MyMedR

Displaying publications 21 - 31 of 31 in total

Abstract:

Sort:

Morphological changes of post-isolation of caprine pancreatic islet

Hani H, Allaudin ZN, Tengku Ibrahim TA, Mohd-Lila MA, Sarsaifi K, Camalxaman SN, et al.

In Vitro Cell Dev Biol Anim, 2015 Feb;51(2):113-20.
PMID: 25303943 DOI: 10.1007/s11626-014-9821-7

Pancreatic islet transplantation is commonly used to treat diabetes. Cell isolation and purification methods can affect the structure and function of the isolated islet cells. Thus, the development of cell isolation techniques that preserve the structure and function of pancreatic islet cells is essential for enabling successful transplantation procedures. The impact of purification procedures on cell function can be assessed by performing ultrastructure and in vivo studies. Thus, the aim of this study was to evaluate the effect of caprine islets purification procedure on islet cell ultrastructure and functional integrity prior to and post-isolation/purification. The islets were isolated from caprine pancreas by using an optimized collagenase XI-S concentration, and the cells were subsequently purified using Euro-Ficoll density gradient. In vitro viability of islets was determined by fluorescein diacetate and propidium iodide staining. Static incubation was used to assess functionality and insulin production by islet cells in culture media when exposed to various levels of glucose. Pancreatic tissues were examined by using light microscopy, fluorescence microscopy, scanning, and transmission electron microscopy. In vivo viability and functionality of caprine islets were assessed by evaluating the transplanted islets in diabetic mice. Insulin assay of glucose-stimulated insulin secretion test showed that the insulin levels increased with increasing concentration of glucose. Thus, purified islets stimulated with high glucose concentration (25 mM) secreted higher levels of insulin (0.542 ± 0.346 μg/L) than the insulin levels (0.361 ± 0.219, 0.303 ± 0.234 μg/L) secreted by exposure to low glucose concentrations (1.67 mM). Furthermore, insulin levels of recipient mice were significantly higher (p

Matched MeSH terms: Islets of Langerhans/cytology*; Islets of Langerhans/ultrastructure*; Islets of Langerhans Transplantation/methods*
Improvement of isolated caprine islet survival and functionality in vitro by enhancing of PDX1 gene expression

Hani H, Allaudin ZN, Mohd-Lila MA, Sarsaifi K, Rasouli M, Tam YJ, et al.

Xenotransplantation, 2017 05;24(3).
PMID: 28397308 DOI: 10.1111/xen.12302

BACKGROUND: Dead islets replaced with viable islets are a promising offer to restore normal insulin production to a person with diabetes. The main reason for establishing a new islet source for transplantation is the insufficiency of human donor pancreas while using xenogeneic islets perhaps assists this problem. The expression of PDX1 is essential for the pancreas expansion. In mature β-cells, PDX1 has several critical roles such as glucose sensing, insulin synthesis, and insulin secretion. In this study, we aimed to evaluate the expression of pancreatic duodenal homeobox-1 (PDX1) in treated caprine islets in culture and to assess the protective effects of antioxidant factors on the PDX1 gene in cultured caprine islets.
MATERIALS AND METHODS: Purified islets were treated with serum-free, serum, IBMX, tocopherol, or IBMX and tocopherol media. Quantitative polymerase chain reaction and Western blotting were carried out to compare the expression levels of PDX1 in treated purified islets cultured with different media.
RESULTS: Islets treated with IBMX/tocopherol exhibited the highest fold change in the relative expression of PDX1 on day 5 post-treatment (relative expression: 6.80±2.08), whereas serum-treated islets showed the lowest fold changes in PDX1 expression on day 5 post-treatment (0.67±0.36), as compared with the expression on day 1 post-treatment. Insulin production and viability tests of purified islets showed superiority of islet at supplemented serum-free media with IBMX/tocopherol compared to other cultures (53.875%±1.59%).
CONCLUSIONS: Our results indicated that supplemented serum-free medium with tocopherol and IBMX enhances viability and PDX1 gene expression compared to serum-added and serum-free media.

