Absorption studies after ileal J-pouch anastomosis for ulcerative colitis. A prospective study

Prevalence and Risk Factors for Functional Vitamin B12 Deficiency in Patients with Crohn's Disease

BACKGROUND

Crohn's disease (CD) is a risk factor for vitamin B12 deficiency due to frequent involvement of the terminal ileum. Conventional screening for B12 deficiency with serum B12 is relatively insensitive and measures total B12 concentration, of which a minority is present in a biologically active form. Holotranscobalamin (holoTC) combined with methylmalonic acid (MMA) is believed to be more accurate in identifying impaired B12 status. We evaluated the prevalence and risk factors for B12 deficiency using holoTC supported by MMA among patients with CD.

METHODS

We performed a single-center service evaluation of 381 patients with CD who underwent B12 assessment (holoTC/MMA) and compared them with 141 patients with ulcerative colitis. Eighty-nine patients with CD underwent paired serum B12 and holoTC. Among patients with CD, risk factors including terminal ileal resection length, ileal inflammation on endoscopy, and disease characteristics on magnetic resonance imaging were recorded.

RESULTS

Prevalence of B12 deficiency among patients with CD was 33% compared with 16% in ulcerative colitis (P < 0.0001). In 89 patients who underwent paired tests, conventional testing identified B12 deficiency in 5% of patients with CD, which increased to 32% using holoTC/MMA. Independent risk factors for B12 deficiency were ileal resection length ≤20 cm (odds ratio: 3.0, 95% confidence interval, 1.5-6.0, P = 0.002) and >20 cm (odds ratio: 6.7, 95% confidence interval, 3.0-14.7, P < 0.0001) and ileal inflammation (odds ratio: 3.9, 95% confidence interval, 2.2-6.9, P < 0.0001). On magnetic resonance imaging, active terminal ileal inflammation (P = 0.02) and an increased disease burden (≥1 skip lesion, P = 0.01 and prestenotic dilatation >3 cm, P = 0.01) were associated with B12 deficiency.

CONCLUSIONS

Vitamin B12 deficiency is common in patients with CD. holoTC supported by MMA identifies patients with B12 deficiency considered replete on conventional testing.

Kinetics of primary bile acids in patients after proctocolectomy and ileal pouch-anal anastomosis

BACKGROUND

The high incidence of cholesterol gallstones in patients after proctocolectomy with ileal pouch-anal anastomosis (IPAA) may be due to an increased loss of bile acids. We aimed to evaluate the kinetics of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) in these patients.

METHODS

Pool sizes, synthesis rates, and fractional turnover rates of CA and CDCA were determined by combined capillary gas chromatography/isotope ratio mass spectrometry in serum samples after administration of [¹³C]CA and [¹³C]CDCA in 6 patients and 9 healthy volunteers.

RESULTS

In patients with IPAA, pool sizes of CA and CDCA were 11.5 (8.2-23.8) and 12.1 (6.7-20.1) µmol/kg, respectively, and were significantly lower than in healthy controls [36.0 (24-47) and 29.0 (21-42) µmol/kg, respectively; p < 0.05, each]. Fractional turnover rates of CA [1.19 (1.06-1.82) vs. 0.31 (0.13-0.54) per day] and CDCA [1.01 (0.50-1.63) vs. 0.23 (0.09-0.36) per day] were increased fourfold in patients with IPAA (p < 0.05, each). Synthesis rates of CDCA [10.2 (5.2-32.9) vs. 6.6 (2.7-10.5) µmol/kg per day, p = 0.05] and CA [15.1 (9.3-39.4) vs. 11.5 (3.1-20.5) µmol/kg per day, n.s.] tended to be higher in patients with IPAA than in controls.

CONCLUSION

The reduced pool size of primary bile acids may contribute to the high incidence of cholesterol gallstones in patients after proctocolectomy and IPAA.

Nutrition considerations surrounding restorative proctocolectomy

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for patients with ulcerative colitis and familial polyposis coli syndromes. Pouch construction uses the distal 30-40 cm of ileum, and there exists a potential for postoperative nutrition consequences. These include vitamin B(12) deficiency, iron deficiency, bile acid malabsorption, and abnormalities of trace elements, fluids, and electrolytes. Patients who have undergone an ileal pouch-anal anastomosis procedure often describe specific food sensitivities that may require diet alteration, even more so than do patients with permanent ileostomy. There may be roles for postoperative probiotic supplementation in an attempt to decrease the rate of "pouchitis" and appropriate preoperative nutrition support to minimize the risk of perioperative complications.

