Alan Harzman

Liposome Bupivacaine for Postsurgical Analgesia in Adult Patients Undergoing Laparoscopic Colectomy: Results from Prospective Phase IV Sequential Cohort Studies Assessing Health Economic Outcomes

Background Opioid-based postsurgical analgesia exposes patients undergoing laparoscopic colectomy to elevated risk for gastrointestinal motility problems and other opioid-related adverse events (ORAEs). The purpose of our research was to investigate postsurgical outcomes, including opioid consumption, hospital length of stay, and ORAE risk associated with a multimodal analgesia regimen, employing a single administration of liposome bupivacaine as well as other analgesics that act by different mechanisms. Methods We analyzed combined results from 6 Phase IV, prospective, single-center studies in which patients undergoing laparoscopic colectomy received opioid-based intravenous patient-controlled analgesia (PCA) or multimodal analgesia incorporating intraoperative administration of liposome bupivacaine. As-needed rescue therapy was available to all patients. Primary outcome measures were postsurgical opioid consumption, hospital length of stay, and hospitalization costs. Secondary measures included time to first rescue opioid use, patient satisfaction with analgesia (assessed using a 5-point Likert scale), and ORAEs. Results Eighty-two patients underwent laparoscopic colectomy and did not meet intraoperative exclusion criteria (PCA n = 56; multimodal analgesia n = 26). Compared with the PCA group, the multimodal analgesia group had significantly lower mean total postsurgical opioid consumption (96 vs 32 mg, respectively; P < 0.0001) and shorter median postsurgical hospital length of stay (3.0 vs 4.0 days; P = 0.0019). Geometric mean costs were

Purinergic Autocrine Regulation of Mechanosensitivity and Serotonin Release in a Human EC Model: ATP-gated P2X3 Channels in EC are Downregulated in Ulcerative Colitis

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Molecular Signaling and Dysfunction of the Human Reactive Enteric Glial Cell Phenotype: Implications for GI Infection, IBD, POI, Neurological, Motility, and GI Disorders.

13,018 in the multimodal analgesia and PCA groups, respectively (P = 0.2612). Median time to first rescue opioid use was longer in the multimodal analgesia group versus PCA group (1.1 hours vs 0.6 hours, respectively; P=0.0003). ORAEs were experienced by 41% of patients receiving intravenous opioid PCA and 8% of patients receiving multimodal analgesia (P = 0.0019). Study limitations included use of an open-label, nonrandomized design; small population size; and the inability to isolate treatment-related effects specifically attributable to liposome bupivacaine. Conclusions Compared with intravenous opioid PCA, a liposome bupivacaine-based multimodal analgesia regimen reduced postsurgical opioid use, hospital length of stay, and ORAEs, and may lead to improved postsurgical outcomes following laparoscopic colectomy.

Neuropharmacology of Purinergic Receptors in Human Submucous Plexus: Involvement of P2X1, P2X2, P2X3 Channels, P2Y and A3 Metabotropic Receptors in Neurotransmission

