Imperial College London

DrNicholasPenney

Faculty of MedicineDepartment of Surgery & Cancer

Honorary Clinical Research Fellow
 
 
 
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n.penney

 
 
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Queen Elizabeth the Queen Mother Wing (QEQM)St Mary's Campus

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Summary

 

Publications

Publication Type
Year
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38 results found

Penney N, Yeung K, Garcia Perez I, Posma J, Kopytek A, Garratt B, Ashrafian H, Frost G, Marchesi J, Purkayastha S, Hoyles L, Darzi A, Holmes Eet al., 2022, Multi-omic phenotyping reveals host-microbe responses to bariatric surgery, glycaemic control and obesity, communications medicine, Vol: 2, Pages: 1-18, ISSN: 2730-664X

Background: Resolution of type 2 diabetes (T2D) is common following bariatric surgery, particularly Roux-en-Y gastric bypass. However, the underlying mechanisms have not been fully elucidated.Methods: To address this we compare the integrated serum, urine and faecal metabolic profiles of participants with obesity +/- T2D (n=80, T2D=42) with participants who underwent Roux-en-Y gastric bypass or sleeve gastrectomy (pre and 3-months post-surgery; n=27), taking diet into account. We co-model these data with shotgun metagenomic profiles of the gut microbiota to provide a comprehensive atlas of host-gut microbe responses to bariatric surgery, weight-loss and glycaemic control at the systems level.Results: Here we show that bariatric surgery reverses several disrupted pathways characteristic of T2D. The differential metabolite set representative of bariatric surgery overlaps with both diabetes (19.3% commonality) and body mass index (18.6% commonality). However, the percentage overlap between diabetes and body mass index is minimal (4.0% commonality), consistent with weight-independent mechanisms of T2D resolution. The gut microbiota is more strongly correlated to body mass index than T2D, although we identify some pathways such as amino acid metabolism that correlate with changes to the gut microbiota and which influence glycaemic control.Conclusion: We identify multi-omic signatures associated with responses to surgery, body mass index, and glycaemic control. Improved understanding of gut microbiota - host co-metabolism may lead to novel therapies for weight-loss or diabetes. However, further experiments are required to provide mechanistic insight into the role of the gut microbiota in host metabolism and establish proof of causality.

Journal article

Yeung K, Whiley L, Penney N, Ashrafian H, Purkayastha S, Darzi A, Holmes Eet al., 2022, SERUM LIPIDOMIC SIGNATURES OF TYPE 2 DIABETES AND EARLY SURGICAL DIABETES RESOLUTION Basic science and research in bariatric surgery, Publisher: SPRINGER, Pages: 485-485, ISSN: 0960-8923

Conference paper

Yeung K, Penney N, Whiley L, Ashrafian H, Purkayastha S, Holmes E, Darzi Aet al., 2022, SERUM AMINO ACID RATIOS AS PROXIES TO MECHANISMS CONTRIBUTING TO IMPROVED METABOLIC HEALTH AFTER BARIATRIC SURGERY Basic science and research in bariatric surgery, 25th IFSO World Congress, Publisher: SPRINGER, Pages: 483-483, ISSN: 0960-8923

Conference paper

Yeung KTD, Penney N, Whiley L, Ashrafian H, Lewis M, Purkayastha S, Darzi A, Holmes Eet al., 2022, The impact of bariatric surgery on serum tryptophan-kynurenine pathway metabolites, Scientific Reports, Vol: 12, ISSN: 2045-2322

Objectives: This study aims to explore the immediate effects of bariatric surgery on serum tryptophan – kynurenine pathway metabolites in individuals with type 2 diabetes and BMI >30. With the goal of providing insight into the link between tryptophan pathway metabolites, type 2 diabetes, and chronic obesity-induced inflammation. Methods: This longitudinal study included 20 participants. Half were diagnosed with type 2 diabetes. 11 and 9 underwent RYGB and SG respectively. Blood samples were obtained at pre-operative and three months post-operative timepoints. Tryptophan and downstream metabolites of the kynurenine pathway were quantified with an ultrahigh-performance liquid chromatography tandem mass spectrometry with electrospray ionisation method. Results: At 3 months post-operation, RYGB led to significant reductions in tryptophan, kynurenic acid and xanthurenic acid levels when compared to baseline. Significant reductions of the same metabolites after surgery were also observed in individuals with T2D irrespective of surgical procedure. These metabolites were significantly correlated with serum HbA1c levels and BMI. Conclusions: Bariatric surgery, in particular RYGB reduces serum levels of tryptophan and its downstream kynurenine metabolites. These metabolites are associated with T2D and thought to be potentially mechanistic in the systemic processes of obesity induced inflammation leading to insulin resistance. Its reduction after surgery is associated with an improvement in glycaemic control (HbA1c).

