Amelioration of intracerebroventricular streptozotocin-induced cognitive dysfunction by Ocimum sanctum L. through the modulation of inflammation and GLP-1 levels.

DPP-4 inhibitors have been shown to reverse amyloid deposition in Alzheimer's disease (AD) patients with cognitive impairment. Ocimum sanctum L. leaves reported the presence of important phytoconstituents which are reported to have DPP-4 inhibitory activity. To investigate the effects of petroleum ether extract of Ocimum sanctum L. (PEOS) in Intracerebroventricular streptozotocin (ICV-STZ) induced AD rats. ICV-STZ (3 mg/kg) was injected bilaterally into male Wistar rats, while sham animals received the artificial CSF. The ICV-STZ-induced rats were administered with three doses of PEOS (100, 200, and 400 mg/kg, p.o.) for thirty days. All experimental rats were subjected to behaviour parameters (radial arm maze task and novel object recognition test), neurochemical parameters such as GLP-1, Aß42, and TNF-α levels, and histopathological examination (Congo red staining) of the left brain hemisphere. PEOS significantly reversed the spatial learning and memory deficit exhibited by ICV-STZ-induced rats. Furthermore, PEOS also shows promising results in retreating Aß deposition, TNF α, and increasing GLP-1 levels. The histopathological study also showed a significant dose-dependent reduction in amyloid plaque formation and dense granule in PEOS -treated rats as compared to the ICV-STZ induced rats (Negative control). The results show that extract of Ocimum sanctum L. attenuated ICV-STZ-induced learning and memory deficits in rats and has the potential to be employed in the therapy of AD.

Norlignans as potent GLP-1 secretagogues from the fruits of Amomum villosum.

The dried fruit of Amomum villosum (Amomi Fructus) is an important spices and traditional Chinese medicine. In this study, the EtOH extract of Amomi Fructus was revealed with hypoglycemic effects on db/db mice by increasing plasma insulin levels. After extracted with EtOAc, the EtOAc fraction showed increased activity in stimulating glucagon-like peptide-1 (GLP-1) secretion compared with the EtOH extract. In order to clarify the antidiabetic constituents, four undescribed norlignans, amovillosumins A‒D, were isolated from the EtOAc fraction, and the subsequent chiral resolution yielded three pairs of enantiomers. Their structures were determined by extensive spectroscopic data (1D and 2D NMR, HRESIMS, IR, UV and [α]D) and ECD calculations. Amovillosumins A and B significantly stimulated GLP-1 secretion by 375.1% and 222.7% at 25.0 µM, and 166.9% and 62.7% at 12.5 µM, representing a new type of GLP-1 secretagogues.

High Hydrostatic Pressure Processing of Human Milk Increases Apelin and GLP-1 Contents to Modulate Gut Contraction and Glucose Metabolism in Mice Compared to Holder Pasteurization.

BACKGROUND: High hydrostatic pressure (HHP) processing is a non-thermal method proposed as an alternative to Holder pasteurization (HoP) for the sterilization of human breast milk (BM). HHP preserves numerous milk bioactive factors that are degraded by HoP, but no data are available for milk apelin and glucagon-like peptide 1 (GLP-1), two hormones implicated in the control of glucose metabolism directly and via the gut-brain axis. This study aims to determine the effects of HoP and HHP processing on apelin and GLP-1 concentrations in BM and to test the effect of oral treatments with HoP- and HHP-BM on intestinal contractions and glucose metabolism in adult mice. METHODS: Mice were treated by daily oral gavages with HoP- or HHP-BM during one week before intestinal contractions, and glucose tolerance was assessed. mRNA expression of enteric neuronal enzymes known to control intestinal contraction was measured. RESULTS: HoP-BM displayed a reduced concentration of apelin and GLP-1, whereas HHP processing preserved these hormones close to their initial levels in raw milk. Chronic HHP-BM administration to mice increased ileal mRNA nNos expression level leading to a decrease in gut contraction associated with improved glucose tolerance. CONCLUSION: In comparison to HoP, HPP processing of BM preserves both apelin and GLP-1 and improves glucose tolerance by acting on gut contractions. This study reinforces previous findings demonstrating that HHP processing provides BM with a higher biological value than BM treated by HoP.

