A Prospective Randomized Multicenter Trial of Distal Pancreatectomy With and Without Routine Intraperitoneal Drainage.

OBJECTIVE: The objective of this study was to test the hypothesis that distal pancreatectomy (DP) without intraperitoneal drainage does not affect the frequency of grade 2 or higher grade complications. BACKGROUND: The use of routine intraperitoneal drains during DP is controversial. Prior to this study, no prospective trial focusing on DP without intraperitoneal drainage has been reported. METHODS: Patients undergoing DP for all causes at 14 high-volume pancreas centers were preoperatively randomized to placement of a drain or no drain. Complications and their severity were tracked for 60 days and mortality for 90 days. The study was powered to detect a 15% positive or negative difference in the rate of grade 2 or higher grade complications. All data were collected prospectively and source documents were reviewed at the coordinating center to confirm completeness and accuracy. RESULTS: A total of 344 patients underwent DP with (N = 174) and without (N = 170) the use of intraperitoneal drainage. There were no differences between cohorts in demographics, comorbidities, pathology, pancreatic duct size, pancreas texture, or operative technique. There was no difference in the rate of grade 2 or higher grade complications (44% vs. 42%, P = 0.80). There was no difference in clinically relevant postoperative pancreatic fistula (18% vs 12%, P = 0.11) or mortality (0% vs 1%, P = 0.24). DP without routine intraperitoneal drainage was associated with a higher incidence of intra-abdominal fluid collection (9% vs 22%, P = 0.0004). There was no difference in the frequency of postoperative imaging, percutaneous drain placement, reoperation, readmission, or quality of life scores. CONCLUSIONS: This prospective randomized multicenter trial provides evidence that clinical outcomes are comparable in DP with or without intraperitoneal drainage.

Isolation of Pancreatic Cancer Cells from a Patient-Derived Xenograft Model Allows for Practical Expansion and Preserved Heterogeneity in Culture.

Commercially available, highly passaged pancreatic cancer (PC) cell lines are of limited translational value. Attempts to overcome this limitation have primarily consisted of cancer cell isolation and culture directly from human PC specimens. However, these techniques are associated with exceedingly low success rates. Here, we demonstrate a highly reproducible culture of primary PC cell lines (PPCLs) from patient-derived xenografts, which preserve, in part, the intratumoral heterogeneity known to exist in PC. PPCL expansion from patient-derived xenografts was successful in 100% of attempts (5 of 5). Phenotypic analysis was evaluated with flow cytometry, immunofluorescence microscopy, and short tandem repeat profiling. Importantly, tumorigenicity of PPCLs expanded from patient-derived xenografts was assessed by subcutaneous injection into nonobese diabeteic.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ mice. Morphologically, subcutaneous injection of all PPCLs into mice yielded tumors with similar characteristics to the parent xenograft. PPCLs uniformly expressed class I human leukocyte antigen, epithelial cell adhesion molecule, and cytokeratin-19. Heterogeneity within each PPCL persisted in culture for the frequency of cells expressing the cancer stem cell markers CD44, CD133, and c-Met and the immunologic markers human leukocyte antigen class II and programmed death ligand 1. This work therefore presents a reliable method for the rapid expansion of primary human PC cells and, thereby, provides a platform for translational investigation and, importantly, potential personalized therapeutic approaches.

TRIF-dependent innate immune activation is critical for survival to neonatal gram-negative sepsis.

Current evidence suggests that neonatal immunity is functionally distinct from adults. Although TLR signaling through the adaptor protein, MyD88, has been shown to be critical for survival to sepsis in adults, little is known about the role of MyD88 or TRIF in neonatal sepsis. We demonstrate that TRIF(-/-) but not MyD88(-/-) neonates are highly susceptible to Escherichia coli peritonitis and bacteremia. This was associated with decreased innate immune recruitment and function. Importantly, we found that the reverse was true in adults that MyD88(-/-) but not TRIF(-/-) or wild-type adults are susceptible to E. coli peritonitis and bacteremia. In addition, we demonstrate that TRIF but not MyD88 signaling is critical for the TLR4 protective adjuvant effect we have previously demonstrated. These data suggest a differential requirement for the survival of neonates versus adults to Gram-negative infection, and that modulation of TRIF in neonates can be used to augment survival to neonatal sepsis.

