Histopathology of Colectomy Specimens Predicts Endoscopic Pouch Phenotype in Patients with Ulcerative Colitis.

BACKGROUND: The endoscopic appearance in patients with "pouchitis" after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) can be quite heterogenous. Patients with an endoscopic phenotype resembling Crohn's disease (CD) are at high risk of pouch loss. AIMS: We aimed to assess how the histopathology of colectomy specimens predicts endoscopic pouch phenotypes in UC. METHODS: We retrospectively assessed pouchoscopies from patients with UC who underwent IPAA and classified pouch findings into 7 main phenotypes: (1) normal, (2) afferent limb involvement, (3) inlet involvement, (4) diffuse, (5) focal inflammation of the pouch body, (6) cuffitis, and (7) pouch with fistulas noted ≥ 6 months from ileostomy takedown. We assessed the clinical and pathological data including deep, focal inflammation, granulomas, and terminal ileal involvement in the colectomy specimens. Logistic regression analysis was performed to identify contributing factors to each phenotype. RESULTS: This study included 1,203 pouchoscopies from 382 patients with UC. On multivariable analysis, deep inflammation was significantly associated with pouch fistulas (Odds ratio 3.27; 95% confidence interval 1.65-6.47; P = 0.0007). Of the 75 patients with deep inflammation, only two patients (2.7%) were diagnosed with CD based on pathology review. Terminal ileal involvement significantly increased the risk of afferent limb involvement (Odds ratio 2.96; 95% confidence interval 1.04-8.47; P = 0.04). There were no significant associations between other microscopic features and phenotypes. CONCLUSIONS: We identify histologic features of colectomy specimens in UC that predict subsequent pouch phenotypes. Particularly, deep inflammation in the resected colon was significantly associated with pouch fistulas, a pouch phenotype with poor prognosis.

Histologic changes caused by injection of a novel submucosal lifting agent for endoscopic resection in GI lesions.

BACKGROUND AND AIMS: ORISE Gel is a recently introduced, U.S. Food and Drug Administration-approved submucosal lifting agent used in endoscopic resection of GI lesions. Histologically evident gel deposits in resected specimens may pose a potential diagnostic pitfall. To aid in recognition of this procedure-related artifact, we report the largest histologic series of ORISE Gel in endoscopic and surgical resection specimens to date. METHODS: Fifty-eight EMR/endoscopic submucosal dissection (ESD) specimens with ORISE Gel injection and 5 interval surgical resection specimens with previous ORISE Gel injection were included. Patient demographics and endoscopy reports were obtained. Histologic slides from all cases were reviewed. Histochemical stains were performed on select cases. RESULTS: Fifty-one EMR and 7 ESD specimens were identified. In 51 of 58 (88%) endoscopic resection specimens, amorphous, pale blue-gray, finely granular material was evident in the submucosa, as well as focally within the mucosa in 4 cases. Most cases showed homogeneous near-complete filling of the submucosa with this material, whereas a few demonstrated areas of condensation and retraction. Mucicarmine and periodic acid-Schiff stains were negative for mucin. Interval surgical resection specimens revealed extensive deposition of dense, eosinophilic material with associated multinucleated giant cells in the submucosa in all cases, with transmural extension in 3 cases. CONCLUSION: ORISE Gel injection during endoscopic resection of GI lesions results in deposition of amorphous, blue-gray material seen in histologic sections, whereas interval surgical resection specimens demonstrate dense, eosinophilic material with an associated giant cell reaction. Awareness of these artifacts will help avoid misinterpretation of their presence as pathologic findings.

Clinical Data Do Not Reliably Predict Duodenal Histology at Follow-up in Celiac Disease: A 13 Center Correlative Study.