Background:Alterations in 5-hydroxytryptamine (HT) signaling in inflamed gut may contribute to pathogenesis of inflammatory bowel diseases. Adenosine 5′-triphosphate (ATP) regulates mucosal-mechanosensory reflexes and ATP receptors are sensitive to mucosal inflammation. Yet, it remains unknown whether ATP can modulate 5-HT signaling in enterochromaffin cells (EC). We tested the novel purinergic hypothesis that ATP is a critical autocrine regulator of EC mechanosensitivity and whether EC expression of ATP-gated P2X3-ion channels is altered in inflammatory bowel diseases. Methods:Laser confocal (fluo-4) Ca2+ imaging was performed in 1947 BON cells. Chemical stimulation or mechanical stimulation (MS) was used to study 5-HT or ATP release in human BON or surgical mucosal specimens, and purine receptors by reverse transcription-polymerase chain reaction, Western Blot, or P2X3-immunoreactivity in BON or 5-HT+ human EC (hEC) in 11 control and 10 severely inflamed ulcerative colitis (UC) cases. Results:ATP or MS triggered Ca2+-transients or 5-HT release in BON. ATP or adenosine diphosphate increased 5-HT release 5-fold. MS caused ATP release, detected after 5′ecto-ATPase inhibition by ARL67156. ARL67156 augmented and apyrase blocked Ca2+/5-HT mechanosensitive responses. 2-Methyl-thio-adenosine diphosphate 5′-monophosphate-evoked (P2Y1,12) or mechanically-evoked responses were blocked or augmented by a P2Y1,12 antagonist, MRS2179, in different cells or inhibited by U73122. A P2Y12 antagonist, 2MeSAMP, augmented responses. A P2X1,3 agonist, &agr;,&bgr;-MeATP, triggered Ca2+ responses, whereas a P2X1,2/3,3 antagonist, 2′,3′-O-(2,4,6-trinitrophenyl)-ATP, blocked mechanical responses or cell-surface 5′ATP-TR labeling. In hEC, &agr;,&bgr;-MeATP stimulated 5-HT release. In UC, P2X3-immunoreactivity decreased from 15% to 0.2% of 5-HT+hECs. Human mucosa and BON expressed P2X1, P2X3, P2X4, P2X5, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, and P2Y12R-messenger RNA transcripts. Conclusions:ATP is a critical determinant of mechanosensation and 5-HT release via autocrine activation of slow P2Y1-phospholipase C/inositol-1,4,5-triphosphate-Ca2+ or inhibitory P2Y12-purinergic pathways, and fast ATP-gated P2X3-channels. UC downregulation of P2X3-channels (or A2B) is postulated to mediate abnormal 5-HT signaling.

Gastrointestinal tract-derived pulse granulomata: clues to an underrecognized pseudotumor.

Background:Clinical observations or animal studies implicate enteric glial cells in motility disorders, irritable bowel syndrome, inflammatory bowel disease, gastrointestinal (GI) infections, postoperative ileus, and slow transit constipation. Mechanisms underlying glial responses to inflammation in human GI tract are not understood. Our goal was to identify the “reactive human enteric glial cell (rhEGC) phenotype” induced by inflammation, and probe its functional relevance. Methods:Human enteric glial cells in culture from 15 GI-surgical specimens were used to study gene expression, Ca2+, and purinergic signaling by Ca2+/fluo-4 imaging and mechanosensitivity. A nanostring panel of 107 genes was designed as a read out of inflammation, transcription, purinergic signaling, vesicular transport protein, channel, antioxidant, and other pathways. A 24-hour treatment with lipopolysaccharide (200 &mgr;g/mL) and interferon-&ggr; (10 &mgr;g/mL) was used to induce inflammation and study molecular signaling, flow-dependent Ca2+ responses from 3 mL/min to 10 mL/min, adenosine triphosphate (ATP) release, and ATP responses. Results:Treatment induced a “rhEGC phenotype” and caused up-regulation in messenger RNA transcripts of 58% of 107 genes analyzed. Regulated genes included inflammatory genes (54%/IP10; IFN-&ggr;; CxCl2; CCL3; CCL2; C3; s100B; IL-1&bgr;; IL-2R; TNF-&agr;; IL-4; IL-6; IL-8; IL-10; IL-12A; IL-17A; IL-22; and IL-33), purine-genes (52%/AdoR2A; AdoR2B; P2RY1; P2RY2; P2RY6; P2RX3; P2RX7; AMPD3; ENTPD2; ENTPD3; and NADSYN1), channels (40%/Panx1; CHRNA7; TRPV1; and TRPA1), vesicular transporters (SYT1, SYT2, SNAP25, and SYP), transcription factors (relA/relB, SOCS3, STAT3, GATA_3, and FOXP3), growth factors (IGFBP5 and GMCSF), antioxidant genes (SOD2 and HMOX1), and enzymes (NOS2; TPH2; and CASP3) (P < 0.0001). Treatment disrupted Ca2+ signaling, ATP, and mechanical/flow-dependent Ca2+ responses in human enteric glial cells. ATP release increased 5-fold and s100B decreased 33%. Conclusions:The “rhEGC phenotype” is identified by a complex cascade of pro-inflammatory pathways leading to alterations of important molecular and functional signaling pathways (Ca2+, purinergic, and mechanosensory) that could disrupt GI motility. Inflammation induced a “purinergic switch” from ATP to adenosine diphosphate/adenosine/uridine triphosphate signaling. Findings have implications for GI infection, inflammatory bowel disease, postoperative ileus, motility, and GI disorders.