Patient-derived xenograft models for pancreatic adenocarcinoma demonstrate retention of tumor morphology through incorporation of murine stromal elements.

Direct implantation of viable surgical specimens provides a representative preclinical platform in pancreatic adenocarcinoma. Patient-derived xenografts consistently demonstrate retained tumor morphology and genetic stability. However, the evolution of the tumor microenvironment over time remains poorly characterized in these models. This work specifically addresses the recruitment and incorporation of murine stromal elements into expanding patient-derived pancreatic adenocarcinoma xenografts, establishing the integration of murine cells into networks of invading cancer cells. In addition, we provide methods and observations in the establishment and maintenance of a patient-derived pancreatic adenocarcinoma xenograft model. A total of 25 histologically confirmed pancreatic adenocarcinoma specimens were implanted subcutaneously into nonobese diabetic severe combined immunodeficiency mice. Patient demographics, staging, pathological analysis, and outcomes were analyzed. After successful engraftment of tumors, histological and immunofluorescence analyses were performed on explanted tumors. Pancreatic adenocarcinoma specimens were successfully engrafted in 15 (60%) of 25 attempts. Successful engraftment does not appear to correlate with clinicopathologic factors or patient survival. Tumor morphology is conserved through multiple passages, and tumors retain metastatic potential. Interestingly, despite morphological similarity between passages, human stromal elements do not appear to expand with invading cancer cells. Rather, desmoplastic murine stroma dominates the xenograft microenvironment after the initial implantation. Recruitment of stromal elements in this manner to support and maintain tumor growth represents a novel avenue for investigation into tumor-stromal interactions.

Primary outgrowth cultures are a reliable source of human pancreatic stellate cells.

Recent advances demonstrate a critical yet poorly understood role for the pancreatic stellate cell (PSC) in the pathogenesis of chronic pancreatitis (CP) and pancreatic cancer (PC). Progress in this area has been hampered by the availability, fidelity, and/or reliability of in vitro models of PSCs. We examined whether outgrowth cultures from human surgical specimens exhibited reproducible phenotypic and functional characteristics of PSCs. PSCs were cultured from surgical specimens of healthy pancreas, CP and PC. Growth dynamics, phenotypic characteristics, soluble mediator secretion profiles and co-culture with PC cells both in vitro and in vivo were assessed. Forty-seven primary cultures were established from 52 attempts, demonstrating universal α-smooth muscle actin and glial fibrillary acidic protein but negligible epithelial surface antigen expression. Modification of culture conditions consistently led to cytoplasmic lipid accumulation, suggesting induction of a quiescent phenotype. Secretion of growth factors, chemokines and cytokines did not significantly differ between donor pathologies, but did evolve over time in culture. Co-culture of PSCs with established PC cell lines resulted in significant changes in levels of multiple secreted mediators. Primary PSCs co-inoculated with PC cells in a xenograft model led to augmented tumor growth and metastasis. Therefore, regardless of donor pathology, outgrowth cultures produce PSCs that demonstrate consistent growth and protein secretion properties. Primary cultures from pancreatic surgical specimens, including malignancies, may represent a reliable source of human PSCs.

Downstream mediators of the intratumoral interferon response suppress antitumor immunity, induce gemcitabine resistance and associate with poor survival in human pancreatic cancer.