Validated nonbiopsy methods to assure duodenal mucosal healing in celiac disease are lacking, yet ongoing mucosal injury is associated with anemia, osteoporosis, and lymphoma. Most providers utilize clinical data as surrogates of mucosal status to avoid additional esophagogastroduodenoscopy. The reliability of such surrogates to predict mucosal recovery has been incompletely evaluated. The aim of this study was to rigorously assess patterns of histologic mucosal recovery at follow-up in celiac disease and to correlate findings with clinical data. Gastrointestinal pathologists from 13 centers evaluated initial and follow-up duodenal biopsies from 181 celiac disease patients. Marsh scores and intraepithelial lymphocytes (IELs)/100 enterocytes were assessed blindly. Histology at follow-up was correlated with symptoms, immunoglobulin A anti-tissue transglutaminase titers and gluten-free diet adherence. Fifty-six/181 (31%) patients had persistent villous blunting and 46/181 (25%) patients had just persistently elevated IELs at follow-up, with only 79/181 (44%) patients having complete histologic remission. IEL normalization (82/181; 45%) lagged villous recovery (125/181;69%). In a minority of patients, villous blunting was limited to proximal duodenal biopsies. No correlation was found between Marsh scores and symptoms, normalization of immunoglobulin A anti-tissue transglutaminase serology, or diet adherence. Children showed greater recovery of Marsh score ( P <0.001) and IELs ( P <0.01) than adults. Persistent mucosal injury is common in celiac disease, with discordant villous/IEL normalization. Pathologist awareness of expected findings in celiac disease follow-up biopsies, including their frequent lack of correlation with clinical data, is important for patient management, and has implications for eligibility criteria for therapeutics currently in development.

Agent-based model of epithelial host-pathogen interactions in anastomotic leak.

BACKGROUND: There is a growing recognition of the significance of host-pathogen interactions (HPIs) in gut biology leading to a reassessment of the role of bacteria in intestinal anastomotic leak. Understanding the complexities of the early postsurgical gut HPI requires integrating knowledge of both epithelial and bacterial behaviors to generate hypotheses of potential mechanisms of interaction. Agent-based modeling is a computational method well suited to achieve this goal, and we use an agent-based model (ABM) to examine alterations in the HPI affecting reestablishment of the epithelial barrier that may subsequently lead to anastomotic leak. METHODS: Computational agents representing Pseudomonas aeruginosa were added to a previously validated ABM of epithelial restitution. Simulated experiments were performed examining the effect of radiation on bacterial binding to epithelial cells, plausibility of putative binding targets, and potential mechanisms of epithelial cell killing by virulent bacteria. RESULTS: Simulation experiments incorporating radiation effects on epithelial monolayers produced binding patterns akin to those seen in vitro and suggested that promotility integrin-laminin associations represent potential sites for bacterial binding and disruption of restitution. Simulations of potential mechanisms of epithelial cell killing suggested that an injected cytotoxin was the means by which virulent bacteria produced the tissue destruction needed to generate an anastomotic leak, a mechanism subsequently confirmed with genotyping of the virulent P aeruginosa strain. CONCLUSIONS: This study emphasizes the utility of ABM as an adjunct to traditional research methods and provides insights into the potentially critical role of HPI in the pathogenesis of anastomotic leak.

Overview of Ancillary Techniques in Cervical Cytology.

BACKGROUND: The association between high-risk serotypes of human papillomavirus (hr-HPV) and cervical cancer is well-established. SUMMARY: In order to improve the sensitivity of cervical cytology testing, hr-HPV testing has rapidly become part of routine cervical cancer screening, either in conjunction with cytology or as primary testing. In this review, we discuss the overall utility and strategies of hr-HPV testing, as well as the advantages and limitations of potential triage strategies for hr-HPV-positive women, including HPV genotyping, p16/Ki-67 dual staining, and methylation assays. KEY MESSAGE: hr-HPV testing is discussed as primary screening and HPV genotyping, p16/Ki-67 dual staining, and methylation assays are discussed as ancillary techniques to cytology in the triage of hr-HPV-positive women undergoing cervical cancer screening.

