Juris J Meier

Publications of Juris J Meier

• Impaired Crosstalk between Pulsatile Insulin and Glucagon Secretion in Prediabetic Individuals.

  Authors: Stefan Rohrer, Björn A Menge, Lena Grüber, Carolyn F Deacon, Wolfgang E Schmidt, Johannes D Veldhuis, Jens J Holst, Juris J Meier

  The Journal of clinical endocrinology and metabolism. 03/2012;

  Introduction:Postprandial hyperglucagonemia is frequently found in patients with diabetes. Recently, a loss of the inverse relationship between pulsatile insulin and glucagon secretion has beenIntroduction:Postprandial hyperglucagonemia is frequently found in patients with diabetes. Recently, a loss of the inverse relationship between pulsatile insulin and glucagon secretion has been reported in patients with type 2 diabetes. The crosstalk between pulsatile islet hormone secretion in prediabetic individuals has not yet been examined.Patients and Methods:Eleven individuals with impaired glucose tolerance and/or impaired fasting glucose and 13 nondiabetic controls were examined after mixed meal ingestion. Glucose, insulin, and glucagon levels were determined frequently and analyzed by deconvolution and cross-correlation methods.Results:Postprandial glucose levels were higher in prediabetic individuals (P = 0.017). Insulin concentrations were not different between the groups (P = 0.29). Postprandial glucagon levels were higher in the impaired glucose tolerance/impaired fasting glucose individuals (P = 0.039). Pulsatile insulin and glucagon secretion was apparent in both groups, but there were no differences in the frequency or mass of insulin and glucagon pulses between the groups. An inverse relationship between the insulin and glucagon concentration time curves was found in the control subjects (P < 0.05). This association was not detectable in the prediabetic individuals.Conclusions:Increased postprandial glucagon concentrations in prediabetic individuals are accompanied by a loss of the pulsatile insulin-glucagon crosstalk. This suggests that disturbances in islet hormone pulsatility precede the actual manifestation of hyperglycemia.

• Long-term recovery of β-cell function after partial pancreatectomy in humans.

  Authors: Bjoern A Menge, Thomas G K Breuer, Peter R Ritter, Waldemar Uhl, Wolfgang E Schmidt, Juris J Meier

  Metabolism: clinical and experimental. 11/2011;

  Glucose homeostasis is significantly altered immediately after partial pancreatectomy. The present study examined the long-term consequences of a hemipancreatectomy in 10 patients with chronicGlucose homeostasis is significantly altered immediately after partial pancreatectomy. The present study examined the long-term consequences of a hemipancreatectomy in 10 patients with chronic pancreatitis and 10 patients with benign pancreatic and extrapancreatic tumors. A 240-minute oral glucose challenge was performed before and shortly after pancreatic surgery, as well as after a follow-up of 3.1 ± 0.5 years. Plasma concentrations of glucose, insulin, and C-peptide were determined; and indices of insulin sensitivity and insulin secretion were calculated. In both groups of patients, fasting and postchallenge glucose concentrations were significantly altered immediately after surgery, but returned to preoperative levels at the time of follow-up (P < .0001). Postchallenge insulin and C-peptide concentrations were reduced immediately after surgery (P < .0001), but were partly normalized at the time of follow-up (P < .0001). These changes were not accompanied by improvements in insulin sensitivity (Matsuda index). However, the oral disposition index revealed a significant recovery of β-cell function at the time of follow-up (P < .05). These findings demonstrate a capacity for recovery of glucose control after partial pancreatectomy and suggest that β-cell function can improve significantly over time even in adult humans.

• Dapagliflozin versus glipizide as add-on therapy in patients with type 2 diabetes who have inadequate glycemic control with metformin: a randomized, 52-week, double-blind, active-controlled noninferiority trial.

  Authors: Michael A Nauck, Stefano Del Prato, Juris J Meier, Santiago Durán-García, Katja Rohwedder, Martina Elze, Shamik J Parikh

  Diabetes care. 08/2011; 34(9):2015-22.

  Although initially effective, sulfonylureas are associated with poor glycemic durability, weight gain, and hypoglycemia. Dapagliflozin, a selective inhibitor of sodium-glucose cotransporter 2Although initially effective, sulfonylureas are associated with poor glycemic durability, weight gain, and hypoglycemia. Dapagliflozin, a selective inhibitor of sodium-glucose cotransporter 2 (SGLT2), reduces hyperglycemia by increasing urinary glucose excretion independent of insulin and may cause fewer of these adverse effects. We compared the efficacy, safety, and tolerability of dapagliflozin with the sulfonylurea glipizide in patients with type 2 diabetes inadequately controlled with metformin monotherapy. This 52-week, double-blind, multicenter, active-controlled, noninferiority trial randomized patients with type 2 diabetes (baseline mean HbA(1c), 7.7%), who were receiving metformin monotherapy, to add-on dapagliflozin (n = 406) or glipizide (n = 408) up-titrated over 18 weeks, based on glycemic response and tolerability, to ≤10 or ≤20 mg/day, respectively. The primary end point, adjusted mean HbA(1c) reduction with dapagliflozin (-0.52%) compared with glipizide (-0.52%), was statistically noninferior at 52 weeks. Key secondary end points: dapagliflozin produced significant adjusted mean weight loss (-3.2 kg) versus weight gain (1.2 kg; P < 0.0001) with glipizide, significantly increased the proportion of patients achieving ≥5% body weight reduction (33.3%) versus glipizide (2.5%; P < 0.0001), and significantly decreased the proportion experiencing hypoglycemia (3.5%) versus glipizide (40.8%; P < 0.0001). Events suggestive of genital infections and lower urinary tract infections were reported more frequently with dapagliflozin compared with glipizide but responded to standard treatment and rarely led to study discontinuation. Despite similar 52-week glycemic efficacy, dapagliflozin reduced weight and produced less hypoglycemia than glipizide in type 2 diabetes inadequately controlled with metformin. Long-term studies are required to further evaluate genital and urinary tract infections with SGLT2 inhibitors.