The cancer microenvironment allows tumor cells to evade immune surveillance through a variety of mechanisms. While interferon-γ (IFNγ) is central to effective antitumor immunity, its effects on the microenvironment are not as clear and have in some cancers been shown to induce immune checkpoint ligands. The heterogeneity of these responses to IFNγ remains poorly characterized in desmoplastic malignancies with minimal inflammatory cell infiltration, such as pancreatic cancer (PC). Thus, the IFNγ response within and on key cells of the PC microenvironment was evaluated. IFNγ induced expression of human leukocyte antigen (HLA) class I and II on PC cell lines, primary pancreatic cancer epithelial cells (PPCE) and patient-derived tumor-associated stroma, concomitant with an upregulation of PDL1 in the absence of CD80 and CD86 expression. As expected, IFNγ also induced high levels of CXCL10 from all cell types. In addition, significantly higher levels of CXCL10 were observed in PC specimens compared to those from chronic pancreatitis, whereby intratumoral CXCL10 concentration was an independent predictor of poor survival. Immunohistochemical analysis revealed a subset of CXCR3-positive cancer cells in over 90 % of PC specimens, as well as on a subset of cultured PC cell lines and PPCE, whereby exposure to CXCL10 induced resistance to the chemotherapeutic gemcitabine. These findings suggest that IFNγ has multiple effects on many cell types within the PC microenvironment that may lead to immune evasion, chemoresistance and shortened survival.

The inflammatory milieu within the pancreatic cancer microenvironment correlates with clinicopathologic parameters, chemoresistance and survival.

BACKGROUND: The tumor microenvironment impacts pancreatic cancer (PC) development, progression and metastasis. How intratumoral inflammatory mediators modulate this biology remains poorly understood. We hypothesized that the inflammatory milieu within the PC microenvironment would correlate with clinicopathologic findings and survival. METHODS: Pancreatic specimens from normal pancreas (n = 6), chronic pancreatitis (n = 9) and pancreatic adenocarcinoma (n = 36) were homogenized immediately upon resection. Homogenates were subjected to multiplex analysis of 41 inflammatory mediators. RESULTS: Twenty-three mediators were significantly elevated in adenocarcinoma specimens compared to nonmalignant controls. Increased intratumoral IL-8 concentrations associated with larger tumors (P = .045) and poor differentiation (P = .038); the administration of neoadjuvant chemotherapy associated with reduced IL-8 concentrations (P = .003). Neoadjuvant therapy was also associated with elevated concentrations of Flt-3 L (P = .005). Elevated levels of pro-inflammatory cytokines IL-1ß (P = .017) and TNFα (P = .033) were associated with a poor histopathologic response to neoadjuvant therapy. Elevated concentrations of G-CSF (P = .016) and PDGF-AA (P = .012) correlated with reduced overall survival. Conversely, elevated concentrations of FGF-2 (P = .038), TNFα (P = .031) and MIP-1α (P = .036) were associated with prolonged survival. CONCLUSION: The pancreatic cancer microenvironment harbors a unique inflammatory milieu with potential diagnostic and prognostic value.

Design and experimental evaluation of an anti-leak feeding tube.

BACKGROUND: Enteral feeding via gastrostomy or jejunostomy tube is often required to adequately treat patients with cancer, gastrointestinal disorders, and cerebral vascular accident. Although sufficient to provide adequate caloric intake, the present design of a gastrostomy tube is inadequate. Leakage of gastric contents onto the skin is commonplace prompting emergency department visits and skin damage that requires costly nonoperative and operative intervention. We introduce a new gastrostomy tube design and prototype that inhibits leakage by using an adjustable external retaining member, which compresses against the feeding tube shaft thereby preventing dynamic friction. METHODS: A conventional external retaining member of a 22 French gastrostomy tube was tested against a novel compression-fitting external retaining member. Each gastrostomy tube was clamped to a scale and the external retaining member moved to slide along the tubing at a constant rate, and the applied frictional force was recorded. Thirty repetitions were performed. RESULTS: The experimental prototype generated ×2.5-3 the frictional force preventing tube excursion. Mean (standard deviation) forces were 18 (3) versus 46 (4) ounces (n = 10, P = 2.57E-13) and 15 (4) versus 48 (4) ounces (n = 10, P = 1.90E-13) for conventional and experimental designs, respectively. Simulated in situ environment mean forces were 19 (3) versus 39 (3) ounces (n = 10, P = 3.30E-11) for conventional and experimental designs, respectively. CONCLUSIONS: The experimental design created an increased static frictional force that inhibited the movement of the external retaining member against the gastrostomy tube. Clinical implementation is the next step to evaluate for reduced feeding tube morbidity and healthcare expenses by preventing leakage of gastric contents.