Matched MeSH terms: Islets of Langerhans/cytology; Islets of Langerhans/drug effects; Islets of Langerhans/physiology*
Cinnamic acid exerts anti-diabetic activity by improving glucose tolerance in vivo and by stimulating insulin secretion in vitro

Hafizur RM, Hameed A, Shukrana M, Raza SA, Chishti S, Kabir N, et al.

Phytomedicine, 2015 Feb 15;22(2):297-300.
PMID: 25765836 DOI: 10.1016/j.phymed.2015.01.003

Although the anti-diabetic activity of cinnamic acid, a pure compound from cinnamon, has been reported but its mechanism(s) is not yet clear. The present study was designed to explore the possible mechanism(s) of anti-diabetic activity of cinnamic acid in in vitro and in vivo non-obese type 2 diabetic rats. Non-obese type 2 diabetes was developed by injecting 90 mg/kg streptozotocin in 2-day-old Wistar pups. Cinnamic acid and cinnamaldehyde were administered orally to diabetic rats for assessing acute blood glucose lowering effect and improvement of glucose tolerance. Additionally, insulin secretory activity of cinnamic acid and cinnamaldehyde was evaluated in isolated mice islets. Cinnamic acid, but not cinnamaldehyde, decreased blood glucose levels in diabetic rats in a time- and dose-dependent manner. Oral administration of cinnamic acid with 5 and 10 mg/kg doses to diabetic rats improved glucose tolerance in a dose-dependent manner. The improvement by 10 mg/kg cinnamic acid was comparable to that of standard drug glibenclamide (5 mg/kg). Further in vitro studies showed that cinnamaldehyde has little or no effect on glucose-stimulated insulin secretion; however, cinnamic acid significantly enhanced glucose-stimulated insulin secretion in isolated islets. In conclusion, it can be said that cinnamic acid exerts anti-diabetic activity by improving glucose tolerance in vivo and stimulating insulin secretion in vitro.

Matched MeSH terms: Islets of Langerhans/drug effects*
Fulltext Glucocorticoid Signaling Enhances Expression of Glucose-Sensing Molecules in Immature Pancreatic Beta-Like Cells Derived from Murine Embryonic Stem Cells In Vitro

Ghazalli N, Wu X, Walker S, Trieu N, Hsin LY, Choe J, et al.

Stem Cells Dev, 2018 07 01;27(13):898-909.
PMID: 29717618 DOI: 10.1089/scd.2017.0160

Pluripotent stem cells may serve as an alternative source of beta-like cells for replacement therapy of type 1 diabetes; however, the beta-like cells generated in many differentiation protocols are immature. The maturation of endogenous beta cells involves an increase in insulin expression starting in late gestation and a gradual acquisition of the abilities to sense glucose and secrete insulin by week 2 after birth in mice; however, what molecules regulate these maturation processes are incompletely known. In this study, we aim to identify small molecules that affect immature beta cells. A cell-based assay, using pancreatic beta-like cells derived from murine embryonic stem (ES) cells harboring a transgene containing an insulin 1-promoter driven enhanced green fluorescent protein reporter, was used to screen a compound library (NIH Clinical Collection-003). Cortisone, a glucocorticoid, was among five positive hit compounds. Quantitative reverse transcription-polymerase chain reaction analysis revealed that glucocorticoids enhance the gene expression of not only insulin 1 but also glucose transporter-2 (Glut2; Slc2a2) and glucokinase (Gck), two molecules important for glucose sensing. Mifepristone, a pharmacological inhibitor of glucocorticoid receptor (GR) signaling, reduced the effects of glucocorticoids on Glut2 and Gck expression. The effects of glucocorticoids on ES-derived cells were further validated in immature primary islets. Isolated islets from 1-week-old mice had an increased Glut2 and Gck expression in response to a 4-day treatment of exogenous hydrocortisone in vitro. Gene deletion of GR in beta cells using rat insulin 2 promoter-driven Cre crossed with GRflox/flox mice resulted in a reduced gene expression of Glut2, but not Gck, and an abrogation of insulin secretion when islets were incubated in 0.5 mM d-glucose and stimulated by 17 mM d-glucose in vitro. These results demonstrate that glucocorticoids positively regulate glucose sensors in immature murine beta-like cells.