Prevalence and outcome of anemia after restorative proctocolectomy: a clinical literature review

PURPOSE

Iron and/or vitamin B12 deficiency anemias, which have adverse effects on patients' quality of life, are commonly observed and often overlooked complications after restorative proctocolectomy. We performed a systematic review of publications on the prevalence of anemia as well as on the impact of anemia on a range of clinical, functional, quality of life, and economic outcomes in restorative proctocolectomy patients. This information is important to help healthcare providers through a comprehensive overview to increase awareness about a condition that could require therapy to improve patient healthcare and quality of life.

METHODS

We reviewed the English language publications on the incidence of anemia and its adverse effect after restorative proctocolectomy The United States National Library of Medicine database (MEDLINE), the Excerpta Medica database (EMBASE), the Cochran Library, and the Google search engine were searched for published articles on the prevalence and impact of anemia in post-restorative proctocolectomy surgical patients.

RESULTS

The long-term complication most frequently described after RPC is pouchitis. Pouchitis is significantly associated with iron deficiency anemia caused by pouch mucosal bleeding. Other causes are insufficient and/or impaired iron absorption. It has also been observed, however, that restorative proctocolectomy patients with underlying familial adenomatous polyposis rarely develop pouchitis yet show higher rates of iron deficiency anemia compared to those patients with underlying ulcerative colitis. Other causes shown as independent risk factors for iron deficiency anemia in restorative proctocolectomy patients are malignancy, desmoid tumors, and J-pouch configuration. Vitamin B12 deficiency anemia is also common after restorative proctocolectomy. About one-third of restorative proctocolectomy patients show abnormal Schilling test and 5 percent have low referenced serum cobalamin. It has been observed that the degree resection of the terminal-ileum, malabsorption, bacterial overgrowth, and dietary factors are among the known causes of cobalamin deficiency. Folate deficiency has not been reported in restorative proctocolectomy patients. Describing restorative proctocolectomy surgery and its outcomes, in patients without anemia, the quality of life is reported excellent regardless of operative technique.

CONCLUSIONS

Anemia is not uncommon following restorative proctocolectomy and has been shown to have negative effects on the patient's quality of life and the economy and may substantially increase healthcare costs. The treatment of anemia and its underlying causes is important to improving clinical and economic outcomes.

Restorative proctocolectomy for ulcerative colitis: impact on lipid metabolism and adipose tissue and serum fatty acids

The aim of this prospective study was to evaluate the changes of the metabolism of circulating and storage lipids in patients with ulcerative colitis after restorative proctocolectomy. Fifteen consecutive patients and 15 sex- and age-matched healthy controls were enrolled. Disease activity, diet, inflammatory parameters, plasma lipoprotein concentrations, and fatty acids (FA) of serum phospholipids and of the subcutaneous adipose tissue were assessed at colectomy and at ileostomy closure. In ulcerative colitis patients, total cholesterol and docosahexaenoic acid were lower than in healthy subjects (p < 0.01 and p < 0.05). The median interval between colectomy and ileostomy closure was 6 (range 2-9) months. During that interval, the inflammatory parameters improved, high-density lipoproteins (HDL) cholesterol increased (p < 0.01), and low-density (LDL) cholesterol decreased (p = 0.01). At ileostomy closure, serum arachidonic acid levels were increased (p = 0.04), whereas serum oleic acid level was decreased (p = 0.02). In this interval, no significant alteration, either in serum n-3 FA precursors or in the FA of subcutaneous adipose tissue, was observed. The increase of serum arachidonic acid after colectomy might suggest a lower utilization for inflammatory process. The reduction of LDL cholesterol is an index of malabsorption probably due to the accelerated transit and to the exclusion of the terminal ileum caused by the covering ileostomy.

Impact of surgery on the development of duodenal cancer in patients with familial adenomatous polyposis

PURPOSE

Precancerous duodenal lesions in patients with familial adenomatous polyposis can be detected with duodenoscopy and treatment may prevent the development of cancer. We proposed to determine the frequency, natural history, cumulative risk, and risk factors of the precancerous duodenal lesions in a series of patients diagnosed in northern Italy.

