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Dive into the research topics where Stephen J. O'Keefe is active.

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Featured researches published by Stephen J. O'Keefe.


The American Journal of Gastroenterology | 2002

Hypocaloric jejunal feeding is better than total parenteral nutrition in acute pancreatitis: results of a randomized comparative study.

Souheil G. Abou-Assi; Kimberly Craig; Stephen J. O'Keefe

OBJECTIVES:The aims of this study were to define the indications for, and to evaluate the cost-effectiveness of, nutritional support in patients with acute pancreatitis.METHODS:All admissions during the 12-month period from January through December 2000, were entered into a common management protocol consisting of an initial 48-h fast with i.v. fluids and analgesics. After 48 h, those patients who were improving were restarted on oral feeding (group O). The remaining patients were randomized to receive naso-jejunal (group EN) or parenteral feeding (group TPN). The randomization study was continued until 50 patients had been accrued. Outcomes in the three groups were compared with respect to length of hospital stay, duration of feeding, complications, and hospital costs.RESULTS:A total of 156 admissions were evaluated in the first 12 months. Of these, 87% patients had mild disease, 10% moderate, and 3% severe; 62% were related to alcohol abuse, 18% gallstones, and 8% idiosyncratic drug reactions. Of the patients, 75% improved on 48 h bowel rest and i.v. fluids, and were discharged within 4 days. The remainder were randomized to jejunal elemental (n = 26) or parenteral (n = 27) feeding. Duration of feeding was shorter with EN (6.7 vs 10.8 days, p < 0.05) and nutrition costs were lower, representing an average cost saving of


The American Journal of Clinical Nutrition | 2013

Diet, microbiota, and microbial metabolites in colon cancer risk in rural Africans and African Americans

Junhai Ou; Franck Carbonero; Erwin G. Zoetendal; James P. DeLany; Wang M; Newton K; Gaskins Hr; Stephen J. O'Keefe

2362.00 per patient fed. EN was less effective in meeting estimated nutritional requirements (54 vs 88%, p < 0.0001), but metabolic (p < 0.003) and septic complications (p = 0.01) were lower. Subgroup analysis of patients with severe disease showed similar findings.CONCLUSION:Despite concerns that metabolic expenditure is increased and that food-stimulated pancreatic secretion might exacerbate the disease process, hypocaloric enteral feeding seems to be safer and less expensive than parenteral feeding and bowel rest in patients with acute pancreatitis.


Nature Communications | 2015

Fat, fibre and cancer risk in African Americans and rural Africans

Stephen J. O'Keefe; Jia V. Li; Leo Lahti; Junhai Ou; Franck Carbonero; Khaled Mohammed; Joram M. Posma; James Kinross; Elaine Wahl; Elizabeth H. Ruder; Kishore Vipperla; Vasudevan G. Naidoo; Lungile Mtshali; Sebastian Tims; Philippe G. Puylaert; James P. DeLany; Alyssa M. Krasinskas; Ann C. Benefiel; Hatem O. Kaseb; Keith Newton; Jeremy K. Nicholson; Willem M. de Vos; H. Rex Gaskins; Erwin G. Zoetendal

BACKGROUND Epidemiologic studies have suggested that most cases of sporadic colon cancer can be attributed to diet. The recognition that colonic microbiota have a major influence on colonic health suggests that they might mediate colonic carcinogenesis. OBJECTIVE To examine the hypothesis that the influence of diet on colon cancer risk is mediated by the microbiota through their metabolites, we measured differences in colonic microbes and their metabolites in African Americans with a high risk and in rural native Africans with a low risk of colon cancer. DESIGN Fresh fecal samples were collected from 12 healthy African Americans aged 50-65 y and from 12 age- and sex-matched native Africans. Microbiomes were analyzed with 16S ribosomal RNA gene pyrosequencing together with quantitative polymerase chain reaction of the major fermentative, butyrate-producing, and bile acid-deconjugating bacteria. Fecal short-chain fatty acids were measured by gas chromatography and bile acids by liquid chromatography-mass spectrometry. RESULTS Microbial composition was fundamentally different, with a predominance of Prevotella in native Africans (enterotype 2) and of Bacteroides in African Americans (enterotype 1). Total bacteria and major butyrate-producing groups were significantly more abundant in fecal samples from native Africans. Microbial genes encoding for secondary bile acid production were more abundant in African Americans, whereas those encoding for methanogenesis and hydrogen sulfide production were higher in native Africans. Fecal secondary bile acid concentrations were higher in African Americans, whereas short-chain fatty acids were higher in native Africans. CONCLUSION Our results support the hypothesis that colon cancer risk is influenced by the balance between microbial production of health-promoting metabolites such as butyrate and potentially carcinogenic metabolites such as secondary bile acids.


