Oncologic outcomes following transanal total mesorectal excision: the United States experience.

AIM: The benefits and short-term outcomes of transanal total mesorectal excision (taTME) for rectal cancer have been demonstrated previously, but questions remain regarding the oncologic outcomes following this challenging procedure. The purpose of this study was to analyze the oncologic outcomes following taTME at high-volume centers in the USA. METHODS: This was a multicenter, retrospective observational study of 8 tertiary care centers. All consecutive taTME cases for primary rectal cancer performed between 2011 and 2020 were included. Clinical, histopathologic, and oncologic data were analyzed. Primary endpoints were rate of local recurrence, distal recurrence, 3-year disease recurrence, and 3-year overall survival. Secondary endpoints included perioperative complications and TME specimen quality. RESULTS: A total of 391 patients were included in the study. The median age was 57 years (IQR: 49, 66), 68% of patients were male, and the median BMI was 27.4 (IQR: 24.1, 31.0). TME specimen was complete or near complete in 94.5% of cases and the rates of positive circumferential radial margin and distal resection margin were 2.0% and 0.3%, respectively. Median follow-up time was 30.7 months as calculated using reverse-KM estimator (CI 28.1-33.8) and there were 9 cases (2.5%) of local recurrence not accounting for competing risk. The 3-year estimated rate of disease recurrence was 19% (CI 15-25%) and the 3-year estimated overall survival was 90% (CI 87-94%). CONCLUSION: This large multicenter study confirms the oncologic safety and perioperative benefits of taTME for rectal cancer when performed by experienced surgeons at experienced referral centers.

Intraluminal Anastomotic Assessment Using Indocyanine Green Near-Infrared Imaging for Left-Sided Colonic and Rectal Resections: a Systematic Review.

BACKGROUND: Indocyanine green fluorescence angiography (ICG-FA) has been used in colorectal surgery to assess anastomotic perfusion and reduce the risks of anastomotic leaks. The main objective of this paper is to review the data on the transanal application of ICG-FA for the intraluminal assessment of colorectal anastomosis. METHODS: A literature search was conducted for articles published between 2011 and 2021 using PubMed and Cochrane databases, related to the application of ICG for the intraluminal assessment of colorectal anastomosis. Original scientific manuscripts, review articles, meta-analyses, and case reports were considered eligible. RESULTS: A total of 305 studies have been identified. After abstract screening for duplicates, 285 articles remained. Of those, 271 were not related to the topic of interest, 4 were written in a language other than English, and 4 had incomplete data. Six articles remained for the final analysis. The intraluminal assessment of colorectal anastomosis with ICG-FA is feasible, safe, and may reduce the incidence of leaks. CONCLUSION: The intraluminal assessment of anastomotic perfusion via ICG-FA may be a promising novel application of ICG technology. More data is needed to support this application further to reduce leak rates after colorectal surgery, and future randomized clinical trials are awaited.

Early versus delayed ileocolic resection for complicated Crohn's disease: is "cooling off" necessary?

BACKGROUND: Ileal Crohn's disease (CD) complicated by intraabdominal abscess, phlegmon, fistula, and/or microperforation is commonly treated with antibiotics, bowel rest, and percutaneous drainage followed by interval ileocolic resection (ICR). This "cool off" strategy is intended to facilitate the safe completion of a one-stage resection using a minimally invasive approach and minimize perioperative complications. There is limited data evaluating the benefits of delayed versus early resection. METHODS: A retrospective review of a prospectively maintained inflammatory bowel disease (IBD) database at a tertiary center was queried from 2013-2020 to identify patients who underwent ICR for complicated ileal CD confirmed on preoperative imaging. ICR cohorts were classified as early (≤ 7 days) vs delayed (> 7 days) based on the interval from diagnostic imaging to surgery. Operative approach and 30-day postoperative morbidity were analyzed. RESULTS: Out of 474 patients who underwent ICR over the 7-year period, 112 patients had complicated ileal CD including 99 patients (88%) with intraabdominal abscess. Early ICR was performed in 52 patients (46%) at a median of 3 days (IQR 2, 5) from diagnostic imaging. Delayed ICR was performed in 60 patients (54%) following a median "cool off" period of 23 days of non-operative treatment (IQR 14, 44), including preoperative percutaneous abscess drainage in 17 patients (28%). A higher proportion of patients with intraabdominal abscess underwent delayed vs early ICR (57% vs 43%, p = 0.19). Overall, there were no significant differences in the rate of laparoscopy (96% vs 90%), conversion to open surgery (12% vs 17%), rates of extended bowel resection (8% vs 13%), additional concurrent procedures (44% vs 52%), or fecal diversion (10% vs 2%) in the early vs delayed ICR groups. The median postoperative length of stay was 5 days in both groups with an overall 25% vs 17% (p = 0.39) 30-day postoperative complication rate and a 6% vs 5% 30-day readmission rate in early vs delayed ICR groups, respectively. Overall median follow-up time was 14.3 months (IQR 1.2, 24.1) with no difference in the rate of subsequent CD-related intestinal resection (4% vs 5%) between the two groups. CONCLUSIONS: In this contemporary series, at a high-volume tertiary referral center, a "cool off" delayed resectional approach was not found to reduce perioperative complications in patients undergoing ICR for complicated ileal Crohn's disease. Laparoscopic ICR can be performed within one week of diagnosis with low rates of conversion and postoperative complications.