Effects of three types of bariatric interventions on myocardial infarct size and vascular function in rats with type 2 diabetes mellitus.

AIMS: The effects of three types of bariatric interventions on myocardial infarct size were tested in the rat model of type 2 diabetes mellitus (T2DM). We also evaluated the effects of bariatric surgery on no-reflow phenomenon and vascular dysfunction caused by T2DM. MAIN METHODS: Rats with T2DM were assigned into groups: without surgery, sham-operated, ileal transposition, Roux-en-Y gastric bypass, and sleeve gastrectomy. Oral glucose tolerance, glucagon-like peptide-1, and insulin levels were measured. Six weeks after surgery, the animals were subjected to myocardial ischemia-reperfusion followed by histochemical determination of infarct size (IS), no-reflow zone, and blood stasis area size. Vascular dysfunction was characterized using wire myography. KEY FINDINGS: All bariatric surgery types caused significant reductions in animal body weight and resulted in T2DM compensation. All bariatric interventions partially normalized glucagon-like peptide-1 responses attenuated by T2DM. IS was significantly smaller in animals with T2DM. Bariatric surgery provided no additional IS limitation compared with T2DM alone. Bariatric surgeries reversed T2DM-induced enhanced contractile responses of the mesenteric artery to 5-hydroxytryptamine. Sleeve gastrectomy normalized decreased nitric oxide synthase contribution to the endothelium-dependent vasodilatation in T2DM. SIGNIFICANCE: T2DM resulted in a reduction of infarct size and no-reflow zone size. Bariatric surgery provided no additional infarct-limiting effect, but it normalized T2DM-induced augmented vascular contractility and reversed decreased contribution of nitric oxide to endothelium-dependent vasodilatation typical of T2DM. All taken together, we suggest that this type of surgery may have a beneficial effect on T2DM-induced cardiovascular diseases.

Glucagon-Like Peptide-1 Regulates the Proopiomelanocortin Neurons of the Arcuate Nucleus both Directly and Indirectly via Presynaptic Action.

Glucagon-like peptide-1 (GLP-1) exerts its anorexigenic effect at least partly via the proopiomelanocortin (POMC) neurons of the arcuate (ARC) nucleus. These neurons are known to express GLP-1 receptor (GLP-1R). The aim of the study was to determine whether in addition to its direct effect, GLP-1 also modulates how neuronal inputs can regulate the POMC neurons by acting on presynaptic terminals, ultrastructural and electrophysiological studies were performed on tissues of adult male mice. GLP-1R-immunoreactivity was associated with the cell membrane of POMC neurons and with axon terminals forming synapses on these cells. The GLP-1 analog exendin 4 (Ex4) markedly increased the firing rate of all examined POMC neurons and depolarized these cells. These effects of Ex4 were prevented by intracellular administration of the G-protein blocker guanosine 5'-[ß-thio]diphosphate trilithium salt (GDP-ß-S). Ex4 also influenced the miniature postsynaptic currents (mPSCs) and evoked PSCs of POMC neurons. Ex4 increased the frequency of miniature excitatory PSCs (EPSCs) and the amplitude of the evoked EPSCs in half of the POMC neurons. Ex4 increased the frequency of miniature inhibitory PSCs (IPSCs) and the amplitudes of the evoked IPSCs in one-third of neurons. These effects of Ex4 were not influenced by intracellular GDP-ß-S, indicating that GLP-1 signaling directly stimulates a population of axon terminals innervating the POMC neurons. The different Ex4 responsiveness of their mPSCs indicates the heterogeneity of the POMC neurons of the ARC. In summary, our data demonstrate that in addition to its direct excitatory effect on the POMC neurons, GLP-1 signaling also facilitates the presynaptic input of these cells by acting on presynaptically localized GLP-1R.

Glucagon-Like Peptide Analogs Are Superior for Diabetes and Weight Control in Patients on Antipsychotic Medications: A Retrospective Cohort Study.