Journal article

Penney N, Yeung D, Garcia-Perez I, POSMA J, Kopytek A, Garratt B, Ashrafian H, Frost G, Marchesi J, Purkayastha S, Hoyles L, Darzi A, Holmes Eet al., 2021, Longitudinal Multi-omic Phenotyping Reveals Host-microbe Responses to Bariatric Surgery, Glycaemic Control and Obesity

<jats:title>Abstract</jats:title> <jats:p>Resolution of type-2 diabetes (T2D) is common following bariatric surgery, particularly Roux-en-Y gastric bypass (RYGB). However, the underlying mechanisms have not been fully elucidated. To address this we compared the integrated serum, urine and faecal metabolic profiles of obese participants with and without T2D (n=81, T2D=42) with participants who underwent RYGB or sleeve gastrectomy (pre and 3-months post-surgery; n=27), taking diet into account. We co-modelled these data with shotgun metagenomic profiles of the gut microbiota to provide a comprehensive atlas of host-gut microbe responses to bariatric surgery, weight-loss and glycaemic control at the systems level. Bariatric surgery reversed a number of disrupted pathways characteristic of T2D. The differential metabolite set representative of bariatric surgery overlapped with both diabetes (19.3% commonality) and BMI (18.6% commonality). However, the percentage overlap between diabetes and BMI was minimal (4.0% commonality), consistent with weight-independent mechanisms of T2D resolution. The gut microbiota was more strongly correlated to BMI than T2D, although we identified some pathways such as amino acid metabolism that correlated with changes to the gut microbiota and which influence glycaemic control. Improved understanding of GM-host co-metabolism may lead to novel therapies for weight-loss or diabetes.</jats:p>

Journal article

Yeung KTD, Penney N, Harling L, Darzi A, Ashrafian Het al., 2021, Response to comment on "'Does sleeve gastrectomy expose the distal esophagus to severe reflux?' So what? Keep the big picture in perspective", Annals of Surgery, Vol: 274, Pages: e793-e794, ISSN: 0003-4932

Journal article

Currie AC, Penney N, Kamocka A, Singh P, Abbassi-Ghadi N, Preston SRet al., 2021, Systematic review on reporting of components and outcomes in randomized clinical trials of paraoesophageal hernia mesh repair, British Journal of Surgery, Vol: 108, Pages: 256-264, ISSN: 0007-1323

BackgroundSurgical interventions, such as paraoesophageal hernia (POH) repair, are complex with multiple components that require consideration in the reporting of clinical trials. Many aspects of POH repair, including mesh hiatal reinforcement and fundoplication type, are contentious. This review summarizes the reporting of components and outcomes in RCTs of POH repair.MethodsSystematic searches identified RCTs of POH repair published from 1995 to 2020. The patient selection criteria for RCT involvement were noted. The components of the surgical interventions in these RCTs were recorded using the CONSORT guidelines for non-pharmacological treatments, Template for Intervention Description and Replication (TIDieR) and Blencowe frameworks. The outcomes were summarized and definitions sought for critical variables, including recurrence.ResultsOf 1918 abstracts and 21 screened full-text articles, 12 full papers reporting on six RCTs were included in the review. The patient selection criteria and definitions of POH between trials varied considerably. Although some description of trial interventions was provided in all RCTs, this varied in depth and detail. Four RCTs described efforts to standardize the trial intervention. Outcomes were reported inconsistently, were rarely defined fully, and overall trial conclusions varied during follow-up.ConclusionThis lack of detail on the surgical intervention in POH repair RCTs prevents full understanding of what exact procedure was evaluated and how it should be delivered in clinical practice to gain the desired treatment effects. Improved focus on the definitions, descriptions and reporting of surgical interventions in POH repair is required for better future RCTs.