A randomized prospective multicenter trial of pancreaticoduodenectomy with and without routine intraperitoneal drainage.

OBJECTIVE: To test by randomized prospective multicenter trial the hypothesis that pancreaticoduodenectomy (PD) without the use of intraperitoneal drainage does not increase the frequency or severity of complications. BACKGROUND: Some surgeons have abandoned the use of drains placed during pancreas resection. METHODS: We randomized 137 patients to PD with (n = 68, drain group) and without (n = 69, no-drain group) the use of intraperitoneal drainage and compared the safety of this approach and spectrum of complications between the 2 groups. RESULTS: There were no differences between drain and no-drain cohorts in demographics, comorbidities, pathology, pancreatic duct size, pancreas texture, baseline quality of life, or operative technique. PD without intraperitoneal drainage was associated with an increase in the number of complications per patient [1 (0-2) vs 2 (1-4), P = 0.029]; an increase in the number of patients who had at least 1 ≥grade 2 complication [35 (52%) vs 47 (68%), P = 0.047]; and a higher average complication severity [2 (0-2) vs 2 (1-3), P = 0.027]. PD without intraperitoneal drainage was associated with a higher incidence of gastroparesis, intra-abdominal fluid collection, intra-abdominal abscess (10% vs 25%, P = 0.027), severe (≥grade 2) diarrhea, need for a postoperative percutaneous drain, and a prolonged length of stay. The Data Safety Monitoring Board stopped the study early because of an increase in mortality from 3% to 12% in the patients undergoing PD without intraperitoneal drainage. CONCLUSIONS: This study provides level 1 data, suggesting that elimination of intraperitoneal drainage in all cases of PD increases the frequency and severity of complications.

What is next for social media for Surgery?

Social media has morphed from an interesting phenomenon to an essential part of surgical publishing. This contribution, "What Is Next for Social Media for Surgery," reviews how we arrived at this point, how we are currently engaged in Surgery in social media, and where we, as editors-in-chief, envision social media heading over the next several years.

Carbamazepine suppresses calpain-mediated autophagy impairment after ischemia/reperfusion in mouse livers.

Onset of the mitochondrial permeability transition (MPT) plays a causative role in ischemia/reperfusion (I/R) injury. Current therapeutic strategies for reducing reperfusion injury remain disappointing. Autophagy is a lysosome-mediated, catabolic process that timely eliminates abnormal or damaged cellular constituents and organelles such as dysfunctional mitochondria. I/R induces calcium overloading and calpain activation, leading to degradation of key autophagy-related proteins (Atg). Carbamazepine (CBZ), an FDA-approved anticonvulsant drug, has recently been reported to increase autophagy. We investigated the effects of CBZ on hepatic I/R injury. Hepatocytes and livers from male C57BL/6 mice were subjected to simulated in vitro, as well as in vivo I/R, respectively. Cell death, intracellular calcium, calpain activity, changes in autophagy-related proteins (Atg), autophagic flux, MPT and mitochondrial membrane potential after I/R were analyzed in the presence and absence of 20 µM CBZ. CBZ significantly increased hepatocyte viability after reperfusion. Confocal microscopy revealed that CBZ prevented calcium overloading, the onset of the MPT and mitochondrial depolarization. Immunoblotting and fluorometric analysis showed that CBZ blocked calpain activation, depletion of Atg7 and Beclin-1 and loss of autophagic flux after reperfusion. Intravital multiphoton imaging of anesthetized mice demonstrated that CBZ substantially reversed autophagic defects and mitochondrial dysfunction after I/R in vivo. In conclusion, CBZ prevents calcium overloading and calpain activation, which, in turn, suppresses Atg7 and Beclin-1 depletion, defective autophagy, onset of the MPT and cell death after I/R.

