Ileal resection enhances jejunal absorptive adaptation for water and electrolytes to extrinsic denervation: implications for segmental small bowel transplantation

Stool dynamics after extrinsic nerve injury during right colectomy with extended D3-mesenterectomy

INTRODUCTION

To improve oncological outcome in right colon cancer surgery, an extended mesenterectomy (D3) is under evaluation. In this procedure, all tissue anterior and posterior to the superior mesenteric vessels from the middle colic to ileocolic artery origin is removed, causing injury to the superior mesenteric nerve plexus. The aim was to study the effects of this injury on bowel dynamics and quality of life (QoL).

METHODS

Patients undergoing right colectomy with conventional D2- and extended D3-mesenterectomy were asked to record stool number and consistency for 60 d after surgery and complete questionnaires regarding QoL and bowel function (BF) before and after recovery from surgery. We compared early postoperative stool dynamics and long-term QoL in the groups and presented graphs depicting the temporal profile of stool numbers and consistency.

RESULTS

Thirty-three patients operated with a D3-resection and 12 patients with a D2-resection participated. The results revealed significantly higher stool numbers in the D3-group until day 26, with significantly more loose-watery stools until day 40. The most pronounced difference was found on day 9 (Mean difference in the total number of stools: 2.25 stools/day, p=.004. Mean difference in loose-watery stools/day: 2.81 p<.001). About 25% in the D2- and 69.7% in the D3-group reported having more than three stools/day in the early postoperative phase. There were no differences in long-term QoL and BF between the groups except in stool consistency (p=.039).

DISCUSSION/CONCLUSIONS

Denervation following extended D3-mesenterectomy leads to transitory reduced consistency and increased frequency. It does not affect long-term QoL or BF.

Expression and function of intestinal hexose transporters after small intestinal denervation

BACKGROUND

The role of neural regulation in expression and function of intestinal hexose transporters is unknown. The aim of this study is to determine the role of intestinal innervation in gene expression and function of the membrane hexose transporters, SGLT1, GLUT2, and GLUT5 in the enterocyte. We hypothesize that denervation of the small intestine decreases expression of hexose transporters, which leads to decreased glucose absorption.

METHODS

Six groups of Lewis rats were studied (n = 6 each) as follows: control, 1 week after sham laparotomy, 1 and 8 weeks after syngeneic (no immune rejection) orthotopic small-bowel transplantation (SBT) (SBT1 and SBT8) to induce complete extrinsic denervation, and 1 and 8 weeks after selective disruption of intrinsic neural continuity to jejunoileum by gut transection and reanastomosis (T/A1 and T/A8). All tissue was harvested between 8 AM and 10 AM. In duodenum, jejunum, and ileum, mucosal messenger RNA (mRNA) levels were quantitated by real-time polymerase chain reaction (PCR), protein by Western blotting, and transporter-mediated glucose absorption using the everted sleeve technique.

RESULTS

Across the 6 groups, the relative gene expression of hexose transporter mRNA and protein levels were unchanged, and no difference in transporter-mediated glucose uptake was evident in any region. The glucose transporter affinity (K(m)) and functional transporter levels (V(max)) calculated for duodenum and jejunum showed no difference among the 6 groups.

CONCLUSION

Baseline regulation of hexose transporter function is not mediated tonically by intrinsic or extrinsic neural continuity to the jejunoileum.

Electrolyte imbalances in pediatric living related small bowel transplantation

BACKGROUND

Pediatric small bowel transplantations are associated with pronounced electrolyte disturbances in the postoperative period. We investigated the pattern of electrolyte disturbances with regard to enteral malabsorption, renal compensation, and the influence of immunosuppression.

METHODS

We reviewed 11 small bowel transplantations between October 2002 and February 2007. The data collected included frequent serum, ostomy, and urine electrolyte profiles, renal function parameters, and FK 506 levels in the postoperative period up until either discharge or graft loss.

RESULTS

Our results show enteral losses most prominent during the first 4 weeks postoperatively that are only partially compensated by the kidneys. Subsequently, enteral losses improved, although renal function remained challenged, particularly glomerular filtration and phosphorus, magnesium losses, which correlated with high FK 506 levels.

CONCLUSION

Our data reveal several electrolyte imbalances different and unique to postoperative small bowel transplants. Although enteral losses improve along with graft villi formation, electrolyte abnormalities continue, to which FK 506-mediated renal toxicity might contribute.

Splanchnic Circulation Is a Critical Neural Target in Angiotensin II Salt Hypertension in Rats

Chronic angiotensin II (Ang II) infusion, in rats fed high salt, engages the sympathetic nervous system to increase venomotor tone. The splanchnic sympathetic nervous system is the most important regulator of venous tone, indicating that splanchnic sympathetic nervous system activity may be increased in Ang II salt hypertension. We hypothesized that celiac ganglionectomy (CGx), to selectively disrupt sympathetic innervation to the splanchnic circulation, would attenuate arterial pressure (AP), and venous tone increases in Ang II salt hypertension. Rats fed 2% or 0.4% NaCl were instrumented to allow AP measurement by radiotelemetry at the same time as surgical CGx or sham operation. Ang II was delivered by minipump (150 ng/kg per minute) for 14 days. CGx reduced AP independent of salt diet during control. CGx markedly attenuated Ang II hypertension in rats on 2% NaCl but had little effect in rats fed 0.4% NaCl. To test the possibility that CGx exerted its effects via renal denervation, rats were subjected to the same protocol but received selective bilateral renal denervation. Renal denervation decreased AP during control but had no protective effect on Ang II hypertension and actually tended to exacerbate the pressor response. Finally, separate groups of rats underwent CGx or sham operation and were instrumented to allow repeated measures of mean circulatory filling pressure, an index of venous tone. In addition to attenuating Ang II salt hypertension, CGx completely prevented Ang II salt-induced increases in mean circulatory filling pressure and substantially attenuated depressor responses to acute ganglion blockade. We conclude that, in the presence of high salt, Ang II activates the splanchnic sympathetic nervous system to increase venomotor tone and AP.