Journal article

Liu Z, Coales I, Penney N, McDonald J, Phetcharaburanin J, Seyfried F, Li Jet al., 2020, A subset of Roux-en-Y Gastric Bypass bacterial consortium colonizes the gut of non-surgical rats without inducing host-microbial metabolic changes, mSystems, Vol: 5, ISSN: 2379-5077

Roux-en-Y gastric bypass (RYGB) is an effective weight loss surgery, resulting in a characteristic increase of fecal Gammaproteobacteria. The contribution of this compositional change to metabolic benefits of RYGB is currently debatable. Therefore, this study employed 16S rRNA gene sequencing and metabolic profiling to monitor the dynamic colonization of the RYGB microbial consortium and their metabolic impact on the host. Eleven Wistar rats received vancomycin and enrofloxacin, followed by fecal microbiota transplantation (FMT) of cecal slurry obtained from either RYGB- or sham-operated rats. Urine and feces from the microbiota recipients (RYGB microbiota recipients [RYGBr], n = 6; sham microbiota recipients [SHAMr], n = 5) were collected pre- and post-antibiotics and 1, 3, 6, 9, and 16 days post-FMT. No significant differences in body weight and food intake were observed between RYGBr and SHAMr. While neither group reached the community richness of that of their donors, by day 6, both groups reached the richness and diversity of that prior to antibiotic treatment. However, the typical signature of RYGB microbiome—increased Enterobacteriaceae—was not replicated in these recipients after two consecutive FMT, suggesting that the environmental changes induced by the anatomical rearrangements of RYGB could be key for sustaining such a consortium. The transplanted bacteria did not induce the same metabolic signature of urine and feces as those previously reported in RYGB-operated rats. Future work is required to explore environmental factors that shape the RYGB microbiota in order to further investigate the metabolic functions of the RYGB microbiota, thereby teasing out the mechanisms of the RYGB surgery.IMPORTANCE Roux-en-Y gastric bypass (RYGB) surgery results in a long-term gut bacterial shift toward Gammaproteobacteria in both patients and rodents. The contribution of this compositional shift, or the RYGB bacterial cons

Journal article

Penney N, Barton W, Posma J, Darzi A, Frost G, Cotter P, Holmes E, Shanahan F, O Sullivan O, Garcia Perez Iet al., 2020, Investigating the role of diet and exercise in gut microbe-hostcometabolism, mSystems, Vol: 5, Pages: 1-16, ISSN: 2379-5077

We investigated the individual and combined effects of diet and physical exercise on metabolism and the gut microbiome to establish how these lifestyle factors influence host-microbiome cometabolism. Urinary and fecal samples were collected from athletes and less active controls. Individuals were further classified according to an objective dietary assessment score of adherence to healthy dietary habits according to WHO guidelines, calculated from their proton nuclear magnetic resonance (1H-NMR) urinary profiles. Subsequent models were generated comparing extremes of dietary habits, exercise, and the combined effect of both. Differences in metabolic phenotypes and gut microbiome profiles between the two groups were assessed. Each of the models pertaining to diet healthiness, physical exercise, or a combination of both displayed a metabolic and functional microbial signature, with a significant proportion of the metabolites identified as discriminating between the various pairwise comparisons resulting from gut microbe-host cometabolism. Microbial diversity was associated with a combination of high adherence to healthy dietary habits and exercise and was correlated with a distinct array of microbially derived metabolites, including markers of proteolytic activity. Improved control of dietary confounders, through the use of an objective dietary assessment score, has uncovered further insights into the complex, multifactorial relationship between diet, exercise, the gut microbiome, and metabolism. Furthermore, the observation of higher proteolytic activity associated with higher microbial diversity indicates that increased microbial diversity may confer deleterious as well as beneficial effects on the host.

Journal article

Petropoulou K, Salt LJ, Edwards CH, Warren FJ, Garcia-Perez I, Chambers ES, Alshaalan R, Khatib M, Perez-Moral N, Cross KL, Kellingray L, Stanley R, Koev T, Khimyak YZ, Narbad A, Penney N, Serrano-Contreras JI, Charalambides MN, Miguens Blanco J, Castro Seoane R, McDonald JAK, Marchesi JR, Holmes E, Godsland IF, Morrison DJ, Preston T, Domoney C, Wilde PJ, Frost GSet al., 2020, A natural mutation in Pisum sativum L. (pea) alters starch assembly and improves glucose homeostasis in humans, Nature Food

Journal article

Yeung KTD, Penney N, Ashrafian L, Darzi A, Ashrafian Het al., 2020, Does sleeve gastrectomy expose the distal esophagus to severe reflux?: A systematic review and meta-analysis, Annals of Surgery, Vol: 271, Pages: 257-265, ISSN: 0003-4932

