Bile composition after total proctocolectomy with interposed jejunal segment as neorectum

Cholesterol metabolism and non-cholesterol sterols in patients with ileal pouch anastomosis

BACKGROUND

Previous studies suggest only minor changes in bile acid metabolism after panproctocolectomy with ileal pouch construction.

AIMS/METHODS

To investigate these changes further, we studied cholesterol absorption and serum, biliary and fecal non-cholesterol sterols and lipids in 12 ileal pouch patients and 10 controls.

RESULTS

In patients, cholesterol absorption was markedly reduced and was associated with low serum total and LDL cholesterol and LDL triglyceride levels, but surprisingly, cholesterol synthesis, as indicated by sterol-balance data or serum cholesterol precursor levels, was within low normal limits. The high proportions of serum plant sterol to cholesterol, particularly that of campesterol, were not related to cholesterol absorption, but were attributable to a markedly reduced biliary cholesterol secretion. Interestingly, in these patients the fractional absorption of campesterol was normal, whereas that of sitosterol, like cholesterol, was reduced and was positively related to the intestinal influx of cholesterol. The patients' serum cholestanol proportion was normal, but the proportion of the cholestanol formed during intestinal passage was significantly reduced (17.9% vs 65.2% in controls).

CONCLUSIONS

Thus ileal pouch patients are characterized by sterol malabsorption, lowered serum total and LDL-cholesterol levels, but unexpectedly without any increase in cholesterol synthesis. The lack of high serum cholestanol, shown earlier frequently in unoperated patients with ulcerative colitis, may indicate reversible cholestasis, a finding deserving further exploration.

Ileal pouch-anal anastomosis for ulcerative colitis and polyposis coli: is the risk of carcinoma formation conclusively averted?

We took biopsies from the ileal pouch mucosa of 26 patients (13 with ulcerative colitis, 13 with polyposis coli) at least 1 year after the newly formed pouch was finally linked to the faecal flow. Histochemical mucin differentiation was carried out in addition to the ordinary stains. All patients underwent colonization of pouch mucosa with goblet cell multiplication, reduction or loss of villi, and formation of crypts. Only 19 patients could be classified morphologically as bearing large bowel mucosa in the ilea] pouch. Patients with one incidence of ulcerative colitis developed one criterion, those with two incidences two criteria, and those with seven incidences three criteria of the original colitic disease. Patients with two incidences of colitis and those with 10 incidences of polyposis coli developed an excess of sialomucine formation, which is known as an obligate pre-cancerosis. These findings prove, that in ileal pouches, even when affected by systemic diseases with extraintestinal manifestations, a new kind of mucosa develops, which is also prediposed to carcinoma formation. Papers reporting adenocarcinoma arising in ileostomy areas as well as in ileoanal anastomosis, and ileal reservoirs, confirm this presumption. Assuming this conclusion, restorative proctocolectomy cannot hinder malignant transformation of intestinal mucosa, but only delay the onset of cancer, thereby making lifelong follow-ups necessary.

Effect of terminal ileal transposition on intestinal absorption following proctocolectomy

A terminal ileal transposition procedure, in which a distal jejunal segment is interposed between the terminal ileum and the anus following proctocolectomy, is described. Adult mongrel dogs had either terminal ileal transposition (n = 5) or ileoanal anastomosis (n = 6) following two-stage proctocolectomy. Untreated dogs were used as controls (n = 7). Twelve weeks after the second-stage operation, a perfusion study was performed. After terminal ileal transposition the transposed terminal ileum showed a high absorptive capability for sodium, chloride and bile acids (P < 0.05, P < 0.05 and P < 0.001 respectively). After ileoanal anastomosis the absorptive capability of the terminal ileum was not enhanced significantly. In the mid-jejunum, the absorption of bile acids, chloride and glucose was enhanced (all P < 0.05) only after terminal ileal transposition. Terminal ileal transposition improves the absorptive capability of the terminal ileum and the mid-jejunum compared with conventional ileoanal anastomosis in this model.

Gallstones and their composition in patients with ileoanal anastomosis

Cholelithiasis is known to occur in 15%-24.5% of proctocolectomized patients. However, the clinical features and chemical analysis of gallstones in these patients have not been reported. We describe two cases of cholelithiasis that developed in patients after proctocolectomy with ileoanal anastomosis. These patients had a high output of watery stools and more frequent bowel movements than the average for Japanese patients with ileoanal anastomosis. The chemical composition of the resected gallstones was 93.0% cholesterol and 80.9%, respectively, in the two patients, indicating that cholesterol gallstones are formed in patients with ileoanal anastomosis after proctocolectomy.

Rapid cholesterol nucleation time and cholesterol gall stone formation after subtotal or total colectomy in humans

Changes in biliary lipid composition, pH, ionised calcium, total and unconjugated bilirubin, and cholesterol nucleation time of gall bladder bile samples were examined in six patients who had undergone subtotal or total colectomy between five months and seven years previously, and values were compared with those in control patients with no gall stones. The colectomy group mainly comprised patients with ulcerative colitis and familial adenomatosis coli, in whom only a short length of the terminal ileum (mean (SEM) 2.25 (0.57) cm) had been resected. The reconstruction procedures were ileoanal anastomosis in two patients, terminal ileostomy in two, ileorectal anastomosis in one, and J shaped ileal pouch-anal anastomosis in one patient. The distributions of age, sex, and relative body weight were similar in the two groups. The gall bladder bile was lithogenic in the post colectomy group--these patients had a significantly increased cholesterol saturation index (p < 0.01) and rapid cholesterol nucleation time (p < 0.05) compared with the control group. A significant increase in the molar percentage of cholesterol and a decrease in that of total bile acid associated with significantly decreased secondary bile acids (p < 0.05) were observed in the post colectomy group. Gall stones formed in two of six patients after colectomy were cholesterol stones containing more than 80% cholesterol by dry weight. Total and unconjugated bilirubin, pH, and ionised calcium values were similar in the two groups. The results indicate that after total or subtotal colectomy the composition of gall bladder bile increases the risk of cholesterol gall stone formation.

