Dietary glycyl-glutamine supplementation ameliorates intestinal integrity, inflammatory response, and oxidative status in association with the gut microbiota in LPS-challenged piglets.

During weaning transition, mammalian newborns suffer severe enteric infections and thus induced gut microbiota dysbiosis, which in turn aggravates enteric disorder. The synthetic dipeptide glycyl-glutamine (GlyGln) has been used as a diet supplement to improve the weaning transition of newborns. However, the effect of dietary GlyGln supplementation on the gut microbiota of piglets with enteric infection remains unclear. Here, weaned piglets received a basal diet or a basal diet supplemented with 0.25% GlyGln for 3 weeks. Five piglets in each group received an intraperitoneal injection of lipopolysaccharide (LPS) (100 µg per kg BW) (LPS and GlyGln + LPS groups) and meanwhile five piglets in a control group received an intraperitoneal injection of saline (Ctrl group). The results showed that dietary GlyGln supplementation improved the LPS induced inflammation response and damage to the ileum morphology by increasing interleukin 10, tight junction proteins, villus height, and the ratio villus height/crypt depth, but decreasing the crypt depth. For the oxidative status, dietary GlyGln supplementation increased the ileal superoxide dismutase and meanwhile reduced the malondialdehyde and nitric oxide synthase activity (NOS) (total NOS and inducible NOS), compared with that in the LPS group. LPS challenge reduced the diversity of gut microbiota and enriched the facultative anaerobic Escherichia coli. The GlyGln restored alpha diversity and the structure of the gut microbiota by enriching obligate anaerobes and short-chain fatty acid (SCFA)-producing bacteria, including Clostridium, Lachnospira, Phascolarctobacterium, Roseburia, Lachnospiraceae, and Synergistetes. GlyGln enriched the gut microbiota function of carbohydrate metabolism and elevated the ileal SCFA concentrations of propionic acid and butyric acid that had been decreased by the LPS challenge. The beneficial effects of dietary GlyGln supplementation are closely associated with its enriched bacteria and SCFAs. Taken together, dietary GlyGln supplementation improved the gut microbiota dysbiosis induced by LPS challenge and enriched obligate anaerobes and SCFA-producing bacteria, which contributed to the amelioration of intestinal integrity, inflammatory responses, and oxidative status.

Efficacy of alanyl glutamine in nutritional support therapy for patients with sepsis: A protocol for systematic review and meta-analysis.

BACKGROUND: Sepsis is a systemic inflammatory response caused by infection, which is a common complication after severe infection, trauma, shock, and surgery, and is also an important factor in inducing septic shock and multiple organ dysfunction syndrome (MODS), and has become one of the important causes of death in critically ill patients. Septic patients with gastrointestinal transport function weakened, are prone to malnutrition, resulting in decreased immune function, thereby affecting the therapeutic effect. Clinical practice shows that the nutritional metabolism and immune response of patients with sepsis can be effectively improved by giving alanyl glutamine nutritional support treatment, but there is no evidence of evidence-based medicine. The study carried out in this protocol aims to evaluate the effectiveness of alanyl glutamine in nutritional support therapy for patients with sepsis. METHODS: The Cochrane Library, PubMed, Embase, Web of Science, WHO International Clinical Trials Registry Platform, CNKI, CBM, VIP, and Wanfang databases were searched by computer, to retrieve all randomized controlled trials (RCTs) on nutritional support for the treatment of sepsis with alanyl glutamine from the date of database establishment to December 2020. Two researchers independently selected the study, extracted and managed the data. RevMan5.3 software was used to analyze the included literature. RESULTS: This study observed the changes of serum albumin (ALB), prealbumin (PAB), hemoglobin (Hb), C-reactive protein (CRP), immunoglobulin (IgG, IgA, and IgM), APACHE II score before and after treatment to evaluate the efficacy of alanyl glutamine in nutritional support therapy for patients with sepsis. CONCLUSION: This study will provide reliable evidence for the application of alanyl glutamine in nutritional support therapy for patients with sepsis. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/VRZPJ.