MINI: The reported prevalence of new-onset or worsening gastroesophageal reflux disease after sleeve gastrectomy is controversial. Subsequent esophagitis and Barrett's esophagus can be serious unintended sequalae. The aim of this study was to systematically appraise all existing published data to assess the effect of sleeve gastrectomy on gastroesophageal reflux, esophagitis, and Barrett's esophagus. OBJECTIVE: The aim of this study was to appraise the prevalence of gastroesophageal reflux disease (GERD), esophagitis, and Barrett's esophagus (BE) after sleeve gastrectomy (SG) through a systematic review and meta-analysis. BACKGROUND: The precise prevalence of new-onset or worsening GERD after SG is controversial. Subsequent esophagitis and BE can be a serious unintended sequalae. Their postoperative prevalence remains unclear. METHODS: A systematic literature search was performed to identify studies evaluating postoperative outcomes in primary SG for morbid obesity. The primary outcome was prevalence of GERD, esophagitis, and BE after SG. Meta-analysis was performed to calculate combined prevalence. RESULTS: A total of 46 studies totaling 10,718 patients were included. Meta-analysis found that the increase of postoperative GERD after sleeve (POGAS) was 19% and de novo reflux was 23%. The long-term prevalence of esophagitis was 28% and BE was 8%. Four percent of all patients required conversion to RYGB for severe reflux. CONCLUSIONS: The postoperative prevalence of GERD, esophagitis, and BE following SG is significant. Symptoms do not always correlate with the presence of pathology. As the surgical uptake of SG continues to increase, there is a need to ensure that surgical decision-making and the consent process for this procedure consider these long-term complications while also ensuring their postoperative surveillance through endoscopic and physiological approaches. The long-term outcomes of this commonly performed bariatric procedure should be considered alongsid

Journal article

Ahmed K, Penney N, Darzi A, Purkayastha Set al., 2018, Taste changes after bariatric surgery: a systematic review, Obesity Surgery, Vol: 28, Pages: 3321-3332, ISSN: 0960-8923

BACKGROUND: Alterations in taste perception and preferences may contribute to dietary changes and subsequent weight loss following bariatric surgery. METHODS: A systematic search was performed to identify all articles investigating gustation, olfaction, and sensory perception in both animal and human studies following bariatric procedures. RESULTS: Two hundred fifty-five articles were identified after database searches, bibliography inclusions and deduplication. Sixty-one articles were included. These articles provide evidence supporting changes in taste perception and hedonic taste following bariatric procedures. Taste sensitivity to sweet and fatty stimuli appears to increase post-operatively. Additionally, patients also have a reduced hedonic response to these stimuli. CONCLUSIONS: Available evidence suggests that there is a change in taste perception following bariatric procedures, which may contribute to long-term maintenance of weight loss following surgery.

Journal article

Selvendran SS, Penney NC, Aggarwal N, Darzi AW, Purkayastha Set al., 2018, Treatment of Obesity in Young People-a Systematic Review and Meta-analysis., Obes Surg, Vol: 28, Pages: 2537-2549

Obesity in the young is increasingly prevalent. Early, effective intervention is paramount. Treatment options are lifestyle modifications, pharmacological therapies, endoscopic treatments and bariatric surgery. However, the relative effectiveness of these treatments in young patients remains unclear. We systematically identify and meta-analyse studies evaluating weight loss treatments in young people (< 21 years) with obesity. From 16,372 identified studies, 83 were eligible for meta-analysis. Bariatric surgery resulted in high short/medium-term weight loss (pooled estimate 14.04 kg/m2). Lifestyle and pharmacological therapies impacted weight more moderately (pooled estimate 0.99 and 0.94 kg/m2 respectively). Due to its high efficacy, bariatric surgery should be considered earlier when treating obesity in young people. However, due to the invasiveness and inherent risks of bariatric surgery, all other weight loss routes should be exhausted first.