OBJECTIVE: Glucagon-like peptide (GLP-1) analogs promote diabetes control and weight loss. Most GLP-1 analogs also lower adverse cardiovascular outcomes, making them ideal agents for patients with severe mental illness. The objective of this study was to analyze diabetic patients taking antipsychotic medications, comparing those on GLP-1 analogs with those on other diabetes treatments. METHODS: A total of 46 patients referred to outpatient diabetes clinics between July 2010 and April 2017 who were prescribed antipsychotic medications during the entire study period were included in this retrospective analysis. Eleven (24%) patients were started on a GLP-1 analog (cases), and 35 (76%) were treated with alternative antidiabetic agents (controls). RESULTS: Cases and controls did not differ in age, sex, height, weight, or medical therapies at the time of referral. Within 1 year, a reduction in mean ± SE glycosylated hemoglobin (HbA1c) levels was noted for both groups (cases: -1.26% ± 0.17%, controls: -1.47% ± 0.45%). However, while patients on GLP-1 analogs lost 7.07 ± 2.62 kg, control patients gained 1.93 ± 1.14 kg (P < .05). Blunted HbA1c reductions were also noted in patients who took antipsychotic medication in addition to antidepressant medication (on antidepressant medication [n = 22]: -0.77% ± 0.29%, off antidepressant medication [n = 9]: -2.97% ± 0.6%, P < .001). This observation did not apply to patients treated with GLP-1 analogs, as they had larger HbA1c reductions than patients on alternative regimens (controls [n = 15]: -0.46% ± 0.4%, cases [n = 7]: -1.43% ± 0.15%, P < .05). CONCLUSIONS: GLP-1 analogs promote both diabetes and weight control in diabetic patients on antipsychotic medications with or without antidepressant medications.

The Novel Dual GLP-1/GIP Receptor Agonist DA-CH5 Is Superior to Single GLP-1 Receptor Agonists in the MPTP Model of Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disease for which there is no cure. In a clinical trial, the glucagon-like peptide-1 (GLP-1) receptor agonist exendin-4 has shown good protective effects in PD patients. The hormone glucose-dependent insulinotropic polypeptide (GIP) has also shown protective effects in animal models of PD. OBJECTIVE: We tested DA-CH5, a novel dual GLP-1/GIP receptor agonist. METHODS: DA-CH5 activity was tested on cells expressing GLP-1, GLP-2, GIP or glucagon receptors. The ability to cross the blood-brain barrier (BBB) of DA-CH5, exendin-4, liraglutide or other dual receptor agonists was tested with fluorescein-labelled peptides. DA-CH5, exendin-4 and liraglutide were tested in the MPTP mouse model of PD. RESULTS: Analysing the receptor activating properties showed a balanced activation of GLP-1 and GIP receptors while not activating GLP-2 or glucagon receptors. DA-CH5 crossed the BBB better than other single or other dual receptor agonists. In a dose-response comparison, DA-CH5 was more effective than the GLP-1 receptor agonist exendin-4. When comparing the neuroprotective effect of DA-CH5 with Liraglutide, a GLP-1 analogue, both DA-CH5 and Liraglutide improved MPTP-induced motor impairments. In addition, the drugs reversed the decrease of the number of neurons expressing tyrosine hydroxylase (TH) in the SN, alleviated chronic inflammation, reduced lipid peroxidation, inhibited the apoptosis pathway (TUNEL assay) and increased autophagy -related proteins expression in the substantia nigra (SN) and striatum. Importantly, we found DA-CH5 was superior to Liraglutide in reducing microglia and astrocyte activation, improving mitochondrial activity by reducing the Bax/Bcl-2 ratio and normalising autophagy as found in abnormal expression of LC3 and p62. CONCLUSION: The results demonstrate that the DA-CH5 is superior to liraglutide and could be a therapeutic treatment for PD.

Glycemic effect of pancreatic preproglucagon in mouse sleeve gastrectomy.

Intestinally derived glucagon-like peptide-1 (GLP-1), encoded by the preproglucagon (Gcg) gene, is believed to function as an incretin. However, our previous work questioned this dogma and demonstrated that pancreatic peptides rather than intestinal Gcg peptides, including GLP-1, are a primary regulator of glucose homeostasis in normal mice. The objective of these experiments was to determine whether changes in nutrition or alteration of gut hormone secretion by bariatric surgery would result in a larger role for intestinal GLP-1 in the regulation of insulin secretion and glucose homeostasis. Multiple transgenic models, including mouse models with intestine- or pancreas tissue-specific Gcg expression and a whole-body Gcg-null mouse model, were generated to study the role of organ-specific GLP-1 production on glucose homeostasis under dietary-induced obesity and after weight loss from bariatric surgery (vertical sleeve gastrectomy; VSG). Our findings indicated that the intestine is a major source of circulating GLP-1 after various nutrient and surgical stimuli. However, even with the 4-fold increase in intestinally derived GLP-1 with VSG, it is pancreatic peptides, not intestinal Gcg peptides, that are necessary for surgery-induced improvements in glucose homeostasis.

