Ileal pouch-anal anastomosis, conventional ileostomy and ileorectal anastomosis modify cholesterol metabolism

Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient

IMPORTANCE

The Gram-negative bacterium Bacteroides fragilis is a common member of the human gut microbiota that colonizes multiple host niches and can influence human physiology through a variety of mechanisms. Identification of genes that enable B. fragilis to grow across a range of host environments has been impeded in part by the relatively limited genetic tractability of this species. We have developed a high-throughput genetic resource for a B. fragilis strain isolated from a UC pouchitis patient. Bile acids limit microbial growth and are altered in abundance in UC pouches, where B. fragilis often blooms. Using this resource, we uncovered pathways and processes that impact B. fragilis fitness in bile and that may contribute to population expansions during bouts of gut inflammation.

Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient

Bacteroides fragilis comprises 1-5% of the gut microbiota in healthy humans but can expand to >50% of the population in ulcerative colitis (UC) patients experiencing inflammation. The mechanisms underlying such microbial blooms are poorly understood, but the gut of UC patients has physicochemical features that differ from healthy patients and likely impact microbial physiology. For example, levels of the secondary bile acid deoxycholate (DC) are highly reduced in the ileoanal J-pouch of UC colectomy patients. We isolated a B. fragilis strain from a UC patient with pouch inflammation (i.e. pouchitis) and developed it as a genetic model system to identify genes and pathways that are regulated by DC and that impact B. fragilis fitness in DC and crude bile. Treatment of B. fragilis with a physiologically relevant concentration of DC reduced cell growth and remodeled transcription of one-quarter of the genome. DC strongly induced expression of chaperones and select transcriptional regulators and efflux systems and downregulated protein synthesis genes. Using a barcoded collection of ≈50,000 unique insertional mutants, we further defined B. fragilis genes that contribute to fitness in media containing DC or crude bile. Genes impacting cell envelope functions including cardiolipin synthesis, cell surface glycosylation, and systems implicated in sodium-dependent bioenergetics were major bile acid fitness factors. As expected, there was limited overlap between transcriptionally regulated genes and genes that impacted fitness in bile when disrupted. Our study provides a genome-scale view of a B. fragilis bile response and genetic determinants of its fitness in DC and crude bile.

Risk factors for developing high-output ileostomy in CRC patients: a retrospective study

BACKGROUND

Anastomotic leakage is one of the most serious postoperative complications of rectal cancer. Prophylactic ileostomy has been widely used to reduce the risk and severity of complications of anastomotic leakage. However, prophylactic ileostomy itself has some complications, and ileostomy high output syndrome (HOS) is one of them. This study was performed to explore the risk factors of HOS in ileostomy.

METHODS

A total of 114 patients with HOS were screened out from 494 eligible ileostomy patients in the last 5 years. The relationship between HOS and the clinicopathological data was analyzed using the Chi-square test and Fisher's exact probability. Multivariate analysis was performed by logistic regression.

RESULTS

The incidence of HOS was 23.07% in this study. Dehydration was the most common symptom of HOS (37.7%). There was no clear correlation between HOS occurrence with sex, age, gross typing, histological grade, tumor location, lymph node metastasis, and TNM stage (p > 0.05). The incidence of HOS was 14/18 in inflammatory bowel disease patients, 18/28 in diabetes mellitus patients, and 23/72 in neoadjuvant chemoradiotherapy patients, 13/17 in total colectomy and abdominal infection patients. Multivariate analysis showed that they are risk factors for HOS (p < 0.05).

CONCLUSION

HOS occurred occasionally but rarely studied and lacks attention. Inflammatory bowel disease, diabetes mellitus, neoadjuvant radiotherapy chemotherapy, total colectomy and abdominal infection are the risk factors for HOS.

