Prof Richard C G POLLOK
Professor of Gastroenterology & GI infection
During my specialist medical training in gastroenterology I was awarded a Wellcome Trust doctoral Clinical Training Fellowship in 1999 to examine the mucosal immune response to the gut infection . I was awarded The Digestive Disease Foundation (CORE) National Research Prize for this work. Since my appointment at St George’s in 2002 I have expanded my portfolio of research portfolio with fuding from the Wellcome Trust, Crohn’s and Colitis UK and the UK Clinical Research Network. I was appointed Professor of Practice-Gastroenterology and Gastrointestinal Infection at St George’s University of London in 2020.
My research is primarily focused on IBD and GI infection with over 100 peer reviewed publications, many appear in high impact international journals such as the Lancet, JAMA, Gastroenterology and Gut.
I have been Principal Investigator of more than 30 clinical research studies leading a trial team at St George’s University of London.
I lead international collaborations with NHS and academic partners including Imperial College London, Leeds University and Christian Medical College, Velore, India. The impact of my workhas grown as evidenced by more than 2000 citations of my work in the literature and its translation into clinical guidelines.
Alongside my research activity, I am a full time NHS clinician, with activities including out-patient and in-patient consultation, endoscopy, service development and education. I was Clinical Director of Specialist Medicine at St George’s University Hospitals NHS Foundation Trust between 2008 and 2011 including a portfolio for education and research.
I mow lead the South London Gastroenterology Clinical Research Network and am a national Gastroenterology CRN committee member overseeing a portfolio of commercial and NIHR-funded clinical trials. In this role I have driven recruitment to clinical studies in Gastroenterology, which has more than doubled regionally in the past 5 years
The three major themes to my research portfolio are:
(1) The study of health related outcomes in IBD and GI infection. This includes national studies evaluating the health burden of Clostridium difficile infection in IBD. I am currently leading collaboration with researchers at Imperial College London examining long-term surgical outcomes and prescribing patterns in IBD patients studying an IBD population cohort over 20 years using a UK national dataset. More recently we have evaluated the impact of depression on patients with IBD. Since 2008 our group has published many highly cited original articles in the field of IBD epidemiology and recently published in the top journal in the field Gut.
(2) Non-invasive techniques in the diagnosis and assessment of IBD and GI infection. Successful projects include an evaluation of the role of proteomics technology in the diagnosis of Tuberculosis and IBD, in collaboration with Professor Krishna at SGUL, we published our findings in the Lancet. We have also evaluated novel ultrasound techniques, in collaboration with the Radiology team at St George’s University Hospitals NHS Foundation Trust , for in the diagnosis and assessment of IBD.
(3) Clinical observational and therapeutic studies . We have recruited more than 1000 patients to a range of studies outlined below. Examples include recruitment of patients to the international IBD genetics consortium contributing to a recent paper published in JAMA on rare genetic determinants of IBD. HALT-IT is a large international NIHR-funded trial of a treatment for bleeding in the stomach and small bowel-or work was recently pubished in the Lancet. I have been instrumental in enterprise development and was awarded 2 NHS innovation awards for development of proteomic–based diagnostic methods and a novel endoscopic device.
I enjoy a wide range of teaching and educational activities at St George’s including Final year medical examiniation and interviewing prospective medical students. As director for the Early Years clinical Experience (EYCE) Undergraduate Medicine course I led the development and inception of this course for 1st and 2nd years devised to provide an experience of the clinical milieu in the early years of medical training. I supervise and mentor my team of MD/PhD research fellows,
Blackwell J, Saxena S, Petersen I, Hotopf M, Creese H, Bottle A, Alexakis C, Pollok R, POP-IBD study group
Depression in individuals who subsequently develop Inflammatory Bowel Disease: a population-based nested case-control study
Gut. 2020 Oct 27:gutjnl-2020-322308. doi: 10.1136/gutjnl-2020-322308.
Dorrington AM, Selinger CP, Parkes GC, Smith M, Pollok RC, Raine T.
The Historical Role and Contemporary Use of Corticosteroids in Inflammatory Bowel Disease.
J Crohns Colitis. 2020 Sep 16;14(9):1316-1329. doi: 10.1093/ecco-jcc/jjaa053.
