Ileal Interposition is not only specifically a bariatric surgery, but also is used
to treat diseases that target the metabolic syndrome such as T2DM. Moreover, both
foregut (excluding of the duodenum) and hindgut mechanisms are utilized in these procedures
11], 14], 15]. These procedures not only for obese subjects, but is also used for non-obese subjects
8], 16]–18].
Several studies have shown that these types of surgical procedures can improve glycemic
control, (including reductions in HbA1c, fasting blood glucose (FBG), postprandial
glucose (PPG)) and also may improve the metabolic parameters. These results persisted
in all patients during the 3-year follow-up 12], 16]–18].
Weight loss by these procedures was attributed to the increased release of peptides
secreted in the ileum, GLP-1 and peptide YY (PYY), which has anorectic effects 19]. In the ileal interposition procedure, earlier exposure of food to ileum and rapid
stimulation of the interposed ileal segment by ingested food leads to augmented glucagon-like
peptide 1 (GLP-1) secretion 12], 17]. GLP-1 resulted in delaying gastric emptying, promotes satiety, suppressing appetite,
inhibiting glucagon secretion, decreasing gluconeogenesis, and stimulating the glycogenesis
20], 21].
Ghrelin stimulates the secretion of hyperglycemic hormones such as glucagon, cortisol
and growth hormone and also inhibit insulin secretion. Ghrelin is an orexigenic hormone
(appetite stimulant). In the SG component of the IISG and IIDSG procedures, serum
level of ghrelin is reduced and patients feel satiety and restrict their caloric intake
22]–24].
Ileal Interposition is a procedure that does not lead to malabsorption. In IIDSG procedure,
duodenum and part of the jejunum are bypassed and can cause malabsorption. All patients
are recommended to take iron, calcium, B12, and multivitamins supplementation regularly
12], 25].
De paula et al. in their study have reported objective improvement of retinopathy
and symptomatic improvement in neuropathy 18]. Also, other studies have reported that after the metabolic surgery, a significant
reduction in oral hypoglycemic agents (OHAs) and insulin therapy was observed for
glycemic control 11], 17], 18].
Usually, patients with shorter duration of diabetes, higher BMI (Body Mass Index)
and higher C-peptide level respond better to these surgical procedures 11], 26], 27].
In some studies minor and early postoperative complications such as vomiting, esophagitis,
bowel obstruction, gout, and urinary tract infection have been observed. But so far,
no major long-term surgical complications have been reported 18], 23]. In advanced T2DM, iatrogenic hypoglycemia can be a limiting factor for these procedures
28].
In a study published recently, Ugale et al. introduced a novel tool known as Diabetes
Remission Score (DRS) for choosing the type of surgery and predicting diabetes remission
following IISG or IIDSG. The study aimed at presenting an effective and useful method
based on parameters such as the duration of diabetes, BMI and stimulated C-peptide
response prior to surgery for predicting post surgery diabetes remission 8]. The DRS included three grades as grade 1 (mild, DRS 7–8), grade 2 (moderate, 9–11)
and grade 3 (severe, DRS 12–14). Higher scores could be associated with lower chance
of remission.
In conclusion, the results of various studies have shown the safety, feasibility,
and efficacy of the surgical procedure for the treatment of T2DM. Although it is an
effective treatment option, this procedure is not recommended for general use and
long-term studies are needed to confirm these findings and potential side effects
on a larger number of patients.