Barrier Of Gastrointestinal Tract Research Articles

New insights into nanomedicines for oral delivery of glucagon-like peptide-1 analogs.

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that arises when the body cannot respond fully to insulin, leading to impaired glucose tolerance. Currently, the treatment embraces non-pharmacological actions (e.g., diet and exercise) co-associated with the administration of antidiabetic drugs. Metformin is the first-line treatment for T2DM; nevertheless, alternative therapeutic strategies involving glucagon-like peptide-1 (GLP-1) analogs have been explored for managing the disease. GLP-1 analogs trigger insulin secretion and suppress glucagon release in a glucose-dependent manner thereby, reducing the risk of hyperglycemia. Additionally, GLP-1 analogs have an extended plasma half-life compared to the endogenous peptide due to their high resistance to degradation by dipeptidyl peptidase-4. However, GLP-1 analogs are mainly administered via subcutaneous route, which can be inconvenient for the patients. Even considering an oral delivery approach, GLP-1 analogs are exposed to the harsh conditions of the gastrointestinal tract (GIT) and the intestinal barriers (mucus and epithelium). Hereupon, there is an unmet need to develop non-invasive oral transmucosal drug delivery strategies, such as the incorporation of GLP-1 analogs into nanoplatforms, to overcome the GIT barriers. Nanotechnology has the potential to shield antidiabetic peptides against the acidic pH and enzymatic activity of the stomach. In addition, the nanoparticles can be coated and/or surface-conjugated with mucodiffusive polymers and target intestinal ligands to improve their transport through the intestinal mucus and epithelium. This review focuses on the main hurdles associated with the oral administration of GLP-1 and GLP-1 analogs, and the nanosystems developed to improve the oral bioavailability of the antidiabetic peptides. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

A comparative analysis of gastrointestinal tract barrier function and immune markers in gilt vs. sow progeny at birth and weaning.

Progeny born to primiparous sows (gilt progeny; GP) have lower birth, weaning and slaughter weights than sow progeny (SP). GP also have reduced gastrointestinal tract (GIT) development, as evidenced by lower organ weights. Therefore, the aim of this experiment was to quantify changes in GIT barrier function that occur in birth and weaning, representing two major challenges to the young piglet. The effects of parity (GP vs. SP) in GIT barrier integrity function were quantified at four timepoints: birth (~0h), 24h after birth (24h), 1-d preweaning (PrW), and 1-d postweaning (PoW) in commercially reared piglets. Due to inherent differences between newborn and weanling pigs, the results were analyzed in two cohorts, birth (0 vs. 24h, n = 31) and weaning (PrW vs. PoW, n = 40). Samples of the stomach, jejunum, ileum, and colon were excised after euthanasia and barrier integrity was quantified by measuring transepithelial resistance (TER), macromolecular permeability, the abundance of inflammatory proteins (IL-8, IL-1β, and TNF-α) and tight junction proteins (claudin-2 and -3). Papp was characterized using a dual tracer approach comprising 4 KDa fluorescein isothiocyanate (FD4) and 150kDa tetramethyl rhodamine isothiocyanate (T150)-labeled dextrans. Characteristic effects of the initiation of feeding and weaning were observed on the GIT with the initiation of feeding, such as increasing TER and reducing Papp at 24h, consistent with mucosal growth (P = 0.058) This was accompanied by increased cytokine abundance as evidenced by elevations in TNF-α and IL-1β. However, GP had increased IL-8 abundance (P = 0.011 and 0.063 for jejunum and ileum respectively) at birth than 24h overall. In the weaning cohort, jejunal and ileal permeability to FD4 was higher in GP (P = 0.05 and 0.022, respectively) while only higher ileal T150 was observed in GP (P = 0.032). Ileal claudin-2 abundance tended to be higher in SP overall (P = 0.063), but GP ileal claudin-2 expression was upregulated weaning while no change was observed in SP (P = 0.043). Finally, other than a higher jejunal TNF-α abundance observed in SP (P = 0.016), no other effect of parity was observed on inflammatory markers in the weaning cohort. The results from this study indicate that the GIT of GP have poorer adaptation to early life events, with the response to weaning, being more challenging which is likely to contribute to poorer postweaning growth.

Exploiting Apical Sodium-Dependent Bile Acid Transporter (ASBT)-Mediated Endocytosis with Multi-Functional Deoxycholic Acid Grafted Alginate Amide Nanoparticles as an Oral Insulin Delivery System.