Influence of subliminal intragastric fatty acid infusion on subjective and physiological responses to positive emotion induction in healthy women: A randomized trial.

BACKGROUND: Subliminal intragastric fatty acid infusion attenuates subjective and brain responses to negative emotion induction. However, the underlying gut-brain signaling mechanisms remain unclear, and it is unknown whether such effect equally applies to positive emotion. OBJECTIVE: We aimed to investigate the interaction between fatty acid-induced gut-brain signaling and subjective responses to positive emotion, and the potential mediational role of gastrointestinal (GI) hormones. DESIGN: Twelve fasting healthy women underwent intragastric infusion of 2.5 g lauric acid or saline, after which either positive or neutral emotion was induced for 30 min, in 4 separate visits. Appetite-related sensations, subjective emotional state, and GI hormones were measured at baseline and every 10 min after infusion. Heart rate variability was measured at baseline and at t = 20-30 min to quantify vagal tone (root mean square of successive differences, RMSSD), and sympathovagal balance (low frequency to high frequency ratio, LF/HF). RESULTS: Fatty acid infusion did not influence appetite-related sensations (as expected), nor emotional state ratings (contrary to expectations). As anticipated, fatty acid stimulated release of CCK at t = 20-40 min (p < 0.001), and GLP1 at t = 30-40 min (p < 0.001), but not PYY. Interestingly, positive emotion induction suppressed plasma octanoylated ghrelin at t = 20-40 min (p = 0.020). Further, both positive emotion and fatty acid attenuated RMSSD (p = 0.012 & 0.0073, respectively). Positive emotion attenuated LF/HF after fatty acid (p = 0.0006), but raised LF/HF after saline (p = 0.004). CONCLUSIONS: Subliminal fatty acid did not influence subjective responses to positive emotion induction. However, positive emotion induction suppressed octanoylated ghrelin release. Moreover, both positive emotion and subliminal fatty acid decreased cardiac vagal tone. Further, the fatty acid reversed the effect of positive emotion on sympathovagal balance.

Therapeutic Effects of Sleeve Gastrectomy and Ileal Transposition on Type 2 Diabetes in a Non-Obese Rat Model by Regulating Blood Glucose and Reducing Ghrelin Levels.

BACKGROUND Nowadays, more than 170 million patients suffer from diabetes mellitus worldwide. This study aimed to investigate the effects of sleeve gastrectomy (SG) and ileal transposition (IT) surgery on the control of diabetes. MATERIAL AND METHODS Goto-Kakizaki rats were used to establish type 2 diabetes models and undergo SG or IT surgery. At 2 months post-surgery, insulin, glucose, triglycerides (TG), total cholesterol (TC), glucose tolerance, glucagon-like peptide-1 (GLP-1) levels, and insulin sensitivity were evaluated. RESULTS SG significantly shortened operative time and post-operative recovery time compared to IT surgery (P<0.05). SG and IT surgery resulted in significantly induced weight loss, significantly decreased levels of glucose, and significantly enhanced levels of Ghrelin compared the Sham surgery group (P<0.001). SG and IT surgery resulted in significantly increased GLP-1 levels compared to Sham surgery (P<0.001). SG resulted in better reduction of oral glucose tolerance test (OGTT) glucose compared to IT surgery (P<0.05). SG and IT surgery significantly upregulated insulin tolerance test (ITT) levels compared to Sham surgery (P<0.001). SG induced better reductions in TC and TG compared to IT surgery (P<0.05). CONCLUSIONS In non-obese rats with spontaneous diabetes, both SG and IT surgery were found to control diabetes by regulating body weight and levels of glucose, Ghrelin, GLP-1, OGTT glucose, insulin, TC, and TG. Moreover, SG demonstrated advantages of shorter operative time, shorter post-operative recovery time, and better control of diabetes compared to IT surgery.

Site-specific integration of light chain and heavy chain genes of antibody into CHO-K1 stable hot spot and detection of antibody and fusion protein expression level.