Kennedy NA, Hansen R, Younge L,.. Pollok RC.., Sebastian Shaji
Organisational changes and challenges for inflammatory bowel disease services in the UK during the COVID-19 pandemic
Frontline Gastroenterology Sep 2020, 11 (5) 343-350; DOI: 10.1136/flgastro-2020-101520
Blackwell J, Saxena S, Jayasooriya N, Bottle A, Petersen I, Hotopf M, Alexakis C, Pollok RC
Prevalence and duration of gastrointestinal symptoms before diagnosis of Inflammatory Bowel Disease and predictors of timely specialist review: a population-based study.
J Crohns Colitis. 2020 Jul 15:jjaa146. doi: 10.1093/ecco-jcc/jjaa146. Online ahead of print. J Crohns Colitis. 2020. PMID: 32667962
Din S, Kent A, Pollok R et al. joint first authors, Management of acute severe ulcerative colitis in the context of the COVID-19 pandemic: a RAND appropriateness panel, Gut. 2020 Jun: gutjnl-2020-321927. doi: 10.1136/gutjnl-2020-321927. Online ahead of print. Gut. 2020. PMID: 32513653
Kennedy NA, Jones GR, Lamb CA et al, British Society of Gastroenterology guidance for management of inflammatory bowel disease during the COVID-19 pandemic. Gut. 2020 Jun;69(6):984-990. doi: 10.1136/gutjnl-2020-321244. Epub 2020 Apr 17
Haemorrhagic Alleviation with Tranexamic acid-Intestinal Tract international collaborative Group.
Tranexamic acid for the treatment of gastrointestinal bleeding: an international, randomised, double blind controlled trial.
Lancet. 2020 Jun 20;395(10241):1927-1936. doi: 10.1016/S0140-6736(20)30848-5. Lancet. 2020. PMID: 32563378
Rajkumar C, Wilks M, Islam J, Ali K, Raftery J, Davies KA, Timeyin J, Cheek E, Cohen J; Investigators.
Do probiotics prevent antibiotic-associated diarrhoea? Results of a multicentre randomized placebo-controlled trial.
J Hosp Infect. 2020 Jun;105(2):280-288. doi: 10.1016/j.jhin.2020.01.018. Epub 2020 Feb 7. PMID: 32035998.
Selinger CP, Parkes GC, Bassi A, Limdi JK, Ludlow H, Patel P, Smith M, Saluke S, Ndlovu Z, George B, Saunders J, Adamson M, Fraser A, Robinson J, Donovan F, Parisi I, Tidbury J, Gray L, Pollok R, Scott G, Raine T.
Aliment Pharmacol Ther. 2019 Nov;50(9):1009-1018. doi: 10.1111/apt.15497. Epub 2019 Oct 8. PMID: 31595533
Taylor SA, Mallett S, Bhatnagar G, Morris S, Quinn L, Tomini F, Miles A, Baldwin-Cleland R, Bloom S, Gupta A, Hamlin PJ, Hart AL, Higginson A, Jacobs I, McCartney S, Murray CD, Plumb AA, Pollok RC, Rodriguez-Justo M, Shabir Z, Slater A, Tolan D, Travis S, Windsor A, Wylie P, Zealley I, Halligan S.
Health Technol Assess. 2019 Aug;23(42):1-162. doi: 10.3310/hta23420.
Blackwell J, Saxena S, Alexakis C, Bottle A, Cecil E, Majeed A, PollokRC.
Aliment Pharmacol Ther. 2019 Sep;50(5):556-567. doi: 10.1111/apt.15390.
Kennedy, N.A., Heap, G.A., Green, H.D.et al. on behalf of UK Inflammatory Bowel Disease Pharmacogenetics Study Group, incl. POLLOK R. Predictors of anti-TNF treatment failure in anti-TNF-naive patients with active luminal Crohn’s disease: a prospective, multicentre, cohort study.
Lancet Gastroenterol Hepatol. 2019 May;4(5):341-353. doi: 10.1016/S2468-1253(19)30012-3. Epub 2019 Feb 27. PMID: 30824404
Walker GJ, Harrison JW, Heap GA, Voskuil MD, Andersen V, Anderson CA, Ananthakrishnan AN, Barrett JC, Beaugerie L, Bewshea CM, Cole AT, Cummings FR, Daly MJ, Ellul P, Fedorak RN, Festen EAM, Florin TH, Gaya DR, Halfvarson J, Hart AL, Heerasing NM, Hendy P, Irving PM, Jones SE, Koskela J, Lindsay JO, Mansfield JC, McGovern D, Parkes M, PollokRCG, Ramakrishnan S, Rampton DS, Rivas MA, Russell RK, Schultz M, Sebastian S, Seksik P, Singh A, So K, Sokol H, Subramaniam K, Todd A, Annese V, Weersma RK, Xavier R, Ward R, Weedon MN, Goodhand JR, Kennedy NA, Ahmad T; IBD Pharmacogenetics Study Group.