Effect of stevia aqueous extract on the antidiabetic activity of saxagliptin in diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Stevia rebaudiana Bertoni is a perennial herb that belongs to the Asteraceae family. It is a natural sweetener plant known as "Sweet Leaf", "Sweet Herbs" and "Honey Leaf", which is estimated to be 300 times more sweetening than sugar cane. Stevia has been used as a traditional treatment for diabetes in many countries for hundreds of years. Several animal studies referred to the antihyperglycemic activity of stevia. However, the combined use of stevia with saxagliptin has not been studied so far, so this study has been done. The aim of the present study was to evaluate the antihyperglycemic effect of stevia alone and in combination with saxagliptin. MATERIALS AND METHODS: Diabetes was induced in rats by i.p. injection of streptozotocin and nicotinamide. Animals were divided into five groups, each contains eight rats. Group I: included negative controland group II: included diabetic control that received saline. Group III: included diabetic rats that received 400 mg/kg/day stevia aqueous extract. Group IV: included diabetic rats that received saxagliptin 10 mg/kg/day. Group V: included diabetic rats that received stevia 400 mg/kg + saxagliptin 10 mg/kg. Food and water intake were measured daily while body weight was measured weekly. After 3 weeks animals were sacrificed and blood and tissue samples were collected. Fasting blood glucose (FBG), serum insulin, serum dipeptidylepeptidase-4 (DPP-4), TC, TGs, LDL, HDL, GSH and MDA were measured in treated and control rats by colorimetric and ELISA methods. RESULTS: Both stevia and saxagliptin significantly reduced food, water intake, body weight and FBG. Stevia with saxagliptin produced more significant decrease in FBG. While serum insulin increased significantly in stevia, saxagliptin treated groups and their combination. Serum DPP-4 decreased significantly in all treated groups, concerning lipid profile, stevia and saxagliptin notably lowered TC, TGs, and LDL and increased HDL. Both stevia and saxagliptin remarkably decreased MDA and increased GSH compared to diabetic rats. In addition, stevia significantly improved the antidiabetic effects of saxagliptin. CONCLUSION: Stevia has an antihyperglycemic effect and could enhance the antidiabetic activity of saxagliptin. DPP-4 attenuation, antihyperlipidemic and antioxidant activity as well as improvement of insulin sensitivity may be involved in the antidiabetic action of stevia.

Examining Absorbed Doses of Indigenously Developed 177Lu-PSMA-617 in Metastatic Castration-Resistant Prostate Cancer Patients at Baseline and During Course of Peptide Receptor Radioligand Therapy.