The role of laparoscopic surgery in repeat ileocolic resection for Crohn's disease.

AIM: Laparoscopic surgery is the preferred approach for primary uncomplicated ileocolic resection (ICR); however, its role for repeat resections is unclear. This study assessed the outcomes of primary and repeated ICRs for Crohn's disease to examine rates of laparoscopy and patient morbidity. METHODS: A retrospective review of a prospectively maintained database was conducted at a tertiary centre between 2013 and 2019. All patients undergoing ICRs for Crohn's disease were included. The cohort was divided into three groups based on number of resections-primary (1R), secondary (2R) and tertiary or more (>2R) groups. The primary outcome was 30-day postoperative morbidity. RESULTS: Over a 6-year period, 474 patients underwent ICR for Crohn's disease, including 369 primary (1R, 77.8%) and 105 repeat (≥2R, 22.2%) resections. A laparoscopic approach was less common in the ≥2R versus 1R groups (79.0% vs. 93.8%, P < 0.001), but rates of conversion to an open procedure were comparable. Morbidity was higher amongst repeat resections although this was not significant (20.0% vs. 14.1%, P = 0.18). Amongst cases approached laparoscopically (n = 429), rates of conversion and postoperative morbidity did not differ by stage of resection, although operative time was longer for repeat operations. Even in the group undergoing laparoscopy for tertiary or greater resections (>2R, n = 29), the rates of conversion (10%) and morbidity (14%) were relatively low. CONCLUSION: In this contemporary series of primary and reoperative ICR for ileal CD, a laparoscopic approach is feasible and safe for the majority of repeat ICRs when performed at a high volume centre.

Anti-ß-sheet conformation monoclonal antibody reduces tau and Aß oligomer pathology in an Alzheimer's disease model.

BACKGROUND: Oligomeric forms of amyloid-ß (Aß) and tau are increasing being recognized as key toxins in the pathogenesis of Alzheimer's disease (AD). METHODS: We developed a novel monoclonal antibody (mAb), GW-23B7, that recognizes ß-sheet secondary structure on pathological oligomers of neurodegenerative diseases. RESULTS: The pentameric immunoglobulin M kappa chain (IgMκp) we developed specifically distinguishes intra- and extracellular pathology in human AD brains. Purified GW-23B7 showed a dissociation constant in the nanomolar range for oligomeric Aß and did not bind monomeric Aß. In enzyme-linked immunosorbent assays, it recognized oligomeric forms of both Aß and hyperphosphorylated tau. Aged triple-transgenic AD mice with both Aß and tau pathology infused intraperitoneally for 2 months showed IgMκp in the soluble brain homogenate, peaking at 24 h postinoculation. Treated mice exhibited significant cognitive rescue on radial arm maze testing compared with vehicle control-infused mice. Immunohistochemically, treatment resulted in a significant decrease of extracellular pathology. Biochemically, treatment resulted in significant reductions of oligomeric forms of Aß and tau. CONCLUSIONS: These results suggest that GW-23B7, an anti-ß-sheet conformational mAb humanized for clinical trials, may be an effective therapeutic agent for human AD.

