strains commonly used across a variety of research laboratories. Genetically, they are characterized by various mutations in mexT or mexF.

Regulation of selective autophagy onset by a Ypt/Rab GTPase module.

The key regulators of intracellular trafficking, Ypt/Rab GTPases, are stimulated by specific upstream activators and, when activated, recruit specific downstream effectors to mediate membrane-transport events. The yeast Ypt1 and its human functional homolog hRab1 regulate both endoplasmic reticulum (ER)-to-Golgi transport and autophagy. However, it is not clear whether the mechanism by which these GTPases regulate autophagy depends on their well-documented function in ER-to-Golgi transport. Here, we identify Atg11, the preautophagosomal structure (PAS) organizer, as a downstream effector of Ypt1 and show that the Ypt1-Atg11 interaction is required for PAS assembly under normal growth conditions. Moreover, we show that Ypt1 and Atg11 colocalize with Trs85, a Ypt1 activator subunit, and together they regulate selective autophagy. Finally, we show that Ypt1 and Trs85 interact on Atg9-containing membranes, which serve as a source for the membrane component of the PAS. Together our results define a Ypt/Rab module--comprising an activator, GTPase, and effector--that orchestrates the onset of selective autophagy, a process vital for cell homeostasis. Furthermore, because Atg11 does not play a role in ER-to-Golgi transport, we demonstrate here that Ypt/Rabs can regulate two independent membrane-transport processes by recruiting process-specific effectors.

Chmp 1A is a mediator of the anti-proliferative effects of all-trans retinoic acid in human pancreatic cancer cells.

BACKGROUND: We recently have shown that Charged multivesicular protein/Chromatin modifying protein1A (Chmp1A) functions as a tumor suppressor in human pancreatic tumor cells. Pancreatic cancer has the worst prognosis of all cancers with a dismal 5-year survival rate. Preclinical studies using ATRA for treating human pancreatic cancer suggest this compound might be useful for treatment of pancreatic cancer patients. However, the molecular mechanism by which ATRA inhibits growth of pancreatic cancer cells is not clear. The objective of our study was to investigate whether Chmp1A is involved in ATRA-mediated growth inhibition of human pancreatic tumor cells. RESULTS: We performed microarray studies using HEK 293T cells and discovered that Chmp1A positively regulated Cellular retinol-binding protein 1 (CRBP-1). CRBP-1 is a key regulator of All-trans retinoic acid (ATRA) through ATRA metabolism and nuclear localization. Since our microarray data indicates a potential involvement of Chmp1A in ATRA signaling, we tested this hypothesis by treating pancreatic tumor cells with ATRA in vitro. In the ATRA-responsive cell lines, ATRA significantly increased the protein expression of Chmp1A, CRBP-1, P53 and phospho-P53 at serine 15 and 37 position. We found that knockdown of Chmp1A via shRNA abolished the ATRA-mediated growth inhibition of PanC-1 cells. Also, Chmp1A silencing diminished the increase of Chmp1A, P53 and phospho-P53 protein expression induced by ATRA. In the ATRA non-responsive cells, ATRA did not have any effect on the protein level of Chmp1A and P53. Chmp1A over-expression, however, induced growth inhibition of ATRA non-responsive cells, which was accompanied by an increase of Chmp1A, P53 and phospho-P53. Interestingly, in ATRA responsive cells Chmp1A is localized to the nucleus, which became robust upon ATRA treatment. In the ATRA-non-responsive cells, Chmp1A was mainly translocated to the plasma membrane upon ATRA treatment. CONCLUSION: Collectively our data provides evidence that Chmp1A mediates the growth inhibitory activity of ATRA in human pancreatic cancer cells via regulation of CRBP-1. Our results also suggest that nuclear localization of Chmp1A is important in mediating ATRA signaling.

Chmp1A functions as a novel tumor suppressor gene in human embryonic kidney and ductal pancreatic tumor cells.

Chmp1A (Chromatin modifying protein 1A/Charged multivesicular protein 1A) is a member of the ESCRT-III (Endosomal Sorting Complex Required for Transport) family that was shown to function in endosome-mediated trafficking via multivesicular body (MVB) formation and sorting. Recent reports suggest that ESCRT complexes are also involved in cell cycle progression and tumor development. Using in vitro and in vivo model systems, we provide evidence that Chmp1A is a novel tumor suppressor, especially in the pancreas. We demonstrated that short hairpin RNA (shRNA) mediated stable silencing of Chmp1A in HEK 293T cells resulted in an increase of anchorage-independent growth in soft agar assay and tumor formation in xenograft assay. To investigate the involvement of Chmp1A in human tumor development we screened human cancer arrays and pancreatic tissue arrays. We discovered that Chmp1A mRNA and protein was reduced and/or altered (protein) in various human pancreatic tumors. To investigate the biological implication of these data, we either overexpressed or silenced Chmp1A in human pancreatic ductal tumor cells (PanC-1) and studied the effect of these manipulations on cell and tumor growth respectively. Stable overexpression of Chmp1A in PanC-1 cells resulted in cell growth inhibition and tumor xenograft inhibition respectively. In contrast, silencing of Chmp1A in PanC-1 cells resulted in the elevation of cell growth in vitro. Mechanistically, overexpression of Chmp1A strongly increased the protein level of p53 and phospho-P53. Taken together, our data indicates that Chmp1A is a novel tumor suppressor, especially in pancreas and that Chmp1A regulates tumor growth potentially through p53 signaling pathway.

The contribution of heme propionate groups to the conformational dynamics associated with CO photodissociation from horse heart myoglobin.

