Increased Beta-cell Mass Research Articles

In Utero Maternal Benzene Exposure Predisposes to the Metabolic Imbalance in the Offspring

Environmental chemicals play a significant role in the development of metabolic disorders, especially when exposure occurs early in life. We have recently demonstrated that benzene exposure, at concentrations relevant to a cigarette smoke, induces a severe metabolic imbalance in a sex-specific manner affecting male but not female mice. However, the roles of benzene in the development of aberrant metabolic outcomes following gestational exposure, remain largely unexplored. In this study, we exposed pregnant C57BL/6JB dams to benzene at 50 ppm or filtered air for 5 days/week (6h/day from gestational day 1 to birth) and studied male and female offspring metabolic phenotypes in their adult life. While no changes in body weight or body composition were observed between groups, 4-month-old male and female offspring exhibited reduced parameters of energy homeostasis (VO2, VCO2, and heat production). However, only male offspring from benzene-exposed dams were glucose intolerant and insulin resistant at this age. By six months of age, both male and female offspring displayed glucose and insulin intolerance, associated with elevated expression of hepatic gluconeogenesis and inflammatory genes. Additionally, this effect was accompanied by elevated insulin secretion and increased beta-cell mass only in male offspring. Thus, gestational benzene exposure can reprogram offspring for increased susceptibility to metabolic imbalance in adulthood with differential sensitivity between sexes.

Biphasic dynamics of beta cell mass in a mouse model of congenital hyperinsulinism: implications for type 2 diabetes.

Acute hyperglycaemia stimulates pancreatic beta cell proliferation in the mouse whereas chronic hyperglycaemia appears to be toxic. We hypothesise that this toxic effect is mediated by increased beta cell workload, unrelated to hyperglycaemia per se. To test this hypothesis, we developed a novel mouse model of cell-autonomous increased beta cell glycolytic flux caused by a conditional heterozygous beta cell-specific mutation that activates glucokinase (GCK), mimicking key aspects of the rare human genetic disease GCK-congenital hyperinsulinism. In the mutant mice, we observed random and fasting hypoglycaemia (random 4.5-5.4mmol/l and fasting 3.6mmol/l) that persisted for 15months. GCK activation led to increased beta cell proliferation as measured by Ki67 expression (2.7% vs 1.5%, mutant and wild-type (WT), respectively, p < 0.01) that resulted in a 62% increase in beta cell mass in young mice. However, by 8months of age, mutant mice developed impaired glucose tolerance, which was associated with decreased absolute beta cell mass from 2.9mg at 1.5months to 1.8mg at 8months of age, with preservation of individual beta cell function. Impaired glucose tolerance was further exacerbated by a high-fat/high-sucrose diet (AUC 1796 vs 966mmol/l × min, mutant and WT, respectively, p < 0.05). Activation of GCK was associated with an increased DNA damage response and an elevated expression of Chop, suggesting metabolic stress as a contributor to beta cell death. We propose that increased workload-driven biphasic beta cell dynamics contribute to decreased beta cell function observed in long-standing congenital hyperinsulinism and type 2 diabetes.

In Utero Maternal Benzene Exposure Predisposes to the Metabolic Imbalance in the Offspring.

Environmental chemicals play a significant role in the development of metabolic disorders, especially when exposure occurs early in life. We have recently demonstrated that benzene exposure, at concentrations relevant to cigarette smoke, induces a severe metabolic imbalance in a sex-specific manner affecting male but not female mice. However, the roles of benzene in the development of aberrant metabolic outcomes following gestational exposure, remain largely unexplored. In this study, we exposed pregnant C57BL/6JB dams to benzene at 50 ppm or filtered air for 6 h/day from gestational day 0.5 (GD0.5) through GD21 and studied male and female offspring metabolic phenotypes in their adult life. While no changes in body weight or body composition were observed between groups, 4-month-old male and female offspring exhibited reduced parameters of energy homeostasis (VO2, VCO2, and heat production). However, only male offspring from benzene-exposed dams were glucose intolerant and insulin resistant at this age. By 6 months of age, both male and female offspring exhibited marked glucose intolerance however, only male offspring developed severe insulin resistance. This effect was accompanied by elevated insulin secretion and increased beta-cell mass only in male offspring. In support, Homeostatic Model Assessment for Insulin Resistance, the index of insulin resistance was elevated only in male but not in female offspring. Regardless, both male and female offspring exhibited a considerable increase in hepatic gene expression associated with inflammation and endoplasmic reticulum stress. Thus, gestational benzene exposure can predispose offspring to increased susceptibility to the metabolic imbalance in adulthood with differential sensitivity between sexes.