Journal article

Selvendran SS, Penney NC, Aggarwal N, Darzi AW, Purkayastha Set al., 2018, Treatment of obesity in young people—a systematic review and meta-analysis, Obesity Surgery, Vol: 28, Pages: 2537-2549, ISSN: 0960-8923

Obesity in the young is increasingly prevalent. Early, effective intervention is paramount. Treatment options are lifestyle modifications, pharmacological therapies, endoscopic treatments and bariatric surgery. However, the relative effectiveness of these treatments in young patients remains unclear. We systematically identify and meta-analyse studies evaluating weight loss treatments in young people (< 21 years) with obesity. From 16,372 identified studies, 83 were eligible for meta-analysis. Bariatric surgery resulted in high short/medium-term weight loss (pooled estimate 14.04 kg/m2). Lifestyle and pharmacological therapies impacted weight more moderately (pooled estimate 0.99 and 0.94 kg/m2 respectively). Due to its high efficacy, bariatric surgery should be considered earlier when treating obesity in young people. However, due to the invasiveness and inherent risks of bariatric surgery, all other weight loss routes should be exhausted first.

Journal article

Cronin O, Barton W, Skuse P, Penney NC, Garcia-Perez I, Murphy EF, Woods T, Nugent H, Fanning A, Melgar S, Falvey EC, Holmes E, Cotter PD, O'Sullivan O, Molloy MG, Shanahan Fet al., 2018, A prospective metagenomic and metabolomic analysis of the impact of exercise and/or whey protein supplementation on the gut microbiome of sedentary adults, mSystems, Vol: 3, ISSN: 2379-5077

Many components of modern living exert influence on the resident intestinal microbiota of humans with resultant impact on host health. For example, exercise-associated changes in the diversity, composition, and functional profiles of microbial populations in the gut have been described in cross-sectional studies of habitual athletes. However, this relationship is also affected by changes in diet, such as changes in dietary and supplementary protein consumption, that coincide with exercise. To determine whether increasing physical activity and/or increased protein intake modulates gut microbial composition and function, we prospectively challenged healthy but sedentary adults with a short-term exercise regime, with and without concurrent daily whey protein consumption. Metagenomics- and metabolomics-based assessments demonstrated modest changes in gut microbial composition and function following increases in physical activity. Significant changes in the diversity of the gut virome were evident in participants receiving daily whey protein supplementation. Results indicate that improved body composition with exercise is not dependent on major changes in the diversity of microbial populations in the gut. The diverse microbial characteristics previously observed in long-term habitual athletes may be a later response to exercise and fitness improvement. IMPORTANCE The gut microbiota of humans is a critical component of functional development and subsequent health. It is important to understand the lifestyle and dietary factors that affect the gut microbiome and what impact these factors may have. Animal studies suggest that exercise can directly affect the gut microbiota, and elite athletes demonstrate unique beneficial and diverse gut microbiome characteristics. These characteristics are associated with levels of protein consumption and levels of physical activity. The results of this study show that increasing the fitness levels of physically inactive humans leads to mo

Journal article

Barton W, Penney NC, Cronin O, Garcia-Perez I, Molloy MG, Holmes E, Shanahan F, Cotter PD, O'Sullivan Oet al., 2018, The microbiome of professional athletes differs from that of more sedentary subjects in composition and particularly at the functional metabolic level, Gut, Vol: 67, Pages: 625-633, ISSN: 0017-5749

OBJECTIVE: It is evident that the gut microbiota and factors that influence its composition and activity effect human metabolic, immunological and developmental processes. We previously reported that extreme physical activity with associated dietary adaptations, such as that pursued by professional athletes, is associated with changes in faecal microbial diversity and composition relative to that of individuals with a more sedentary lifestyle. Here we address the impact of these factors on the functionality/metabolic activity of the microbiota which reveals even greater separation between exercise and a more sedentary state. DESIGN: Metabolic phenotyping and functional metagenomic analysis of the gut microbiome of professional international rugby union players (n=40) and controls (n=46) was carried out and results were correlated with lifestyle parameters and clinical measurements (eg, dietary habit and serum creatine kinase, respectively). RESULTS: Athletes had relative increases in pathways (eg, amino acid and antibiotic biosynthesis and carbohydrate metabolism) and faecal metabolites (eg, microbial produced short-chain fatty acids (SCFAs) acetate, propionate and butyrate) associated with enhanced muscle turnover (fitness) and overall health when compared with control groups. CONCLUSIONS: Differences in faecal microbiota between athletes and sedentary controls show even greater separation at the metagenomic and metabolomic than at compositional levels and provide added insight into the diet-exercise-gut microbiota paradigm.