Matched MeSH terms: Islets of Langerhans/metabolism
Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications

Gao B, Wang L, Han S, Pingguan-Murphy B, Zhang X, Xu F

Crit Rev Biotechnol, 2016 Aug;36(4):619-29.
PMID: 25669871 DOI: 10.3109/07388551.2014.1002381

Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.

Matched MeSH terms: Islets of Langerhans*
Fulltext Effect of Hydrolyzed Bird's Nest on β-Cell Function and Insulin Signaling in Type 2 Diabetic Mice

Choy KW, Zain ZM, Murugan DD, Giribabu N, Zamakshshari NH, Lim YM, et al.

Front Pharmacol, 2021;12:632169.
PMID: 33986669 DOI: 10.3389/fphar.2021.632169

Type 2 diabetes mellitus is characterized by both resistance to the action of insulin and defects in insulin secretion. Bird's nest, which is derived from the saliva of swiftlets are well known to possess multiple health benefits dating back to Imperial China. However, it's effect on diabetes mellitus and influence on the actions of insulin action remains to be investigated. In the present study, the effect of standardized aqueous extract of hydrolyzed edible bird nest (HBN) on metabolic characteristics and insulin signaling pathway in pancreas, liver and skeletal muscle of db/db, a type 2 diabetic mice model was investigated. Male db/db diabetic and its euglycemic control, C57BL/6J mice were administered HBN (75 and 150 mg/kg) or glibenclamide (1 mg/kg) orally for 28 days. Metabolic parameters were evaluated by measuring fasting blood glucose, serum insulin and oral glucose tolerance test (OGTT). Insulin signaling and activation of inflammatory pathways in liver, adipose, pancreas and muscle tissue were evaluated by Western blotting and immunohistochemistry. Pro-inflammatory cytokines were measured in the serum at the end of the treatment. The results showed that db/db mice treated with HBN significantly reversed the elevated fasting blood glucose, serum insulin, serum pro-inflammatory cytokines levels and the impaired OGTT without affecting the body weight of the mice in all groups. Furthermore, HBN treatment significantly ameliorated pathological changes and increased the protein expression of insulin, and glucose transporters in the pancreatic islets (GLUT-2), liver and skeletal muscle (GLUT-4). Likewise, the Western blots analysis denotes improved insulin signaling and antioxidant enzyme, decreased reactive oxygen species producing enzymes and inflammatory molecules in the liver and adipose tissues of HBN treated diabetic mice. These results suggest that HBN improves β-cell function and insulin signaling by attenuation of oxidative stress mediated chronic inflammation in the type 2 diabetic mice.

Matched MeSH terms: Islets of Langerhans
Fulltext Effects of Tocotrienols on Insulin Secretion-Associated Genes Expression of Rat Pancreatic Islets in a Dynamic Culture

Chia LL, Jantan I, Chua KH, Lam KW, Rullah K, Aluwi MF

Front Pharmacol, 2016;7:291.
PMID: 27625609 DOI: 10.3389/fphar.2016.00291

Tocotrienols (T3) are well-known for their antioxidant properties besides showing therapeutic potential in clinical complications such as hyperlipidemia induced by diabetes. The aim of this study was to determine the effects of δ-T3, γ-T3, and α-T3 on insulin secretion-associated genes expression of rat pancreatic islets in a dynamic culture. Pancreatic islets freshly isolated from male Wistar rats were treated with T3 for 1 h at 37°C in a microfluidic system with continuous operation. The cells were collected for total RNA extraction and reverse-transcribed, followed by measurement of insulin secretion-associated genes expression using quantitative real-time polymerase chain reaction. Molecular docking experiments were performed to gain insights on how the T3 bind to the receptors. Short-term exposure of δ- and γ-T3 to pancreatic β cells in a stimulant glucose condition (16.7 mM) significantly regulated preproinsulin mRNA levels and insulin gene transcription. In contrast, α-T3 possessed less ability in the activation of insulin synthesis level. Essentially, potassium chloride (KCl), a β cell membrane depolarising agent added into the treatment further enhanced the insulin production. δ- and γ-T3 revealed significantly higher quantitative expression in most of the insulin secretion-associated genes groups containing 16.7 mM glucose alone and 16.7 mM glucose with 30 mM KCl ranging from 600 to 1200 μM (p < 0.05). The findings suggest the potential of δ-T3 in regulating insulin synthesis and glucose-stimulated insulin secretion through triggering pathway especially in the presence of KCl.