A primer on standards setting as it applies to surgical education and credentialing.

BACKGROUND: Surgical technological advances in the past three decades have led to dramatic reductions in the morbidity associated with abdominal procedures and permanently altered the surgical practice landscape. Significant changes continue apace including surgical robotics, natural orifice-based surgery, and single-incision approaches. These disruptive technologies have on occasion been injurious to patients, and high-stakes assessment before adoption of new technologies would be reasonable. METHODS: We reviewed the drivers for well-established psychometric techniques available for the standards-setting process. RESULTS: We present a series of examples that are relevant in the surgical domain including standards setting for knowledge and skills assessments. CONCLUSIONS: Defensible standards for knowledge and procedural skills will likely become part of surgical clinical practice. Understanding the methodology for determining standards should position the surgical community to assist in the process and lead within their clinical settings as standards are considered that may affect patient safety and physician credentialing.

Failure to follow evidence-based best practice guidelines in the treatment of severe acute pancreatitis.

OBJECTIVES: Evidence-based guidelines for the treatment of severe acute pancreatitis have been established. This study was conducted to investigate the hypothesis that deviation from guidelines occurs frequently. METHODS: With institutional review board approval, the outside medical records of patients with severe pancreatitis who were transferred to the study institution during the period from July 2005 to May 2012 were reviewed. Severe pancreatitis was defined using the Atlanta Classification criteria. Records were reviewed with respect to published guidelines defining the appropriate use of imaging, antibiotics and nutritional support. RESULTS: A total of 538 patients with acute pancreatitis were identified. Of 67 patients with severe acute pancreatitis, 44 (66%) were male. The mean age of the patients was 55 years. Forty-five of 61 (74%) patients for whom relevant data were available were imaged upon admission, but only 15 (31%) patients were imaged appropriately by computerized tomography with i.v. contrast to assess the presence of necrosis or other complications. In patients for whom relevant data were available, prophylactic antibiotics were initiated in the absence of culture data or a specific infectious target in 26 (53%) patients. Total parenteral nutrition (TPN) was administered to 38 (60%) of 63 patients for whom relevant data were available; only 10 (17%) patients received enteric feeding. No nutritional support was provided to 15 (23%) patients. CONCLUSIONS: Adherence to best practice guidelines in the treatment of severe pancreatitis is poor. The consistent application of current knowledge might improve outcomes in these patients.

Autophagy suppresses age-dependent ischemia and reperfusion injury in livers of mice.

BACKGROUND & AIMS: As life expectancy increases, there are greater numbers of patients with liver diseases who require surgery or transplantation. Livers of older patients have significantly less reparative capacity following ischemia and reperfusion (I/R) injury, which occurs during these operations. There are no strategies to reduce the age-dependent I/R injury. We investigated the role of autophagy in the age dependence of sensitivity to I/R injury. METHODS: Hepatocytes and livers from 3- and 26-month-old mice were subjected to in vitro and in vivo I/R, respectively. We analyzed changes in autophagy-related proteins (Atg). Mitochondrial dysfunction was visualized using confocal and intravital multi-photon microscopy of isolated hepatocytes and livers from anesthetized mice, respectively. RESULTS: Immunoblot, autophagic flux, genetic, and imaging analyses all associated the increase in sensitivity to I/R injury with age with decreased autophagy and subsequent mitochondrial dysfunction due to calpain-mediated loss of Atg4B. Overexpression of either Atg4B or Beclin-1 recovered Atg4B, increased autophagy, blocked the onset of the mitochondrial permeability transition, and suppressed cell death after I/R in old hepatocytes. Coimmunoprecipitation analysis of hepatocytes and Atg3-knockout cells showed an interaction between Beclin-1 and Atg3, a protein required for autophagosome formation. Intravital multi-photon imaging revealed that overexpression of Beclin-1 or Atg4B attenuated autophagic defects and mitochondrial dysfunction in livers of older mice after I/R. CONCLUSIONS: Loss of Atg4B in livers of old mice increases their sensitivity to I/R injury. Increasing autophagy might ameliorate liver damage and restore mitochondrial function after I/R.

