Fat digestion using RELiZORB in children with short bowel syndrome who are dependent on parenteral nutrition: Protocol for a 90-day, phase 3, open labeled study.

BACKGROUND: Short bowel syndrome (SBS) is a leading cause of intestinal failure resulting in parenteral nutrition (PN) dependence and nutritional deficiencies. Long-term PN use is associated with the development of sepsis and intestinal failure-associated liver disease. Achieving enteral autonomy is the optimal way to prevent these complications. In SBS, the decreased intestinal length, bile acid deficiency, and rapid transit time contribute to fat malabsorption and continued PN dependence. We propose the use of an immobilized lipase cartridge (ILC; RELiZORB) that connects in-line with enteral feed tubing sets and is designed to breakdown the majority of fats provided in enteral nutrition (EN). Preclinical studies have demonstrated both improved fat and fat-soluble vitamin absorption with ILC use in a porcine model of SBS. To evaluate the clinical applicability of these findings, we designed a phase 3, open labeled, single center, clinical trial to determine the safety, tolerability, and efficacy of the RELiZORB enzyme cartridge when used daily with EN for 90 days. METHODS: The patient population will include PN dependent children with SBS, aged 2-18 years. The primary outcome is the change in PN calories from baseline, assessed weekly throughout the study. Changes in growth Z-scores, 72-hour fecal fat and coefficient of fat absorption, plasma fatty acids and fat-soluble vitamins will also be evaluated. Assessment of change in continuous outcomes will be made using the area under the curve, expressed as a percent change relative to baseline, calculated over study day 7 to 90 (AUC7-90). The incidence of adverse events will be monitored and summarized by system organ class. DISCUSSION: If successful, RELiZORB may offer a safe alternative to reducing PN dependence and achieving enteral autonomy in pediatric intestinal failure. These results would be clinically significant given the clear association between long-term PN use and complications in SBS. TRIAL REGISTRATION: ClinicalTrials.gov NCT03530852; registered on May 21st, 2018, last update posted on September 14th, 2022.

A Digestive Cartridge Reduces Parenteral Nutrition Dependence and Increases Bowel Growth in a Piglet Short Bowel Model.

OBJECTIVE: To determine whether the use of an immobilized lipase cartridge (ILC) to hydrolyze fats in enteral nutrition (EN) reduces parenteral nutrition (PN) dependence in a porcine model of short bowel syndrome with intestinal failure (SBS-IF). BACKGROUND: SBS-IF occurs after intestinal loss resulting in malabsorption and PN dependence. Limited therapeutic options are available for achieving enteral autonomy. METHODS: Eleven Yorkshire piglets underwent 75% jejunoileal resection and were randomized into control (n=6) and treatment (n = 5) groups. PN was initiated postoperatively and reduced as EN advanced if predefined clinical criteria were fulfilled. Animals were studied for 14 days and changes in PN/EN calories were assessed. Intestinal adaptation, absorption, and nutrition were evaluated at the end of the study (day 15). Comparisons between groups were performed using analysis of covariance adjusted for baseline. RESULTS: ILC animals demonstrated a 19% greater reduction in PN calories ( P < 0.0001) and higher mean EN advancement (66% vs 47% of total calories, P < 0.0001) during the 14-day experiment. Treatment animals had increased intestinal length (19.5 vs 0.7%, P =0.03) and 1.9-fold higher crypt cell proliferation ( P =0.02) compared with controls. By day 15, ILC treatment resulted in higher plasma concentrations of glucagon-like peptide-2 ( P = 0.02), eicosapentaenoic acid ( P < 0.0001), docosahexaenoic acid ( P = 0.004), vitamin A ( P = 0.02), low-density lipoprotein ( P = 0.02), and high-density lipoprotein ( P = 0.04). There were no differences in liver enzymes or total bilirubin between the two groups. CONCLUSIONS: ILC use in conjunction with enteral feeding reduced PN dependence, improved nutrient absorption, and increased bowel growth in a porcine SBS-IF model. These results support a potential role for the ILC in clinical SBS-IF.

Outcomes and Perioperative Nutritional Management in a Porcine Model of Short Bowel Syndrome.

INTRODUCTION: Short bowel syndrome (SBS) results from significant intestinal loss and is characterized by insufficient absorption of nutrients and fluids. Preclinical large animal SBS models typically require parenteral nutrition (PN) support and may not be appropriate for studying interventions to improve intestinal absorption or adaptation. Here, we describe the development of a porcine SBS model that does not require PN support. METHODS: Eight male Yorkshire piglets underwent either a 75% or 90% jejunoileal resection (n = 5) or no resection (n = 3). Continuous enteral nutrition (EN) was provided via a gastrostomy tube. The final SBS model consisted of a 75% resection and nutrition provided via combination EN (60%) and per oral pig chow (40%). Body weight and concentration of fat-soluble vitamins were assessed on postoperative days (POD) 7, 14, and 21. For assessing fat malabsorption, the coefficient of fat absorption (CFA) was calculated following a 72-h stool collection. RESULTS: Resected animals had decreased weight gain compared to unresected controls (POD21 + 8.3% versus +28.8%, P = 0.048). Vitamin D concentration was significantly lower in resected animals compared to controls on POD 7, POD 14, and POD 21. Serum vitamin E concentration was also lower on POD 21. Resected animals developed fat malabsorption with lower CFA (76.5% versus 95.3%, P = 0.014). CONCLUSIONS: We describe the development of a porcine SBS model that does not require PN support. Piglets in this model gain less weight, demonstrate fat malabsorption, and develop fat-soluble vitamin deficiencies. This model will benefit investigations of intestinal absorption or adaptation while potentially decreasing costs and confounding complications related to PN administration.

Yeast Chfr homologs retard cell cycle at G1 and G2/M via Ubc4 and Ubc13/Mms2-dependent ubiquitination.

Checkpoint with forkhead-associated and RING (Chfr) is a ubiquitin ligase (E3) that establishes an antephase or prometaphase checkpoint in response to mitotic stress. Though ubiquitination is essential for checkpoint function, the sites, linkages and ubiquitin conjugating enzyme (E2) specificity are controversial. Here we dissect the function of the two Chfr homologs in S. cerevisiae, Chf1 and Chf2, overexpression of which retard cell cycle at both G(1) and G(2). Using a genetic assay, we establish that Ubc4 is required for Chf2-dependent G(1) cell cycle delay and Chf protein turnover. In contrast, Ubc13/Mms2 is required for G(2) delay and does not contribute to Chf protein turnover. By reconstituting cis and trans-ubiquitination activities of Chf proteins in purified systems and characterizing sites modified and linkages formed by tandem mass spectrometry, we discovered that Ubc13/Mms2- dependent modifications are a distinct subset of those catalyzed by Ubc4. Mutagenesis of Lys residues identified in vitro indicates that site-specific Ubc4-dependent Chf protein autoubiquitination is responsible for Chf protein turnover. Thus, combined genetic and biochemical analyses indicate that Chf proteins have dual E2 specificity accounting for different functions in the cell cycle.