Mathematical Model for the Dynamics of beta-cell Mass, Insulin-Glucose Kinetics Incorporating the Effect of Cortisol, Epinephrine and Physiological Delay

This work presents a mathematical model for the dynamics of β-cell mass, insulin-glucose kinetics incorporating the effect of cortisol, epinephrine and physiological delay. Parameter is define and incorporated in this work to represent the effectiveness of cortisol in suppressing insulin, also the parameter is define and incorporated to represent cortisol induced glucose increase with representing physiological delay as the factor that affect glucose-insulin homeostasis. The model consists of a system of three non-linear ordinary differential equations. The model is use to investigate the combine effect of cortisol and epinephrine with physiological delay on; glucose, insulin and beta-cell mass dynamics. The results of the study show that: In the combined presence of cortisol and epinephrine, the blood glucose increase more and the blood insulin decrease due to suppression by the hormone, despite the fact that there is increase in beta-cell mass, the system remains extremely hyperglycemic. The analytical results further show that continuous; stress, excitement and/or trauma lead to constant secretion of cortisol and epinephrine into the blood stream. Frequent secretion of cortisol and epinephrine increases the risk of diabetes in humans.

Lactational metformin exposure programs offspring white adipose tissue glucose homeostasis and resilience to metabolic stress in a sex-dependent manner

We previously demonstrated that exposing mouse dams to metformin during gestation results in increased beta-cell mass at birth and increased beta-cell insulin secretion in adult male offspring. Given these favorable changes after a gestational maternal metformin exposure, we wanted to understand the long-term metabolic impact on offspring after exposing dams to metformin during the postnatal window. The newborn period provides a feasible clinical window for intervention and is important for beta-cell proliferation and metabolic tissue development. Using a C57BL/6 model, we administered metformin to dams from the day of birth to postnatal day 21. We monitored maternal health and offspring growth during the lactation window, as well as adult glucose homeostasis through in vivo testing. At necropsy we assessed pancreas and adipocyte morphology using histological and immunofluorescent staining techniques. We found that metformin exposure programmed male and female offspring to be leaner with a higher proportion of small adipocytes in the gonadal white adipose tissue (GWAT). Male, but not female, offspring had an improvement in glucose tolerance as young adults concordant with a mild increase in insulin secretion in response to glucose in vivo. These data demonstrate long-term metabolic programming of offspring associated with maternal exposure to metformin during lactation.

Type 2 diabetes mellitus: pathogenesis and genetic diagnosis.

Type 2 diabetes mellitus (T2DM) is a heterogeneous condition that is related to both defective insulin secretion and peripheral insulin resistance. Beta cells are the major organ for secreting insulin hence, it is important to maintain an adequate beta-cell mass in response to various changes. Insulin resistance is a major cause of T2DM leads to elevated free fatty acid (FFA) levels which increases beta-cell mass and insulin secretion to compensate for insulin insensitivity. Chronic increase of plasma FFA levels results in disturbances in lipid metabolism, which contributes to decreased beta-cell function and lipotoxicity thus promoting T2DM. In the present review, we have discussed the process of beta-cell destruction, the role of genes in contributing to the fast increase in the progression of T2DM in detail. More than 130 variants in various T2DM susceptibility and candidate genes have been discovered to be associated with T2DM. Still, these variants elucidate only a small amount of total heritability of T2DM. Further, there is also an inventory of presently used therapeutic tools and a review of novel therapeutic approaches like incretin-based therapies or sodium-glucose transporter-2 inhibitors. Additionally, providing a concise but comprehensive update, this review will be essential to every clinician involved in the treatment of diabetes mellitus.