Matched MeSH terms: Islets of Langerhans
Tocotrienols Stimulate Insulin Secretion of Rat Pancreatic Isolated Islets in a Dynamic Culture

Chia LL, Jantan I, Chua KH

Curr Pharm Biotechnol, 2017;18(7):560-568.
PMID: 28786357 DOI: 10.2174/1389201018666170808144703

BACKGROUND: Tocotrienols (T3) are the naturally occurring vitamin E derivatives that possess antioxidant properties and therapeutic potential in diabetic complications. The bioactivities of the derivatives are determined by the number and arrangement of methyl substitution on the structure.
OBJECTIVE: The objective of this study was to determine the effects of T3 derivatives, σ-T3, γ-T3 and α-T3 on insulin secretion of rat pancreatic islets in a dynamic culture.
METHOD: Pancreatic islets isolated from male Wistar rats were treated with T3 for 1 h at 37°C in a microfluidic system with continuous operation that provided a stable cell culture environment. Glucose (2.8 mM and 16.7 mM, as basal and stimulant, respectively) and potassium chloride (KCl) (30 mM) were added to the treatment in calcium free medium. The supernatant was collected for insulin measurements.
RESULTS: Short-term exposure (1 h) of σ-T3 to β cells in the stimulant glucose condition significantly potentiated insulin secretion in a dose-dependent manner. γ-T3 and α-T3 also displayed dosedependent effect but were less effective in the activation of insulin secretion. Essentially, KCl, a pancreatic β cell membrane depolarizing agent, added into the treatment further enhanced the insulin secretion of σ-T3, γ-T3 and α-T3 with ED50 values of 504, 511 and 588 µM, respectively.
CONCLUSION: The findings suggest the potential of σ-T3 in regulating glucose-stimulated insulin secretion (GSIS) in response to the intracellular calcium especially in the presence of KCl.

Matched MeSH terms: Islets of Langerhans/drug effects*; Islets of Langerhans/metabolism
The antioxidant effect of the Malaysian Gelam honey on pancreatic hamster cells cultured under hyperglycemic conditions

Batumalaie K, Qvist R, Yusof KM, Ismail IS, Sekaran SD

Clin Exp Med, 2014 May;14(2):185-95.
PMID: 23584372 DOI: 10.1007/s10238-013-0236-7

Type 2 diabetes consists of progressive hyperglycemia, insulin resistance, and pancreatic β-cell failure which could result from glucose toxicity, inflammatory cytokines, and oxidative stress. In the present study, we investigate the effect of pretreatment with Gelam honey (Melaleuca spp.) and the individual flavonoid components chrysin, luteolin, and quercetin, on the production of reactive oxygen species (ROS), cell viability, lipid peroxidation, and insulin content in hamster pancreatic cells (HIT-T15 cells), cultured under normal and hyperglycemic conditions. Phenolic extracts from a local Malaysian species of Gelam honey (Melaleuca spp.) were prepared using the standard extraction methods. HIT-T15 cells were cultured in 5 % CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 μg/ml) as well as some of its flavonoid components chrysin, luteolin, and quercetin (20, 40, 60, and 80 μM), prior to stimulation by 20 and 50 mM of glucose. The antioxidative effects were measured in these cultured cells at different concentrations and time point by DCFH-DA assay. Pretreatment of cells with Gelam honey extract or the flavonoid components prior to culturing in 20 or 50 mM glucose showed a significant decrease in the production of ROS, glucose-induced lipid peroxidation, and a significant increase in insulin content and the viability of cells cultured under hyperglycemic condition. Our results show the in vitro antioxidative property of the Gelam honey and the flavonoids on the β-cells from hamsters and its cytoprotective effect against hyperglycemia.