Sexually Transmitted Infectious Colitis vs Inflammatory Bowel Disease: Distinguishing Features From a Case-Controlled Study

RATIONALE The role of purinergic signaling in human ENS is not well understood. We sought to further characterize the neuropharmacology of purinergic receptors in human ENS and test the hypothesis that endogenous purines are critical regulators of neurotransmission. EXPERIMENTAL APPROACH LSCM-Fluo-4/(Ca(2+))-imaging of postsynaptic Ca(2+) transients (PSCaTs) was used as a reporter of synaptic transmission evoked by fiber tract electrical stimulation in human SMP surgical preparations. Pharmacological analysis of purinergic signaling was done in 1,556 neurons (identified by HuC/D-immunoreactivity) in 235 ganglia from 107 patients; P2XR-immunoreactivity was evaluated in 19 patients. Real-time MSORT (Di-8-ANEPPS) imaging tested effects of adenosine on fast excitatory synaptic potentials (fEPSPs). RESULTS Synaptic transmission is sensitive to pharmacological manipulations that alter accumulation of extracellular purines: Apyrase blocks PSCaTs in a majority of neurons. An ecto-NTPDase-inhibitor 6-N,N-diethyl-D-β,γ-dibromomethyleneATP or adenosine deaminase augments PSCaTs. Blockade of reuptake/deamination of eADO inhibits PSCaTs. Adenosine inhibits fEPSPs and PSCaTs (IC50 = 25 µM), sensitive to MRS1220-antagonism (A3AR). A P2Y agonist ADPβS inhibits PSCaTs (IC50 = 111 nM) in neurons without stimulatory ADPbS responses (EC50 = 960 nM). ATP or a P2X1,2,2/3 (α,β-MeATP) agonist evokes fast, slow, biphasic Ca(2+) transients or Ca(2+) oscillations (ATP,EC50 = 400 mM). PSCaTs are sensitive to P2X1 antagonist NF279. Low (20 nM) or high (5 µM) concentrations of P2X antagonist TNP-ATP block PSCaTs in different neurons; proportions of neurons with P2XR-immunoreactivity follow the order P2X2 > P2X1 >> P2X3; P2X1 + P2X2 and P2X3 + P2X2 are co-localized. RT-PCR identified mRNA-transcripts for P2X1-7, P2Y1,2,12-14R. CONCLUSIONS Purines are critical regulators of neurotransmission in human ENS. Purinergic signaling involves P2X1, P2X2, P2X3 channels, P2X1 + P2X2 co-localization and inhibitory P2Y or A3 receptors. These are potential novel therapeutic targets for neurogastroenterology.

Practice gaps in gastrointestinal and endoscopic surgery (2011): A report from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES) Continuing Education Committee