Possible mechanisms involved in improved beta cell function in pregnant women with type 1 diabetes

Pregnancy is known to be associated with an increased demand for insulin that is normally compensated by an increased beta cell mass and insulin secretion. Recent studies have suggested enhanced beta cell function during pregnancy in women with type 1 diabetes (T1D). To explore the possible mechanisms behind enhanced beta cell function during pregnancy in women with T1D we investigated the impact of circulating factors in serum from nine women from each group of pregnant women with and without T1D, after pregnancy and non-diabetic non-pregnant women on rat islet cell proliferation and apoptosis, and on T-lymphocyte activation. In addition, circulating levels of pancreatic hormones and selected cytokines and adipokines were measured. Rat islet cell proliferation was higher in serum from pregnant women with T1D (p < 0.05) compared to T1D women after pregnancy. Apoptosis in INS-1E cell was lower (p < 0.05) in serum from pregnant women with T1D compared to T1D women after pregnancy. T-lymphocyte cell (Jurkat) proliferation was reduced by serum from pregnant women without T1D only (p < 0.05). Higher C-peptide levels and lower levels of ghrelin, IL-6, MCP-1, IL-8 and adipsin were observed in pregnant women with T1D compared to T1D women after pregnancy. In conclusion, the improved beta cell function in women with T1D during pregnancy may be due to lower levels of proinflammatory cytokines and/or higher levels of pregnancy-associated growth factors.

86-OR: High-Fat Diet Prevents Autoimmune Diabetes in NOD Mice

Type 1 diabetes (T1D) has a strong genetic predisposition and requires an environmental trigger to initiate autoimmune destruction of beta cells. The rate of childhood obesity has risen in parallel to the rate of T1D, suggesting high fat diet (HFD) may be an environmental trigger in the development of autoimmune diabetes. Supporting this hypothesis, HFD can induce insulin resistance, beta cell stress, dysfunctional insulin production, and beta cell death. To explore the role of HFD in the development of T1D, 4 week-old non-obese diabetic (NOD) female mice were placed on HFD or chow diet (CD). At 10 weeks of age NOD mice fed with HFD demonstrated a significant increase in body weight and non-fasting blood glucose along with mild glucose intolerance compared with NOD CD fed mice. Histological analysis at 10 weeks of age revealed significantly less pancreatic immune cell infiltration and increased beta cell mass in HFD fed mice compared to CD fed mice. By 15 weeks of age, HFD fed NOD animals demonstrated impaired glucose tolerance similar to CD fed mice, increased glucose-stimulated insulin secretion and total insulin content, and insulin resistance. Surprisingly, at 25 weeks of age the HFD fed NOD mice were completely protected from the development of diabetes, while as expected 70% of NOD CD fed mice had developed diabetes. In summary, this study demonstrates that in the NOD model of T1D HFD reduced islet immune cell infiltration, increased beta cell mass, insulin content and insulin secretion protecting the mice from development of diabetes. The mechanism underlying this protection seems to be two-fold: expansion of beta cell mass and prevention of autoimmune-mediated beta cell death. Our data correlate with other recent studies indicating that early stimulation of beta cell replication can induce immune tolerance in NOD animals preventing T1D. Identification of the mechanisms by which HFD leads to prevention of diabetes in NOD animals may lead to the development of novel therapeutic interventions to prevent T1D in humans. Disclosure A.L. Clark: None. Z. Yan: None. S.X. Chen: None. M. Fuess: None. G. McGinn: None. M.S. Remedi: None. Funding National Institutes of Health (P30DK020579, K12HD076224-04)

Lactational metformin exposure programs offspring white adipose tissue glucose homeostasis and resilience to metabolic stress in a sex-dependent manner.