Loss of MEN1 function impairs DNA repair capability of pancreatic neuroendocrine tumors.

Somatic MEN1 mutations occur in up to 50% of pancreatic neuroendocrine tumors (PanNETs). Clinical studies have shown that radiation therapy (IR) is effective in a subset of PanNETs, but it remains unclear why some patients respond better to IR than others. Herein, we study whether MEN1 loss of function increases radiosensitivity of PanNETs and determine its effect on DNA double-strand break (DSB) repair. After creating a MEN1 knockout PanNET cell line, we confirmed reduced DSB repair capacity in MEN1-deficient cells and linked these findings to a defect in homologous recombination, as well as reduced BRCA2 expression levels. Consistent with this model, we found that MEN1 mutant cells displayed increased sensitivity to the highly trapping poly (ADP-ribose) polymerase (PARP) 1 inhibitor talazoparib in vitro. Our results suggest that combining IR with PARP inhibition may be beneficial in patients with PanNETs and MEN1 loss of function.

Epigenetic Dysregulation of 5-hydroxymethylcytosine in Well-Differentiated Pancreatic Neuroendocrine Tumors.

Dysregulation of epigenetic mechanisms, reflected by loss of expression of 5-hydroxymethylcytosine (5-hmC) is being increasingly recognized as a marker of aggressive behavior in several neoplasms; however, the role of such epigenetic modifiers in pancreatic neuroendocrine tumors (PanNETs) has not been studied. Annotated cohort of 60 PanNETs was evaluated for 5-hmC expression using immunohistochemistry. Univariable and multivariable analyses were performed. To determine intratumor heterogeneity of 5-hmC expression, 26 additional synchronous metastatic deposits of PanNETs from 8 patients were evaluated for 5-hmC expression. 5-hmC level showed significant association with the presence of distant metastases (P=0.02), female sex (P=0.04), and Ki-67 proliferation index (P=0.002). A multivariate model created using the stepwise logistic regression analysis showed the presence of nodal metastases (odds ratio=6.15), lymphovascular invasion (odds ratio=4.07) and lack of 5-hmC expression (odds ratio=5.34) were predictive of the risk of distant metastasis in PanNETs with a c-statistic of 0.845. Epigenetic intratumoral heterogeneity of 5-hmC expression was seen in 37.5% cases (3/8). Our work provides evidence that epigenetic regulators are involved in the pathobiology of PanNETs and immunohistochemical analysis of 5-hmC may be able to refine prognostic evaluation of these tumors.

The human microbiome and surgical disease.

OBJECTIVE: The purpose of this review article is to summarize what is currently known about microbes associated with the human body and to provide examples of how this knowledge impacts the care of surgical patients. BACKGROUND: Pioneering research over the past decade has demonstrated that human beings live in close, constant contact with dynamic communities of microbial organisms. This new reality has wide-ranging implications for the care of surgical patients. METHODS AND RESULTS: Recent advances in the culture-independent study of the human microbiome are reviewed. To illustrate the translational relevance of these studies to surgical disease, we discuss in detail what is known about the role of microbes in the pathogenesis of obesity, gastrointestinal malignancies, Crohn disease, and perioperative complications including surgical site infections and sepsis. The topics of mechanical bowel preparation and perioperative antibiotics are also discussed. CONCLUSIONS: Heightened understanding of the microbiome in coming years will likely offer opportunities to refine the prevention and treatment of a wide variety of surgical conditions.

Devastating Postpartum Complications in an Adolescent Linked to New-Onset Inflammatory Bowel Disease and Antiphospholipid Antibody Syndrome.

Pregnancy can affect the severity of inflammatory bowel disease (IBD), and pregnant women with IBD are at a higher risk for venous thromboembolism compared with the general population. We report a previously healthy 16-year-old female who developed bloody diarrhea and venous thromboembolism following childbirth, with further evaluation revealing IBD and antiphospholipid antibody syndrome. This case highlights the impact pregnancy can have on IBD and other immunological disorders, and the potentially life-threatening risk of thrombosis in pregnant women with IBD.

