The gastrointestinal tract is the site of most drug delivery and therapeutic interventions for the management and treatment of numerous diseases. However, selective access to its mucosa, especially in the small bowel, is challenging. Here we develop an orally administered gut-coating formulation that provides a transient coating of the bowel. Through a materials screening campaign, we identified a sucrose octasulfate aluminium complex and further engineered the pH-dependent material into a complex coacervate formulation linked via pH-independent electrostatic interaction, which allowed an effective transient physical coating on the gastrointestinal mucosa, independent of gastric acid exposure. We tested the therapeutic values of this technology in two settings. Oral administration of this gut-coating formulation modulated the nutrient contact with bowel mucosa, which lowered the glucose responses in rodent models indicating a potential therapeutic utility in diabetes. Furthermore, the formulation protected biological agents from gastric acid exposure and degradation, which enabled oral delivery to the small bowel mucosa.

Bhutta HY, Deelman TE, le Roux CW, Ashley SW, Rhoads DB, Tavakkoli A. Intestinal sweet-sensing pathways and metabolic changes after Roux-en-Y gastric bypass surgery. Am J Physiol Gastrointest Liver Physiol 307: G588 -G593, 2014. First published July 3, 2014 doi:10.1152/ajpgi.00405.2013.-Studies suggest that improvements in type 2 diabetes (T2D) post-Roux-en-Y gastric bypass (RYGB) surgery are attributable to decreased intestinal glucose absorption capacity mediated by exclusion of sweet taste-sensing pathways in isolated proximal bowel. We probed these pathways in rat models that had undergone RYGB with catheter placement in the biliopancreatic (BP) limb to permit post-RYGB exposure of isolated bowel to sweet taste stimulants. Lean Sprague Dawley (n ϭ 13) and obese Zucker diabetic fatty rats (n ϭ 15) underwent RYGB with BP catheter placement. On postoperative day 11 (POD 11), rats received catheter infusions of saccharin [sweet taste receptor (T1R2/3) agonist] or saline (control). Jejunum was analyzed for changes in glucose transporter/sensor mRNA expression and functional sodium-glucose transporter 1 (SGLT1)-mediated glucose uptake. Saccharin infusion did not alter glucose uptake in the Roux limb of RYGB rats. Intestinal expression of the glucose sensor T1R2 and transporters (SGLT1, glucose transporter 2) was similar in saccharin-vs. saline-infused rats of both strains. However, the abundance of SGLT3b mRNA, a putative glucose sensor, was higher in the common limb vs. BP/Roux limb in both strains of bypassed rats and was significantly decreased in the Roux limb after saccharin infusion. We concluded that failure of BP limb exposure to saccharin to increase Roux limb glucose uptake suggests that isolation of T1R2/3 is unlikely to be involved in metabolic benefits of RYGB, as restimulation failed to reverse changes in intestinal glucose absorption capacity. The altered expression pattern of SGLT3 after RYGB warrants further investigation of its potential involvement in resolution of T2D after RYGB.Roux-en-Y gastric bypass; obesity; type 2 diabetes mellitus; intestinal sweet taste sensor; sodium-glucose transporter 1 IN RECENT DECADES, BARIATRIC SURGERY has evolved into the foremost therapy for obesity. Moreover, one of the weight loss operations, Roux-en-Y Gastric Bypass surgery (RYGB), is associated with a high rate of remission of type 2 diabetes mellitus (T2D), with an early and weight-independent mechanism that improves glucose homeostasis (2, 17). However, the mechanisms mediating the resolution of T2D remain poorly understood.Intense investigation of contributory factors has implicated several mechanisms, including alterations in incretin levels, the gut microbiome, bile acids, and an area of interest to our lab, namely intestinal nutrient sensing. The surgical isolation of duodenum and proximal jejunum appear to be critical in mediating resolution of T2D, supported by outcomes following endoluminal sleeve device insertion and surgical procedures (e.g., RYGB, biliopancreatic diversion), which exclude a sim...