Gut | 2011

Randomised placebo-controlled trial of teduglutide in reducing parenteral nutrition and/or intravenous fluid requirements in patients with short bowel syndrome

Palle B. Jeppesen; Richard Gilroy; M. Pertkiewicz; Johane P. Allard; Bernard Messing; Stephen J. O'Keefe

Rates of colon cancer are much higher in African Americans (65:100,000) than in rural South Africans (<5:100,000). The higher rates are associated with higher animal protein and fat and lower fiber consumption, higher colonic secondary bile acids, lower colonic short chain fatty acid quantities and higher mucosal proliferative biomarkers of cancer risk in otherwise healthy middle aged volunteers. Here we investigate further the role of fat and fiber in this association. We performed two-week food exchanges in subjects from the same populations, where African Americans were fed a high-fiber, lowfat African-style diet, and rural Africans a high-fat low-fiber western-style diet under close supervision. In comparison to their usual diets, the food changes resulted in remarkable reciprocal changes in mucosal biomarkers of cancer risk and in aspects of the microbiota and metabolome known to affect cancer risk, best illustrated by increased saccharolytic fermentation and butyrogenesis and suppressed secondary bile acid synthesis in the African Americans.


Gastroenterology | 2012

Teduglutide Reduces Need for Parenteral Support Among Patients With Short Bowel Syndrome With Intestinal Failure

Palle B. Jeppesen; M. Pertkiewicz; Bernard Messing; Kishore Iyer; Douglas L. Seidner; Stephen J. O'Keefe; Alastair Forbes; Hartmut Heinze; Bo Joelsson

Background and aims Teduglutide, a GLP-2 analogue, may restore intestinal structural and functional integrity by promoting repair and growth of the mucosa and reducing gastric emptying and secretion, thereby increasing fluid and nutrient absorption in patients with short bowel syndrome (SBS). This 24-week placebo-controlled study evaluated the ability of teduglutide to reduce parenteral support in patients with SBS with intestinal failure. Methods In 83 patients randomised to receive subcutaneous teduglutide 0.10 mg/kg/day (n=32), 0.05 mg/kg/day (n=35) or placebo (n=16) once daily, parenteral fluids were reduced at 4-week intervals if intestinal fluid absorption (48 h urine volumes) increased ≥10%. Responders were subjects who demonstrated reductions of ≥20% in parenteral volumes from baseline at weeks 20 and 24. The primary efficacy end point, a graded response score (GRS), took into account higher levels and earlier onset of response, leading to longer duration of response. The intensity of the response was defined as a reduction from baseline in parenteral volume (from 20% to 100%), and the duration of the response was considered the response at weeks 16, 20 and 24. The results were tested according to a step-down procedure starting with the 0.10 mg/kg/day dose. Results Using the GRS criteria, teduglutide in a dose of 0.10 mg/kg/day did not have a statistically significant effect compared with placebo (8/32 vs 1/16, p=0.16), while teduglutide in a dose of 0.05 mg/kg/day had a significant effect (16/35, p=0.007). Since parenteral volume reductions were equal (353±475 and 354±334 ml/day), the trend towards higher baseline parenteral volume (1816±1008 vs 1374±639 ml/day, p=0.11) in the 0.10 mg/kg/day group compared with the 0.05 mg/kg/day group may have accounted for this discrepancy. Three teduglutide-treated patients were completely weaned off parenteral support. Serious adverse events were distributed similarly between active treatment groups and placebo. Villus height, plasma citrulline concentration and lean body mass were significantly increased with teduglutide compared with placebo. Conclusions Teduglutide was safe, well tolerated, intestinotrophic and suggested pro-absorptive effects facilitating reductions in parenteral support in patients with SBS with intestinal failure. ClinicalTrials.gov number NCT00172185.


Current Opinion in Gastroenterology | 2008

Nutrition and colonic health: the critical role of the microbiota.

