Recombinant Mouse PAP Has pH-Dependent Ectonucleotidase Activity and Acts through A1-Adenosine Receptors to Mediate Antinociception

Prostatic acid phosphatase (PAP) is expressed in nociceptive neurons and functions as an ectonucleotidase. When injected intraspinally, the secretory isoforms of human and bovine PAP protein have potent and long-lasting antinociceptive effects that are dependent on A1-adenosine receptor (A1R) activation. In this study, we purified the secretory isoform of mouse (m)PAP using the baculovirus expression system to determine if recombinant mPAP also had antinociceptive properties. We found that mPAP dephosphorylated AMP, and to a much lesser extent, ADP at neutral pH (pH 7.0). In contrast, mPAP dephosphorylated all purine nucleotides (AMP, ADP, ATP) at an acidic pH (pH 5.6). The transmembrane isoform of mPAP had similar pH-dependent ectonucleotidase activity. A single intraspinal injection of mPAP protein had long-lasting (three day) antinociceptive properties, including antihyperalgesic and antiallodynic effects in the Complete Freund's Adjuvant (CFA) inflammatory pain model. These antinociceptive effects were transiently blocked by the A1R antagonist 8-cyclopentyl-1, 3-dipropylxanthine (CPX), suggesting mPAP dephosphorylates nucleotides to adenosine to mediate antinociception just like human and bovine PAP. Our studies indicate that PAP has species-conserved antinociceptive effects and has pH-dependent ectonucleotidase activity. The ability to metabolize nucleotides in a pH-dependent manner could be relevant to conditions like inflammation where tissue acidosis and nucleotide release occur. Lastly, our studies demonstrate that recombinant PAP protein can be used to treat chronic pain in animal models

Crosstalk between Spinal Astrocytes and Neurons in Nerve Injury-Induced Neuropathic Pain

Emerging research implicates the participation of spinal dorsal horn (SDH) neurons and astrocytes in nerve injury-induced neuropathic pain. However, the crosstalk between spinal astrocytes and neurons in neuropathic pain is not clear. Using a lumbar 5 (L5) spinal nerve ligation (SNL) pain model, we testified our hypothesis that SDH neurons and astrocytes reciprocally regulate each other to maintain the persistent neuropathic pain states. Glial fibrillary acidic protein (GFAP) was used as the astrocytic specific marker and Fos, protein of the protooncogene c-fos, was used as a marker for activated neurons. SNL induced a significant mechanical allodynia as well as activated SDH neurons indicated by the Fos expression at the early phase and activated astrocytes with the increased expression of GFAP during the late phase of pain, respectively. Intrathecal administration of c-fos antisense oligodeoxynucleotides (ASO) or astroglial toxin L-α-aminoadipate (L-AA) reversed the mechanical allodynia, respectively. Immunofluorescent histochemistry revealed that intrathecal administration of c-fos ASO significantly suppressed activation of not only neurons but also astrocytes induced by SNL. Meanwhile, L-AA shortened the duration of neuronal activation by SNL. Our data offers evidence that neuronal and astrocytic activations are closely related with the maintenance of neuropathic pain through a reciprocal “crosstalk”. The current study suggests that neuronal and non-neuronal elements should be taken integrally into consideration for nociceptive transmission, and that the intervention of such interaction may offer some novel pain therapeutic strategies

The Role of Glypicans in Wnt Inhibitory Factor-1 Activity and the Structural Basis of Wif1's Effects on Wnt and Hedgehog Signaling