JAMA. 2019 Feb 26;321(8):773-785. doi: 10.1001/jama.2019.0709. PMID: 30806694.
Parkes M on behalf of IBD BioResource Investigators
Gut. 2019 Sep;68(9):1537-1540. doi: 10.1136/gutjnl-2019-318835. Epub 2019 Jul 3. PMID:31270165.
Samaan MA, Forsyth K, Segal JP, De Jong D, Vleugels JLA, Elkady S, Kabir M, Campbell S, Kok K, Armstrong DG, Penez L, Arenaza AP, Seward E, Vega R, Mehta S, Rahman F, McCartney S, Bloom S, Patel K, Pollok R, Westcott E, Darakhshan A, Williams A, Koumoutsos I, Ray S, Mawdsley J, Anderson S, Sanderson JD, Dekker E, D’Haens GR, Hart A, Irving PM.
J Crohns Colitis. 2019 May 27;13(6):735-743. doi: 10.1093/ecco-jcc/jjy225. PMID: 30590513.
Miles A, Bhatnagar G, Halligan S, Gupta A, Tolan D, Zealley I, Taylor SA; METRIC investigator Pollok R
Eur Radiol. 2019 Mar;29(3):1083-1093. doi: 10.1007/s00330-018-5661-2. Epub 2018 Aug 20. PMID: 30128615.
Hakim A, Alexakis C, Pilcher J, Tzias D, Mitton S, Paul T, Saxena S, Pollok R, Kumar S Comparison of small intestinal contrast ultrasound with magnetic resonance enterography in pediatric Crohn’s disease
JGH Open (2019) 1–6. PMID: 000
Alexakis C, Saxena S, Chhaya V, Cecil E, Majeed A, Pollok R.
Am J Gastroenterol. 2018 Nov;113(11):1689-1700. doi: 10.1038/s41395-018-0273-7. Epub 2018 Oct 15. PMID: 30323269.
Taylor SA, Mallett S, Bhatnagar G, Baldwin-Cleland R, Bloom S, Gupta A, Hamlin PJ, Hart AL, Higginson A, Jacobs I, McCartney S, Miles A, Murray CD, Plumb AA, Pollok RC, Punwani S, Quinn L, Rodriguez-Justo M, Shabir Z, Slater A, Tolan D, Travis S, Windsor A, Wylie P, Zealley I, Halligan S; METRIC study investigators.
Lancet Gastroenterol Hepatol. 2018 Aug;3(8):548-558. doi: 10.1016/S2468-1253(18)30161-4. Epub 2018 Jun 18. PMID: 29914843.
Ahmad A, Laverty AA, Alexakis C, Cowling T, Saxena S, Majeed A, POLLOK RCG.
BMJ Open Gastroenterol. 2018 Mar 20;5(1):e000191. doi: 10.1136/bmjgast-2017-000191. eCollection 2018. PMID: 29607052
Alexandros Onoufriadis, Kristina Stone, Antreas Katsiamides, Ariella Amar, Yasmin Omar, Katrina M de Lange, Kirstin Taylor, Jeffrey C Barrett, Richard POLLOK, Bu’Hussain Hayee, John C Mansfield, Jeremy D Sanderson, Michael A Simpson, Christopher G Mathew, Natalie J Prescott
J Crohns Colitis 2018 12 (3), 321-326
Kumar S, Chis Ster I, POLLOK R, Muscat I, Planche TD.
Infect Control Hosp Epidemiol. 2018 May;39(5):603-607. doi: 10.1017/ice.2018.38. Epub 2018 Feb 27. P
Alexakis C, Kumar S, Saxena S, POLLOK R
Aliment Pharmacol Ther. 2017 Aug;46(3):225-235. doi: 10.1111/apt.14171.
Alexakis C, Saxena S, Chhaya V, Cecil E, Curcin V, POLLOK R
Inflamm Bowel Dis. 2017 Apr;23(4):672-680. doi: 10.1097/MIB.0000000000001031.
Alexakis C, Gordon K, Mellor R, Chong H, Mortimer P, POLLOK R.