Heme oxygenase-2 modulates early pathogenesis after traumatic injury to the immature brain.

We determined if heme oxygenase-2 (HO-2), an enzyme that degrades the pro-oxidant heme, confers neuroprotection in the developing brain after traumatic brain injury (TBI). Male HO-2 wild-type (WT) and homozygous knockout (KO) mice at postnatal day 21 were subjected to TBI and euthanized 1, 7, and 14 days later. Relative cerebral blood flow, measured by laser Doppler, cortical and hippocampal pathogenesis, and motor recovery were evaluated at all time points. Cerebral blood flow was found to be similar between experimental groups. Blood flow significantly decreased immediately after injury, returned to baseline by 1 day, and was significantly elevated by 7 days, post-injury. Nonheme iron preferentially accumulated in the ipsilateral cortex, hippocampus, and external capsule in both WT and KO brain-injured genotypes. There were, however, a significantly greater number of TUNEL-positive cells in the hippocampal dentate gyrus and a significantly greater cortical lesion volume in KOs relative to WTs within the first week post-injury. By 14 days post-injury, however, cortical lesion volume and cell density in the hippocampal CA3 region and dorsal thalamus were similar between the two groups. Assays of fine motor function (grip strength) over the first 2 weeks post-injury revealed a general pattern of decreased strength in the contralateral forelimbs of KOs as compared to WTs. Together, these findings demonstrate that deficiency in HO-2 alters both the kinetics of secondary damage and fine motor recovery after TBI.

Rhabdomyosarcoma of the Adult Prostate: A Case Report With Complete Molecular Profile.

Primary rhabdomyosarcoma of the adult prostate is rare and associated with an aggressive clinical course. Given the limited number of cases reported about the prostate, little is known about the impact of molecular mutations on tumor biology and prognosis in adults. In this article, we present a case of primary embryonal rhabdomyosarcoma of the adult prostate with a complete molecular mutational profile of the tumor.

Role of Ancillary Techniques in Gynecologic Cytopathology Specimens.

The association between high-risk genotypes of human papillomavirus (hr-HPV) and cervical cancer is well established. As hr-HPV testing is rapidly becoming a part of routine cervical cancer screening, either in conjunction with cytology or as primary testing, the management of hr-HPV-positive women has to be tailored in a way that increases the detection of cervical abnormalities while decreasing unnecessary colposcopic biopsies or other invasive procedures. In this review, we discuss the overall utility and strategies of hr-HPV testing, as well as the advantages and limitations of potential triage strategies for hr-HPV-positive women, including HPV genotyping, p16/Ki-67 dual staining, and methylation assays.

Mucoepidermoid Carcinoma: A Comparison of Histologic Grading Systems and Relationship to MAML2 Rearrangement and Prognosis.

Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy, but categorization is complicated by variability in grading systems and uncertain prognostic significance of MAML2 rearrangement. The aims of this study were to determine the prognostic significance of MEC grading systems and MAML2 rearrangement status. Fifty-three carcinomas originally diagnosed as MEC (45 primary; 8 recurrent) of major and minor salivary glands were graded according to modified Healey, Brandwein, AFIP, and Katabi systems. Fluorescence in situ hybridization for MAML2 rearrangement was performed. Clinical features and outcomes were recorded. Twenty-five (47%) carcinomas scored the same in all grading systems. The most common histologic feature leading to a diagnosis of intermediate grade was isolated solid growth. Brandwein assigned the highest percentage of high grade (29%) and AFIP the highest percentage of low grade (80%). MAML2 was rearranged in 37/46 (80%) cases. Forty-three (81%) were morphologically compatible with MEC, and these were more likely to be low-intermediate grade and MAML2-rearranged. Of primary carcinomas, 6 (13%) recurred. Statistically significant univariate risk factors for recurrence included non-MEC morphology, stage T4, and high Brandwein grade. Margin status, MAML2 rearrangement, and isolated solid growth were not predictive of recurrence. A binary grading system (Brandwein high vs. low-plus-intermediate) could be considered to better reflect biological behavior in MEC. Our study confirms that MAML2 wildtype tumors more likely represent high grade non-MECs, and prior studies demonstrating worse prognosis in MAML2-nonrearranged MECs may be diluted by high-grade non-MECs.