We previously demonstrated that exposing mouse dams to metformin during gestation results in increased beta-cell mass at birth and increased beta-cell insulin secretion in adult male offspring. Given these favorable changes after a gestational maternal metformin exposure, we wanted to understand the long-term metabolic impact on offspring after exposing dams to metformin during the postnatal window. The newborn period provides a feasible clinical window for intervention and is important for beta-cell proliferation and metabolic tissue development. Using a C57BL/6 model, we administered metformin to dams from the day of birth to postnatal day 21. We monitored maternal health and offspring growth during the lactation window, as well as adult glucose homeostasis through in vivo testing. At necropsy we assessed pancreas and adipocyte morphology using histological and immunofluorescent staining techniques. We found that metformin exposure programmed male and female offspring to be leaner with a higher proportion of small adipocytes in the gonadal white adipose tissue (GWAT). Male, but not female, offspring had an improvement in glucose tolerance as young adults concordant with a mild increase in insulin secretion in response to glucose in vivo. These data demonstrate long-term metabolic programming of offspring associated with maternal exposure to metformin during lactation.

Luseogliflozin increases beta cell proliferation through humoral factors that activate an insulin receptor- and IGF-1 receptor-independent pathway.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, which prevent the renal reabsorption of glucose, decrease blood glucose levels in an insulin-independent manner. We previously reported creating a mouse model of systemic inhibition of target receptors for both insulin and IGF-1 by treating animals with OSI-906, a dual insulin/IGF-1 receptor inhibitor, for 7days. The OSI-906-treated mice exhibited an increased beta cell mass, hepatic steatosis and adipose tissue atrophy, accompanied by hyperglycaemia and hyperinsulinaemia. In the present study, we investigated the effects of an SGLT2 inhibitor, luseogliflozin, on these changes in OSI-906-treated mice. We treated C57BL/6J male mice either with vehicle, luseogliflozin, OSI-906 or OSI-906 plus luseogliflozin for 7days, and phenotyping was performed to determine beta cell mass and proliferation. Subsequently, we tested whether serum-derived factors have an effect on beta cell proliferation in genetically engineered beta cells, mouse islets or human islets. SGLT2 inhibition with luseogliflozin significantly ameliorated hyperglycaemia, but not hyperinsulinaemia, in the OSI-906-treated mice. Liver steatosis and adipose tissue atrophy induced by OSI-906 were not altered by treatment with luseogliflozin. Beta cell mass and proliferation were further increased by SGLT2 inhibition with luseogliflozin in the OSI-906-treated mice. Luseogliflozin upregulated gene expression related to the forkhead box M1 (FoxM1)/polo-like kinase 1 (PLK1)/centromere protein A (CENP-A) pathway in the islets of OSI-906-treated mice. The increase in beta cell proliferation was recapitulated in a co-culture of Irs2 knockout and Insr/IR knockout (βIRKO) beta cells with serum from both luseogliflozin- and OSI-906-treated mice, but not after SGLT2 inhibition in beta cells. Circulating factors in both luseogliflozin- and OSI-906-treated mice promoted beta cell proliferation in both mouse islets and cadaveric human islets. These results suggest that luseogliflozin can increase beta cell proliferation through the activation of the FoxM1/PLK1/CENP-A pathway via humoral factors that act in an insulin/IGF-1 receptor-independent manner.

Islets from human donors with higher but not lower hemoglobin A1c levels respond to gastrin treatment in vitro.

Gastrin is a peptide hormone, which in combination with other factors such as TGFα, EGF or GLP-1, is capable of increasing beta cell mass and lowering blood glucose levels in adult diabetic mice. In humans, administration of a bolus of gastrin alone induces insulin secretion suggesting that gastrin may target islet cells. However, whether gastrin alone is sufficient to exert an effect on isolated human islets has been controversial and the mechanism remained poorly understood. Therefore, in this study we started to examine the effects of gastrin alone on cultured adult human islets. Treatment of isolated human islets with gastrin I for 48 h resulted in increased expression of insulin, glucagon and somatostatin transcripts. These increases were significantly correlated with the levels of donor hemoglobin A1c (HbA1c) but not BMI or age. In addition, gastrin treatment resulted in increased expression of PDX1, NKX6.1, NKX2.2, MNX1 and HHEX in islets from donors with HbA1c greater than 42 mmol/mol. The addition of YM022, an antagonist of the gastrin receptor cholecystokinin B receptor (CCKBR), together with gastrin eliminated these effects, verifying that the effects of gastrin are mediated through CCKBR.CCKBR is expressed in somatostatin-expressing delta cells in islets from all donors. However, in the islets from donors with higher HbA1c (greater than 42 mmol/mol [6.0%]), cells triple-positive for CCKBR, somatostatin and insulin were detected, suggesting a de-differentiation or trans-differentiation of endocrine cells. Our results demonstrate a direct effect of gastrin on human islets from prediabetic or diabetic individuals that is mediated through CCKBR+ cells. Further, our data imply that gastrin may be a potential treatment for diabetic patients.