Proper assignment of cellular fates relies on correct interpretation of Wnt and Hedgehog (Hh) signals. Members of the Wnt Inhibitory Factor-1 (WIF1) family are secreted modulators of these extracellular signaling pathways. Vertebrate WIF1 binds Wnts and inhibits their signaling, but its Drosophila melanogaster ortholog Shifted (Shf) binds Hh and extends the range of Hh activity in the developing D. melanogaster wing. Shf activity is thought to depend on reinforcing interactions between Hh and glypican HSPGs. Using zebrafish embryos and the heterologous system provided by D. melanogaster wing, we report on the contribution of glypican HSPGs to the Wnt-inhibiting activity of zebrafish Wif1 and on the protein domains responsible for the differences in Wif1 and Shf specificity. We show that Wif1 strengthens interactions between Wnt and glypicans, modulating the biphasic action of glypicans towards Wnt inhibition; conversely, glypicans and the glypican-binding “EGF-like” domains of Wif1 are required for Wif1's full Wnt-inhibiting activity. Chimeric constructs between Wif1 and Shf were used to investigate their specificities for Wnt and Hh signaling. Full Wnt inhibition required the “WIF” domain of Wif1, and the HSPG-binding EGF-like domains of either Wif1 or Shf. Full promotion of Hh signaling requires both the EGF-like domains of Shf and the WIF domains of either Wif1 or Shf. That the Wif1 WIF domain can increase the Hh promoting activity of Shf's EGF domains suggests it is capable of interacting with Hh. In fact, full-length Wif1 affected distribution and signaling of Hh in D. melanogaster, albeit weakly, suggesting a possible role for Wif1 as a modulator of vertebrate Hh signaling

Laparoscopic repair of complicated umbilical hernia with Strattice Laparoscopic™ reconstructive tissue matrix

INTRODUCTION: Complex hernias continue to present a challenge. Surgical techniques for repair are carefully considered to reduce risk for complications. Laparoscopic repairs improve postoperative infection rates, and placement of biologic mesh decreases mesh infection rates. However, laparoscopic repairs using biologic mesh is generally challenging due to difficulty with maneuverability. PRESENTATION OF CASE: We present a case of a complex ventral hernia that was laparoscopically repaired using a new FDA cleared laparoscopic biologic graft. The patient had multiple comorbidities, including obesity, hepatitis C, endocarditis secondary to IV drug use, tobacco smoking, bilateral inguinal hernia, and recurrent umbilical hernia. The recurrent hernia was larger, irreducible, and discolored compared to original defect. The patient underwent laparoscopic repair with primary closure and reinforcement with Strattice™ Tissue Matrix Laparoscopic (LifeCell Corporation, Branchburg, NJ). At nine months postoperative, the patient had no evidence of recurrence, infection, or chronic pain, demonstrating early success from the surgical management. DISCUSSION: Presence of multiple comorbidities and incarcerated recurrent hernia increase risk for complications during and/or after hernia repair. Considering these factors, laparoscopic repair with Strattice Laparoscopic and defect closure was a reasonable technique for repair. CONCLUSION: Laparoscopic suture repair reinforced with biologic dermal tissue matrix was successfully performed during a complex hernia repair

SAGES TAVAC safety and effectiveness analysis: da Vinci\u3csup\u3e®\u3c/sup\u3e Surgical System (Intuitive Surgical, Sunnyvale, CA)

© 2015, Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). Background: The da Vinci® Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) is a computer-assisted (robotic) surgical system designed to enable and enhance minimally invasive surgery. The Food and Drug Administration (FDA) has cleared computer-assisted surgical systems for use by trained physicians in an operating room environment for laparoscopic surgical procedures in general, cardiac, colorectal, gynecologic, head and neck, thoracic and urologic surgical procedures. There are substantial numbers of peer-reviewed papers regarding the da Vinci® Surgical System, and a thoughtful assessment of evidence framed by clinical opinion is warranted. Methods: The SAGES da Vinci® TAVAC sub-committee performed a literature review of the da Vinci® Surgical System regarding gastrointestinal surgery. Conclusions by the sub-committee were vetted by the SAGES TAVAC Committee and SAGES Executive Board. Following revisions, the document was evaluated by the TAVAC Committee and Executive Board again for final approval. Results: Several conclusions were drawn based on expert opinion organized by safety, efficacy, and cost for robotic foregut, bariatric, hepatobiliary/pancreatic, colorectal surgery, and single-incision cholecystectomy. Conclusions: Gastrointestinal surgery with the da Vinci® Surgical System is safe and comparable, but not superior to standard laparoscopic approaches. Although clinically acceptable, its use may be costly for select gastrointestinal procedures. Current data are limited to the da Vinci® Surgical System; further analyses are needed

SAGES TAVAC safety and effectiveness analysis: da Vinci(®) Surgical System (Intuitive Surgical, Sunnyvale, CA).

