AccScience Publishing / STI / Volume 46 / Issue 1 / DOI: 10.36922/sti.0280
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REVIEW

Transit Bipartition—From L-Cell Physiology to Metabolic Outcomes: A Narrative Review

Vincenzo Consalvo1* ,  Sofia Guadalupe Rodriguez1 ,  Andrea Gambetti1 ,  Luca Buonaiuto2 ,  Vincenzo Salsano3 ,  Diego Foschi1 ,  Giuliano Sarro1
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1 Department of General and Bariatric Surgery, San Gaudenzio Clinic, Novara, Novara, Italy
2 Department of General and Bariatric Surgery, Policlinic of Monza, Monza, Province of Monza and Brianza, Italy
3 Department of Visceral Surgery, Clementville Clinic, Montpellier, Occitania, France
STI 2026, 46(1), 37–46; https://doi.org/10.36922/sti.0280
Received: 28 August 2025 | Revised: 19 November 2025 | Accepted: 25 November 2025 | Published online: 10 February 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

Metabolic surgery is designed to enhance the hormonal effects of incretins, rather than to induce purely restrictive or malabsorptive outcomes. Transit bipartition is an emerging metabolic procedure that aims to shorten the time to peak plasma concentrations of incretins, such as glucagon-like peptide-1 and peptide YY. This is achieved by accelerating the transit of chyme to the distal ileum, thereby reactivating and chronically stimulating its endocrine function. In this narrative review, we explore the underlying hormonal mechanisms, beginning with the physiology of the L cell, and elucidate the advantages of transit bipartition. We also summarize findings from current meta-analyses on the procedure's outcomes and complications, followed by a discussion of its advantages and disadvantages. Based on the existing theoretical and scientific evidence, we conclude that sleeve gastrectomy with transit bipartition is a safe and effective procedure with an acceptable rate of short- to medium-term complications.

Keywords
Gut hormones
L cell
Metabolic surgery
One-anastomosis transit bipartition;
Roux-en-Y transit bipartition
Single anastomosis sleeve ileal bypass
Sleeve gas-trectomyy with transit bipartition
References
  1. Reimann F, Tolhurst G, Gribble FM. G-protein-coupled receptors in intestinal chemosensation. Cell Metab. 2012;15(4):421-431. doi:10.1016/j.cmet.2011.12.019
  2. Spreckley E, Murphy KG. Neuroenergetics and brain health. Front Nutr. 2015;2:23. doi:10.3389/fnut.2015.00023
  3. Cummings DE, Overduin J. Gastrointestinal regulation of food intake. J Clin Invest. 2007;117(1):13-23. doi:10.1172/JCI30227
  4. Wren AM, Bloom SR. Gut hormones and appetite control. Gastroenterology. 2007;132(6):2116-2130. doi:10.1053/j.gastro.2007.03.048
  5. Holst JJ, Rosenkilde MM. Oxyntomodulin: past, present and future. Peptides. 2025;188:171393. doi:10.1016/j.peptides.2025.171393
  6. Drucker DJ. Glucagon-like peptide 2. J Clin Endocrinol Metab. 2001;86(4):1759-1764. doi:10.1210/jcem.86.4.7386
  7. Eissele R, Göke R, Willemer S, et al. Glucagon-like peptide-1 cells in the gastrointestinal tract and pancreas of rat, pig and man. Eur J Clin Invest. 1992;22(4):283-291. doi:10.1111/j.1365-2362.1992.tb01464.x
  8. Petersen N, Reimann F, Van Es JH, et al. Targeting development of incretin-producing cells increases insulin secretion. J Clin Invest. 2015;125(1):379-385. doi:10.1172/JCI75838
  9. Habib AM, Richards P, Rogers GJ, Reimann F, Gribble FM. Co-localisation and secretion of glucagon-like peptide-1 and peptide YY from primary cultured human L cells. Diabetologia. 2013;56(6):1413-1416. doi:10.1007/s00125-013-2887-z