Long-term c-Kit overexpression in beta cells compromises their function in ageing mice.

c-Kit signalling regulates intracellular pathways that enhance beta cell proliferation, insulin secretion and islet vascularisation in mice up to 28weeks of age and on short-term high-fat diet. However, long-term c-Kit activation in ageing mouse islets has yet to be examined. This study utilises beta cell-specific c-Kit-overexpressing transgenic (c-KitβTg) ageing mice (~60weeks) to determine the effect of its activation on beta cell dysfunction and insulin secretion. Wild-type and c-KitβTg mice, aged 60weeks, were examined using metabolic tests to determine glucose tolerance and insulin secretion. Pancreas histology and proteins in isolated islets were examined to determine the expression of beta cell transcription factors, proliferation and intracellular signalling. To determine the role of insulin receptor signalling in ageing c-KitβTg mice, we generated beta cell-specific inducible insulin receptor knockout in ageing c-KitβTg mice (c-KitβTg;βIRKO mice) and examined the ageing mice for glucose tolerance and islet histology. Ageing c-KitβTg mice progressively developed glucose intolerance, compared with age-matched wild-type littermates, due to impaired insulin secretion. Increased beta cell mass, proliferation and nuclear forkhead box transcription factor O1 (FOXO1) expression and reduced exocytotic protein levels were detected in ageing c-KitβTg mouse islets. Protein analyses of isolated islets showed increased insulin receptor, phosphorylated IRS-1Ser612 and cleaved poly(ADP-ribose) polymerase levels in ageing c-KitβTg mice. Ageing c-KitβTg mouse islets treated ex vivo with insulin demonstrated reduced Akt phosphorylation, indicating that prolonged c-Kit induced beta cell insulin insensitivity. Ageing c-KitβTg;βIRKO mice displayed improved glucose tolerance and beta cell function compared with ageing c-KitβTg mice. These findings indicate that long-term c-Kit overexpression in beta cells has a negative impact on insulin exocytosis and that temporally dependent regulation of c-Kit-insulin receptor signalling is important for optimal beta cell function.

38-OR: Beta-Arrestin-1 Regulates Pancreatic Beta-Cell Function and Plays a Key Role in Maintaining Whole Body Glucose Homeostasis

Beta-arrestin-1 and -2 (barr1 and barr2, respectively) are major GPCR-associated signaling molecules that are widely expressed throughout the body. Studies with whole body barr1 and barr2 KO mice have shown that beta-arrestins play important roles in key metabolic functions. In this study, we inactivated the barr1 gene in a conditional fashion specifically in beta-cells of adult mice (beta-barr1-KO mice). In vivo studies showed that beta-barr1-KO mice exhibited a pronounced impairment in glucose tolerance and glucose-stimulated insulin secretion (GSIS), when mice were maintained on high-fat diet (HFD). Studies with isolated perifused pancreatic islets prepared from HFD beta-barr1-KO mice confirmed that barr1 deletion in beta-cells led to a significant decrease in GSIS. Interestingly, HFD beta-barr1-KO mice displayed pronounced reductions in beta-cell mass and the rate of beta-cell proliferation, suggesting that barr1 is required for the expansion of beta-cell mass that occurs during HFD feeding. To test whether enhanced barr1 signaling in beta-cells might ameliorate the metabolic deficits associated with the consumption of a HFD, we also generated transgenic mice over-expressing barr1 in beta-cells (RIPII-barr1 mice). These transgenic mice displayed metabolic phenotypes that were opposite to those observed with the beta-barr1-KO mice, including improved glucose tolerance and GSIS in vivo as well as increased beta-cell mass. This is the first study demonstrating that barr1 is critical for the proper function of pancreatic beta-cells and for maintaining whole body glucose homeostasis. Identification of the cellular mechanisms through which barr1 signaling promotes beta-cell function and proliferation may lead to the development of novel drugs useful for the treatment of type 2 diabetes. Disclosure L.F. Barella: None. M. Rossi: None. S. Pydi: None. S. Jain: None. L. Zhu: None. W. Chen: None. J. Wess: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases

237-LB: Identification of Small Molecules That Increase Beta-Cell Mass in Hyperinsulinemic Zebrafish Alström Syndrome Model

Alström syndrome is an autosomal recessive obesity ciliopathy caused by loss-of-function mutations in the ALMS1 gene. In addition to multi-organ dysfunction, such as cardiomyopathy, retinal degeneration, and renal dysfunction, the disorder is characterized by high rates of obesity, insulin resistance and early onset type 2 diabetes mellitus (T2DM). We previously published data supporting the alms1 loss-of-function zebrafish mutant as a monogenic model for mechanistic interrogation of T2DM phenotypes. Both adult and larval alms1-/- animals exhibit reduced insulin+ areas alongside defective peripheral glucose uptake and concomitant hyperinsulinemia in larval alms1-/- animals. Gene expression changes in beta-cells isolated from alms1-/- mutants revealed changes consistent with insulin hyperproduction, insulin hypersecretion and glucose sensing failure. Therefore, we used this model, in which hyperinsulinemia is the primary and causative defect underlying generation of T2DM, in a high-throughput screen to examine small molecule compounds effecting pancreatic mass in vivo. The external development, simple growing conditions, and large number of progeny in the zebrafish allow for rapid screening with parallel elimination of lethal compounds. We examined the Microsource Spectrum Collection 2000, a library of 2,560 compounds, for those which increase beta-cell mass in wildtype, alms1-/- animals or both. These identified compounds are indicated in future studies for beta-cell proliferation pathways, T2DM diabetes-specific interactions, and potential targets for future therapeutic development. Disclosure J. Dunleavey: None. D.A. Annis: None. T.L. Hostelley: None. N.A. Zaghloul: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases

The Bile Acid TUDCA Improves Beta-Cell Mass and Reduces Insulin Degradation in Mice With Early-Stage of Type-1 Diabetes.

Type 1 diabetes (T1D) is characterized by impairment in beta-cell mass and insulin levels, resulting in hyperglycemia and diabetic complications. Since diagnosis, appropriate control of glycaemia in T1D requires insulin administration, which can result in side effects, such as hypoglycemia. In this sense, some bile acids have emerged as new therapeutic targets to treat T1D and T2D, as well as metabolic diseases. The taurine conjugated bile acid, tauroursodeoxycholic (TUDCA) reduces the incidence of T1D development and improves glucose homeostasis in obese and T2D mice. However, its effects in early-stage of T1D have not been well explored. Therefore, we have assessed the effects of TUDCA on the glycemic control of mice with early-stage T1D. To achieve this, C57BL/6 mice received intraperitoneal administration of streptozotocin (STZ, 40 mg/kg) for 5 days. Once diabetes was confirmed in the STZ mice, they received TUDCA treatment (300 mg/kg) or phosphate buffered saline (PBS) for 24 days. After 15 days of treatment, the STZ+TUDCA mice showed a 43% reduction in blood glucose, compared with the STZ group. This reduction was likely due to an increase in insulinemia. This increase in insulinemia may be explained, at least in part, by a reduction in hepatic IDE activity and, consequently, reduction on insulin clearance, as well as an increase in beta-cell mass and a higher beta-cell number per islet. Also, the groups did not present any alterations in insulin sensitivity. All together, these effects contributed to the improvement of glucose metabolism in T1D mice, pointing TUDCA as a potential therapeutic agent for the glycemic control in early-stage of T1D.