Pulse granulomata (PG) in the lung and oral pathology literature are presumed due to food (pulse) introduced by mucosal injury. Herein, we report the largest series of PG in the gastrointestinal tract (GIT): 22 resections were prospectively collected from 17 patients (8 men, range=28 to 85 y). All patients had a history of intestinal injury/disease: diverticulitis, fistula, adenocarcinoma, perforation, ulcerative colitis, appendicitis, anastomotic site leak, and/or stent leak. Nine of 22 specimens were designated “masses”; most of these were clinically concerning for neoplasia. Sites of involvement included the small and large intestine, appendix, liver, gallbladder, mesentery, omentum, peritoneum, cervix, ovary, and skin. PG were typically nodular (21/22) and multifocal (15/22); most involved the external surface of the bowel (20/22), and they ranged in size from 1.5 to 100 mm. Histologically, they contained variable amounts of hyaline ribbons and rings, inflammation, foreign body giant cells, calcifications, and food; larger lesions displayed circumferential stellate fibrosis (12/22). We describe 3 morphologic variants: hyaline predominant (mimicking amyloid), cellular predominant (mimicking spindle cell neoplasms), and sclerosing mesenteritis-like. All patients are alive and well at the time of follow-up. Histologically processed legumes showed similar structures as those identified in PG, providing support for an entrapped food origin. In summary, we detail important clinicopathologic clues, describe the PG morphologic spectrum, and demonstrate how to distinguish PG from their mimics. Although PG can present as clinically concerning masses, we conclude that they are pseudotumors arising secondary to entrapped food introduced through mucosal trauma, similar to their lung and oral counterparts.

UTP – Gated Signaling Pathways of 5-HT Release from BON Cells as a Model of Human Enterochromaffin Cells

OBJECTIVES Sexually transmitted infectious (STI) colitis often raises concern for inflammatory bowel disease (IBD). In this study, we compare histologic features of IBD with STI colitis caused by syphilis and lymphogranuloma venereum. METHODS The STI colitis group included 10 unique colorectal biopsy specimens in patients with clinically confirmed syphilis and/or lymphogranuloma venereum. The STI biopsy specimens were compared with patients matched for age, sex, and site with Crohn disease (n = 10) or ulcerative colitis (n = 10). All IBD controls had an established history of IBD (up to 276 months of follow-up, mean follow-up = 102 months). RESULTS Discriminating features (P < .05) of STI colitis included its exclusive identification in human immunodeficiency virus-positive men who have sex with men, anal pain, and anal discharge. STI colitis contained the triad of (1) minimal active chronic crypt centric damage, (2) a lack of mucosal eosinophilia, and (3) submucosal plasma cells, endothelial swelling, and perivascular plasma cells. Nondiscriminating features (P > .05) included rectal bleeding, endoscopic appearance, skip lesions, ulcerations, aphthoid lesions, granulomata, foreign body giant cells, neural hyperplasia, fibrosis, and lymphoid aggregates. CONCLUSIONS While STI colitis shares many overlapping features with IBD, histologic and clinical discriminating features may be helpful when confronted with that differential diagnosis.

The Efficacy of Adjuvant Chemotherapy in Patients With Stage Ii/iii Resected Rectal Cancer Treated With Neoadjuvant Chemoradiation Therapy

The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) [1] had its first scientific meeting in the 1980 s and has grown since to represent a worldwide community of over 6,000 surgeons and other health-care professionals who bring minimal access surgery, endoscopy, and emerging techniques to patients across the world. As part of its mission, SAGES has developed and implemented an overarching educational program to help its members improve outcomes for patients who require minimally invasive and endoscopic procedures. The program’s continuing medical education (CME) objectives are to assist surgeons in (1) improving knowledge of gastrointestinal and related diseases, (2) assessing current and emerging surgical therapies, (3) acquiring competence to perform and teach appropriate therapies, and (4) measuring effectiveness of therapies in terms of outcomes. The SAGES Annual Meeting has evolved into the major platform for CME activities and services offered by SAGES, with over 2,000 attendees. Teaching forums include scientific sessions, poster sessions, symposia, didactic postgraduate courses, and hands-on laboratory training sessions. In addition to the Annual Meeting, coendorsed programs and online educational materials through SAGES University [2] contribute to the comprehensive CME program provided by the society. The SAGES Continuing Education Committee is charged with maintaining compliance with Accreditation Council of Continuing Medical Education (ACCME) requirements overall and for individual CME programs. The ACCME accreditation process requires that ‘‘CME providers incorporate into CME activities the educational needs that underlie the professional practice gaps of their own learners’’ [3]. The ACCME also emphasizes that CME providers must show ‘‘that planning includes the identification of a professional practice gap from which needs were identified’’ [3]. SAGES identifies practice gaps through analysis of survey data collected at the Annual Meeting and at 3-month follow-up. Through this process a ‘‘Gaps Bank’’ has been created and maintained to inform the Executive Committee, Board of Governors, and program leaders about members’ self-identified learning needs as upcoming meeting topics are outlined. In addition, Session Chairs and speakers utilize the Gaps Bank when selecting and formulating specific didactic topics and associated learning objectives. This report summarizes the SAGES Continuing T. M. Farrell (&) Department of Surgery, University of North Carolina at Chapel Hill, CB 7081, Chapel Hill, NC 27599-7081, USA e-mail: tfarrell@med.unc.edu

