Jejunoileal transplantation. Effects on characteristics of canine jejunal motor activity in vivo

Migrating contractions of the afferent and Roux limbs show peristaltic movement independently of each other in conscious dogs after Roux-en-Y reconstruction after distal gastrectomy

PURPOSE

The Roux-en-Y (RY) procedure is used frequently for surgical reconstruction after gastrectomy. However, a minority of patients suffer a serious motility disorder of the Roux and afferent limb postoperatively. We conducted this study to clarify the association between the motility and peristaltic direction of two limbs in conscious dogs.

METHODS

We performed distal gastrectomy on five dogs and implanted seven force transducers on the serosal surfaces of the remnant gastric body and afferent and Roux limbs. We then analyzed the electric signals from these force transducers.

RESULTS

Migrating contractions were observed in the two limbs, but not in the gastric remnant body. Migrating contractions in the forward direction propagated independently from the most proximal side in each limb. There was no propagation of contraction across the jejunojejunostomy between the two limbs.

CONCLUSIONS

Each proximal part of the Roux and afferent limbs has an independent motility pacemaker in conscious dogs after gastrectomy with RY reconstruction.

Comparison of postoperative motility in hand-sewn end-to-end anastomosis and functional end-to-end anastomosis: an experimental study in conscious dogs

BACKGROUND AND AIMS

The objective of this study is to compare the postoperative motility between hand-sewn end-to-end anastomosis and functional end-to-end anastomosis.

METHODS

Fifteen conscious dogs were divided into three groups: normal intact dog group, end-to-end anastomosis group (EE), and functional end-to-end anastomosis group (FEE). In the EE and FEE groups, the dogs underwent a transection of the jejunum 30 cm distal to the Treitz ligament and anastomosis in each method. To compare the gastrointestinal motility, the time to the appearance and the rate of propagation of interdigestive migrating motor contractions (IMC) across the anastomosis, as well as the motility index (MI) at the oral and anal sides of the anastomosis, were measured using strain gauge force transducers. Furthermore, the histological examination of intrinsic nerve fibers was evaluated.

RESULTS

The time to the appearance of propagation of IMC in the EE and FEE was not significantly different. The propagation rates of IMC in the EE and FEE completely recovered within 4 weeks of the surgery. The MI in the EE and FEE was not significantly different. In addition, no continuity of intrinsic nerve fibers across the anastomosis could be identified in either group.

CONCLUSIONS

In the present study, there are no significant differences between the EE and FEE with regard to the time of the appearance and the rate of propagation of IMC. These results suggest that the effect of functional end-to-end anastomosis on postoperative motility is not different from that of hand-sewn end-to-end anastomosis.

Correlation of motility and neuronal integrity with a focus on the grade of intestinal allograft rejection

Intestinal graft motility after small bowel transplantation (SBT) is poorly characterized. The aim of this study was to compare motor patterns with myenteric neuronal cell population as a parameter of graft viability at various degrees of acute cellular rejection (ACR). Three grades of ACR were achieved in orthotopic allografts. Syngeneic transplants and allografts with immunosuppression served as controls. Motor activities were recorded using strain gauge force transducers and analyzed visually. Quantifications of myenteric neurons in whole mounts of intestinal grafts were used to evaluate neuronal population. A typical migrating motor complex (MMC) was found in syngeneic and allogenic transplants with immunosuppression. A high prevalence of discrete clustered contractions (DCC) and nonpropagating contractions (NPC) without MMC was seen in moderately and severely rejected allografts. Neuronal cell loss in the allografts, which could be one of the causes of motor dysfunction, was noted in moderate rejection (19.3%) and progressed until severe rejection (60.1%). Monitoring motility patterns in SBT could be an effective tool for assessing intestinal rejection. Allograft dysmotility, such as absence of MMC and high prevalence of DCC or NPC, could be useful markers of progression of acute rejection and help guide treatment decisions.

Canine ileal motor activity after a model of jejunoileal autotransplantation

OBJECTIVE

To determine mechanisms by which extrinsic innervation to the jejunoileum controls ileal motility.

SUMMARY BACKGROUND DATA

Small bowel transplantation is complicated by diarrhea and delayed gastric emptying, possibly secondary to altered motility. Ileal motility after small bowel transplantation is poorly characterized.

METHODS

Motor activity was recorded from four dogs during fasting and after feeding small (64 Kcal) or large (256 Kcal) meals. Short-chain fatty acids known to induce unique ileal motor patterns were administered into the distal ileum during fasting. Dogs were studied before and after jejunoileal denervation simulating autotransplantation.

RESULTS

After jejunoileal denervation, the ileal migrating motor complex (MMC) persisted but was no longer temporally coordinated with duodenal MMCs. Spontaneous giant migrating contractions occurred more frequently after denervation and more commonly originated proximally in the jejunum, but the velocity of migration did not differ. In contrast, the incidence and characteristics of spontaneous discrete clustered contractions (DCCs) did not differ. Short-chain fatty acids reproducibly initiated giant migrating contractions and discrete clustered contractions in the distal ileum without differences before and after denervation. Large but not small meals inhibited the ileal MMC after denervation.

CONCLUSIONS

Extrinsic innervation and/or intrinsic neural continuity with the duodenum and/or colon control temporal coordination of ileal motility with the duodenum and modulate postprandial inhibition of fasting motility and presence of giant migrating contractions. These changes in motility patterns may prove important in mediating enteric dysfunction after small bowel transplantation.

Effects of intestinal transplantation on postprandial motility and regulation of intestinal transit

BACKGROUND

The effects of intestinal transplantation on gut motility have not been completely defined. In this study we examine the effects of ileal transplantation on ileal smooth muscle contractility, together with gastroduodenal emptying, intestinal flow, and transit rates in a canine model of short-gut syndrome.

METHODS

Animals (n = 22) were instrumented with strain gauge transducers, collection cannulae, and infusion catheters to assess motility, intestinal flow and transit rates, and gastroduodenal emptying. Ten animals served to define normal parameters. Six animals underwent a 70% resection of the proximal small intestine to serve as short-gut controls. Six animals underwent removal of a 100-cm segment of the ileum, with cold storage, and autotransplantation the following day combined with a 70% resection of proximal bowel.

RESULTS

Transplant animals exhibited delayed gastroduodenal emptying, reduced intestinal flow rates, and postprandial phasic contractions that were similar to short-gut controls. However, transplant animals experienced rapid intestinal transit compared with short-gut controls (4.8 +/- 0.4 cm/min vs 2.0 +/- 0.3 cm/min; mean +/- SEM; P <.05).

CONCLUSIONS

The transplanted intestine, even with 18 hours of cold storage, exhibits a relatively normal postprandial motor response. However, adaptive responses of the transplanted intestine, such as regulation of intestine transit, may be impaired by neuromuscular injury associated with denervation or ischemia.