Aim: The objective of this study was to estimate the absorbed doses to the normal organs and tumor lesions in metastatic castration-resistant prostate cancer (mCRPC) patients treated with indigenously developed 177Lu-PSMA-617 that could establish optimal treatment protocol with minimum risk to the dose-limiting organs. Furthermore, attempt was also made to compare radiation absorbed doses for normal organs and tumor lesions in subsequent cycles of 177Lu-PSMA-617 peptide receptor radioligand therapy (PRLT) in the same group of patients during the course of treatment. Methods: A total of 30 patients of proven mCRPC were enrolled for this prospective study. These patients received up to 5 cycles of treatment with 177Lu-PSMA-617 PRLT (1 cycle for 13 patients, 2 cycles for 9 patients, 3 cycles for 3 patients, and 5 cycles for 5 patients), at 11-12-week intervals between the two successive therapies. The patients underwent postadministration whole-body scintigraphy at five time points: 0.5 (prevoid), 2, 12, 24, and 72/96 h (postvoid). From time-activity curves generated by drawing regions of interests on the images, number of disintegrations was determined. Tumor masses were estimated from pretherapeutic 68Ga-PSMA-11 positron emission tomography-computed tomography images. Absorbed doses for organs and tumors were calculated using OLINDA 2.0 software. Results: The average activity of 177Lu-PSMA-617 (mean ± SD) administered per patient per cycle was 4.94 ± 0.45 GBq. The mean absorbed organ doses (mean ± SD) from first therapy cycle in Gy/GBq were as follows: kidneys 0.52 ± 0.16, spleen 0.17 ± 0.07, liver 0.08 ± 0.05, salivary glands 0.53 ± 0.30, lacrimal glands 1.45 ± 0.85, nasal mucosa membrane 0.46 ± 0.19, urinary bladder 0.23 ± 0.02, and bone marrow 0.04 ± 0.03. The mean effective dose for whole body from first therapy cycle was 0.05 ± 0.03 Sv/GBq. Among all the normal organs, lacrimal glands received the highest absorbed dose. The median dose for all lesions, bone lesions, lymph nodes, primary site, liver lesion, lung lesion, and soft tissue deposit from first therapy cycle was determined to be 4.17, 4.23, 3.96, 4.36, 10.27, 0.78, and 4.68 Gy/GBq respectively. Absorbed doses received by the normal organs in five consecutive cycles follow three different trends, (a) for kidneys, salivary glands, and nasal mucous membrane, absorbed doses increased from first therapy cycle to second therapy cycle and then slowly decreased in subsequently therapy cycles; (b) for spleen, liver, and lacrimal glands, absorbed doses decreased with the successive therapy cycles; and (c) in case of bone marrow, bladder, and whole body, mean absorbed dose almost remained constant in each therapy cycle. Absorbed doses to the lesions gradually decreased with increase of the number of therapy cycles. Conclusions: The organ and tumor absorbed doses of 177Lu-PSMA-617 in mCRPC patients were found to be comparable to the data reported in the literature. The highest absorbed organ dose was observed in lacrimal glands and being a dose limiting organ, a cumulative activity up to 32.5 GBq (878 mCi) of 177Lu-PSMA-617 in 4-5 therapy cycles appears safe and feasible to achieve full therapeutic window.

Supplementation with γ-glutamylcysteine (γ-GC) lessens oxidative stress, brain inflammation and amyloid pathology and improves spatial memory in a murine model of AD.

INTRODUCTION: The accumulation of oxidative stress, neuroinflammation and abnormal aggregation of amyloid ß-peptide (Aß) have been shown to induce synaptic dysfunction and memory deficits in Alzheimer's disease (AD). Cellular depletion of the major endogenous antioxidant Glutathione (GSH) has been linked to cognitive decline and the development of AD pathology. Supplementation with γ-glutamylcysteine (γ-GC), the immediate precursor and the limiting substrate for GSH biosynthesis, can transiently augment cellular GSH levels by bypassing the regulation of GSH homeostasis. METHODS: In the present study, we investigated the effect of dietary supplementation of γ-GC on oxidative stress and Aß pathology in the brains of APP/PS1 mice. The APP/PS1 mice were fed γ-GC from 3 months of age with biomarkers of apoptosis and cell death, oxidative stress, neuroinflammation and Aß load being assessed at 6 months of age. RESULTS: Our data showed that supplementation with γ-GC lowered the levels of brain lipid peroxidation, protein carbonyls and apoptosis, increased both total GSH and the glutathione/glutathione disulphide (GSH/GSSG) ratio and replenished ATP and the activities of the antioxidant enzymes (superoxide dismutase (SOD), catalase, glutamine synthetase and glutathione peroxidase (GPX)), the latter being a key regulator of ferroptosis. Brain Aß load was lower and acetylcholinesterase (AChE) activity was markedly improved compared to APP/PS1 mice fed a standard chow diet. Alteration in brain cytokine levels and matrix metalloproteinase enzymes MMP-2 and MMP-9 suggested that γ-GC may lower inflammation and enhance Aß plaque clearance in vivo. Spatial memory was also improved by γ-GC as determined using the Morris water maze. CONCLUSION: Our data collectively suggested that supplementation with γ-GC may represent a novel strategy for the treatment and/or prevention of cognitive impairment and neurodegeneration.

Alanyl-Glutamine Restores Tight Junction Organization after Disruption by a Conventional Peritoneal Dialysis Fluid.