METHODS

A prospective, endoscopic, follow-up protocol was performed in 50 patients examined by gastroduodenoscopy at two years of interval or less. The presence and severity of precancerous lesions of the duodenal mucosa were evaluated by Spigelman score. Twenty-five patients (50 percent) had proctocolectomy and ileoanal anastomosis, 15 (30 percent) had colectomy and ileorectal anastomosis, and 5 (10 percent) had proctocolectomy and definitive ileostomy from 0 to 3 years before the admission to the surveillance program. All patients showed more than a thousand adenomas in the colorectal mucosa. No patients with attenuated polyposis were found.

RESULTS

At the first endoscopy, duodenal adenomas could be detected in 19 of 50 patients (38 percent), whereas at the end of the follow-up, 43 (86 percent) had duodenal lesions. The final mean Spigelman score increased during the follow-up period (P<0.001 respect to baseline values). No duodenal cancer could be detected. Eleven patients had or developed severe precancerous duodenal lesions (Stage IV) treated with endoscopic or surgical resection. The distribution of patients with Stage IV according to the surgery of the colon was: 2 of 25 treated with ileoanal anastomosis and 8 of 15 with ileorectal anastomosis (P=0.0024, Fisher's exact test).

CONCLUSIONS

Patients with familial adenomatous polyposis are at risk of significant neoplasia. The natural history of precancerous lesions might be related to surgical treatment of colorectal neoplasms.

Long term metabolic consequences of ileal pouch-anal anastomosis for ulcerative colitis

OBJECTIVES

Chronic inflammation in the ileal pouch is the most significant late complication after ileal pouch-anal anastomosis (IPAA). It leads to changes in mucosal morphology, with consequent decreased vitamin B12, bile acid and cholesterol absorption documented. The aims of this study were to evaluate long term metabolic consequences at least 5 yr after IPAA and the influence of pouchitis on pouch histology and on bile acid, lipid, and vitamin B12, A, E, and D metabolism.

METHODS

A total of 104 patients with a J-pouch who were operated on between 1985 and 1994, as well as 21 ulcerative colitis patients with a conventional ileostomy were enrolled for the study. Routine blood tests, vitamin status, vitamin B12 levels, and bile acid absorption were determined, as well as endoscopy with biopsies. The pouchitis disease activity index (PDAI) was calculated. On the basis of histology, IPAA patients were divided into three subgroups: 1) those with no villous atrophy, 2) those with partial villous atrophy, and 3) those with subtotal or total villous atrophy.

RESULTS

Incidence of pouchitis was 42.3%, and was strongly associated with villous atrophy. In IPAA patients with subtotal or total villous atrophy (32.7%), serum levels of albumin, calcium, total cholesterol, triglycerides, and vitamin E were significantly reduced (p < 0.05). The lowest bile acid and vitamin B12 absorption rates were seen in patients with inflammation in the proximal limb. Vitamin D deficiency was seen in 10.6%, and vitamin A and B12 deficiency in approximately 5% of IPAA patients.

CONCLUSIONS

Metabolic consequences after IPAA are associated with pouchitis, grade of villous atrophy, and extent of inflammation in the remaining ileum. Patients with active chronic inflammation need long term follow-up.

Comparison of micronutrients in patients having had panproctocolectomy and either ileal pouch anal anastomosis or Brooke ileostomy for chronic ulcerative colitis (UC)

OBJECTIVE

Patients having panproctocolectomy undergo major metabolic changes. A recent study suggested that patients who have had a panproctocolectomy and ileal pouch-anal anastomosis (IPAA) may be trace element-deficient, while other recent evidence has suggested a gradual decrease in vitamin B12. This study was undertaken to compare patients who had a panproctocolectomy for UC in combination with either an IPAA or a Brooke ileostomy (BI), and to determine whether the type of surgery post-proctocolectomy influences the absorption of trace elements, as well as comparing the levels after both operations with the normal population values.

PATIENTS AND METHODS

One hundred randomly selected patients who had had a panproctocolectomy for UC (50 IPAA, 50 BI) were invited to take part in the study by letter. The patients who consented had blood taken for haemoglobin, serum iron, ferritin, serum folate, red cell folate, vitamin B12, insulin-like growth factor-1 (IGF-1), albumin, and the trace elements copper, magnesium, manganese, selenium, and zinc.

