Stefan Birrer

OBJECTIVE: To analyze the feasibility, safety, complication and death rates, and early functional results of the transverse coloplasty pouch procedure after low anterior rectal resection and total mesorectal excision. SUMMARY BACKGROUND DATA: The authors previously developed a novel neorectal reservoir, the transverse coloplasty pouch, in an animal model; they report the first clinical data of a prospective phase 1 study. METHODS: Forty-one patients underwent low anterior rectal resection with total mesorectal excision for rectal cancer (n = 37) or benign pathology (n = 4). The continuity was restored with a transverse coloplasty pouch anastomosis, and the colon was defunctionalized for 3 months. Patients were followed up at 2-month intervals for functional outcome. RESULTS: Intraoperative complications occurred in three patients (7%), none related to the transverse coloplasty pouch. There were no hospital deaths and the total complication rate was 27% (11/41); an anastomotic leakage rate of 7% was recorded. The stool frequency was 3.4 per 24 hours at 2 months follow-up and gradually decreased to 2.1 per 24 hours at 8 months. Stool dysfunctions such as stool urgency, fragmentation, and incontinence grade 1 and 2 were regularly observed until 6 months; the incidence significantly decreased thereafter. None of the patients had difficulties in pouch evacuation. CONCLUSIONS: The transverse coloplasty pouch is a small-volume reservoir that can safely be used for reconstruction after sphincter-preserving rectal resection. The early functional outcome is favorable and can be compared to other colonic reservoirs. The concept of reducing early dysfunction seen after straight coloanal anastomosis and avoiding long-term problems of pouch evacuation is supported by this study. Future trials will compare the transverse coloplasty pouch with other techniques of restorative resections of the rectum.

Triggering receptor expressed on myeloid cells (TREM)-1 is a cell surface molecule on neutrophils and monocytes/macrophages implicated in the amplification of inflammatory responses by enhancing degranulation and secretion of proinflammatory mediators. Macrophages play an important role in the intestinal mucosal immune system, because they are preferentially localized in the subepithelial region. Despite the presence of enormous numbers of bacteria in the colonic mucosa and the close proximity between mucosal macrophages and luminal bacteria, the intestinal mucosa normally displays minimal signs of inflammation. In this study, we show that the resident macrophage population in normal human small and large intestine contains only few TREM-1-expressing macrophages (<10%), whereas the overwhelming majority of monocytes (>90%) and macrophages from lymph nodes or tonsils (>80%) express TREM-1 on the cell surface. These findings were confirmed by FACS analysis and immunostainings of frozen tissue sections. The differential expression of TREM-1 greatly affects the functional capacities of monocytes and tissue macrophages. Although monocytes and macrophages from spleen, lymph nodes, or tonsils show a substantial increase in oxidative burst after TREM-1 cross-linking, no effect is seen in intestinal macrophages. Intriguingly, in contrast to monocytes, intestinal macrophages fail to up-regulate TREM-1 in response to TNF. This refractory state may be induced in intestinal macrophages by the local presence of IL-10 and TGF-beta, because these two immunoregulatory cytokines synergistically down-regulate TREM-1 expression on monocytes in vitro. The absence of TREM-1 expression on lamina propria macrophages is likely to prevent excessive inflammatory reactions, and thus, excessive tissue damage in the intestine.

We investigated clonal intratumor heterogeneity by comparing different areas of each tumor in 20 gastrointestinal cancers from female patients (1 esophageal cancer, 5 stomach cancers, and 14 colorectal cancers). In all 19 cases informative for X-inactivation analysis with the M27 beta and/or the phosphoglycerate kinase probes, the tumors were clonal. Separate areas from a given tumor showed identical X-inactivation patterns, providing evidence for its single-cell origin. Of 20 cancers, 11 showed p53 gene mutations (base pair insertions, point mutations, and one case of a base pair deletion) in exons 5-8. A particular p53 gene mutation was identical in all tumor areas investigated per case. The minisatellite probes detected loss of heterozygosity or new mutant alleles at 1p33, 1q21, 5q35, 17p13, or 18q21. In seven cases mutations at particular loci were restricted to one or two areas per tumor, while in another seven cases they were common to all tumor areas. Loss of heterozygosity or new alleles detected at the microsatellite loci D2S123, D3S1611, D5S107, D17S261, or D18S34 [(CA)n repeats] were common to all tumor areas in 7 of 19 cases. In another seven cases, however, microsatellite mutations at these loci were restricted to one to three areas per tumor. Tracing clonal intratumor heterogeneity would permit one to study the hierarchy of mutational events in cancers where no premalignant lesions can be harvested. Most important, our study indicates that clonal intratumor heterogeneity might lead to sampling errors in the molecular diagnosis of cancer biopsy specimens when using mini- or microsatellite markers.