Non-Cholesterol Sterol Concentrations as Biomarkers for Cholesterol Absorption and Synthesis in Different Metabolic Disorders: A Systematic Review

Non-cholesterol sterols are validated biomarkers for intestinal cholesterol absorption and endogenous cholesterol synthesis. However, their use in metabolic disturbances has not been systematically explored. Therefore, we conducted a systematic review to provide an overview of non-cholesterol sterols as markers for cholesterol metabolism in different metabolic disorders. Potentially relevant studies were retrieved by a systematic search of three databases in July 2018 and ninety-four human studies were included. Cholesterol-standardized levels of campesterol, sitosterol and cholestanol were collected to reflect cholesterol absorption and those of lathosterol and desmosterol to reflect cholesterol synthesis. Their use as biomarkers was examined in the following metabolic disorders: overweight/obesity (n = 16), diabetes mellitus (n = 15), metabolic syndrome (n = 5), hyperlipidemia (n = 11), cardiovascular disease (n = 17), and diseases related to intestine (n = 16), liver (n = 22) or kidney (n = 2). In general, markers for cholesterol absorption and synthesis displayed reciprocal patterns, showing that cholesterol metabolism is tightly regulated by the interplay of intestinal absorption and endogenous synthesis. Distinctive patterns for cholesterol absorption or cholesterol synthesis could be identified, suggesting that metabolic disorders can be classified as 'cholesterol absorbers or cholesterol synthesizers'. Future studies should be performed to confirm or refute these findings and to examine whether this information can be used for targeted (dietary) interventions.

Factors predictive of high-output ileostomy: a retrospective single-center comparative study

Purpose

High-output syndrome (HOS) is a complication of ileostomy, which can affect quality of life significantly; however, its exact cause remains unknown. The aim of this study was to establish the frequency, as well as the preoperative and intraoperative factors predictive of HOS.

Methods

The subjects of this study were 164 consecutive patients who underwent colorectal cancer surgery with ileostomy construction at our institute between January, 2011 and August, 2018. Thirteen patients with postoperative complications reported as causes of HOS, including intraperitoneal abscess, paralytic ileus, and outlet obstruction, were excluded. We used a logistic regression analysis to identify the factors predictive of HOS.

Results

HOS developed in 36 of the 151 patients (23.8%). There were significantly more diabetic patients in the HOS group (P = 0.03), but other patient factors such as age, gender, body mass index, and use of daily laxatives were not significantly different between the groups. The HOS group had significantly more cases of total proctocolectomy (P = 0.04), but other surgical factors such as operative time, and blood transfusion were not significantly different between the two groups.

Conclusions

These results indicate that diabetes and total proctocolectomy are preoperative predictors of HOS, allowing for the possibility of early intervention via post-surgical treatment.

Combined laparoscopic cholecystectomy with ileostomy reversal: A method of delayed definitive management of postoperative gallstone pancreatitis

Traditional management of gallstone pancreatitis (GP) has been to perform cholecystectomy during the same hospital admission after resolution. However, when GP develops in the immediate postoperative period from a major colorectal operation, cholecystectomy may be fraught with difficulty due to the inflammatory response that occurs. Thus, delaying cholecystectomy until the inflammatory response subsides may be worthwhile, and it maximizes the chances of completing the cholecystectomy laparoscopically. We have described our management of 2 patients with GP occurring after colorectal operations, which required proximal diverting ileostomy. In both cases, we deferred management of GP with either endoscopic retrograde cholangiopancreatography (ERCP) or medical conservative measures during the acute attack and performed laparoscopic cholecystectomy during ostomy reversal surgery utilizing the existing ostomy takedown site for port placement. Both patients tolerated this management well.

Relationship between Fecal Content of Fatty Acids and Cyclooxygenase mRNA Expression and Fatty Acid Composition in Duodenal Biopsies, Serum Lipoproteins, and Dietary Fat in Colectomized Familial Adenomatous Polyposis Patients