Production of Monoclonal Antibodies to Pathologic ß-sheet Oligomeric Conformers in Neurodegenerative Diseases.

We describe a novel approach to produce conformational monoclonal antibodies selected to specifically react with the ß-sheet secondary structure of pathological oligomeric conformers, characteristic of many neurodegenerative diseases. Contrary to past and current efforts, we utilize a mammalian non-self-antigen as an immunogen. The small, non-self peptide selected was covalently polymerized with glutaraldehyde until it reached a high ß-sheet secondary structure content, and species between 10-100kDa that are immunogenic, stable and soluble (p13Bri). Inoculation of p13Bri in mice elicited antibodies to the peptide and the ß-sheet secondary structure conformation. Hybridomas were produced and clones selected for their reactivity with at least two different oligomeric conformers from Alzheimer's, Parkinson and/or Prion diseases. The resulting conformational monoclonals are able to detect pathological oligomeric forms in different human neurodegenerative diseases by ELISA, immunohistochemistry and immunoblots. This technological approach may be useful to develop tools for detection, monitoring and treatment of multiple misfolding disorders.

Mucosal immunization with an attenuated Salmonella vaccine partially protects white-tailed deer from chronic wasting disease.

Prion disease is a unique category of illness, affecting both animals and humans, in which the underlying pathogenesis is related to a conformational change of a normal, self-protein called PrP(C) (C for cellular) to a pathological and infectious conformer known as PrP(Sc) (Sc for scrapie). Bovine spongiform encephalopathy (BSE), a prion disease believed to have arisen from feeding cattle with prion contaminated meat and bone meal products, crossed the species barrier to infect humans. Chronic wasting disease (CWD) infects large numbers of deer and elk, with the potential to infect humans. Currently no prionosis has an effective treatment. Previously, we have demonstrated we could prevent transmission of prions in a proportion of susceptible mice with a mucosal vaccine. In the current study, white-tailed deer were orally inoculated with attenuated Salmonella expressing PrP, while control deer were orally inoculated with vehicle attenuated Salmonella. Once a mucosal response was established, the vaccinated animals were boosted orally and locally by application of polymerized recombinant PrP onto the tonsils and rectal mucosa. The vaccinated and control animals were then challenged orally with CWD-infected brain homogenate. Three years post CWD oral challenge all control deer developed clinical CWD (median survival 602 days), while among the vaccinated there was a significant prolongation of the incubation period (median survival 909 days; p=0.012 by Weibull regression analysis) and one deer has remained CWD free both clinically and by RAMALT and tonsil biopsies. This negative vaccinate has the highest titers of IgA in saliva and systemic IgG against PrP. Western blots showed that immunoglobulins from this vaccinate react to PrP(CWD). We document the first partially successful vaccination for a prion disease in a species naturally at risk.

Immunomodulation targeting of both Aß and tau pathological conformers ameliorates Alzheimer's disease pathology in TgSwDI and 3xTg mouse models.

BACKGROUND: Central to the pathogenesis of Alzheimer's disease (AD) and many other neurodegenerative diseases is the conformational change of a normal self-protein into toxic oligomeric species and amyloid deposits. None of these disorders have an effective therapy, but immunization approaches hold great promise. We have previously shown that active immunization with a novel peptide when polymerized into a stable oligomeric conformation, pBri, induced a humoral immune response to toxic Aß species in an AD model, APP/PS1 transgenic (Tg) mice, reducing plaque deposits. pBri is a glutaraldehyde polymerized form of the carboxyl fragment of an amyloidogenic protein, which is deposited in the brains of patients with a rare autosomal dominant disease due to a missense mutation in a stop codon, resulting in the translation of an intronic sequence, with no known sequence homology to any mammalian protein. METHODS: In the current study we tested whether pBri-peptide-based immunomodulation is effective at reducing both vascular amyloid deposits and tau-related pathology using TgSwDI mice with extensive congophilic angiopathy and 3xTg mice with tau pathology. RESULTS: Our results indicate that this immunomodulation approach, which produces a humoral response to proteins in a pathological conformation, is effective at reducing both Aß and tau-related pathologies. CONCLUSIONS: This immunomodulatory approach has the advantage of using a non-self-immunogen that is less likely to be associated with autoimmune toxicity. Furthermore we found that it is able to target all the cardinal features of AD concurrently.