Oral administration of insulin is a potential candidate for managing diabetes. However, it is obstructed by the gastrointestinal tract barriers resulting in negligible oral bioavailability. This investigation presents a novel nanocarrier platform designed to address these challenges. In this regard, the process involved amination of sodium alginate by ethylene diamine, followed by its conjugation with deoxycholic acid. The resulting DCA@Alg@INS nanocarrier revealed a significantly high insulin loading content of 63.6 ± 1.03% and encapsulation efficiency of 87.6 ± 3.84%, with a particle size of 206 nm and zeta potentials of -3 mV. In vitro studies showed sustained and pH-dependent release profiles of insulin from nanoparticles. In vitro cellular studies, confocal laser scanning microscopy and flow cytometry analysis confirmed the successful attachment and internalization of DCA@Alg@INS nanoparticles in Caco-2 cells. Furthermore, the DCA@Alg@INS demonstrated a superior capacity for cellular uptake and permeability coefficient relative to the insulin solution, exhibiting sixfold and 4.94-fold enhancement, respectively. According to the uptake mechanism studies, the results indicated that DCA@Alg@INS was mostly transported through an energy-dependent active pathway since the uptake of DCA@Alg@INS by cells was significantly reduced in the presence of NaN3 by ~ 92% and at a low temperature of 4°C by ~ 94%. Given the significance of administering insulin through oral route, deoxycholic acid-modified alginate nanoparticles present a viable option to surmount various obstacles presented by the gastrointestinal.

Effects of a multispecies direct-fed microbial on gastrointestinal permeability during feed restriction in a growing heifer model

The objectives were to evaluate the effects of a 4-strain direct-fed microbial (DFM) on gastrointestinal tract (GIT) permeability and inflammation during feed restriction (FR) in heifers. Holstein heifers (n = 32; mean ± standard deviation; 295 ± 25 kg body weight; 287 ± 17 d of age) were used in an experiment conducted in 2 replicates (16/replicate). Heifers were randomly assigned to 1 of 2 top-dressed dietary treatments: (1) control (CON; 10 g/d dried lactose; n = 16) or (2) DFM containing a commercial blend of Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus licheniformis, and Bacillus subtilis at 11.8 × 109 cfu/d (PRO; 10 g/d 4-strain DFM; n = 16). The trial consisted of 2 experimental periods (P): P1 (14 d) served as baseline for P2 (5 d), when all heifers were restricted to 40% of their P1 dry matter intake (DMI). On P1 d 12 and P2 d 2 and 5, GIT permeability was evaluated using oral chromium (Cr)-EDTA. By design, FR decreased DMI (60%) and body weight (∼18 kg) in all heifers. Regardless of treatment, during FR, all heifers had decreased circulating glucose, β-hydroxybutyrate, insulin, and l-lactate (4, 14, 45, and 19%, respectively), but increased nonesterified fatty acids, serum amyloid A, and haptoglobin (3.0-, 1.7-, and 5.0-fold, respectively). Circulating white blood cells, neutrophils, lymphocytes, and basophils decreased (4, 7, 5, and 6%, respectively), whereas eosinophils increased (41%) during P2 irrespective of dietary treatment. Circulating IFN-γ inducible protein-10 increased (23%) during FR compared with P1 regardless of treatment. Plasma Cr area under the curve increased in all heifers on d 2 and 5 (10 and 14%, respectively) of P2 relative to P1, but this was unaltered by dietary treatment. In summary, FR compromised GIT barrier function and stimulated an inflammatory response, but this did not appear to be ameliorated by PRO.

21 Intentionally Induced Barrier Dysfunction Causes Inflammation, Decreases Growth, and Alters Carcass Characteristics of Feedlot Cattle

Abstract There are a variety of acute and chronic psychological and physical stressors associated with management practices used in beef production systems. Primary challenges in feedlot cattle include heat stress, acute and subacute acidosis, weaning, transportation, feed deprivation/restriction, and social mixing/crowding. These stressors disturb the homeostatic state of the host and microbiome and cause acute or chronic inflammation resulting in damage to the gastrointestinal tract (GIT) epithelial barrier that leaves the animal vulnerable to enteric pathogens and toxins. A breach of the small intestinal barrier (leaky gut) allows unwanted pathogens and toxins to infiltrate into blood, causing infection, depressed feed intake, and diverts nutritional resources away from anabolic processes. We have demonstrated that intentionally inducing GIT inflammation in feedlot cattle with aspirin, which is known to cause mucosal injury and increase GIT barrier dysfunction, provides a model system to better understand the metabolic cost of leaky gut in grain-fed feedlot cattle. Indeed, aspirin increased leakage of chromium-EDTA into urine, raised serum concentrations of lipopolysaccharide binding protein (LBP), decreased growth by 4.5 to 8.5%, and re-partitioned carcass components from lean tissue (rib-eye area) into fat. Thus, the chronic inflammatory effects of leaky gut have the potential to create a significant economic loss. Our work also shows that in-feed administration of monensin and tylosin have offered a solution to the non-specific immune response observed in grain-fed cattle by increasing jejunal villus height to crypt depth ratio, diminishing leaky gut, and decreasing serum LBP. Finally, we have observed that molasses based liquid supplements increase ruminal butyrate concentration, resulting in improved gut barrier function, decreased serum inflammatory markers, and greater DMI and ADG in newly received feedlot cattle fed a 30% roughage diet.