Stephen J. O'Keefe

BACKGROUND & AIMS Teduglutide, a glucagon-like peptide 2 analogue, might restore intestinal structural and functional integrity by promoting growth of the mucosa and reducing gastric emptying and secretion. These factors could increase fluid and nutrient absorption in patients with short bowel syndrome with intestinal failure (SBS-IF). We performed a prospective study to determine whether teduglutide reduces parenteral support in patients with SBS-IF. METHODS We performed a 24-week study of patients with SBS-IF who were given subcutaneous teduglutide (0.05 mg/kg/d; n = 43) or placebo (n = 43) once daily. Parenteral support was reduced if 48-hour urine volumes exceeded baseline values by ≥ 10%. The primary efficacy end point was number of responders (patients with >20% reduction in parenteral support volume from baseline at weeks 20 and 24). RESULTS There were significantly more responders in the teduglutide group (27/43 [63%]) than the placebo group (13/43 [30%]; P = .002). At week 24, the mean reduction in parenteral support volume in the teduglutide group was 4.4 ± 3.8 L/wk (baseline 12.9 ± 7.8 L/wk) compared with 2.3 ± 2.7 L/wk (baseline 13.2 ± 7.4 L/wk) in the placebo group (P < .001). The percentage of patients with a 1-day or more reduction in the weekly need for parenteral support was greater in the teduglutide group (21/39 [54%]) than in the placebo group (9/39 [23%]; P = .005). Teduglutide increased plasma concentrations of citrulline, a biomarker of mucosal mass. The distribution of treatment-emergent adverse events that led to study discontinuation was similar between patients given teduglutide (n = 2) and placebo (n = 3). CONCLUSIONS Twenty-four weeks of teduglutide treatment was generally well tolerated in patients with SBS-IF. Treatment with teduglutide reduced volumes and numbers of days of parenteral support for patients with SBS-IF; ClinicalTrials.gov Number, NCT00798967.


The Lancet | 1980

Malnutrition and immuno-incompetence in patients with liver disease.

Stephen J. O'Keefe; T.E. Carraher; A.R. E Zayadi; M. Davis; Roger Williams

Purpose of review To highlight mechanisms whereby diet affects colonic function and disease patterns. Recent findings Topical nutrients are preferentially used by the gut mucosa to maintain structure and function. With the colon, topical nutrients are generated by the colonic microbiota to maintain mucosal health. Most importantly, short chain fatty acids control proliferation and differentiation, thereby reducing colon cancer risk. In patients with massive loss of small intestine, short chain fatty acid production supports survival by releasing up to 1000 kcal energy/day. Human studies show that the microbiota synthesizes a large pool of utilizable folate which may support survival in impoverished populations. Unfortunately, the microbiota may also elaborate toxic products from food residues such as genotoxic hydrogen sulfide by sulfur-reducing bacteria in response to a high-meat diet. The employment of culture-free techniques based on 16S regions of DNA has revealed that our colons harbor over 800 bacterial species and 7000 different strains. Evidence suggests that the diet directly influences the diversity of the microbiota, providing the link between diet, colonic disease, and colon cancer. The microbiota, however, can determine the efficiency of food absorption and risk of obesity. Summary Our investigations have focused on a small number of bacterial species: characterization of microbiota and its metabolism can be expected to provide the key to colonic health and disease.


Journal of Nutrition | 2009

Products of the Colonic Microbiota Mediate the Effects of Diet on Colon Cancer Risk

Stephen J. O'Keefe; Junhai Ou; Susanne Aufreiter; Deborah L O'Connor; Sumit Sharma; Jorge L. Sepulveda; Katsumi Shibata; Thomas P. Mawhinney

The incidence of malnutrition and immunocompetence in 156 patients admitted to hospital with liver disease was investigated. Expected weight/height was within the normal range for all groups except those with carcinoma. Triceps skinfold thickness (TSF) was reduced in 49% of patients with cirrhosis and 55% with alcoholic disease. Hypoalbuminaemia was common in all groups, with 66% of those with chronic disease having concentrations below 35 g/dl. Lymphopenia was equally common, 65% of patients with fulminant hepatic failure (FHF) having counts below 1000 cells/mm3. Incidence of total anergy to standard skin tests was 54% overall: 93% in FHF and 60% in cirrhosis and alcoholic disease. There were significant links between reduced TSF and hypoalbuminaemia, lymphopenia and anergy, hypoalbuminaemia and anergy, and anergy and mortality. Reduced TSF was only associated with anergy in patients with chronic disease. The high incidence of immuno-incompetence may underlie the frequent occurrence of spontaneous infections in patients with liver disease, and the association between anergy and malnutrition in patients with chronic liver disease suggests that the anergy may be partly reversible by dietary measures.