J Crohns Colitis. 2017 Apr 1;11(4):454-459. doi: 10.1093/ecco-jcc/jjw173.
Kumar S, Pollok R, Muscat I, Planche T. Diagnosis and outcome of Clostridium difficile infection by toxin enzyme immunoassay and PCR in an island population. J Gastroenterol Hepatol. 2016 Aug 9. doi: 10.1111/jgh.13504.
Subramanian V, Chatu S, Echterdiek F, Banerjee A, Finlayson C, Pollok RC. Patients with Endoscopically Visible Polypoid Adenomatous Lesions Within the Extent of Ulcerative Colitis Have an Increased Risk of Colorectal Cancer Despite Endoscopic Resection. Dig Dis Sci. 2016 Oct;61(10):3031-6. doi: 10.1007/s10620-016-4246-7. Epub 2016 Jul 12.
Aliment Pharmacol Ther. 2016 Sep;44(5):482-94. doi: 10.1111/apt.13700. Epub 2016 Jul 4.
Emerging trends and risk factors for perianal surgery in Crohn’s disease: a 20-year national population-based cohort study. Eur J Gastroenterol Hepatol. 2016 Aug;28(8):890-5.
World J Gastroenterol. 2016 Feb 21;22(7):2165-78. doi: 10.3748/wjg.v22.i7.2165.
World J Gastrointest Surg. 2015 Dec 27;7(12):360-9. doi: 10.4240/wjgs.v7.i12.360.
Chhaya V, Pollok RC, Cecil E, Subramanian V, Curcin V, Majeed A, Saxena S. Impact of early thiopurines on surgery in 2770 children and young people diagnosed with inflammatory bowel disease: a national population-based study. Aliment Pharmacol Ther. 2015 Oct;42(8):990-9. doi: 10.1111/apt.13361. Epub 2015 Aug 13.
Chhaya V, Saxena S, Cecil E, Chatu S, Subramanian V, Curcin V, Majeed A, Pollok RC. The impact of timing and duration of thiopurine treatment on colectomy in ulcerative colitis: a national population-based study of incident cases between 1989-2009. Aliment Pharmacol Ther. 2015 Jan;41(1):87-98.
Chhaya V, Saxena S, Cecil E, Subramanian V, Curcin V, Majeed A, Pollok RC. Impact of Timing and duration of thiopurine treatment on first Perianalsurgery in Crohn’s Disease:UK population-based Study. Inflamm Bowel Dis. 2015 Jan 7
Prescott NJ,..UK IBD Genetics Consortium,..Pollok R et al. Pooled sequencing of 531 genes in inflammatory bowel disease identifies an associated rare variant in BTNL2 and implicates other immune related genes. Nature Genetics 2015
Chatu S, Subramanian V, Saxena S, Pollok RC. The role of thiopurines in reducing the need for surgical resection in Crohn’s disease: a systematic review and meta-analysis. Am J Gastroenterol. 2014 Jan;109(1):23-34
Chatu S, Saxena S, Subramanian V, Curcin V, Yadegarfar G, Gunn L, Majeed A, Pollok RC. The Impact of Timing and Duration of Thiopurine Treatment on First Intestinal Resection in Crohn’s Disease: National UK Population-Based Study 1989-2010. Am J Gastroenterol. 2014 Jan 28
Kumar S, Hakim AF, Alexakis CF, Chhaya VF, Tzias DF, Pilcher JF, Pollok RC. Small intestinal contrast ultrasonography for the detection of small bowel complications in Crohn’s disease: correlation with intra-operative findings and MR enterography. Gastroenterology and Hepatology. 2014; 1440-1746
S Chatu, V Chhaya, R Holmes, P Neild, JY Kang, RC Pollok, A Poullis. Factors associated with vitamin D deficiency in a multicultural inflammatory bowel disease cohort. Frontline Gastroenterology 4 (1), 51-56, 2013 4 2013
Chatu S, Pilcher J, Saxena SK, Fry DH, Pollok RC. Diagnostic accuracy of small intestine ultrasonography using an oral contrast agent in Crohn’s disease: Comparative study from the UK.Clin Radiol. 2012 Jun;67(6):553-9.