Expression cell line constructed by random integration method will often meet with unstable expression problem because target genes may be integrated into unstable region of chromatin. Rational cell line construction can overcome this shortcoming by inserting target gene into stable region of chromatin specifically. Here, we successfully got one knock-in cell line where light chain and heavy chain genes of antibody was site specifically integrated into stable hot spot reported before via homologous dependent recombination method mediated by CRISPR/Cas9. The targeting efficiency was around 1.35%. This cell line together with other three pre-established targeting cell lines (targeting with glucagon-like peptide 1 with human serum albumin fusion protein gene, or NGGH) were all undergoing protein expression level detection. In adherent cell mode, the amount of antibody expressed per cell per day were all around 0.006 pg/cell/day over passage 3, 12, 23, 35 and 50 while the amount of NGGH expressed per cell per day of 3 cell lines were all around 1.2 pg/cell/day over passage 3, 12, 23, 35 and 50. In batch mode, the antibody concentration within supernatant were around 2.5 µg/L over passage 1, 25, and 50 while the NGGH fusion protein concentration within supernatant were around 17 mg/L over passage 1, 25, and 50.

In-depth site-specific O-Glycosylation analysis of therapeutic Fc-fusion protein by electron-transfer/higher-energy collisional dissociation mass spectrometry.

Unexpected O-glycosylations, including O-xylosylations and mucin-type O-glycosylations, have been reported in recent glycosylation analyses of Fc-fusion proteins produced in mammalian cell expression systems. This observation suggests that therapeutic proteins with novel structures can undergo unintended O-glycosylations, having implications regarding their efficacy and safety. Therefore, the implementation of O-glycosylation analysis during product developmental is essential. However, detail site-specific O-glycosylation analysis is difficult because no consensus sequence for mucin-type O-glycosylations is known, and O-glycopeptides often contain multiple or continuous glycosylation sites. Recently, a new mass spectrometric fragmentation method called electron-transfer/higher-energy collisional dissociation (EThcD) has been used for site-specific glycosylation analysis. In this study, we conducted site-specific O-glycosylation analysis of commercially available GLP1-Fc fusion protein with (G4S)3 linker peptide using liquid chromatography/mass spectrometry (LC/MS) with EThcD and a glycoproteomic database search. We successfully identified unexpected O-xylosylations at Ser residues in the (G4S)3 linker peptide, mucin-type O-glycosylations at Thr and Ser residues in the GLP-1 peptide, and Ser residues in the (G4S)3 linker peptide. This study is the first to report these unexpected O-xylosylations and mucin-type O-glycosylations in this therapeutic fusion protein. Mammalian-cell production of therapeutic fusion proteins that contain novel structures may require exhaustive O-glycosylation analysis to ensure their quality, efficacy, and safety.

The investigation of protective effects of glucagon-like peptide-1 (GLP-1) analogue exenatide against glucose and fructose-induced neurotoxicity.

Diabetes mellitus (DM) is one of the most common metabolic disorders characterized by hyperglycemia due to insufficiency of insulin and/or insulin resistance. Clinical studies have revealed a higher risk of neurodegenerative disorders such as Alzheimer's disease or Parkinson's disease in diabetic patients. Recently, glucagon-like peptide-1 (GLP-1) is an attractive potential treatment modality for various neurodegenerative diseases. In our study, we aimed to investigate whether exenatide, a GLP-1 analogue, has neuroprotective effects against glucose and fructose-induced toxicity in human SH-SY5Y neuroblastoma cell line. Neurotoxicity was induced by incubating SH-SY5Y cells with different doses (25-100 mM) of glucose and fructose for 24, 48 and 72 hours. Following determination of the significant toxic doses of glucose and fructose, the cells were treated with various doses of exenatide (10-250 nM) in the presence or absence of glucose and fructose. Neurotoxicity was evaluated by MTT assay and Hoechst 33258 staining. Caspase-3 activity and the levels of advanced glycation end products (AGEs) were determined in the cytosolic fractions of treated cells. Our results demonstrated that both glucose and fructose treatments decreased cell viability in neuronal cells dose and time-dependently. Glucose and fructose-treated groups showed increased numbers of apoptotic cells, caspase-3 activity and AGEs levels. Treatment of the cells with exenatide significantly prevented cell death. The most prominent effect was observed at 100 nM exenatide-treated cultures. Our results suggest that high doses of glucose and fructose may lead to neurotoxicity, and exenatide may have protective effects against neuronal damage through its anti-apoptotic feature.