© 2015, Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). Background: The da Vinci® Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) is a computer-assisted (robotic) surgical system designed to enable and enhance minimally invasive surgery. The Food and Drug Administration (FDA) has cleared computer-assisted surgical systems for use by trained physicians in an operating room environment for laparoscopic surgical procedures in general, cardiac, colorectal, gynecologic, head and neck, thoracic and urologic surgical procedures. There are substantial numbers of peer-reviewed papers regarding the da Vinci® Surgical System, and a thoughtful assessment of evidence framed by clinical opinion is warranted. Methods: The SAGES da Vinci® TAVAC sub-committee performed a literature review of the da Vinci® Surgical System regarding gastrointestinal surgery. Conclusions by the sub-committee were vetted by the SAGES TAVAC Committee and SAGES Executive Board. Following revisions, the document was evaluated by the TAVAC Committee and Executive Board again for final approval. Results: Several conclusions were drawn based on expert opinion organized by safety, efficacy, and cost for robotic foregut, bariatric, hepatobiliary/pancreatic, colorectal surgery, and single-incision cholecystectomy. Conclusions: Gastrointestinal surgery with the da Vinci® Surgical System is safe and comparable, but not superior to standard laparoscopic approaches. Although clinically acceptable, its use may be costly for select gastrointestinal procedures. Current data are limited to the da Vinci® Surgical System; further analyses are needed

SAGES and EAES recommendations for minimally invasive surgery during COVID-19 pandemic

The unprecedented pandemic of COVID-19 has impacted many lives and affects the whole healthcare systems globally. In addition to the considerable workload challenges, surgeons are faced with a number of uncertainties regarding their own safety, practice, and overall patient care. This guide has been drafted at short notice to advise on specific issues related to surgical service provision and the safety of minimally invasive surgery during the COVID-19 pandemic. Although laparoscopy can theoretically lead to aerosolization of blood borne viruses, there is no evidence available to confirm this is the case with COVID-19. The ultimate decision on the approach should be made after considering the proven benefits of laparoscopic techniques versus the potential theoretical risks of aerosolization. Nevertheless, erring on the side of safety would warrant treating the coronavirus as exhibiting similar aerosolization properties and all members of the OR staff should use personal protective equipment (PPE) in all surgical procedures during the pandemic regardless of known or suspected COVID status. Pneumoperitoneum should be safely evacuated via a filtration system before closure, trocar removal, specimen extraction, or conversion to open. All emergent endoscopic procedures performed during the pandemic should be considered as high risk and PPE must be used by all endoscopy staff

Fundamentals of endoscopic surgery: creation and validation of the hands-on test

The Fundamentals of Endoscopic Surgery™ (FES) program consists of online materials and didactic and skills-based tests. All components were designed to measure the skills and knowledge required to perform safe flexible endoscopy. The purpose of this multicenter study was to evaluate the reliability and validity of the hands-on component of the FES examination, and to establish the pass score.Expert endoscopists identified the critical skill set required for flexible endoscopy. They were then modeled in a virtual reality simulator (GI Mentor™ II, Simbionix™ Ltd., Airport City, Israel) to create five tasks and metrics. Scores were designed to measure both speed and precision. Validity evidence was assessed by correlating performance with self-reported endoscopic experience (surgeons and gastroenterologists [GIs]). Internal consistency of each test task was assessed using Cronbach’s alpha. Test–retest reliability was determined by having the same participant perform the test a second time and comparing their scores. Passing scores were determined by a contrasting groups methodology and use of receiver operating characteristic curves.A total of 160 participants (17 % GIs) performed the simulator test. Scores on the five tasks showed good internal consistency reliability and all had significant correlations with endoscopic experience. Total FES scores correlated 0.73, with participants’ level of endoscopic experience providing evidence of their validity, and their internal consistency reliability (Cronbach’s alpha) was 0.82. Test–retest reliability was assessed in 11 participants, and the intraclass correlation was 0.85. The passing score was determined and is estimated to have a sensitivity (true positive rate) of 0.81 and a 1-specificity (false positive rate) of 0.21.The FES hands-on skills test examines the basic procedural components required to perform safe flexible endoscopy. It meets rigorous standards of reliability and validity required for high-stakes examinations, and, together with the knowledge component, may help contribute to the definition and determination of competence in endoscopy