Journal of Nutrition | 2007

Why Do African Americans Get More Colon Cancer than Native Africans

Stephen J. O'Keefe; Daniel C. Chung; Nevine Mahmoud; Antonia R. Sepulveda; Mashudu Manafe; Judith E Arch; Haytham Adada; Tian van der Merwe

It is estimated that most colon cancers can be attributed to dietary causes. We have hypothesized that diet influences the health of the colonic mucosa through interaction with the microbiota and that it is the milieu interior that regulates mucosal proliferation and therefore cancer risk. To validate this further, we compared colonic contents from healthy 50- to 65-y-old people from populations with high and low risk, specifically low risk Native Africans (cancer incidence <1:100,000; n = 17), high risk African Americans (risk 65:100,000; n = 17), and Caucasian Americans (risk 50:100,000; n = 18). Americans typically consume a high-animal protein and -fat diet, whereas Africans consume a staple diet of maize meal, rich in resistant starch and low in animal products. Following overnight fasting, rapid colonic evacuation was performed with 2 L polyethylene glycol. Total colonic evacuants were analyzed for SCFA, vitamins, nitrogen, and minerals. Total SCFA and butyrate were significantly higher in Native Africans than in both American groups. Colonic folate and biotin content, measured by Lactobacillus rhamnoses and Lactobacillus plantarum ATCC 8014 bioassay, respectively, exceeded normal daily dietary intakes. Compared with Africans, calcium and iron contents were significantly higher in Caucasian Americans and zinc content was significantly higher in African Americans, but nitrogen content did not differ among the 3 groups. In conclusion, the results support our hypothesis that the microbiota mediates the effect diet has on colon cancer risk by their generation of butyrate, folate, and biotin, molecules known to play a key role in the regulation of epithelial proliferation.


Nature Reviews Gastroenterology & Hepatology | 2016

Diet, microorganisms and their metabolites, and colon cancer

Stephen J. O'Keefe

The incidence of colorectal cancer (CRC) is dramatically higher in African Americans (AAs) than in Native Africans (NAs) (60:100,000 vs. <1:100,000) and slightly higher than in Caucasian Americans (CAs). To explore whether the difference could be explained by interactions between diet and colonic bacterial flora, we compared randomly selected samples of healthy 50- to 65-y-old AAs (n = 17) with NAs (n = 18) and CAs (n = 17). Diet was measured by 3-d recall, and colonic metabolism by breath hydrogen and methane responses to oral lactulose. Fecal samples were cultured for 7-alpha dehydroxylating bacteria and Lactobacillus plantarum. Colonoscopic mucosal biopsies were taken to measure proliferation rates. In comparison with NAs, AAs consumed more (P < 0.01) protein (94 +/- 9.3 vs. 58 +/- 4.1 g/d) and fat (114 +/- 11.2 vs. 38 +/- 3.0 g/d), meat, saturated fat, and cholesterol. However, they also consumed more (P < 0.05) calcium, vitamin A, and vitamin C, and fiber intake was the same. Breath hydrogen was higher (P < 0.0001) and methane lower in AAs, and fecal colony counts of 7-alpha dehydroxylating bacteria were higher and of Lactobacilli were lower. Colonic crypt cell proliferation rates were dramatically higher in AAs (21.8 +/- 1.1% vs. 3.2 +/- 0.8% labeling, P < 0.0001). In conclusion, the higher CRC risk and mucosal proliferation rates in AAs than in NAs were associated with higher dietary intakes of animal products and higher colonic populations of potentially toxic hydrogen and secondary bile-salt-producing bacteria. This supports our hypothesis that CRC risk is determined by interactions between the external (dietary) and internal (bacterial) environments.

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Junhai Ou

University of Pittsburgh

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Keith Newton

University of Cape Town

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Erwin G. Zoetendal

Wageningen University and Research Centre

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Palle B. Jeppesen

Copenhagen University Hospital

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