PH-triggered dynamic erosive small molecule chlorambucil nano-prodrugs mediate robust oral chemotherapy

Currently, the dynamic erosive small molecule nano-prodrug is of great demand for oral chemotherapy, owing to its precise structure, high drug loading and improved oral bioavailability via overcoming various physiologic barriers in gastrointestinal tract, blood circulation and tumor tissues compared to other oral nanomedicines. Herein, this work highlights the successful development of pH-triggered dynamic erosive small molecule nano-prodrugs based on in vivo significant pH changes, which are synthesized via amide reaction between chlorambucil and star-shaped ortho esters. The precise nano-prodrugs exhibit extraordinarily high drug loading (68.16%), electric neutrality, strong hydrophobicity, and dynamic large-to-small size transition from gastrointestinal pH to tumoral pH. These favorable physicochemical properties can effectively facilitate gastrointestinal absorption, blood circulation stability, tumor accumulation, cellular uptake, and cytotoxicity, therefore achieving high oral relative bioavailability (358.72%) and significant tumor growth inhibition while decreasing side effects. Thus, this work may open a new avenue for robust oral chemotherapy attractive for clinical translation.

NEW ONSET OF INFLAMMATORY BOWEL DISEASE IN A PATIENT WITH EOSINOPHILIC ESOPHAGITIS: 10-YEAR CONSTELLATION OF AUTOIMMUNE GASTROINTESTINAL DISORDERS

Inflammatory bowel disease (IBD) is well known for concurrent immune-mediated disorders such as eosinophilic esophagitis, psoriasis, and rheumatoid arthritis. (1) For the past two decades, we are seeing an increased occurrence of eosinophilic esophagitis (EoE) in long standing IBD patients (2) (3) (4), but the question has arisen as to new onset IBD in chronic EoE patients. One study that involved 4814 patients demonstrated that the prevalence of eosinophilic esophagitis in IBD was 5 times higher compared to general population and EoE in IBD is 2 times higher than expected. (5) Multiple factors have been identified that may trigger the exact inflammatory response in IBD and EoE patients. Both diseases are associated with an exaggerated response to interleukins, especially IL-13 sharing cytokines and helper T cell mediated pathophysiology that is linked to disruption of the gastrointestinal tract barrier. (6) (7).

NEW ONSET OF INFLAMMATORY BOWEL DISEASE IN A PATIENT WITH EOSINOPHILIC ESOPHAGITIS: 10-YEAR CONSTELLATION OF AUTOIMMUNE GASTROINTESTINAL DISORDERS

Abstract INTRODUCTION Inflammatory bowel disease (IBD) is well known for concurrent immune-mediated disorders such as eosinophilic esophagitis, psoriasis, and rheumatoid arthritis.(1) For the past two decades, we are seeing an increased occurrence of eosinophilic esophagitis (EoE) in long standing IBD patients (2) (3) (4), but the question has arisen as to new onset IBD in chronic EoE patients. One study that involved 4814 patients demonstrated that the prevalence of eosinophilic esophagitis in IBD was 5 times higher compared to general population and EoE in IBD is 2 times higher than expected.(5) Multiple factors have been identified that may trigger the exact inflammatory response in IBD and EoE patients. Both diseases are associated with an exaggerated response to interleukins, especially IL-13 sharing cytokines and helper T cell mediated pathophysiology that is linked to disruption of the gastrointestinal tract barrier. (6) (7) CASE DESCRIPTION A 25-year-old healthy male presented back in 2012 with a history of three months of worsening dysphagia that resulted in 15-lb weight loss. Upper endoscopy showed esophagus with small caliber lumen, linear furrows, and thin concentric rings with microscopic evidence of eosinophilic esophagitis. Over the years he developed multiple episodes of persistent dysphagia, several endoscopies demonstrated pangastritis and duodenitis with a new pyloric and duodenal bulb stricture. Due to his remitting-relapsing course despite long-term medical treatment, patient underwent additional workup including an abdominal CT and upper endoscopy that showed worsening of the pyloric stricture that improved after balloon dilation. In 2020, the patient developed diarrhea, rectal bleeding, generalized abdominal pain and 21 lb weight loss despite medical treatment. Colonoscopy showed multiple erosions in the ileum and rectum not seen on previous studies. The biopsy indicated ulcerated mucosa with necrosis in the ileum and rectal area with mixed inflammatory infiltration with the presence of a non-caseating granuloma consistent with Chron’s disease. DISCUSSION It is unclear which disease manifest first or if it is a clustering and co-occurrence of diseases. The fact that both diseases share the same pathogenetic mechanism with overexpression of mucosal interleukin-13 (IL-13) causing loss of functionality of the gastrointestinal barrier could explain symptoms observed on both. Many studies demonstrated that IBD was diagnosed before EoE in almost 2/3 of the cases. The association of EoE-IBD is found significantly more in males and occurs at a younger age compared to IBD alone. Further studies will be needed in order to confirm the co-occurrence of diseases because of the increased risk of IBD-related complications and higher chance of requiring systemic corticosteroids and anti-TNF therapy in patients who have coexisting EoE-IBD.

