Role of Small Intestinal Bacterial Overgrowth (SIBO) and Inflammation in Obese Children

Susanna Esposito; Anna Biscarini; Barbara Federici; Marta Cofini; Alberto Argentiero; Cosimo Neglia; Lucia Lanciotti; Gian Luigi De' Angelis; Nicola Principi

doi:10.3389/fped.2020.00369

Role of Small Intestinal Bacterial Overgrowth (SIBO) and Inflammation in Obese Children

Front Pediatr. 2020 Jul 7:8:369. doi: 10.3389/fped.2020.00369. eCollection 2020.

Authors

Susanna Esposito¹, Anna Biscarini², Barbara Federici³, Marta Cofini², Alberto Argentiero¹, Cosimo Neglia¹, Lucia Lanciotti², Gian Luigi De' Angelis³, Nicola Principi^{4

5}

Affiliations

¹ Pediatric Clinic, Department of Medicine and Surgery, Pietro Barilla Children's Hospital, University of Parma, Parma, Italy.
² Pediatric Clinic, Department of Surgical and Biomedical Sciences, Università degli Studi di Perugia, Perugia, Italy.
³ Gastroenterology Unit, Santa Maria della Misericordia Hospital, Perugia, Italy.
⁴ Unit of Gastroenterology and Digestive Endoscopy, Department of Medicine and Surgery, University of Parma, Parma, Italy.
⁵ Università degli Studi di Milano, Milan, Italy.

Abstract

Knowledge of the real incidence of small intestinal bacterial overgrowth (SIBO) in obese children and its role in obesity development seems essential for a more effective approach to the treatment of this condition. In this prospective, single-blind study, presence of SIBO was evaluated in a group of children with overweight/obesity. A blood sample for evaluation of cytokine profile was collected to establish the potential relationship with inflammatory condition and lactulose breath test (LBT) to diagnose SIBO was performed. A total of 36 patients with excess of adipose tissue were recruited. Among them, 16 (44.4%) were overweight and 20 (45.6%) were obese. Overall, 26 (72.2%) children had a positive LBT and were considered suffering from SIBO, 12 (75.0%) among those overweight and 14 (70.0%) among those obese. Measurement of cytokines (IL-1α, IL-1β, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12p40, IL-12p70, IL-17, IFN-α2, IFN-γ, TNF-α), cytokine antagonists (IL-1ra), chemokines (IP10, MCP-1, MIP1α, MIP1β), and growth factors (EGF, G-CSF, GM-CSF, and VEGF) secreted in culture supernatants by PHA activated-PBMCs revealed that in the study population proinflammatory cytokines IL-1, IL-6, IL-8, IL-12, IFN-γ, IL-18, and TNF-α were high, whereas anti-inflammatory mediators IL-4 and IL-10 were low. However, no significance difference between children with SIBO and those without were evidenced. Evaluation of relationship of severity of SIBO showed a significant positive relationship between EGF or IFN-α2 and H2 but not CH4 levels and an inverse significant relationship with CH4 but not H2. Despite its limitations and further studies are needed, this study seems to indicate that SIBO is extremely common in overweight and obese children and can be demonstrated not only in severely obese subjects but also in moderately overweight patients. The inflammatory state seems to precede obesity development and SIBO does not seem to have relevance in obesity development, with no relationship found between severity of SIBO and inflammatory state.

Keywords: chemokines; cytokines; inflammation; obesity; overweight; small intestinal bacterial overgrowth.