  10. Welch I, Saunders K, Read NW. Effect of ileal and intravenous infusions of fat emulsions on feeding and satiety in human volunteers. Gastroenterology. 1985;89(6):1293-1297. doi:10.1016/0016-5085(85)90645-6
  11. Layer P, Holst JJ, Grandt D, Goebell H. Ileal release of glucagon-like peptide-1 (GLP-1): association with inhibition of gastric acid secretion in humans. Dig Dis Sci. 1995;40(5):1074-1082. doi:10.1007/BF02064202
  12. Nauck MA, Kemmeries G, Holst JJ, Meier JJ. Rapid tachyphylaxis of the GLP-1-induced deceleration of gastric emptying in humans. Diabetes. 2011;60(5):1561-1565. doi:10.2337/db10-0474
  13. Persaud SJ, Bewick GA. Peptide YY: more than just an appetite regulator. Diabetologia. 2014;57(9):1762-1769. doi:10.1007/s00125-014-3292-y
  14. Lloyd KC, Grandt D, Aurang K, Eysselein VE, Schimiczek M, Reeve JR. Inhibitory effect of PYY on vagally stimulated acid secretion is mediated predominantly by Y1 receptors. Am J Physiol. 1996;270(1 Pt 1):G123-G127. doi:10.1152/ajpgi.1996.270.1.G123
  15. Orskov C, Poulsen SS, Moller M, Holst JJ. GLP-1 receptors in the subfornical organ and the area postrema are accessible to circulating GLP-1. Diabetes. 1996;45(6):832-835. doi:10.2337/diab.45.6.832
  16. Vilsboll T, Holst JJ. Incretins, insulin secretion and type 2 diabetes mellitus. Diabetologia. 2004;47(3):357-366. doi:10.1007/s00125-004-1342-6
  17. Batterham RL, Bloom SR. The gut hormone peptide YY regulates appetite. Ann N Y Acad Sci. 2003;994:162-168. doi:10.1111/j.1749-6632.2003.tb03176.x
  18. van Avesaat M, Troost FJ, Ripken D, Hendriks HF, Masclee AA. Ileal brake activation: macronutrient-specific effects on eating behavior? Int J Obes (Lond). 2015;39(2):235-243. doi:10.1038/ijo.2014.112
  19. Holst JJ. Annual Prize Lecture 2024: endogenous physiological mechanisms as basis for the treatment of obesity and type 2 diabetes. J Physiol. 2024;602(24):6613-6629. doi:10.1113/JP287461
  20. Todd JF, Edwards CM, Ghatei MA, Mather HM, Bloom SR. Subcutaneous glucagon-like peptide-1 improves postprandial glycaemic control over a 3-week period in patients with early type 2 diabetes. Clin Sci (Lond). 1998;95(3):325-329.
  21. Batterham RL, Cowley MA, Small CJ, et al. Gut hormone PYY(3-36) physiologically inhibits food intake. Nature. 2002;418(6898):650-654. doi:10.1038/nature00887
  22. Holst JJ, Deacon CF. Glucagon-like peptide-1 mediates the therapeutic actions of DPP-IV inhibitors. Diabetologia. 2005;48(4):612-615. doi:10.1007/s00125-005-1705-7
  23. Nauck MA. Glucagon-like peptide 1 (GLP-1) in the treatment of diabetes. Horm Metab Res. 2004 Nov-Dec;36(11-12):852-858. doi:10.1055/s-2004-826175
  24. Ueno H, Yamaguchi H, Mizuta M, Nakazato M. The role of PYY in feeding regulation. Regul Pept. 2008;145(1-3):12-16. doi:10.1016/j.regpep.2007.09.011
  25. Santoro S. Is the metabolic syndrome a disease of the foregut? Yes, excessive foregut. Ann Surg. 2008;247(6):1074-1075. doi:10.1097/SLA.0b013e3181758ddb
  26. Santoro S, Castro LC, Velhote MC, et al. Sleeve gastrectomy with transit bipartition for metabolic syndrome and obesity. Ann Surg. 2012;256(1):104-110. doi:10.1097/SLA.0b013e31825370c0
  27. le Roux CW, Welbourn R, Werling M, et al. Gut hormones as mediators of appetite and weight loss after Roux-en-Y gastric bypass. Ann Surg. 2007;246(5):780-785. doi:10.1097/SLA.0b013e3180caa3e3