RESULTS

Of the 100 patients, 46 consented to participate in the study (23 IPAA, 23 BI). The age of the BI group was significantly higher than those of the IPAA group (mean age IPAA 44 years, BI 52 years, P < 0.05). There was no significant difference between the two groups with respect to time since operation, mean levels of haemoglobin, iron indices, albumin, serum and red cell folate, vitamin B12, or any of the trace elements examined. Plasma IGF-1 was higher in the IPAA group, but this was no longer significant when adjusted for age.

CONCLUSION

No difference was found in trace element status in patients who had had a panproctocolectomy for UC with either an IPAA or BI. Furthermore, no difference existed between these two groups.

The physiology of ileo-anal pouch function

Even excellent clinical function after ileo-anal pouch construction is associated with a variety of physiological abnormalities. Small bowel intestinal motility is essentially normal but the ileal reservoir serves to markedly suppress the ileal motor response both to progressive distension by intestinal contents and to transmitted myoelectrical complexes. As a result, the healthy pouch can accommodate a large volume of intestinal content before the rising baseline pressure and the appearance of large isolated contraction waves produce an urge to defecate. Evacuation in the normal pouch patient is rapid and highly efficient and is achieved by means of the Valsalva maneuver without any evidence of significant intestinal propulsion. External anal sphincter function is fully preserved but internal anal sphincter function is significantly impaired in the immediate postoperative period. Recovery occurs over the next 6 to 12 months but is often incomplete. Bacterial overgrowth in the pouch and prepouch ileum is almost universal and results in the premature deconjugation of primary bile salts and accumulation of secondary bile salts within the pouch. These produce morphologic changes in the ileal mucosa, and their excretion in pouch effluent gradually depletes the bile salt pool. Anerobic organisms also bind with vitamin B12 and the vitamin B12-intrinsic factor complex, resulting in subtle but measurable reductions in vitamin B12 levels in pouch patients. Finally, anerobic fermentation of mucus and undigested carbohydrate results in excessive quantities of short chain fatty acids within the pouch lumen. The clinical significance of these substances is unclear, but they may have an adverse action on both ileal mucosal and smooth muscle function. In essence, however, the pouch surgeon can maximize the likelihood of good clinical function by constructing a large capacity pouch, by avoiding surgery in patients with clearly deficient anal sphincter mechanisms, and by careful attention to pouch-anal anastomotic technique.

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.

The release of gastric inhibitory peptide, glucagon-like peptide-I, and insulin after oral glucose test in colectomized subjects

BACKGROUND

The physiologic role of the colon as an endocrine organ is not clear. We therefore studied the enteroinsular axis in patients with ulcerative colitis after colectomy.

METHODS

The subjects included 11 patients with a conventional ileostomy, 10 patients with an ileoanal reservoir, and 10 normal controls. The concentrations of glucose, insulin, gastric inhibitory peptide (GIP), and glucagon-like peptide-I (GLP-I) were measured in plasma during an oral glucose test.

RESULTS

The peak level of glucose and peak levels and area under the curve (AUC) of insulin and GIP were higher in patients (P < 0.05). Neither the peak level nor the AUC of GLP-I differed between patients and controls, but time to peak level was four times longer in patients with an ileoanal reservoir (P < 0.05).

CONCLUSION

Colectomy seems to affect the enteroinsular axis, leading to hyperinsulinemia and an impaired glucose tolerance. Moreover, patients with an ileoanal reservoir have a slower GLP-I response after intake of glucose.