A few familial adenomatous polyposis studies have focused upon faecal sterols and bile acids but none has analysed the fecal content of fatty acids. We report here findings of an observational study on 29 colectomized familial adenomatous polyposis patients that describe the fecal content of fatty acids, and relate this to the proportions of fatty acids and levels of cyclooxygenase mRNA expression in duodenal biopsies, levels of serum lipoproteins, and diet. In the ileostomy group separately (n = 12), the fecal content of arachidonic acid was correlated negatively to the proportions of eicosapentaenoic acid and docosahexaenoic acid in duodenal biopsies. Total serum-cholesterol was negatively correlated to the fecal content of saturates and monounsaturates. The fecal palmitoleic acid/palmitic acid ratio was positively correlated to the levels of cyclooxygease-2 expression in duodenal biopsies.In the ileal-pouch-anal anastomosis group separately (n = 17), significant correlations were found between the fecal contents of oleic acid, linoleic acid, and alpha-linolenic acid, and the proportions of myristic acid, oleic acid and eicosaenoic acid in duodenal biopsies. Dietary monounsaturates were positively correlated to different fecal fatty acids. Future studies should focus on molecular mechanisms relevant to fatty acid metabolism, inflammation, and angiogenesis, in addition to nutrition.

Cholesterol metabolism in pediatric short bowel syndrome after weaning off parenteral nutrition

BACKGROUND

Small intestine essentially regulates cholesterol homeostasis.

AIMS

To evaluate cholesterol metabolism in short bowel syndrome (SBS).

METHODS

Cholesterol precursors (e.g., cholestenol, desmosterol and lathosterol) and plant sterols (campesterol and sitosterol), respective markers of cholesterol synthesis and absorption, were determined in SBS patients (n=12) an average of 31 months after weaning off parenteral nutrition and in age-matched controls (n=80).

RESULTS

Among patients, serum cholesterol precursor sterol to cholesterol ratios were 2-10 times higher (P<0.0001 for each). Those without any remaining ileum had 1.2-2.8 times higher precursor sterol to cholesterol ratios than those with an ileal remnant (P<0.05 for each). Serum cholesterol concentration, campesterol/cholesterol and campesterol/sitosterol were 34-39% lower (P<0.05 for each) in relation to controls. Bile acid absorption was markedly impaired (2.4 (0.2-3.2)%). Plant sterol ratios reflected the absolute length of remaining jejunum (r=0.625-0.663), and precursor sterol ratios inversely that of ileum (r=-0.589 to 0.750, P<0.05 for all).

CONCLUSION

After weaning off parenteral nutrition, patients with pediatric onset SBS continue to have marked intestinal malabsorption of bile acids and moderate cholesterol malabsorption resulting in decreased serum cholesterol despite a marked compensatory increase in cholesterol synthesis.

Serum nutrients and habitual dietary intake in colectomized FAP patients in Norway

BACKGROUND

Patients with familial adenomatous polyposis (FAP) are colectomized in young age in order to avoid development of colorectal cancer. Because colectomy radically changes gastrointestinal physiology, and food avoidance may be present, colectomized patients may be at risk for nutritional deficiency.

AIM OF THE STUDY

to evaluate: (1) serum biochemical levels as compared to reference; (2) dietary intake as compared to the recommendations.

METHODS

Blood samples, interviews and food frequency questionnaire were collected from 38 colectomized FAP patients with duodenal adenomas (mean age 40 years, range: 24-70). They were recruited from the Norwegian database on FAP.

RESULTS

Serum albumin was significantly higher (P < or = 0.0001), and Mg (P = 0.02), ferritin (P < or = 0.001), and cholesterol (P = 0.03) significantly lower, than reference levels. Compared to recommendations, a low intake was seen for folate and fiber (<50%), iron, thiamin, riboflavin (< 25%), and omega-3 fatty acids (8%). Sugar intake exceeded the recommendation, mainly due to a high intake of soft drinks. Food avoidance was reported by 53%.

CONCLUSIONS

We would suggest that the nutrient intake among FAP patients should at least meet the recommendations for healthy subjects. Their risk of metachronous cancers should also cause special attention to dietary factors that may prevent nutritional deficiency and carcinogenesis.

Free radical activity and lipid soluble anti-oxidant vitamin status in patients with long-term ileal pouch-anal anastomosis

OBJECTIVE

Ileal pouch-anal anastomosis (IPAA) is the operation of choice for patients with ulcerative colitis. Free radical activity and the status of lipid soluble antioxidant vitamins have not been previously assessed in patients with IPAA. The aim of the present study was to measure the plasma concentrations of lipophyllic antioxidants and free radical activity in IPAA patients and compare them with normal subjects.