Crospovidone and Microcrystalline Cellulose: A Novel Description of Pharmaceutical Fillers in the Gastrointestinal Tract.

Background: Enterochromaffin cells (EC) synthesize and release 5-HT and ATP to trigger or modulate gut neural reflexes and transmit information about visceral/pain sensation. Alterations in 5-HT signaling mechanisms may contribute to the pathogenesis of IBD or IBS, but the pharmacologic or molecular mechanisms modulating Ca2+-dependent 5-HT release are not understood. Previous studies indicated that purinergic signaling via ATP and ADP is an important mechanism in modulation of 5-HT release. However, EC cells also respond to UTP and UDP suggesting uridine triphosphate receptor and signaling pathways are involved as well. We tested the hypothesis that UTP is a regulator of 5-HT release in human EC cells. Methods: UTP signaling mechanisms were studied in BON cells, a human EC model, using Fluo-4/Ca2+imaging, patch-clamp, pharmacological analysis, immunohistochemistry, western blots and qPCR. 5-HT release was monitored in BON or EC isolated from human gut surgical specimens (hEC). Results: UTP, UTPγS, UDP or ATP induced Ca2+oscillations in BON. UTP evoked a biphasic concentration-dependent Ca2+response. Cells responded in the order of UTP, ATP > UTPγS > UDP >> MRS2768, BzATP, α,β-MeATP > MRS2365, MRS2690, and NF546. Different proportions of cells activated by UTP and ATP also responded to UTPγS (P2Y4, 50% cells), UDP (P2Y6, 30%), UTPγS and UDP (14%) or MRS2768 (<3%). UTP Ca2+responses were blocked with inhibitors of PLC, IP3R, SERCA Ca2+pump, La3+sensitive Ca2+channels or chelation of intracellular free Ca2+ by BAPTA/AM. Inhibitors of L-type, TRPC, ryanodine-Ca2+pools, PI3-Kinase, PKC or SRC-Kinase had no effect. UTP stimulated voltage-sensitive Ca2+currents (ICa), Vm-depolarization and inhibited IK (not IA) currents. An IKv7.2/7.3 K+ channel blocker XE-991 mimicked UTP-induced Vm-depolarization and blocked UTP-responses. XE-991 blocked IK and UTP caused further reduction. La3+ or PLC inhibitors blocked UTP depolarization; PKC inhibitors, thapsigargin or zero Ca2+buffer did not. UTP stimulated 5-HT release in hEC expressing TPH1, 5-HT, P2Y4/P2Y6R. Zero-Ca2+buffer augmented Ca2+responses and 5-HT release. Conclusion: UTP activates a predominant P2Y4R pathway to trigger Ca2+oscillations via internal Ca2+mobilization through a PLC/IP3/IP3R/SERCA Ca2+signaling pathway to stimulate 5-HT release; Ca2+influx is inhibitory. UTP-induced Vm-depolarization depends on PLC signaling and an unidentified K channel (which appears independent of Ca2+oscillations or Ica/VOCC). UTP-gated signaling pathways triggered by activation of P2Y4R stimulate 5-HT release.