Effect of a molasses-based liquid supplement on gastrointestinal tract barrier function, inflammation, and performance of newly received feedlot cattle before and after a transport stress.

The objective of this study was to determine the effect of a dry versus a molasses-based liquid supplement on ruminal butyrate concentration, gastrointestinal tract (GIT) barrier function, inflammatory status, and performance of newly received feedlot cattle. In experiment 1, 60 mixed breed steers (234 ± 2.1 kg) were weaned, held overnight at a sale barn, then transported 14 h to Purdue University. After arrival, steers were weighed, blocked by body weight, and allotted within block to treatments (six pens per treatment and five steers per pen). Diets consisted of 45% roughage and 55% concentrate (dry matter basis). Treatments differed in the supplement source as follows: DRY: 10% dry supplement or LIQUID: 10% liquid molasses-based supplement. Feed intake, average daily gain (ADG), and gain:feed were determined for the three 21-d periods and overall. In experiment 2, 16 crossbred heifers (246 ± 7.5 kg) were used (8 heifers per treatment). Diets were the same as in experiment 1 and were fed for 60 d. On d 56 ruminal fluid samples were collected at 0, 3, 6, and 9 h after feeding. To mimic a stress event, heifers were transported for 4 h on d 61, rested overnight, and transported 12 h on d 62. Blood was collected from heifers immediately prior to transport and immediately upon their return. Gut barrier function using a Cr-EDTA marker was determined after transportation. Data were analyzed using the GLIMMIX procedure of SAS. Steers fed the liquid supplement had greater (P ≤ 0.03) ADG through d 42 and overall compared to steers fed the dry supplement. Feed intake did not differ (P = 0.25) between treatments from d 0 to d 21. However, steers fed the liquid supplement showed greater (P < 0.001) dry matter intake after d 21 and overall compared to those fed the dry supplement. Steers fed the liquid supplement tended (P < 0.09) to have reduced serum haptoglobin and lipopolysaccharide-binding protein (LBP) compared to those fed the dry supplement. Heifers fed the liquid supplement had greater (P = 0.02) Cr in urine and tended (P = 0.07) to have lower serum LBP after transport compared to those fed the dry supplement. Heifers fed the liquid supplement had 72% lower serum haptoglobin before, but only a 19% lower serum haptoglobin after transport compared to animals fed the dry supplement (treatment × time; P = 0.07). Therefore, the liquid supplement altered GIT barrier function, and improved inflammatory status, resulting in increased growth of receiving cattle.

Evaluation of the Anticancer and Probiotic Potential of Autochthonous (Wild) Lacticaseibacillus paracasei Strains from New Ecological Niches as a Possible Additive for Functional Dairy Foods.

Probiotics such as Lactobacillus spp. could modulate the intestinal microbiota composition, supporting gastrointestinal tract barrier function and benefiting human health. To evaluate the anticancer and probiotic properties of potentially active autochthonous Lacticaseibacillus paracasei strains on proliferating and differentiated enterocytes, human colon adenocarcinoma cell line HT29 was used as a model. The lactic acid bacteria (LAB) were isolated from new ecological niches-mountain anthills populated by redwood ants (Formica rufa L.). Human colorectal adenocarcinoma cells (HT29, ATCC, HTB-38™) were treated for twenty-four hours with supernatants (SNs) derived from four strains of Lacticaseibacillus paracasei: P4, C8, C15 and M2.1. An MTT assay, alkaline phosphatase activity, IAP, Bax and Bcl-2 gene expression analysis (RT-qPCR) and the Bax/Bcl-2 ratio were evaluated. The MTT assay revealed that the observed effects varied among groups. However, 10% neutralized supernatants from P4, C8, C15 and M2.1 strains did not show cytotoxic effects. In contrast to non-differentiated cells, a significant (p &lt; 0.001) rise in ALP activity in all treatments, with an average of 18%, was established in differentiated cells. The IAP expression was remarkably downregulated in the differentiated M2.1 group (p &lt; 0.05) and upregulated in the non-differentiated P4 (p &lt; 0.05) and M2.1 (p &lt; 0.05) groups. The Bax/Bcl-2 quantity expression ratio in P4 was significantly (p &lt; 0.05) upregulated in proliferating cancer cells, but in P4- and M2.1-differentiated cells these values were downregulated (p &lt; 0.05). The obtained results indicate that the isolated L. paracasei strains possess anticancer and probiotic properties and could be used as additives for functional dairy foods and thus benefit human health.