SAT-162 Hepatocyte Nuclear Factor-4α (HNF44α) as a Target to Treat DM

Diabetes Mellitus (DM) is a metabolic disorder with multiple etiology and characterized by chronic hyperglycemia. It results from total (Type 1) or partial (Type 2) depletion of β cells, associated or not with insulin resistance (IR). Any Processes that promote the functional β-cell mass regeneration may be a target for DM treatment. HNF4α is an important transcription factor for pancreatic β cells because, beyond the control of the insulin gene, it regulates the expression of genes related to glucose metabolism, it is crucial in increasing beta cell mass in response to stress, such as in pregnancy and it is important to β-cell fate. However, little is known of its involvement in pancreatic β-cell apoptosis and regeneration. Based on the fact that HNF4α (1) participates in cell death processes, (2) controls processes of compensatory increase of β-cell mass, and (3) acts directly in regenerative processes, we aimed to unravel possible mechanisms, dependent of HNF4α, which can be used to treat Diabetes Mellitus. First we analyzed, in vitro, the consequence of HNF4α knockdown in human β-cell line EndoC-βH1 in the gene expression of several markers to islet-cell fate and in the cytokine-induced apoptosis. We observed that the siRNA for HNF4α reduced the expression of genes important to β-cell fate (PDX-1, NKX2.2, MAF-A, UCN-3 and KIR) and increased the expression of genes not-related with β-cell (NGN3, SOX9 and GLUCAGON). In additional, HNF4α knockdown prevented the cytokine-induced Caspase-3 cleavage in human EndoC-βH1 and rat INS-1E cell line. Then, we addressed our focus to the HNF4α ability to promote β-cell expansion in response to a metabolic demand. Here we investigated the HNF4α role in the IR-induced β-cell proliferation. We used WildType (C) and Knockout (K) animals for HNF4-alpha (HNF4αloxP/loxP;Ins.Cre). After CRE-recombinase activation the induction of Knockout was confirmed by ipGTT. To induce an IR, animals C and K were treated (D) or not-treated (S) with 100 mg/kg of dexamethasone for 5 consecutive days. Then, we analyzed GSIS, pancreatic morphometry (IHC) and expression of genes involved in pancreatic islet cell proliferation/transdifferentiation. We observed that indeed Dexa induced an IR and a β-cell mass expansion in CD mice, which were not observed in KD mice. Moreover, Dexa induced, in CD mice, an increase in genes involved in islet-cell expansion (Glucagon, Somatostatin, PDX1, PAX4, HHEX, NGN3) and this increased were abolished in KD mice. So, we observed that HNF4α seems to be important in the β-cell fate since its knockdown induces a non-β-cell gene expression in a β-cell line. Moreover, HNF4α acts in the β-cell death process and is involved in the Dexa-induced β-cell mass expansion. Taking together, HNF4α may be a target to prevent β-cell apoptosis and to induce β-cell regeneration. Financial Support: FAPESC/CNPq/CAPES/FAPESP.

SAT-149 The Metabolic Impairments Caused by Fructose and Prednisolone Intake Are Reversible After the Interruption of Exposure