Assessment of administrative data for evaluating the shifting acquisition of Clostridium difficile infection in England. Jen MH, Saxena S, Bottle A, Pollok R, Holmes A, Aylin P. J Hosp Infect. 2012 Mar; 80(3):229-37. Epub 2012 Feb 4
Meta-analysis: diagnostic medical radiation exposure in inflammatory bowel disease. Chatu S, Subramanian V, Pollok RC. Aliment Pharmacol Ther. 2012 Mar;35(5):529-39. Epub 2012 Jan 13
Diagnostic accuracy of small intestine ultrasonography using an oral contrast agent in Crohn’s disease: Comparative study from the UK. Chatu S, Pilcher J, Saxena SK, Fry DH, Pollok RC. Clin Radiol. 2011 Dec 31.
Acute upper gastrointestinal bleeding: identifying low risk patients. Chakrabarty G, Groves C, Pollok R. Gut. 2011
Increased health burden associated with Clostridium difficile diarrhoea in patients with inflammatory bowel disease. Jen MH, Saxena S, Bottle A, Aylin P, Pollok RC. Aliment Pharmacol Ther. 2011 Jun;33(12):1322-31
Unusual causes of diarrhoea and peripheral oedema. Gayatri Chakrabarty, RCG Pollok, P Mortimer. Gastroenterology Today 2011; 21(1): 18-19
Primary cytomegalovirus infectious colitis complicating Crohn’s disease successfully treated with oral valganciclovir. Subramanian V, Finlayson C, Harrison T, Rice P, Pollok R. J Crohn’s Colitis. 2010; 4:199-202
JF Rahier..Pollok R.. et al. European evidence-based Consensus guidelines on the management of opportunistic infections in inflammatory bowel disease. J Crohn’s and Colitis 2010 Jun;4(2):199-202
Pollok RCG. Treatment of Clostridium difficile. N Engl J Med. 2009 Feb 5;360(6):636
Subramanian V, Saxena S, Kang JY, and Pollok R. Pre-operative steroid use in patients with Inflammatory Bowel Disease and post-operative complications: meta-analysis. Am J Gatroenterol. . 2008; 103:2373-81.
Subramanian V, Beharry N, Pollok RC. Determining the proximal extent of ulcerative colitis: white cell scan correlates well with histological assessment. Aliment Pharmacol Ther. 2007 Feb 15;25(4):441-6.
Agranoff D, Fernandez-Reyes D, Papadopoulos M, Rojas S, Herbster M, Loosemore A, Tarelli T, Sheldon J, Schwenk A, Pollok RCG, Rayner C, Krishna S. Identification of diagnostic markers for tuberculosis by serum proteomic fingerprinting. Lancet 2006 Sep 16;368(9540):1012-21.
Subramanian V, Pollok RC, Kang JY, Kumar D. Systematic review of postoperative complications in patients with inflammatory bowel disease treated with immunomodulators.Br J Surg 2006 Jul; 93(7):793-9
Zulu I, Kelly P, Sianongo S, Kaonga K, McDonald V, Farthing M, Pollok RC. Nitazoxanide for persistent diarrhoea in Zambian AIDS patients: a randomised controlled trial. Aliment Pharmacol Ther 2005; 21: 757-763
Irving PM, Alstead EM, Greaves RR, Feakins RM, Pollok RC, Rampton DS. Acute mesenteric infarction: an important cause of abdominal pain in ulcerative colitis. Eur J Gastro Hepatol. 2005 ; 17(12): 1429-1432
RCG Pollok.Investigation of chronic diarrhoea. Gut. 2004 May;53(5):770
JY Kang, A Dhar, R Pollok et al. Diverticular disease of the colon: ethnic differences in frequency. Aliment Pharmacol Ther 2004; 19:765-69
IS Lean, Ac Stuart, M Bajaj-Elliott, RCG Pollok, MJG Farthing, V McDonald. IL-4 and TGF-beta have opposing regulatory effect on interferon–gamma mediated inhibition of Cryptosporidium parvum. Infec Immun 2003; 71(8): 4580-85
RCG Pollok et al. Interferon-gamma induces enterocyte resistance to infection against the intracellular pathogen Cryptosporidium parvum. Gastroenterology 2001; 120: 99-107
T Blanchard, L Milne, RCG Pollok. Lancet 1994; 343: 922. Clostridium difficile diarrhoea and rifabutin. Early chemotherapy of neuro-schistosomiasis. Lancet 1993; 341: 959. RCG Pollok, R Bendall, A Moody, PL Chiodini, DR Churchill. Traveller’s diarrhoea associated with “Cyanobacterium-like-bodies”.Lancet 1992; 340: 556-557