Metabolic consequences of total colectomy

Colectomy is performed for inflammatory bowel disease, familial polyposis syndrome and colorectal carcinoma. Surgical procedures are ileostomy with or without pouch, ileorectal anastomosis or ileal pouch-anal anastomosis. One of the major functions of the intact large intestine is to absorb water and electrolytes. After colectomy, as much as 400-1000 ml of nearly isotonic ileostomy fluid may be excreted, resulting in a chronic salt and water depletion. This is compensated for by an activation of the renin-angiotensin-aldosterone system. Reduced urine volumes may cause kidney stones. Both dehydration and renal sodium retention are probably less frequent in patients with ileal pouch-anal anastomosis. Absorption of nutrients in general is not impaired by colectomy. The large intestine salvages energy from malabsorbed organic matter through absorption of the short-chain fatty acids produced in bacterial fermentation. In ileostomy patients, fermentation is negligible, which leads to a significant loss of energy in the ileostomy fluid. Pouches are colonized by a bacterial flora similar to colonic bacteria. In these patients conservation of energy from malabsorbed substrate may be similar to healthy subjects. Resection of ileum and bacterial colonization may lead to malabsorption of vitamin B12 and bile acids. The latter may cause increased incidence of biliary cholesterol stones. Pouchitis is a frequent problem which may be caused by a deficiency of short-chain fatty acids and glutamine in the pouch contents. It is concluded that although the colon is not essential as a digestive organ in man, colectomy results in a number of metabolic changes. The ileal pouch-anal anastomosis may in part substitute for the functions of the large intestine.

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.

Clinical and physiological aspects of ileal pouch-anal anastomosis

Proctocolectomy with ileal pouch-anal anastomosis is the surgical treatment of choice for severe chronic ulcerative colitis and familial polyposis coli because the entire colonic mucosa is removed while anal function can be preserved and the necessity for permanent ileostomy is eliminated. Long-term functional results are generally gratifying, as defecation frequency and degree of incontinence are acceptable in most patients. Pouchitis, however, a non-specific inflammation of the ileal reservoir, is a major long-term complication occurring in a considerable number of patients. The etiology of pouchitis is unknown. Since pouchitis occurs more frequently or even exclusively in ulcerative colitis patients it is assumed that pouchitis is a novel manifestation of inflammatory bowel disease. However, bacterial overgrowth in the ileal pouch may also play a pathogenetic role. Chronic inflammation and villous atrophy of varying severity is found in virtually all pouches. Acute inflammatory changes and ulceration are associated with pouchitis.

Direct and quantitative vitamin B12 absorption measurement in patients with disorders in the distal part of the bowel. Comparison of stool spot test [SST] with whole body counting in patients with ileal pelvic reservoir, ileostomy or Crohn's disease

Direct and quantitative vitamin B12 absorption studies were performed in 25 patients with disorders in the distal small intestine using whole body counting as the gold standard. Simultaneously, vitamin B12 absorption was also determined by the more simple stool spot test (SST) which incorporates 51CrCl3 as a nonabsorbable marker. The SST provided a reliable direct and quantitative measure of vitamin B12 absorption in patients with previous ileal resections due to Crohn's disease (CD) (n = 7) as compared with whole body counting. In ulcerative colitis (UC) patients with either an ileal pelvic reservoir (n = 10) or a conventional ileostomy (n = 8), markedly shorter bowel transit times and absence of colon may have hindered sufficient mixture of the tracer and marker isotopes which could explain the false absorption values according to the SST in single patients. Therefore, an intact colon and a near-normal bowel transit time seem to be essential for performance of the SST. Whole body counting showed, as expected, that all CD patients except one had decreased vitamin B12 absorption (median 23%; range 3-39%) (normally > 35%). In UC patients with ileostomy, only one had a markedly decreased vitamin B12 absorption, two borderline normal values, while the rest had normal values (median 54%, range 15-76%). All UC patients with ileal pelvic reservoir had normal vitamin B12 absorption values (median 40.5%, range 36-87%). We conclude that vitamin B12 substitution therapy is probably required in patients with CD with ileal resection.(ABSTRACT TRUNCATED AT 250 WORDS)

Attempts to aid the adaptation of pelvic pouch before temporary ileostomy closure

Most patients experience a high stool frequency immediately following the closure of the temporary ileostomy after total colectomy and ileoanal pouch reconstruction. Adaptation occurs within the ensuing weeks to reach a plateau in about three months. Increasing volumes of liquid nutrients were injected, twice daily for two months, into the pelvic pouch through a mucous ileal fistula proximal to the pouch before closing the temporary ileostomy. With this method the number of evacuations per 24 hours was significantly reduced during the first few weeks following the reestablishment of intestinal continuity, compared with a control group (average, 8.5 vs. 18.2, respectively). Patients also had better continence and less urgency to defecate. We suggest this technique in patients undergoing pelvic ileal reconstruction with temporary ileostomy.