Understanding and targeting the molecular basis of peritoneal solute and protein transport is essential to improve peritoneal dialysis (PD) efficacy and patient outcome. Supplementation of PD fluids (PDF) with alanyl-glutamine (AlaGln) increased small solute transport and reduced peritoneal protein loss in a recent clinical trial. Transepithelial resistance and 10 kDa and 70 kDa dextran transport were measured in primary human endothelial cells (HUVEC) exposed to conventional acidic, glucose degradation products (GDP) containing PDF (CPDF) and to low GDP containing PDF (LPDF) with and without AlaGln. Zonula occludens-1 (ZO-1) and claudin-5 were quantified by Western blot and immunofluorescence and in mice exposed to saline and CPDF for 7 weeks by digital imaging analyses. Spatial clustering of ZO-1 molecules was assessed by single molecule localization microscopy. AlaGln increased transepithelial resistance, and in CPDF exposed HUVEC decreased dextran transport rates and preserved claudin-5 and ZO-1 abundance. Endothelial clustering of membrane bound ZO-1 was higher in CPDF supplemented with AlaGln. In mice, arteriolar endothelial claudin-5 was reduced in CPDF, but restored with AlaGln, while mesothelial claudin-5 abundance was unchanged. AlaGln supplementation seals the peritoneal endothelial barrier, and when supplemented to conventional PD fluid increases claudin-5 and ZO-1 abundance and clustering of ZO-1 in the endothelial cell membrane.

Alanyl-glutamine protects the intestinal barrier function in trained rats against the impact of acute exhaustive exercise.

Strenuous exercise triggers deleterious effects on the intestinal epithelium, but their mechanisms are still uncertain. Here, we investigated whether a prolonged training and an additional exhaustive training protocol alter intestinal permeability and the putative effect of alanyl-glutamine (AG) pretreatment in this condition. Rats were allocated into 5 different groups: 1) sedentary; 2 and 3) trained (50 min per day, 5 days per week for 12 weeks) with or without 6 weeks oral (1.5 g/kg) AG supplementation; 4 and 5) trained and subjected to an additional exhaustive test protocol with or without oral AG supplementation. Venous blood samples were collected to determine gasometrical indices at the end of the 12-week protocol or after exhaustive test. Lactate and glucose levels were determined before, during, and after the exhaustive test. Ileum tissue collected after all experimental procedures was used for gene expression analysis of Zonula occludens 1 (ZO-1), occludin, claudin-2, and oligopeptide transporter 1 (PepT-1). Intestinal permeability was assessed by urinary lactulose/mannitol test collected after the 12-week protocol or the exhaustive test. The exhaustive test decreased pH and base excess and increased pCO2. Training sessions delayed exhaustion time and reduced the changes in blood glucose and lactate levels. Trained rats exhibited upregulation of PEPT-1, ZO-1, and occludin mRNA, which were partially protected by AG. Exhaustive exercise induced intestinal paracellular leakage associated with the upregulation of claudin-2, a phenomenon protected by AG treatment. Thus, AG partially prevented intestinal training adaptations but also blocked paracellular leakage during exhaustive exercise involving claudin-2 and occludin gene expression.