Journal article

Kuang Y-S, Lu J-H, Li S-H, Li J-H, Yuan M-Y, He J-R, Chen N-N, Xiao W-Q, Shen S-Y, Qiu L, Wu Y-F, Hu C-Y, Wu Y-Y, Li W-D, Chen Q-Z, Deng H-W, Papasian CJ, Xia H-M, Qiu Xet al., 2017, Connections between human gut microbiome and gestational diabetes mellitus, GIGASCIENCE, Vol: 6, ISSN: 2047-217X

Journal article

Mohanaruban A, Patel N, Ashrafian H, Stoenchev K, Le Roux C, Penney N, Kelly J, Byrne J, Hopkins J, Mason J, Teare Jet al., 2017, ENDOBARRIER (R) : A SAFE AND EFFECTIVE NOVEL TREATMENT FOR OBESITY AND TYPE 2 DIABETES?, Annual General Meeting of the British-Society-of-Gastroenterology (BSG), Publisher: BMJ PUBLISHING GROUP, ISSN: 0017-5749

Introduction Obesity is a modern pandemic. One of the major complications of obesity is the development of diabetes which leads to considerable mortality, morbidity and enormous health care costs.1The EndoBarrier is an endoscopically implantable duodenal-jejunal sleeve bypass (DJSB); anchored in the duodenum, preventing ingested food from coming into contact with the proximal intestine and induces weight loss and improvement in glycaemic control. The aim of this prospective study was to assess the safety and efficacy of the EndoBarrier in obese patients with type 2 diabetes.Method This was a non-randomised study conducted at three investigational sites (Southampton, London, and Manchester) over an 18 month period with clinical and biochemical assessments carried out at 3 monthly intervals. The device was implanted for 12 months with 6 months follow up. All patients were obese with poorly controlled diabetes. Adverse events were recorded and statistical analysis was performed.Results A total of 45 subjects were enrolled into the studyAt 12 months following implant:1) HbA1c significantly reduced from baseline at 0.8% below the mean at baseline (95% CI 0.1–1.6; p<0.05).2) Mean weight loss was 15 kg (95% CI 0.62–29.38; p<0.05)3) BMI was reduced by 4.9kg/m2 (95% CI 1.1–8.7; p<0.005).14 patients withdrew from the study, 6 required premature EndoBarrier removal. Of these, only 2 patients presented with device related complications (device migration and gastrointestinal bleeding), the others withdrew due to unrelated medical adverse events.Conclusion The EndoBarrier appears to be a safe and effective treatment strategy in those who are overweight and have poor glycaemic control despite medical therapy, or in those who are eligible but decline bariatric surgery. Larger randomised controlled trials with longer follow-up periods post-explant of the device need to be performed to investigate the device’s effect

Conference paper

Ahmed K, Penney N, Darzi A, Purkayastha Set al., 2017, CHANGES TO TASTE AFTER BARIATRIC SURGERY: A SYSTEMATIC REVIEW Basic science and research in bariatric surgery, Publisher: SPRINGER, Pages: 437-437, ISSN: 0960-8923

Conference paper

Selvendran S, Penney N, Aggarwal N, Darzi A, Purkayastha Set al., 2017, THE TREATMENT OF OBESITY IN YOUNG PEOPLE - A SYSTEMATIC REVIEW AND META ANALYSIS Bariatric surgery in children, adolescents and young adults, Publisher: SPRINGER, Pages: 418-418, ISSN: 0960-8923

Conference paper

Penney NC, Kinross J, Newton RC, Purkayastha Set al., 2015, The role of bile acids in reducing the metabolic complications of obesity after bariatric surgery: A systematic review, International Journal of Obesity, Vol: 39, Pages: 1565-1574, ISSN: 0307-0565