Rate of appearance of amino acids after a meal regulates insulin and glucagon secretion in patients with type 2 diabetes: a randomized clinical trial.

Background: Meal composition regulates the postprandial response of pancreatic and gastrointestinal hormones and plays an important role in patients with type 2 diabetes (T2D). Proteins have glucagon and insulinotropic effects, which may differ depending on amino acid composition, form of intake, and rate of digestibility and absorption. Objective: The aim of this study was to test effects of isolated pea protein-based (PP) compared with casein protein-based (CP) meals differing in amino acid compositions on endocrine responses to meal tolerance tests (MTTs) in patients with T2D. Design: Thirty-seven individuals with T2D [mean ± SD age: 64 ± 6 y; mean ± SD body mass index (kg/m2): 30.2 ± 3.6; mean ± SD glycated hemoglobin: 7.0% ± 0.6%] were randomly assigned to receive either high-animal-protein (∼80% of total protein) or high-plant-protein (∼72% of total protein) diets (30% of energy from protein, 40% of energy from carbohydrate, 30% of energy from fat) for 6 wk. MTTs were performed at study onset and after 6 wk. Participants received standardized high-protein (30% of energy) meals 2 times/d containing either CP-rich (∼85% wt:wt) or PP-rich (∼95% wt:wt) foods. Results: The CP and PP meals produced differences in insulin, C-peptide, glucagon, and glucose-dependent insulinotropic peptide (GIP) release. Total areas under the curve after CP were significantly lower than after the PP lunch by 40% for insulin and 23% for glucagon. Indexes of insulin sensitivity and secretion were significantly improved for the second CP MTT. This was accompanied by differential rates of appearance of amino acids. The ingestion of PP resulted in significant increases in amino acids after both meals, with a decline between meals. By contrast, CP intake resulted in increases in most amino acids after breakfast, which remained elevated but did not increase further after lunch. Conclusions: PP elicits greater postprandial increases in glucagon than does CP and consequently requires higher insulin to control glucose metabolism, which appears to be related to the rate of amino acid appearance. The metabolic impact of protein quality could be used as a strategy to lower insulin needs in patients with T2D. This trial was registered at www.clinicaltrials.gov as NCT02402985.

Differential role of GPR142 in tryptophan-mediated enhancement of insulin secretion in obese and lean mice.

Tryptophan is reportedly the most potent agonist for GPR142. Glucose-stimulated insulin secretion (GSIS) from pancreatic beta cells are enhanced by GPR142-mediated signal. It is not clear, however, if GPR142-mediated signals is solely attributable to GSIS enhancement after tryptophan load in various pathophysiological settings. This study aims to reveal the significance of GPR142 signaling in tryptophan-mediated GSIS enhancement in normal and obese mice. Tryptophan significantly improved glucose tolerance in both lean and DIO mice, but the extent of improvement was bigger in DIO mice with augmented glucose-stimulated insulin secretion (GSIS) enhancement. The same results were obtained in ob/ob mice. GPR142 deletion almost completely blocked tryptophan actions in lean mice, suggesting that GPR142 signaling was solely responsible for the GSIS enhancement. In obese GPR142KO mice, however, a significant amount of tryptophan effects were still observed. Calcium-sensing receptors (CaSR) are also known to recognize tryptophan as ligand. Expression levels of CaSR were significantly elevated in the pancreas of DIO mice, and CaSR antagonist further blocked tryptophan's actions in DIO mice with GPR142 deletion. Although GPR142 signaling had a major role in tryptophan recognition for the enhancement of GSIS in lean mice, other pathways including CaSR signaling also had a significant role in obese mice, which seemed to contribute to the augmented enhancement of GSIS by tryptophan in these animals.

17-ß Estradiol regulates proglucagon-derived peptide secretion in mouse and human α- and L cells.