Regular ingestion of fructose and continuous glucocorticoid (GC) treatment, separately, may result in metabolic adverse effects (1,2), but their combined impact is not yet understood. Thus, we aimed to evaluate the impact of a combination of fructose and prednisolone ingestion on glucose and lipid metabolism as well as the effect of the interruption of this combined treatment. Male Wistar rats were divided into five groups as follows: control (C) group, fructose (F) group (20% fructose in the drinking water), prednisolone (P) group (12.5 μg/mL prednisolone in the drinking water), fructose plus prednisolone (FP) group (a combination of fructose and prednisolone in the drinking water as for F and P groups) for 90 consecutive days. Half of the rats (group R) from the FP group were maintained for 90 more days with a discontinuation of fructose and prednisolone to monitor the parameters. The combination of fructose and GC intake led to an increase in the circulating triacylglycerol from the fourth week of treatment until the end of treatment (P<0.05, n=10). The FP group also exhibited higher abdominal adiposity and plasma insulin values, reduced insulin sensitivity, increased uricemia, and impaired hepatic redox balance that paralleled with augmented fat content in the liver (p<0.05, n=10). No major impact on blood glucose or glucose tolerance was observed in the FP group. These results observed in the FP group were associated with increased beta-cell mass (p<0.05, n=8). Moreover, the combination of sugar and GC treatment led to a reduction in the total hepatic protein kinase B (PKB) content and to a reduction in the phosphorylated 5’ AMP-activated protein kinase (AMPK) content in the epididymal adipose tissue (p<0.05, n=6). Combination of fructose and GC intake did not impact on proinflammatory protein contents in the adipose tissue. Complete cessation of treatments resulted in the normalization of plasma triacylglycerol and uric acid levels in the R group (p<0.05, n=10). Interruption of sugar and GC treatments also led to normalization of the peripheral insulin sensitivity, hepatic fat content and the hepatic redox state (p<0.05, n-10). We conclude that the combination of fructose and prednisolone intake induces a metabolic syndrome-like phenotype and that interruption of fructose and GC intake recover practically all metabolic impairments. These findings point to the risk of associating GC-based therapies with a regular intake of sweetened beverages and draws attention to the plasticity of the organism and the benefits of removing the causal factors, whenever possible. Reference: (1) Zhang et al., Nutrients. 2017 Mar 29;9(4). pii: E335. (2) Pasieka et al., Metabolites. 2016 Aug 3;6(3). pii: E24. Sources of Research Support: CNPq and CAPES.

GABA Agonist Baclofen Increases Beta cell Mass and C Peptide Level in Patients with Type 1 Diabetes

GABA Agonist Baclofen Increases Beta cell Mass and C Peptide Level in Patients with Type 1 Diabetes

Current Status of Proton Pump Inhibitors in Pharmacotherapy of Diabetes Mellitus

Diabetes mellitus [DM] is a chronic metabolic disorder with its associated complications. Despite the plethora of available anti diabetic drugs to treat DM search continues to discover newer drugs. Proton pump inhibitors [PPIs] are the drugs which have been tested by researchers in animal models and in clinical set up to treat DM. They appeared to be promising drugs to reduce hyperglycemia. They can be used as supportive drugs along with the primary anti diabetic drugs. PPIs enhance rebound gastrin release, increase beta cell mass and insulin release. They are not hypoglycemic drugs. They reduce blood sugar by increase in gastrin and GLP-1 levels, decrease in ghrelin levels, reduced appetite, delayed gastric emptying and enhanced satiety through action on CNS.PPIs are the inhibitors of organic cation transporters (OCTs) for which metformin is the substrate and hence the plasma levels of metformin are increased. The potential and safety of PPIs in treatment of DM should be evaluated by long term clinical trials.

Autologous Peripheral Blood Mononuclear Cells can Lead to Pancreatic Beta Cell Regeneration

Introduction: Type-1 diabetes (T1D) is a disease that leads to pancreatic beta cells death, resulting in complete insulin loss. T1D occurs as a result of autoimmunity which takes insulin producing β cells as a target and is considered as a metabolic disorder causing hyperglycemia resulting from a serious loss of endogenous insulin roduction. Using cadaveric islets as a replacement therapy was done to reverse diabetes. Many various progenitor cell types have been found in the peripheral blood mononuclear cell (PBMC) fraction denoting hose PBMCs may have the ability to differentiate into many mature functional cell types in certain microenvironments. It is settled that circulating peripheral blood mononuclear cells (PBMC) contain germinal cell population which can share in the regeneration of tissues in different organs. Materials and Methods: 2 groups of type I diabetes patients had been monitored in a private clinic, number 40 each group, with 35 females and 45 males. It lied between 8-25 years old with 4-7 years of diabetes onset. The first group was on insulin therapy and they received peripheral blood mononuclear cells concentrate directly in the dorsal pancreatic artery. The second group was only on insulin injection. Results: The results show a significant increase in c peptide levels after direct injection of peripheral blood mononuclear cells in the dorsal pancreatic artery with p-value less than 0.0001. Conclusion: The peripheral blood mononuclear cells can induce beta cell regeneration and increase beta cell mass which is detected by an increase in c peptide levels.