Photoacoustic calorimetry and transient absorption spectroscopy were used to study conformational dynamics associated with CO photodissociation from horse heart myoglobin (Mb) reconstituted with either Fe protoporphyrin IX dimethylester (FePPDME), Fe octaethylporphyrin (FeOEP), or with native Fe protoporphyrin IX (FePPIX). The volume and enthalpy changes associated with the Fe-CO bond dissociation and formation of a transient deoxyMb intermediate for the reconstituted Mbs were found to be similar to those determined for native Mb (DeltaV1 = -2.5+/-0.6 ml mol(-1) and DeltaH1 = 8.1+/-3.0 kcal mol(-1)). The replacement of FePPIX by FeOEP significantly alters the conformational dynamics associated with CO release from protein. Ligand escape from FeOEP reconstituted Mb was determined to be roughly a factor of two faster (tau=330 ns) relative to native protein (tau=700 ns) and accompanying reaction volume and enthalpy changes were also found to be smaller (DeltaV2 = 5.4+/-2.5 ml mol(-1) and DeltaH2 = 0.7+/-2.2 kcal mol(-1)) than those for native Mb (DeltaV2 = 14.3+/-0.8 ml mol(-1) and DeltaH2 = 7.8+/-3.5 kcal mol(-1)). On the other hand, volume and enthalpy changes for CO release from FePPIX or FePPDME reconstituted Mb were nearly identical to those of the native protein. These results suggest that the hydrogen bonding network between heme propionate groups and nearby amino acid residues likely play an important role in regulating ligand diffusion through protein matrix. Disruption of this network leads to a partially open conformation of protein with less restricted ligand access to the heme binding pocket.

A new lectin from the sea worm Serpula vermicularis: isolation, characterization and anti-HIV activity.

A GlcNAc-specific lectin was isolated from the sea worm Serpula vermicularis (SVL) (Annelida) and purified by ion-exchange, affinity and gel permeation chromatography. SVL was a homotetrameric protein with native molecular mass of about 50 kDa, and consisted of identical subunits of 12.7 kDa. The carbohydrate content of 1.9% suggested that the lectin was a glycoprotein, and mainly composed by aspartic and glutamic acids, glycine, valine and serine; with relatively lower content of basic amino acids and cysteine. The first 15 residues of the N-terminal region were determined as ADTPCQMLGSRYGWR. It was stable at pH 6-9 and at temperatures up to 40 degrees C. SVL was Ca(2+)-independent lectin that agglutinated native and trypsinized human erythrocytes. Hapten inhibition studies indicated that SVL showed binding specificity only for N-acetyl-d-glucosamine and its derivatives among the monosaccharides tested and required the presence of hydroxyl group at the C-3 of GlcNAc. The presence of hydrophobic p-nitrophenyl aglycone improved inhibitory potency of N-acetyl-d-glucosamine. Ovomucoid and ovalbumin were found to be inhibitors among the glycoproteins used for inhibition assay. The anti-HIV-1 (human immunodeficiency virus) activity of SVL in vitro was determined: SVL inhibited the production of viral p24 antigen and cytopathic effect induced by HIV-1. The EC(50) values were 0.23 and 0.15 microg x mL(-1) respectively.

A beta-galactose-specific lectin isolated from the marine worm Chaetopterus variopedatus possesses anti-HIV-1 activity.

A 30 kDa beta-galactose-specific lectin named CVL was isolated from the polychaete marine worm Chaetopterus variopedatus (Annelida) and its anti-HIV-1 activity in vitro was determined. Results showed that CVL inhibited cytopathic effect induced by HIV-1 and the production of viral p24 antigen. The EC(50) values were 0.0043 and 0.057 microM, respectively. Time-of-addition analysis of anti-HIV-1 activity indicated its action was at the early stage of virus replication. CVL could blocked the cell-to-cell fusion process of HIV infected and uninfected cells with an EC(50) of 0.073 microM. The inhibition of HIV-1 entry into host cells was demonstrated by using fluorescence-based real-time quantify PCR. At CVL concentration of 0.33 microM and 0.07 microM, 86% and 21% virus attachment were blocked, respectively. The anti-HIV-1 action of CVL might relate to blockade of HIV-1 entry into cells.

New GlcNAc/GalNAc-specific lectin from the ascidian Didemnum ternatanum.

Previously we isolated GlcNAc-specific lectin (DTL) from the ascidian Didemnum ternatanum by affinity chromatography on cross-linked ovalbumin. Here we report the purification and characterization of new D-GlcNAc/D-GalNAc-specific lectin DTL-A from the same ascidian. This lectin was isolated from non-bound cross-linked ovalbumin fraction and further was purified by gel filtration on Sepharose CL-4B, affinity chromatography on GlcNAc-agarose and gel filtration on Superdex 200. SDS-polyacrylamide gel electrophoresis and gel filtration of purified lectin on Sepharose CL-4B indicates that it exists as large aggregates in the native state. Investigations of the carbohydrate specificity of DTL-A by enzyme-linked lectin assay suggest the multi-specificity of this lectin. DTL-A binds BSM, asialo-BSM as well as heparin and dextran sulfate. The binding of DTL-A to BSM was inhibited by monosaccharides D-GlcNAc and D-GalNAc, their alpha- but not beta-anomers. Among polysaccharides and glycoconjugates, DTL-A binding to BSM was effectively inhibited by BSM, asialo-BSM, pronase-treated BSM and synthetic alpha-D-GalNAc-PAA. Fetuin and asialofetuin showed a much lower inhibitory potency, heparin and dextran sulfate were noninhibitory. On the other hand, DTL-A binding to heparin was effectively inhibited by dextran sulfate, fucoidan, whereas BSM showed insignificantly inhibitory effect. DTL-A binding to heparin was not inhibited by D-GlcNAc and D-GalNAc.