Background:Bariatric surgery is currently the most efficacious treatment for obesity and its associated metabolic co-morbidities, such as diabetes. The metabolic improvements occur through both weight-dependent and weight-independent mechanisms. Bile acids (BAs) have emerged as key signalling molecules that have a central role in modulating many of the physiological effects seen after bariatric surgery. This systematic review assesses the evidence from both human and animal studies for the role of BAs in reducing the metabolic complications of obesity following bariatric surgery.Methods:We conducted a systematic search of Medline and Embase databases to identify all articles investigating the role of BAs in mediating the metabolic changes observed following bariatric surgery in both animal and human studies. Boolean logic was used with relevant search terms, including the following MeSH terms: 'bile acids and salts', 'bariatric surgery', 'metabolic surgery', 'gastrointestinal tract/surgery' and 'obesity/surgery'.Results:Following database searches (n=1197), inclusion from bibliography searches (n=2) and de-duplication (n=197), 1002 search results were returned. Of these, 132 articles were selected for full-text review, of which 38 articles were deemed relevant and included in the review. The findings support the effects of BAs on satiety, lipid and cholesterol metabolism, incretins and glucose homoeostasis, energy metabolism, gut microbiota and endoplasmic reticulum stress following bariatric surgery. Many of these metabolic effects are modulated through the BA receptors FXR and TGR5. We also explore a possible link between BAs and carcinogenesis following bariatric surgery.Conclusions:Overall there is good evidence to support the role of BAs in the metabolic effects of bariatric surgery through the above mechanisms. BAs could serve as a novel therapeutic pharmacological target for the treatment of obesity and its associated co-morbidities.

Journal article

Newton RC, Loizides S, Penney N, Singh KKet al., 2015, Laparoscopic management of Bouveret syndrome., BMJ Case Rep, Vol: 2015

Bouveret syndrome is a proximal form of gallstone ileus where a large gallstone lodges in the pylorus or proximal duodenum, having passed through a bilioenteric fistula that has formed secondary to previous cholecystitis. We describe the laparoscopic extraction of a giant 'Bouveret' gallstone from the duodenum of an elderly man with morbid obesity.

Journal article

Villasenor A, Kinross JM, Li JV, Penney N, Barton RH, Nicholson JK, Darzi A, Barbas C, Holmes Eet al., 2014, <SUP>1</SUP>H NMR Global Metabolic Phenotyping of Acute Pancreatitis in the Emergency Unit, JOURNAL OF PROTEOME RESEARCH, Vol: 13, Pages: 5362-5375, ISSN: 1535-3893

Journal article

Newton RC, Penney N, Nind N, Sajid MS, Sains Pet al., 2014, Small bowel malignant melanoma presenting as a perforated jejunal diverticulum: a case report and literature review., Gastroenterology Report, Vol: 4, Pages: 80-83, ISSN: 2052-0034

Although usually harmless and asymptomatic, jejuno-ileal diverticulae are associated with various non-specific gastrointestinal symptoms, and rarely cause surgical emergencies. This case report describes the presentation and management of a patient with an acute abdomen, whose jejunal diverticulum was perforated. Unexpectedly, histopathological assessment demonstrated malignant melanoma lining the diverticulum. Whether this was primary or metastatic is discussed, together with a synopsis of the literature on small bowel diverticulae.

Journal article

Purkayasthas S, Penney NC, Kinross JM, Newton RCet al., 2014, THE ROLE OF BILE ACIDS FOLLOWING METABOLIC SURGERY, 19th World Congress of the International-Federation-for-the-Surgery-of-Obesity-and-Metabolic-Disorders (IFSO), Publisher: SPRINGER, Pages: 1293-1294, ISSN: 0960-8923

Conference paper

Sarvesvaran M, Penney N, White J, Hulme Aet al., 2013, The enhanced recovery program for hip and knee replacements – Our experience, International Journal of Surgery, Vol: 11, Pages: 665-665, ISSN: 1743-9191

Journal article

Phoenix GK, Penney N, Cocker DM, Davies A, Smellie J, Bonanomi G, Thompson J, Efthimiou Eet al., 2013, Comparison of weight loss achieved after laparoscopic adjustable gastric banding between Afro-Caribbean, caucasian and South Asian adult female patients in a london bariatric centre, Annals of the Royal College of Surgeons of England, Vol: 95, Pages: 335-360, ISSN: 0035-8843