Early and long-term effects of colectomy and endorectal pullthrough on bile acid profile

OBJECTIVE

Although total colectomy with mucosal proctectomy and endorectal pullthrough affects two sites critical to the enterohepatic circulation of bile acids, little information is available regarding the manner in which normal digestive physiology is altered by these procedures. This study defines the early and long-term effects of colectomy and endorectal pullthrough on bile acid profile and the long-term effects on biliary lipid metabolism.

SUMMARY BACKGROUND DATA

Specific changes in bile acid absorption have been reported in patients after ileal resection. Recent studies from our laboratory indicate that in the early postoperative period, colectomy with endorectal pullthrough causes a significant decrease in gallbladder bile concentrations of total bile acids, cholesterol, phospholipids, and calcium. The observation by several authors that the pouch undergoes morphologic and perhaps functional adaptation suggest that these changes may be transient and perhaps reversible.

METHODS

These studies were done in an awake, unanesthetized canine model that allows periodic sampling of gallbladder bile without creation of an external biliary fistula and its associated sequelae. Animals were ultimately randomly assigned to either laparotomy and gallbladder cannulation (N = 6), or gallbladder cannulation with total colectomy and ileorectal anastomosis (N = 7), or biliary cannulation, colectomy, mucosal proctectomy and endorectal pullthrough with ileal reservoir (N = 5).

RESULTS

Six weeks after operation, colectomy and ileorectal anastomosis were associated with a significant alteration in the relative composition of bile acids in gallbladder bile. These early changes were manifested by a significant (p < 0.05) increase in taurocholic acid and a concomitant decrease in taurodeoxycholic acid. These changes became even more pronounced in the ileorectal anastomosis group 12 weeks after colectomy and ileorectostomy. Although similar changes in the relative concentrations of individual bile acids occurred in the 6-week endorectal animals, bile acid profile was restored to normal by 12 weeks.

CONCLUSIONS

Colectomy with ileorectal anastomosis leads to early and significant changes in bile acid profile, which persist and become even more pronounced with time. In contrast, the construction of an ileal reservoir after colectomy facilitates restoration of a normal bile acid profile. We propose that these alterations in bile acid metabolism result from adaptation of the ileal reservoir as its mucosa assumes functional characteristics of normal colon.

Early effects of colectomy and endorectal pullthrough operation on biliary lipid composition

In order to determine the effects of total colectomy and endorectal pullthrough with ileal reservoir (ERP) on biliary lipid composition in the early postoperative period, gallbladder bile of dogs was examined after biliary cannulation alone (control); biliary cannulation and colectomy with ileorectal anastomosis (IRA); and biliary cannulation, colectomy with mucosal proctectomy, and ERP. Bile collected from 3 to 6 weeks postoperation was analyzed for total bile acids, cholesterol, phospholipids, bilirubin, and calcium concentrations. Cholesterol saturation was calculated. Serum collected over the same period was analyzed for electrolytes and liver function tests. There was no evidence of sludge or gallstones post-operatively in any animal. Significant decreases in total bile acids, phospholipids, and calcium concentrations were noted in the bile of the IRA group when compared to the bile of the controls (P less than 0.05) and in total bile acids, cholesterol, phospholipids, and calcium in ERP vs controls (P less than 0.05). Moreover, all three biliary lipids and calcium were significantly decreased in ERP animals compared to those in the IRA group (P less than 0.05). No change in cholesterol saturation was noted between any of the three groups. Other than an increase in alkaline phosphatase concentrations compared to preoperative levels (P less than 0.05) which was noted in all groups, no significant changes were noted in serum parameters. We conclude that during the early postoperative period, ERP causes a significant decrease in gallbladder bile concentrations of total bile acids, cholesterol, phospholipids, and calcium which cannot be explained by colectomy alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Ileostomy using an interposed ileal segment to function as a 'neocolon'

A new type of ileostomy was constructed in rats using an interposed ileal (I-I) segment functioning as a neocolon. The effects of this operation in these rats were compared with a control group undergoing conventional ileostomy (I). Rats in the I group lost weight throughout follow-up, whereas rats in the I-I group regained weight and were significantly heavier four weeks after surgery. Transit time from the stomach to the stoma was significantly prolonged in the I-I group (187 +/- 29 minutes) when compared with the I group (141 +/- 17 minutes, P less than 0.01). Serum analysis revealed no significant differences in total protein, lipids, electrolytes (Na, Cl, CO2), and osmolarity between the groups. Biliary bile salt concentration, normalized bile flow, and normalized bile acid output in the I-I group were not different from those in unoperated control rats, suggesting unimpaired bile acid metabolism. These data suggest this operative procedure has the beneficial effects of slowing intestinal transit and promoting postoperative recovery without impairing distal ileal function.