Executive summary of the artificial intelligence in surgery series.

As opportunities for artificial intelligence to augment surgical care expand, the accompanying surge in published literature has generated both substantial enthusiasm and grave concern regarding the safety and efficacy of artificial intelligence in surgery. For surgeons and surgical data scientists, it is increasingly important to understand the state-of-the-art, recognize knowledge and technology gaps, and critically evaluate the deluge of literature accordingly. This article summarizes the experiences and perspectives of a global, multi-disciplinary group of experts who have faced development and implementation challenges, overcome them, and produced incipient evidence thereof. Collectively, evidence suggests that artificial intelligence has the potential to augment surgeons via decision-support, technical skill assessment, and the semi-autonomous performance of tasks ranging from resource allocation to patching foregut defects. Most applications remain in preclinical phases. As technologies and their implementations improve and positive evidence accumulates, surgeons will face professional imperatives to lead the safe, effective clinical implementation of artificial intelligence in surgery. Substantial challenges remain; recent progress in using artificial intelligence to achieve performance advantages in surgery suggests that remaining challenges can and will be overcome.

Critical role for CXC ligand 10/CXC receptor 3 signaling in the murine neonatal response to sepsis.

Previous studies have suggested that neonates rely heavily on innate immunity for their antimicrobial response to bacterial infections. However, the innate immune response by neonates to bacterial infection remains poorly characterized. Here, we show that in a murine model of neonatal polymicrobial sepsis, CXC ligand 10 (CXCL10) concentrations increase in the blood and peritoneum concordant with the peritoneal recruitment of granulocytes and macrophages. Additionally, CXC receptor 3 (CXCR3) expression on elicited peritoneal macrophages and granulocytes increases following sepsis. Blockade of CXCL10 worsens not only recruitment and phagocytic function of peritoneal granulocytes and macrophages but also survival. Deletion of CXCR3 also significantly increases mortality to a septic challenge. Finally, we demonstrate that the protective adjuvant effect of pretreatment with a Toll-like receptor 4 agonist to neonatal sepsis is dependent on an endogenous CXCL10 response and that pretreatment of neonates with CXCL10 can also significantly improve macrophage and granulocyte function and modestly improve outcome to polymicrobial sepsis. Together, these data suggest a critical role for CXCL10 signaling during neonatal sepsis.

Surgical research journals - Under review: An assessment of diversity among editorial boards and outcomes of peer review.

BACKGROUND: The COVID-19 pandemic exposed racism as a public health crisis embedded in structural processes. Editors of surgical research journals pledged their commitment to improve structure and process through increasing diversity in the peer review and editorial process; however, little benchmarking data are available. METHODS: A survey of editorial board members from high impact surgical research journals captured self-identified demographics. Analysis of manuscript submissions from 2016 to 2020 compared acceptance for diversity, equity, and inclusion (DEI)-focused manuscripts to overall rates. RESULTS: 25.6% of respondents were female, 2.9% Black, and 3.3% Hispanic. There was variation in the diversity among journals and in the proportion of DEI submissions they attract, but no clear correlation between DEI acceptance rates and board diversity. CONCLUSIONS: Diversity among board members reflects underrepresentation of minorities seen among surgeons nationally. Recruitment and retention of younger individuals, representing more diverse backgrounds, may be a strategy for change. DEI publication rates may benefit from calls for increasing DEI scholarship more so than changes to the peer review process.