Clinical and experimental data indicate a beneficial effect of estrogens on energy and glucose homeostasis associated with improved insulin sensitivity and positive effects on insulin secretion. The aim of the study was to investigate the impact of estrogens on proglucagon-producing cells, pancreatic α cells, and enteroendocrine L cells. The consequences of sexual hormone deprivation were evaluated in ovariectomized mice (ovx). Ovx mice exhibited impaired glucose tolerance during oral glucose tolerance tests (OGTT), which was associated with decreased GLP-1 intestinal and pancreatic secretion and content, an effect that was reversed by estradiol (E2) treatment. Indeed, E2 increased oral glucose-induced GLP-1 secretion in vivo and GLP-1 secretion from primary culture of mouse and human α cells through the activation of all 3 estrogen receptors (ERs), whereas E2-induced GLP-1 secretion from mouse and human intestinal explants occurred only by ERß activation. Underlying the implication of ERß, its selective agonist WAY20070 was able to restore glucose tolerance in ovx mice at least partly through plasma GLP-1 increase. We conclude that E2 directly controls both α- and L cells to increase GLP-1 secretion, in addition to its effects on insulin and glucagon secretion, highlighting the potential beneficial role of the estrogenic pathway and, more particularly, of ERß agonists to prevent type 2 diabetes.

A Meta-Analysis of GLP-1 After Roux-En-Y Gastric Bypass: Impact of Surgical Technique and Measurement Strategy.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is an effective treatment for diabetes. Glucagon-like peptide-1 (GLP-1) is a gut hormone that is important to glucose homeostasis. OBJECTIVE: This study aimed to assess GLP-1 level and its predictors after RYGB. METHODS: The study design was a meta-analysis. The data sources were MEDLINE, EMBASE, Web of Science, and the Cochrane Databases. The study selection composed of studies with pre- and post-RYGB levels. The main outcomes were as follows: Primary outcome was the change in postprandial GLP-1 levels after RYGB. Secondary outcomes included the changes in fasting glucose, fasting insulin, and fasting GLP-1 levels after RYGB. Meta-regression to determine predictors of changes in GLP-1 levels was performed. Outcomes were reported using Hedge's g. RESULTS: Twenty-four studies with 368 patients were included. Postprandial GLP-1 levels increased after RYGB (Hedge's g = 1.29, p < 0.0001), while fasting GLP-1 did not change (p = 0.23). Peak postprandial GLP-1 levels gave the most consistent results (I 2 = 9.11). Fasting glucose and insulin levels decreased after RYGB (p < 0.0001). Roux limb length was a significant predictor for amount of GLP-1 increase (ß = - 0.01, p = 0.02). Diabetes status, amount of weight loss, length of biliopancreatic limb, and time of measurement were not significant predictors (p > 0.05). CONCLUSION: Postprandial GLP-1 levels increase after RYGB, while fasting levels remain unchanged. Shorter Roux limb length is associated with greater increase in postprandial GLP-1, which may lead to better glycemic control in this population.

Modified Western blotting for insulin and other diabetes-associated peptide hormones.

Now, the quantification of proinsulin/insulin contents within organisms tends to be evaluated only by enzyme-linked immunosorbent assay (ELISA), although assessing the adequacy of results by some quantification method is important. Remarkably, few scientific papers use detection by Western blotting (WB), another immunological assay, of proinsulin/insulin. We found two problems with quantification of insulin and proinsulin by general WB: the shape of an insulin band in gel electrophoresis is distorted, and the retention potency to a blotting membrane of the peptide hormones (mainly insulin) is low. We solved the first problem by optimizing the sodium dodecyl sulfate concentration in the sample buffer and the second problem by glutaraldehyde fixation following treatment with a blocking solution for a short time. The improvements were confirmed by quantification of proinsulin/insulin in standards, MIN6c4 cell lysates, and MIN6c4 culture supernatants. Furthermore, we showed that the modified WB is applicable to other diabetes-associated peptide hormones: insulin analogs, glucagon, GLP-1s, somatostatins, ghrelins, and pancreatic polypeptide. Our data showed that the modified WB can contribute to qualitative or quantitative analyses of diabetes-associated peptides by providing analytical information based on electrophoresis, although ELISA, which is an almost exclusive method in the quantification of peptide hormones, supplies only numerical data.

Hipoglucemias posprandiales como única manifestación de un insulinoma: descripción de un caso excepcional / Postprandial hypoglycemia as the only manifestation of insulinoma: exceptional case report

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