  28. Mahdy T, Emile SH, Madyan A, et al. Evaluation of the efficacy of single anastomosis sleeve ileal (SASI) bypass for patients with morbid obesity: a multicenter study. Obes Surg. 2020;30(3):837-845. doi:10.1007/s11695-019-04296-3
  29. Chaudhari SN, Chen Y, Ferraz-Bannitz R, et al. Altered intestinal bile acid transport provides a therapeutic target in post-bariatric hypoglycaemia. Nat Metab. 2025;7(4):792-807. doi:10.1038/s42255-025-01262-5
  30. Roux CWL, Borg C, Wallis K, et al. Gut hypertrophy after gastric bypass is associated with increased glucagon-like peptide 2 and intestinal crypt cell proliferation. Ann Surg. 2010;252(1):50-56. doi:10.1097/sla.0b013e3181d3d21f
  31. Rutledge R. The mini-gastric bypass: experience with the first 1,274 cases. Obes Surg. 2001;11(3):276-280. doi:10.1381/096089201321336584
  32. Santoro S, Velhote MCP, Malzoni CE, Milleo FQ, Klajner S, Campos FG. Preliminary results from digestive adaptation: a new surgical proposal for treating obesity, based on physiology and evolution. Sao Paulo Med J. 2006;124(4):192-197. doi:10.1590/s1516-31802006000400004
  33. Mahdy T, Wahedi AA, Schou C. Efficacy of single anastomosis sleeve ileal (SASI) bypass for type-2 diabetic morbid obese patients: gastric bipartition, a novel metabolic surgery procedure: a retrospective cohort study. Int Surg J. 2016;34:28-34. doi:10.1016/j.ijsu.2016.08.018
  34. Oliveira CR, Santos-Sousa H, Costa MP, et al. Efficiency and safety of single anastomosis sleeve ileal (SASI) bypass in the treatment of obesity and associated comorbidities: a systematic review and meta-analysis. Langenbeck's Arch Surg. 2024;409(1):221. doi:10.1007/s00423-024-03413-w
  35. Bhandari M, Fobi MAL, Buchwald JN, Bariatric Metabolic Surgery Standardization (BMSS) Working Group. Standardization of bariatric metabolic procedures: world consensus meeting statement. Obes Surg. 2019;29(S4):309-345. doi:10.1007/s11695-019-04032-x
  36. Baltasar A, Bou R, Bengochea M, et al. Duodenal switch: an effective therapy for morbid obesity-intermediate results. Obes Surg. 2001;11(1):54-58. doi:10.1381/096089201321454114
  37. Emile SH, Madyan A, Mahdy T, Elshobaky A, Elbanna HG, Abdel-Razik MA. Single anastomosis sleeve ileal (SASI) bypass versus sleeve gastrectomy: a case-matched multicenter study. Surg Endosc. 2020;35(2):652-660. doi:10.1007/s00464-020-07430-w
  38. Rodrigues de Oliveira Filho J, Bregion PB, Juca RH, Almiron da Rocha Soares G, Ivano VK. Efficacy and safety comparison of single anastomosis sleeve ileal bypass versus one anastomosis gastric bypass: a systematic review and meta-analysis. Surg Obes Relat Dis. 2025;21(11):1219-1231. doi:10.1016/j.soard.2025.07.012
  39. Mahdy T, Gado W, Alwahidi A, Schou C, Emile SH. Sleeve gastrectomy, one-anastomosis gastric bypass (OAGB), and single anastomosis sleeve ileal (SASI) bypass in treatment of morbid obesity: a retrospective cohort study. Obes Surg. 2021;31(4):1579-1589. doi:10.1007/s11695-020-05159-y
  40. Khalaf M, Hamed H. Single-anastomosis sleeve ileal (SASI) bypass: hopes and concerns after a two-year follow-up. Obes Surg. 2020;31(2):667-674. doi:10.1007/s11695-020-04945-y
  41. Romero RJ, Colorado-Subizar R, De Uriarte-Lorente M, Barradas-Lagunes M, Ávila PBD, Romero-Espejo JJ. Single anastomosis sleeve ileal bypass (SASI bypass): short-term outcomes and concerns. Obes Surg. 2021;31(5):2339-2343. doi:10.1007/s11695-020-05145-4
  42. Madyan A, Emile SH, Abdel-Razik MA, Ellithy R, Elbanna HG, Elshobaky A. Laparoscopic single anastomosis sleeve ileal (SASI) bypass for patients with morbid obesity: technical description and short-term outcomes. Surg Laparosc Endosc Percutan Tech. 2020;30(2):e13-e17. doi:10.1097/sle.0000000000000763