Effects of dietary antioxidant supplementation on metabolism and inflammatory biomarkers in heat-stressed dairy cows

Heat-stress-induced inflammation may be ameliorated by antioxidant supplementation due to the purported effects of increased production of reactive oxygen species or oxidative stress on the gastrointestinal tract barrier. Thus, study objectives were to evaluate whether antioxidant supplementation [AGRADO Plus 2.0 (AP); EW Nutrition] affects metabolism and inflammatory biomarkers in heat-stressed lactating dairy cows. Thirty-two mid-lactation multiparous Holstein cows were assigned to 1 of 4 dietary-environmental treatments: (1) thermoneutral (TN) conditions and fed a control diet (TN-CON; n = 8), (2) TN and fed a diet with AP (10 g antioxidant; n = 8), (3) heat stress (HS) and fed a control diet (HS-CON; n = 8), or (4) HS and fed a diet with AP (HS-AP; n = 8). The trial consisted of a 23-d prefeeding phase and 2 experimental periods (P). Respective dietary treatments were top-dressed starting on d 1 of the prefeeding period and continued daily throughout the duration of the experiment. During P1 (4 d), baseline data were collected. During P2 (7 d), HS was artificially induced using an electric heat blanket (Thermotex Therapy Systems Ltd.). During P2, the effects of treatment, day, and treatment-by-day interaction were assessed using PROC MIXED of SAS (SAS Institute Inc.). Heat stress (treatments 3 and 4) increased rectal, vaginal, and skin temperatures (1.2°C, 1.1°C, and 2.0°C, respectively) and respiration rate (33 breaths per minute) relative to TN cows. As expected, HS decreased dry matter intake, milk yield, and energy-corrected milk yield (32%, 28%, and 28% from d 4 to 7, respectively) relative to TN. There were no effects of AP on body temperature indices or production. Milk fat, protein, and lactose concentrations remained unaltered by HS or AP; however, milk urea nitrogen was increased during HS regardless of AP supplementation (26% relative to TN). Circulating glucose remained unchanged by HS, AP, or time. Additionally, HS decreased circulating glucagon (29% from d 3 to 7 relative to TN), but there was no additional effect of AP. There was a tendency for nonesterified fatty acid concentrations to be increased in HS-AP cows throughout P2 (60% relative to TN-CON), whereas it remained similar in all other treatments. Blood urea nitrogen increased for both HS treatments from d 1 to 3 before steadily decreasing from d 5 to 7, with the overall increase being most pronounced in HS-CON cows (27% relative to TN-CON). Further, supplementing AP decreased blood urea nitrogen in HS-AP on d 3 relative to HS-CON (15%). Circulating serum amyloid A tended to be and lipopolysaccharide binding protein was increased by HS, but neither acute-phase protein was affected by AP. Overall, AP supplementation appeared to marginally alter metabolism but did not meaningfully alter inflammation during HS.

Advanced research on extracellular vesicles based oral drug delivery systems.

The oral route is the most convenient and simplest mode of administration. Nevertheless, orally administration of some commonly used therapeutic drugs, such as polypeptides, therapeutic proteins, small-molecule drugs, and nucleic acids, remains a major challenge due to the harsh gastrointestinal environment and the limited oral bioavailability. Extracellular vesicles (EVs) are diverse, nanoscale phospholipid vesicles that are actively released by cells and play crucial roles in intercellular communications. Some EVs have been shown to survive with the gastrointestinal tract (GIT) and can cross biological barriers. The potential of EVs to cross the GIT barrier makes them promising natural delivery carriers for orally administered drugs. Here, we introduce the uniqueness of EVs and their feasibility as oral drug delivery vehicles (ODDVs). Then we provide a general description of the different cellular EVs based oral drug delivery systems (ODDSs) currently under study and emphasize the contribution of endogenous features and multifunctional properties of EVs to the delivery performance. The current obstacles of moving EVs based ODDSs from bench to bedside are also discussed.

