Molecular and cellular biology of small-bowel mucosa

Clinicopathological characteristics and survival analysis of primary duodenal cancers: a 14-year experience in a tertiary centre in South China

BACKGROUND

Primary duodenal cancer (PDC) is rare and few studies have addressed it adequately, especially in China. The present study is to evaluate the clinicopathological features and prognosis of PDC in Chinese patients.

PATIENTS AND METHODS

All the consecutive cases confirmed as PDC by histopathological analysis in The First Affiliated Hospital of Sun Yat-sen University between 1995 and 2008 were included. Clinicopathological details were retrospectively analysed and prognostic factors influencing survival were evaluated.

RESULTS

The patient cohort included 53 men and 38 women, accounting for only 0.02% of all in-patients during this period. Esophagogastroduodenoscopy and gastrointestinal barium radiography were mainstay diagnostic tests for PDC; they detected 88.6% and 83.3% of the tumours, respectively. Tumours mainly occurred in the descending portion of the duodenum (67.0%). Abdominal pain was the most frequent symptom (56.0%). Histologically, adenocarcinoma was the most common type (74.7%). The overall 1-, 3- and 5-year survival rates were 62.6%, 43.7% and 33.1%, respectively. Patients survived longer in the curative surgery group (median survival time of 45 months) than those in the palliative group (6 months) (P < 0.001). Nodal metastasis and positive resection margin had a significant negative impact on survival in patients undergoing potentially curative surgery in a univariate and multivariate model (P < 0.05).

CONCLUSION

Patients with PDC are rare and lack specific presentations. Esophagogastroduodenoscopy and gastrointestinal barium radiography are effective in screening this rare tumour. Nodal metastasis and positive resection margins are associated with a poor prognosis. A curative surgery that achieves complete resection with negative margin should be pursued.

Gene expression in the adapting small bowel after massive small bowel resection

BACKGROUND

Intestinal adaptation occurs in the residual bowel following the loss or resection of a proportion of the small bowel. The purpose of the adaptive response is to return absorptive and digestive properties to near normal levels. This study employed a rat model of massive small bowel resection (MSBR) to study the adaptive response in the residual terminal ileum and the jejunum. The time points were chosen to reflect changes in gene expression early on in the response, because these are the genes that alter to initiate and maximize the response observed during adaptation.

METHODS

Sprague Dawley rats underwent an 80% resection. Differential display polymerase chain reaction (DD-PCR) analysis was performed on mRNA extracted from the remnant ileum and jejunum 0, 1, 2, 4, and 7 days post-MSBR.

RESULTS

DD-PCR identified 11 genes that were possibly regulated following MSBR. Genes confirmed to be regulated were 16S ribosomal RNA, lymphocyte antigen 6 (LY6)-like molecule, Krüppel-like factor-3 (KLF-3), G-protein-binding protein (CRFG), system A transporter 2 (SAT2), and an intestine-specific gene (similar to mKIAA0493).

CONCLUSIONS

DD-PCR analysis showed regulation of a number of genes not previously known to be involved in adaptation after MSBR or previously characterized in the intestine. These genes may be important in bringing about the complement of changes seen during the adaptive response.

Role of neuronal nitric oxide synthase and inducible nitric oxide synthase in intestinal injury in neonatal rats

AIM: To investigate the dynamic change and role of neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) in neonatal rat with intestinal injury and to define whether necrotizing enterocolitis (NEC) is associated with the levels of nitric oxide synthase (NOS) in the mucosa of the affected intestine tissue.

METHODS: Wistar rats less than 24 h in age received an intraperitoneal injection with 5 mg/kg lipopolysaccharide (LPS). Ileum tissues were collected at 1, 3, 6, 12 and 24 h following LPS challenge for histological evaluation of NEC and for measurements of nNOS and iNOS. The correlation between the degree of intestinal injury and levels of NOS was determined.

RESULTS: The LPS-injected pups showed a significant increase in injury scores versus the control. The expression of nNOS protein and mRNA was diminished after LPS injection. There was a negative significant correlation between the nNOS protein and the grade of median intestinal injury within 24 h. The expression of iNOS protein and mRNA was significantly increased in the peak of intestinal injury.

CONCLUSION: nNOS and iNOS play different roles in LPS-induced intestinal injury. Caution should be exerted concerning potential therapeutic uses of NOS inhibitors in NEC.

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