Introduction: It has been shown that following laparoscopic adjustable gastric banding (LAGB) procedures, Afro-Caribbeans achieve poorer weight loss compared with Caucasians. The reasons for this are multifactorial. However, studies have been based on mainly female patients from the US and none to date have been from the UK. Furthermore, South Asians have not previously been compared. The aim of this study was to compare excess weight loss percentage (%EWL) outcomes up to five years following LAGB in Afro-Caribbean, Caucasian and South Asian females in a London-based teaching hospital. Methods: An analysis was carried out of prospectively collected data of female patients aged .16 years of Afro-Caribbean, Caucasian or South Asian origin who underwent LAGB between October 2000 and December 2011. Data included demographics, co-morbidities and anthropometrics. Results: Overall, 596 females underwent LAGB; 316 Caucasians (53.0%), 64 Afro-Caribbeans (10.8%) and 27 South Asians (4.5%) formed the majority of those who disclosed ethnicities. Age and initial body mass index (BMI) were comparable between Afro-Caribbeans and Caucasians (mean BMI: 47.3kg/m2 [standard deviation [SD]: 7.5kg/m2, range: 37.0.78.3kg/m2] vs 45.8kg/m2 [SD: 7.1kg/m2, range: 24.7.79.8kg/m2], p=0.225). A non-significant trend suggested less %EWL in Afro- Caribbeans than in Caucasians at 6 months, and at 1, 2, 3, 4 and 5 years (21.4% vs 24.4%, p=0.26; 27.4% vs 31.3%, p=0.27; 33.0% vs 36.8%, p=0.15; 39.0% vs 45.8%, p=0.14; 34.2% vs 45.3%, p=0.16; 37.1% vs 47.6%, p=0.67). South Asians and Caucasians had a similar age and preoperative BMI (mean BMI: 43.6kg/m2 [range: 32.5.59.1kg/m2] vs 45.8kg/m2 [range: 24.7.79.8kg/m2], p=0.08). The %EWL was greatest at three and four years among South Asians although numbers were small (n=4 and n=3 respectively). Conculsions: A non-significant trend suggests poorer weight loss outcomes in Afro-Caribbeans compared with Caucasians inour cohort. Discussion of realistic weight

Journal article

Penney N, Phoenix G, Sivam V, Deeba S, Smellie Jet al., 2013, The clinical and cost effectiveness of laparoscopic versus open unilateral inguinal hernia repair: the experience of a London teaching hospital, International Surgical Congress of the Association-of-Surgeons-of-Great-Britain-and-Ireland (ASGBI), Publisher: WILEY-BLACKWELL, Pages: 34-34, ISSN: 0007-1323

Conference paper

Penney N, Phoenix G, Cocker D, Davies A, Fourie H, Smellie J, Thompson J, Bonanomi G, Efthimiou Eet al., 2013, Comparison of weight loss achieved after laparoscopic adjustable gastric banding between Afro-Caribbean and Caucasian adult females: a UK perspective, 4th Annual Scientific Meeting of the British-Obesity-and-Metabolic-Surgery-Society (BOMSS), Publisher: WILEY-BLACKWELL, Pages: 10-10, ISSN: 0007-1323

Conference paper

Kinross JMA, Markar S, Karthikesalingam A, Chow A, Penney N, Silk D, Darzi Aet al., 2013, A meta-analysis of probiotic and synbiotic use in elective surgery: Does nutrition modulation of the gut microbiome improve clinical outcome?, Journal of Parenteral and Enteral Nutrition, Vol: 37, Pages: 243-253, ISSN: 0148-6071

Background: Perioperative nutrition modulation of gut microbiota is increasingly used as a strategy for reducing the infective complications of elective surgery. This meta-analysis assessed the effect of probiotic and synbiotic preparations on the incidence of postoperative sepsis. Methods: Randomized controlled trials that compared preoperative dosing of probiotics and synbiotics in patients undergoing elective general surgical procedures were included. The primary outcome measure was the postoperative sepsis rate. Pooled outcome measures were determined using random effects models. Results: Thirteen randomized controlled trials totaling 962 patients were included in this analysis (304 received synbiotics and 182 received probiotics). The incidence of postoperative sepsis was reduced in the probiotic group vs the control (pooled odds ratio [OR] = 0.42; 95% confidence interval [CI], 0.23-0.75; P =.003) and in the synbiotic group vs the control (pooled OR = 0.25; 95% CI, 0.1-0.6; P =.002). However, subgroup analysis failed to identify a significant reduction in the incidence of pneumonia, urinary tract infections, or wound infections in the postoperative phase for either treatment group. Synbiotics reduced the length of postoperative antibiotic use (weighted mean differences = -1.71; 95% CI, -3.2 to -0.21; P =.03). Conclusion: Probiotic and synbiotic nutrition strategies reduce the incidence of postoperative sepsis in the elective general surgery setting. These effects appear more pronounced with the use of synbiotics. High-powered, mechanistic studies are now required for the optimization of pro- and prebiotic regimens to further improve their efficacy. © 2012 American Society for Parenteral and Enteral Nutrition.

Journal article

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