Curcumin encapsulation in self-assembled nanoparticles based on amphiphilic palmitic acid-grafted-quaternized chitosan with enhanced cytotoxic, antimicrobial and antioxidant properties

The practical application of curcumin (CUR) is greatly limited due to its instability, high hydrophobicity, low bioavailability, and inability to cross the mucosal barrier of gastrointestinal tract. To overcome these disadvantages, several delivery systems have been explored to formulate CUR for oral administration. Nanoparticles (NPs) can significantly enhance oral absorption, bioavailability and therapeutic efficacy of drug, however, NPs are limited by the gastrointestinal degradation, mucosal and epithelial barriers. A novel amphiphilic quaternary ammonium chitosan (N-2-HACC) based NP delivery carrier was prepared using palmitic acid (PA) to encapsulate CUR. Palmitoyl chitosan (PA-N-2-HACC) was characterized including FT-IR, 1H NMR, TGA, and CAC. The particle size of PA-N-2-HACC NPs and PA-N-2-HACC NPs loaded with CUR (CUR@PA-N-2-HACC NPs) was 231.6 ± 9.24 nm and 264.5 ± 4.31 nm. The encapsulation efficiency and loading capacity of CUR@PA-N-2-HACC NPs was 75.43 ± 1.25 % and 6.81 ± 0.16 %. CUR@PA-N-2-HACC NPs exhibited sustained and controlled release. Compared with the CUR, minimum inhibitory concentration of the CUR@PA-N-2-HACC NPs against Escherichia coli, Staphylococcus aureus and Candida albicans was reduced by 4.2 times, 1.6 times and 4.6 times, respectively. Moreover, the antioxidant activity of CUR@PA-N-2-HACC NPs was dose-dependent and higher than that of free CUR. The PA-N-2-HACC NPs show little toxicity and are a promising delivery system for encapsulating hydrophobic drugs.

140 Redefining gut Barrier Function for Beef and Dairy Cattle

Abstract Of the many roles that the gastrointestinal tract (GIT) must facilitate, coordinated regulation of molecule movement across the gastrointestinal is key. This coordinated regulation allows for nutrient absorption while limiting permeation of non-desired molecules and is referred to as barrier function. Barrier function of the GIT includes intrinsic, extrinsic, and immunological factors, but generally permeability assessments are conducted to evaluate the whole-animal response and most studies focus on the extrinsic components of GIT barrier function. Common approaches to evaluate GIT permeability include the use of inert external markers varying in size and their measurement in blood or urine. Methodology exists for ex vivo, in vitro, and in vivo assessment; however, only in ex vivo and in vitro methods currently allow regionally specific information. Moreover, ex vivo studies have been essential to further elucidate factors that affect permeability such as osmolality, pH, and bioactive components such as histamine and lipopolysaccharides. For ruminants, extensive microbial degradation challenges the use of fermentable substrates as markers when assessing permeability and there is interest to compartmentalize permeability by region of the GIT. Recent research using dual markers to allow for total GIT and post-ruminal permeability have highlighted that regional permeability responses may be affected by production system, environmental conditions, and dietary characteristics. Future research is needed to improve the understanding of factors that affect GIT permeability, the regions involved, and strategies to support regulation of permeability.

PH-sensitive chitosan-deoxycholic acid/alginate nanoparticles for oral insulin delivery

Oral absorption of peptides/proteins is usually compromised by various gastrointestinal tract barriers. To improve delivery efficiency, chitosan-conjugated deoxycholic acid (CS-DCA) coupled with sodium alginate (ALG) was prepared to load insulin into pH-sensitive nanoparticles. The insulin-loaded chitosan-deoxycholic acid/alginate nanoparticles (CDA NPs) were characterized by size (143.3 ± 10.8 nm), zeta potential (19.5 ± 1.6 mV), entrapment efficiency (61.14 ± 1.67%), and insulin drug loading (3.36 ± 0.09%). The CDA NPs exhibited pH-triggered release characteristics in vitro and protected the wrapped insulin from gastric degradation. Stability of the CDA NPs in enzyme-containing simulated gastrointestinal fluids suggested that the NPs could partially protect the wrapped insulin from enzymatic degradation. Additionally, CS-DCA-modified NPs promoted the permeability of Caco-2 cells and enhanced intracellular absorption of FITC-labeled insulin by 9.4 and 1.2-folds, when compared to insulin solution and unmodified NPs, respectively. The positively charged NPs increased intestinal villi adhesion and enhanced insulin absorption in the intestines of diabetic rat models. Furthermore, the hypoglycemic test showed that CDA NPs prolonged insulin release in vivo and exerted a remarkable hypoglycemic effect on diabetic rats with an oral bioavailability of 15%. In conclusion, CDA NPs is a potential oral insulin delivery system.