Phyllodes Tumor of the Prostate With Epithelial Intestinal Metaplasia.

Phyllodes tumor of the prostate is a rare mesenchymal tumor conventionally regarded as a stromal tumor of undetermined malignant potential. While the initial presentation is that of urinary obstruction and/or hematuria, the subsequent clinical behavior is thought to be a function of stromal cellularity and cytologic changes of malignancy. Of histologic interest, the epithelial component of this tumor varies, including intestinal metaplasia, as seen in the present case.

Second primary rhabdomyosarcoma of the uterine cervix presenting with synchronous ovarian Sertoli-Leydig cell tumor: An illustrative case of DICER1 syndrome.

•Embryonal rhabdomyosarcoma of the uterine cervix and ovarian Sertoli-Leydig cell tumors are associated with DICER1 mutation•DICER1-associated tumors should prompt genetic counseling and testing•Somatic and germline genetic mutation profiles can be used to differentiate second primary from recurrent tumors.

Inflammation and Spinal Cord Injury: Infiltrating Leukocytes as Determinants of Injury and Repair Processes.

The immune response that accompanies spinal cord injury contributes to both injury and reparative processes. It is this duality that is the focus of this review. Here we consider the complex cellular and molecular immune responses that lead to the infiltration of leukocytes and glial activation, promote oxidative stress and tissue damage, influence wound healing, and subsequently modulate locomotor recovery. Immunomodulatory strategies to improve outcomes are gaining momentum as ongoing research carefully dissects those pathways, which likely mediate cell injury from those, which favor recovery processes. Current therapeutic strategies address divergent approaches including early immunoblockade and vaccination with immune cells to prevent early tissue damage and support a wound-healing environment that favors plasticity. Despite these advances, there remain basic questions regarding how inflammatory cells interact in the injured spinal cord. Such questions likely arise as a result of our limited understanding of immune cell/neural interactions in a dynamic environment that culminates in progressive cell injury, demyelination, and regenerative failure.

Candida albicans isolates from the gut of critically ill patients respond to phosphate limitation by expressing filaments and a lethal phenotype.

Candida albicans is an opportunistic pathogen that proliferates in the intestinal tract of critically ill patients where it continues to be a major cause of infectious-related mortality. The precise cues that shift intestinal C. albicans from its ubiquitous indolent colonizing yeast form to an invasive and lethal filamentous form remain unknown. We have previously shown that severe phosphate depletion develops in the intestinal tract during extreme physiologic stress and plays a major role in shifting intestinal Pseudomonas aeruginosa to express a lethal phenotype via conserved phosphosensory-phosphoregulatory systems. Here we studied whether phosphate dependent virulence expression could be similarly demonstrated for C. albicans. C. albicans isolates from the stool of critically ill patients and laboratory prototype strains (SC5314, BWP17, SN152) were evaluated for morphotype transformation and lethality against C. elegans and mice during exposure to phosphate limitation. Isolates ICU1 and ICU12 were able to filament and kill C. elegans in a phosphate dependent manner. In a mouse model of intestinal phosphate depletion (30% hepatectomy), direct intestinal inoculation of C. albicans caused mortality that was prevented by oral phosphate supplementation. Prototype strains displayed limited responses to phosphate limitation; however, the pho4Δ mutant displayed extensive filamentation during low phosphate conditions compared to its isogenic parent strain SN152, suggesting that mutation in the transcriptional factor Pho4p may sensitize C. albicans to phosphate limitation. Extensive filamentation was also observed in strain ICU12 suggesting that this strain is also sensitized to phosphate limitation. Analysis of the sequence of PHO4 in strain ICU12, its transcriptional response to phosphate limitation, and phosphatase assays confirmed that ICU12 demonstrates a profound response to phosphate limitation. The emergence of strains of C. albicans with marked responsiveness to phosphate limitation may represent a fitness adaptation to the complex and nutrient scarce environment typical of the gut of a critically ill patient.