METHOD

Forty-eight IPAA patients and 50 healthy controls were studied. A dietary assessment of vitamin E (alpha-tocopherol) and carotene was undertaken and plasma antioxidant status was assessed. Plasma malondialdehyde (MDA) was measured to assess the extent of free radical damage. In IPAA patients, association between the degree of inflammation in the pouch mucosa and the plasma concentration of lipophyllic antioxidants and extent of free radical activity was investigated.

RESULTS

The dietary intake of carotene was similar in both groups. Intake of vitamin E was significantly lower in patients than controls (P = 0.01). In the IPAA group plasma concentrations of alpha-carotene, beta-carotene and lycopene were significantly lower (P < 0.001) and alpha-tocopherol:cholesterol ratio significantly higher (P < 0.001). Free radical damage was significantly greater in patients than controls (P < 0.01). There were no significant correlations between the degree of inflammation in the pouch and plasma concentrations of MDA, carotenoids, alpha-tocopherol:cholesterol ratio or intake of vitamins.

CONCLUSION

Compared with normal subjects, patients with IPAA have significantly lower plasma concentrations of lipophyllic antioxidants alpha-carotene, beta-carotene and lycopene and higher free radical activity suggesting increased oxidative stress. These differences do not appear to be related to diet and do not correlate with histological severity of pouch inflammation.

Effects of plant stanol esters supplied in a fat free milieu by pastilles on cholesterol metabolism in colectomized human subjects

BACKGROUND AND AIM

Nutritional products containing fat-soluble phytosterol esters for serum cholesterol lowering have traditionally been oil-based. Their cholesterol-lowering efficacy when provided by low-fat vehicles with a diet of normal fat content is questionable. The aims of the present study were to find out whether 1-week consumption of plant stanol esters in pastilles alters absorption percentage of labeled esterified and free cholesterol and fecal elimination of sterols, including phytosterols (n = 9), and to define the impact of dietary fat on intestinal sterol ester hydrolysis (n = 8) in colectomized human subjects.

METHODS AND RESULTS

Levels of lipoprotein cholesterol and triacylglycerols, non-cholesterol sterols and squalene in serum, neutral sterols, non-cholesterol sterols, fat and bile acids in feces, cholesterol absorption efficiency and cholesterol synthesis were analyzed at baseline and at the end of the treatment period. Analyses of esterified and free cholesterol and phytosterols were performed during diets with normal and low-fat content. Serum levels of total and low-density lipoprotein cholesterol decreased by 9% and 14%, respectively (P < 0.01 for both), and absorption of 3H-esterified and 14C-free cholesterol decreased in proportion to baseline values (r = -0.58, P < 0.05) by over 40% (P < 0.01) in colectomized patients with stanol ester pastilles. Fecal elimination of cholesterol was increased by about 35% and almost 60% of campestanol and sitostanol esters were hydrolyzed during their transit in gastrointestinal tract when consumed with a normal fat diet (mean daily fat 93 +/- 13g ) for 1 week. The hydrolysis of plant stanol esters was more pronounced with a normal than with a low-fat diet (70% versus 40%, P < 0.001).

CONCLUSIONS

We conclude that plant stanol esters provided in fat free milieu exert favourable effects on serum lipid profile by decreasing absorption of cholesterol in colectomized human subjects, even though the intestinal hydrolysis of plant stanol esters is weaker on low than normal fat diet.

Cholestanol: A serum marker to guide LDL cholesterol-lowering therapy

Statins have been the mainstay of lipid-lowering therapy since their introduction. However, as lower LDL cholesterol targets are sought, adjunct therapies are becoming increasingly important. Few patients reach new targets with statin monotherapy. We propose that the cholestanol:cholesterol ratio can be used to guide lipid-lowering therapy and result in greater numbers of patients reaching target LDL cholesterol. By determining whether a patient is mainly a synthesizer or absorber of cholesterol, customized regimens can be used and are expected to improve patient outcomes and minimize costs of treatment.