Development of an M cell targeted nanocomposite system for effective oral protein delivery: preparation, in vitro and in vivo characterization

BackgroundThere is a strong need for non-invasive and patient-friendly delivery systems of protein drugs for long-term therapy. However, oral delivery of protein drugs is a big challenge due to many barriers including instability in the gastrointestinal (GI) tract and low permeability. To overcome the absorption barriers in GI tract and improve the patient compliance, this study aimed to develop an M cell targeted-nanocomposite delivery system of protein drugs.ResultsAn aminoclay-protein core complex (AC-Ins) was prepared by using insulin as a model protein and then sequentially coated with Ulex europaeus agglutinin 1 (UEA-1) for M-cell targeting and the pH sensitive polymer, Eudragit® L100 (EUAC-Ins). All nanoparticles were obtained with a high entrapment efficiency (> 90%) and their structural characteristics were confirmed by Fourier transform-infrared spectroscopy, energy dispersive X-ray spectroscopy, and circular dichroism. Among the developed nanoparticles, EUAC-Ins effectively suppressed drug release at pH 1.2, while rapidly released drugs at pH 6.8 due to dissolution of the outer coating layer. The conformational stability of insulin entrapped in EUAC-Ins was well maintained in the presence of proteolytic enzymes. Compared to free insulin, EUAC-Ins increased the membrane transport of insulin by 4.4-fold in M cells. In parallel, oral administration of EUAC-Ins in mice enhanced insulin uptake by 4.1-fold in the intestinal Peyer’s patches and 2.6-fold in intestinal epithelium tissues with normal villi, compared to free insulin. Orally administered EUAC-Ins decreased significantly the blood glucose level in diabetic mice, while the effect of oral insulin solution was negligible.ConclusionAn M cell targeted-ternary nanocomposite system obtained by dual coating of the aminoclay-protein core complex with UEA-1 and a pH dependent polymer is promising as an effective oral protein delivery carrier.

Processing index of barley grain and dietary undigested neutral detergent fiber concentration affected chewing behavior, ruminal pH, and total tract nutrient digestibility of heifers fed a high-grain diet.

The objective of this study was to investigate the effects of processing index (PI) of barley grain and dietary undigested neutral detergent fiber (uNDF) concentration on dry matter (DM) intake, chewing activity, ruminal pH and fermentation characteristics, total tract digestibility, gastrointestinal barrier function, and blood metabolites of finishing beef heifers. The PI was measured as the density after processing expressed as a percentage of the density before processing, and a smaller PI equates to a more extensively processed. Six ruminally cannulated heifers (average body weight, 715 ± 29 kg) were used in a 6 × 6 Latin square design with three PI (65%, 75%, and 85%) × 2 uNDF concentration (low and high; 4.6% vs. 5.6% of DM) factorial arrangement. The heifers were fed ad libitum a total mixed ration consisting of 10% barley silage (low uNDF), or 5% silage and 5% straw (high uNDF), 87% dry-rolled barley grain, and 3% mineral and vitamin supplements. Interactions (P < 0.01) of PI × uNDF were observed for DM intake, ruminating and total chewing time, and DM digestibility in the total digestive tract. Intake of DM, organic matter (OM), starch, and crude protein (CP) did not differ (P > 0.14) between low and high uNDF diets, but intakes of NDF and acid detergent fiber were greater (P = 0.01) for high uNDF diets regardless of barley PI. Heifers fed high uNDF diets had longer (P = 0.05) eating times (min/d or min/kg DM) and tended (P = 0.10) to have longer total chewing times (min/kg DM) than those fed low uNDF diets. Additionally, heifers sorted (P = 0.01) against long particles (>19 mm) for high uNDF diets but not for low uNDF diets. Altering PI of barley grain did not affect (P > 0.12) total volatile fatty acid (VFA) concentration, molar percentages of individual VFA, or duration of ruminal pH < 5.8 and <5.6. Total VFA concentration was less (P = 0.01), acetate percentage was greater (P = 0.01), and duration of ruminal pH < 5.8 and <5.6 was less (P = 0.05) for high compared with low uNDF diets. Digestibility of DM, OM, and CP was greater (P = 0.02) for low vs. high uNDF diets with PI of 65% and 75%, with no difference between low and high uNDF diets at PI of 85%. Blood metabolites and gastrointestinal tract barrier function were not affected (P ≥ 0.10) by the treatments. These results suggest that increasing dietary uNDF concentration is an effective strategy to improve ruminal pH status in finishing cattle, regardless of the extent of grain processing, whereas manipulating the extent of barley processing did not reduce the risk of ruminal acidosis.