Matched MeSH terms: Islets of Langerhans/drug effects*; Islets of Langerhans/physiology
Pancreatoprotective effects of Geniotrigona thoracica stingless bee honey in streptozotocin-nicotinamide-induced male diabetic rats

Aziz MSA, Giribabu N, Rao PV, Salleh N

Biomed Pharmacother, 2017 May;89:135-145.
PMID: 28222394 DOI: 10.1016/j.biopha.2017.02.026

Stingless bee honey (SLBH) has been claimed to possess multiple health benefits. Its anti-diabetic properties are however unknown. In this study, ability of SLBH from Geniotrigona thoracica stingless bee species in ameliorating pancreatic damage and in maintaining metabolic profiles were investigated in diabetic condition.
METHODS: SLBH at 1 and 2g/kg/b.w. was given orally to streptozotocin (STZ)-nicotinamide-induced male diabetic rats for 28days. Metabolic parameters (fasting blood glucose-FBG and lipid profiles-LP and serum insulin) were measured by biochemical assays. Distribution and expression level of insulin, oxidative stress marker i.e. catalase, inflammatory markers i.e. IKK-β, TNF-α, IL-1β and apoptosis marker i.e. caspase-9 in the pancreatic islets were identified and quantified respectively by immunohistochemistry. Levels of NF-κβ in pancreas were determined by enzyme-linked immunoassay (ELISA).
RESULTS: SLBH administration to diabetic male rats prevented increase in FBG, total cholesterols (TC), triglyceride (TG) and low density lipoprotein (LDL) levels. However, high density lipoprotein (HDL) and serum insulin levels in diabetic rats receiving SLBH increased. Additionally, histopathological changes and expression level of oxidative stress, inflammation and apoptosis markers in pancreatic islets of diabetic rats decreased with increased expression level of insulin in the islets. LC-MS analysis revealed the presence of several compounds in SLBH that might be responsible for these effects.
CONCLUSIONS: SLBH has great potential to be used as agent to protect the pancreas against damage and dysfunction where these could account for its anti-diabetic properties.

Matched MeSH terms: Islets of Langerhans/drug effects; Islets of Langerhans/pathology
Oleoyl-lysophosphatidylinositol enhances glucagon-like peptide-1 secretion from enteroendocrine L-cells through GPR119

Arifin SA, Paternoster S, Carlessi R, Casari I, Ekberg JH, Maffucci T, et al.

Biochim Biophys Acta Mol Cell Biol Lipids, 2018 09;1863(9):1132-1141.
PMID: 29883799 DOI: 10.1016/j.bbalip.2018.06.007

The gastrointestinal tract is increasingly viewed as critical in controlling glucose metabolism, because of its role in secreting multiple glucoregulatory hormones, such as glucagon like peptide-1 (GLP-1). Here we investigate the molecular pathways behind the GLP-1- and insulin-secreting capabilities of a novel GPR119 agonist, Oleoyl-lysophosphatidylinositol (Oleoyl-LPI). Oleoyl-LPI is the only LPI species able to potently stimulate the release of GLP-1 in vitro, from murine and human L-cells, and ex-vivo from murine colonic primary cell preparations. Here we show that Oleoyl-LPI mediates GLP-1 secretion through GPR119 as this activity is ablated in cells lacking GPR119 and in colonic primary cell preparation from GPR119-/- mice. Similarly, Oleoyl-LPI-mediated insulin secretion is impaired in islets isolated from GPR119-/- mice. On the other hand, GLP-1 secretion is not impaired in cells lacking GPR55 in vitro or in colonic primary cell preparation from GPR55-/- mice. We therefore conclude that GPR119 is the Oleoyl-LPI receptor, upstream of ERK1/2 and cAMP/PKA/CREB pathways, where primarily ERK1/2 is required for GLP-1 secretion, while CREB activation appears dispensable.

Matched MeSH terms: Islets of Langerhans/drug effects; Islets of Langerhans/metabolism

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links