Intestinal tissues induce an SNP mutation in Pseudomonas aeruginosa that enhances its virulence: possible role in anastomotic leak.

The most feared complication following intestinal resection is anastomotic leakage. In high risk areas (esophagus/rectum) where neoadjuvant chemoradiation is used, the incidence of anastomotic leaks remains unacceptably high (≈ 10%) even when performed by specialist surgeons in high volume centers. The aims of this study were to test the hypothesis that anastomotic leakage develops when pathogens colonizing anastomotic sites become in vivo transformed to express a tissue destroying phenotype. We developed a novel model of anastomotic leak in which rats were exposed to pre-operative radiation as in cancer surgery, underwent distal colon resection and then were intestinally inoculated with Pseudomonas aeruginosa, a common colonizer of the radiated intestine. Results demonstrated that intestinal tissues exposed to preoperative radiation developed a significant incidence of anastomotic leak (>60%; p<0.01) when colonized by P. aeruginosa compared to radiated tissues alone (0%). Phenotype analysis comparing the original inoculating strain (MPAO1- termed P1) and the strain retrieved from leaking anastomotic tissues (termed P2) demonstrated that P2 was altered in pyocyanin production and displayed enhanced collagenase activity, high swarming motility, and a destructive phenotype against cultured intestinal epithelial cells (i.e. apoptosis, barrier function, cytolysis). Comparative genotype analysis between P1 and P2 revealed a single nucleotide polymorphism (SNP) mutation in the mexT gene that led to a stop codon resulting in a non-functional truncated protein. Replacement of the mutated mexT gene in P2 with mexT from the original parental strain P1 led to reversion of P2 to the P1 phenotype. No spontaneous transformation was detected during 20 passages in TSB media. Use of a novel virulence suppressing compound PEG/Pi prevented P. aeruginosa transformation to the tissue destructive phenotype and prevented anastomotic leak in rats. This work demonstrates that in vivo transformation of microbial pathogens to a tissue destroying phenotype may have important implications in the pathogenesis of anastomotic leak.

Avoiding colectomy during surgical management of fulminant Clostridium difficile colitis.

BACKGROUND: Clostridium difficile is the most common cause of nosocomial diarrhea in adults. Over the last decade, there has been a substantial increase in the disease-associated morbidity and mortality rate from this infection accompanied by identification of new hypervirulent strains. Fulminant colitis, a severe and complicated form of the disease that frequently necessitates surgical intervention, occurs in 3-8% of patients infected with C. difficile. The postoperative mortality rate for fulminant colitis continues to be dire, ranging from 34-57%. METHODS: Review of the literature to offer insight into the dilemma associated with the surgical management of fulminant C. difficile colitis and provide alternatives to total abdominal colectomy for treatment. RESULTS: Several recent studies have elucidated factors that contribute to the unacceptably high postoperative mortality rate: Surgical intervention too late in the course of the disease, lack of clearly defined guidelines for patient selection, and difficulty in predicting the clinical course of the disease. Perforation, need for vasopressor support, and end-organ damage all affect the postoperative mortality rate negatively. CONCLUSION: A high clinical suspicion and careful patient selection for colectomy is imperative to improve postoperative survival. An alternative surgical strategy for fulminant C. difficile colitis is laparoscopic creation of an ileostomy with total colonic washout.