Co-encapsulation by Flash NanoPrecipitation of Insulin, Trypsin Inhibitor and Caprate Permeabilization Enhancer for Oral Administration

&lt;img src=” https://s3.amazonaws.com/production.scholastica/article/18519/large/1235741_graphical_abstract.jpg?1608410554”&gt; We describe inverse-Flash NanoPrecipitation as a new scalable platform for co-encapsulation of insulin (a model therapeutic peptide) with soybean trypsin inhibitor (a peptidase inhibitor) and so-dium caprate (a permeation enhancer) forming 300 nm particles for oral delivery. The co-encapsulation of the protein therapeutic with a protease inhibitor and a permeation enhancer into nanoparticles addresses enzymatic attack on the protein drug and the transport across the gastroin-testinal tract barrier. Inverse-Flash NanoPrecipitation (iFNP) encompasses two sequential precipita-tion processes. First, insulin, soybean trypsin inhibitor (SBTI), and hydroxypropyl methylcellulose acetate-succinate polymer (HPMCAS, a stabilizing block copolymer)(at mass ratios of 1:4:5) are rapidly precipitated into an organic antisolvent forming the inverted nano-core (iNC) with 50 wt% insulin and SBTI. Encapsulation efficiencies are greater than 98%. The second step involves the precipitation of sodium caprate and a stabilizing polymer coating onto the iNCs surface. HPMCAS, chitosan, and PEG polymers are used to coat the iNCs to generate nanoparticles with anionic, cation-ic, and neutral surfaces, respectively. This demonstrates that the iFNP platform can encapsulate complex biologics mixtures at high loadings into particles with customizable surface properties.

Exploiting disease-induced changes for targeted oral delivery of biologics and nanomedicines in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and progressive disorder with destructive inflammation in the gastrointestinal tract (GIT). Biologics have changed the management of IBD, but have serious limitations, which is associated with their systemic administration via injection. Oral administration is the most accepted route of drug administration. However, the physiological barriers of the GIT pose significant challenges for oral administration of biologics, making this route of administration currently unavailable. The status of tissue barriers to oral drug delivery is altered in IBD. This may bring more challenges, but also present opportunities for oral delivery of biologics. This article provides an overview of disease-induced alterations of GIT barriers in IBD and discusses challenges, opportunities and commonly-utilised strategies for oral delivery of complex therapeutics, including biologics and nanomedicines.

Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle.

Stress negatively affects the gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. A deeper understanding of how diet and stress impacts the GIT barrier function in feedlot cattle is needed. Aspirin decreases mucus production and mucosal repair in the GIT and could be used as a model for GIT barrier dysfunction research. The objective of this study was to evaluate the effectiveness of aspirin to induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425.0 ± 8.6 kg) were allotted to 0, 50, 100, or 200 mg/kg body weight (BW) aspirin doses based on BW. Experiment 1 consisted of two periods separated by 4 wk where four heifers per treatment received the same aspirin dose during each period. Heifers were fed a 49.4% corn silage and 50.6% concentrate diet. The 200 mg/kg BW aspirin treatment was dosed as a 100 mg/kg BW aspirin oral bolus 36 and 24 h prior to Cr-ethylenediaminetetraacetic acid (EDTA) dosing (1 liter; 180 mM). The 50 and 100 mg/kg BW aspirin treatments were dosed as an oral bolus 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr. Serum was collected at 0 and 48 h and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6, serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase. In experiment 2, sixteen crossbred steers (576.0 ± 14.2 kg) fed a similar diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (eight steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected, and claudin (CLDN) 1, 2, and 3, occludin, and zonula occludens tight junction messenger ribonucleic acid (mRNA) expression was determined. Data were analyzed using the MIXED procedure of SAS. Urinary Cr excretion increased linearly at hours 3, 6, 9, and 12 (P ≤ 0.04) as aspirin dose increased from 0 to 200 mg/kg. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rates and linearly decreased mean retention time of Cr (P = 0.02). Aspirin increased SAA (P = 0.04) and tended to increase LBP (P = 0.09) in serum but did not affect any other serum inflammatory marker (P ≥ 0.19). Aspirin tended to increase jejunal CLDN-1 mRNA expression (P = 0.10) but did not affect the mRNA expression of other genes regulating tight junction function (P ≥ 0.20). Results from this study indicate that aspirin disrupts the GIT barrier function in beef cattle and has a potential as a model in GIT permeability research.