Impact of baseline characteristics on glycemic effects of add-on saxagliptin or acarbose to metformin therapy: Subgroup analysis of the SMART study in Chinese patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: This secondary analysis of the 24-week SMART study examined the efficacy of add-on saxagliptin or acarbose to metformin across different patient subgroups with type 2 diabetes mellitus, based on baseline characteristics. MATERIALS AND METHODS: Randomized patients (n = 481) were classified into subgroups based on their baseline age (<65, ≥65 years), body mass index (BMI; <24, 24-<28, ≥28 kg/m2 ), glycated hemoglobin (HbA1c; <8%, 8-<9%, 9-<10%, ≥10%) and renal function (creatinine clearance 50-<80, ≥80 mL/min). Treatment effects on primary outcome (HbA1c) and key secondary outcomes of fasting plasma glucose (FPG), 2-h postprandial glucose and homeostatic model assessment of ß-cell function were assessed across patient subgroups. RESULTS: For saxagliptin, reductions in HbA1c from baseline to week 24 were consistent across different subgroups regardless of baseline age, body mass index, HbA1c and renal function (range -0.66 to -1.16%). Saxagliptin was associated with consistent reductions in FPG (-0.60 to -1.33 mmol/L) and 2-h postprandial glucose (-0.48 to -1.95 mmol/L) across the majority of subgroups studied. The efficacy of acarbose on FPG attenuated progressively with increasing baseline HbA1c (+0.86 to -1.43 mmol/L); an increase from baseline FPG was observed in patients with HbA1c >9%. The effect of acarbose on postprandial glucose was also variable (+0.23 to -3.38 mmol/L). CONCLUSIONS: As add-on to metformin, both saxagliptin and acarbose reduced HbA1c regardless of baseline HbA1c, age, body mass index and renal function; however, only saxagliptin was effective at a stable glycemic control (FPG and PPG). The efficacy of acarbose on FPG and PPG was significantly attenuated in patients with higher baseline HbA1c (≥8%).

Alanyl-glutamine protects the intestinal barrier function in trained rats against the impact of acute exhaustive exercise

Strenuous exercise triggers deleterious effects on the intestinal epithelium, but their mechanisms are still uncertain. Here, we investigated whether a prolonged training and an additional exhaustive training protocol alter intestinal permeability and the putative effect of alanyl-glutamine (AG) pretreatment in this condition. Rats were allocated into 5 different groups: 1) sedentary; 2 and 3) trained (50 min per day, 5 days per week for 12 weeks) with or without 6 weeks oral (1.5 g/kg) AG supplementation; 4 and 5) trained and subjected to an additional exhaustive test protocol with or without oral AG supplementation. Venous blood samples were collected to determine gasometrical indices at the end of the 12-week protocol or after exhaustive test. Lactate and glucose levels were determined before, during, and after the exhaustive test. Ileum tissue collected after all experimental procedures was used for gene expression analysis of Zonula occludens 1 (ZO-1), occludin, claudin-2, and oligopeptide transporter 1 (PepT-1). Intestinal permeability was assessed by urinary lactulose/mannitol test collected after the 12-week protocol or the exhaustive test. The exhaustive test decreased pH and base excess and increased pCO2. Training sessions delayed exhaustion time and reduced the changes in blood glucose and lactate levels. Trained rats exhibited upregulation of PEPT-1, ZO-1, and occludin mRNA, which were partially protected by AG. Exhaustive exercise induced intestinal paracellular leakage associated with the upregulation of claudin-2, a phenomenon protected by AG treatment. Thus, AG partially prevented intestinal training adaptations but also blocked paracellular leakage during exhaustive exercise involving claudin-2 and occludin gene expression.

Preventive Effects of Tryptophan-Methionine Dipeptide on Neural Inflammation and Alzheimer's Pathology.

Preventive approaches for age-related memory decline and dementia have become a high priority in the aging society because of the lack of therapeutic approaches. Recent epidemiological studies have reported that fermented dairy products can help prevent dementia. Previously, we identified tryptophan-tyrosine (WY) and tryptophan-methionine (WM) peptides as the suppressants of activation of the primary microglia and showed that WY peptide consumption suppresses inflammation in the brains of Alzheimer's disease model mice. However, the effects of the WM peptide on inflammation in the brain and Alzheimer's pathology have not been investigated. Here, we evaluated the effect of WM peptide consumption on Alzheimer's disease model (5×FAD) mice. In 5×FAD mice, intake of WM peptide suppressed the production of inflammatory cytokines, activation of microglia, and infiltration of activated microglia around ß amyloid (Aß) depositions. WM peptide intake reduced Aß deposition in the cortex and hippocampus and then improved the object recognition memory. Taken together with previous reports, the current findings indicate that ingestion of tryptophan-related peptides or food material rich in tryptophan-related peptides, thereby regulating microglial activity, represents a potential preventive approach for cognitive decline and dementia related to inflammation.