  43. Saber AA, Shoar S, Khoursheed M. Intra-thoracic sleeve migration (ITSM): an underreported phenomenon after laparoscopic sleeve gastrectomy. Obes Surg. 2017;27(8):1917-1923. doi:10.1007/s11695-017-2589-6
  44. Ataya K, Patel N, Aljaafreh A, et al. Global Obesity Collaborative. Outcomes of single anastomosis sleeve ileal (SASI) bypass as an alternative procedure in treating obesity: an updated systematic review and meta-analysis. Obes Surg. 2024;34(9):3285-3297. doi:10.1007/s11695-024-07366-3
  45. Chu Y, Widjaja J, Wang J, et al. Comparison of three different anastomotic methods of sleeve gastrectomy with transit bipartition using an obese rodent model. Sci Rep. 2023;13(1):21247. doi:10.1038/s41598-023-48059-8
  46. Demir C, Arslan E, Sariyildiz G, Anil C, Banli O. Laparoscopic sleeve gastrectomy with transit loop bipartition and transit bipartition in type 2 diabetic patients with obesity: a retrospective analysis. Surg Laparosc Endosc Percutan Tech. 2023;33(4):357-364. doi:10.1097/sle.0000000000001189
  47. Tinoco A, Gottardi LF, Boechat ED. Gastric cancer in the excluded stomach 10 years after gastric bypass. Surg Case Rep. 2015;2015:1-3. doi:10.1155/2015/468293
  48. Wu W, Widjaja J, Lu S, Hong J, Yao L, Zhu X. Comparison of the outcomes of single anastomosis duodeno-ileostomy with sleeve gastrectomy (SADI-S), single anastomosis sleeve ileal (SASI) bypass with sleeve gastrectomy, and sleeve gastrectomy using a rodent model with diabetes. Obes Surg. 2022;32(4):1209-1215. doi:10.1007/s11695-022-05920-5
  49. M, Sartori A, Zulian V, Iannelli A. Reviving weight loss and metabolic obesity-related comorbidities: mid-term results of single anastomosis sleeve ileal (SASI) bypass for failed sleeve gastrectomy. A retrospective cohort study. Int J Surg. 2025;111(10):6961-6969. doi:10.1097/JS9.0000000000002874
  50. Aghajani E, Schou C, Gislason H, Nergaard BJ. Mid-term outcomes after single anastomosis sleeve ileal (SASI) bypass in treatment of morbid obesity. Surg Endosc. 2023;37(8):6220-6227. doi:10.1007/s00464-023-10112-y
  51. Hage K, Perrotta G, Betancourt RS, et al. Future prospects of metabolic and bariatric surgery: a comprehensive review. Healthcare (Basel). 2024;12(17):1707. doi:10.3390/healthcare12171707
  52. Vennapusa A, Panchangam BRK, Madivada MSS. A feasibility study of novel "laparoscopic sleeve gastrectomy with loop gastroileal bypass" for obesity: an Indian experience. Int Surg J. 2017;102(11-12):504-513. doi:10.9738/intsurg-d-18-00007.1
  53. Mui WLM, Lee DWH, Lam KKY. Laparoscopic sleeve gastrectomy with loop bipartition: A novel metabolic operation in treating obese type II diabetes mellitus. Int J Surg Case Rep. 2013;5(2):56-58. doi:10.1016/j.ijscr.2013.12.002
  54. Al M, Taskin HE. Weight loss, type 2 diabetes, and nutrition in 355 patients with obesity undergoing sleeve gastrectomy with transit bipartition: two-year outcomes. Obes Facts. 2022;15(5):717-729. doi:10.1159/000526718
  55. Valezi AC, Campos ACL, Von Bahten LC. Brazilian multi-society position statement on emerging bariatric and metabolic surgical procedures. ABCD Arq Bras Cir Dig. 2023;36:e1759. doi:10.1590/0102-672020230041e1759
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Surgical Technology International, Electronic ISSN: 1090-3941 Published by AccScience Publishing
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