• Chronic reduction of fasting glycemia with insulin glargine improves first- and second-phase insulin secretion in patients with type 2 diabetes.

  Authors: Christian Pennartz, Nina Schenker, Björn A Menge, Wolfgang E Schmidt, Michael A Nauck, Juris J Meier

  Diabetes care. 07/2011; 34(9):2048-53.

  Insulin secretion is often diminished in hyperglycemic patients with type 2 diabetes. We examined whether chronic basal insulin treatment with insulin glargine improves glucose-induced insulinInsulin secretion is often diminished in hyperglycemic patients with type 2 diabetes. We examined whether chronic basal insulin treatment with insulin glargine improves glucose-induced insulin secretion. Fourteen patients with type 2 diabetes on metformin monotherapy received an add-on therapy with insulin glargine over 8 weeks. Intravenous glucose tolerance tests (IVGTTs) were performed before and after the intervention, with and without previous adjustment of fasting glucose levels using a 3-h intravenous insulin infusion. Fasting glycemia was lowered from 179.6 ± 7.5 to 117.6 ± 6.5 mg/dL (P < 0.001), and HbA(1c) levels declined from 8.4 ± 0.5 to 7.1 ± 0.2% (P = 0.0046). The final insulin dose was 59.3 ± 10.2 IU. Acute normalization of fasting glycemia by intravenous insulin reduced C-peptide levels during the IVGTT (P < 0.0001). In contrast, insulin and C-peptide responses to intravenous glucose administration were significantly greater after the glargine treatment period (P < 0.0001, respectively). Both first- and second-phase insulin secretion increased significantly after the glargine treatment period (P < 0.05, respectively). These improvements in insulin secretion were observed during both the experiments with and without acute adjustment of fasting glycemia. Chronic supplementation of long-acting basal insulin improves glucose-induced insulin secretion in hyperglycemic patients with type 2 diabetes, whereas acute exogenous insulin administration reduces the β-cell response to glucose administration. These data provide a rationale for basal insulin treatment regiments to improve postprandial endogenous insulin secretion in hyperglycemic patients with type 2 diabetes.

• Loss of inverse relationship between pulsatile insulin and glucagon secretion in patients with type 2 diabetes.

  Authors: Björn A Menge, Lena Grüber, Signe M Jørgensen, Carolyn F Deacon, Wolfgang E Schmidt, Johannes D Veldhuis, Jens J Holst, Juris J Meier

  Diabetes. 06/2011; 60(8):2160-8.

  In patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered inIn patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered in type 2 diabetes is not known. Twelve patients with type 2 diabetes and 13 nondiabetic individuals were examined in the fasting state and after mixed meal ingestion. Deconvolution analyses were performed on insulin and glucagon concentration time series sampled at 1-min intervals. Both insulin and glucagon were secreted in distinct pulses, occurring at ∼5-min intervals. In patients with diabetes, postprandial insulin pulse mass was reduced by 74% (P < 0.001). Glucagon concentrations were increased in the patients during fasting and after meal ingestion (P < 0.05), specifically through an increased glucagon pulse mass (P < 0.01). In healthy subjects, the increase in postprandial insulin levels was inversely related to respective glucagon levels (P < 0.05). This relationship was absent in the fasting state and in patients with diabetes. Glucagon and insulin are secreted in a coordinated, pulsatile manner. A plausible model is that the postprandial increase in insulin burst mass represses the corresponding glucagon pulses. Disruption of the insulin-glucagon interaction in patients with type 2 diabetes could potentially contribute to hyperglucagonemia.

• Rapid tachyphylaxis of the glucagon-like peptide 1-induced deceleration of gastric emptying in humans.

  Authors: Michael A Nauck, Guido Kemmeries, Jens J Holst, Juris J Meier

  Diabetes. 03/2011; 60(5):1561-5.

  Glucagon-like peptide (GLP)-1 lowers postprandial glycemia primarily through inhibition of gastric emptying. We addressed whether the GLP-1-induced deceleration of gastric emptying is subject toGlucagon-like peptide (GLP)-1 lowers postprandial glycemia primarily through inhibition of gastric emptying. We addressed whether the GLP-1-induced deceleration of gastric emptying is subject to rapid tachyphylaxis and if so, how this would alter postprandial glucose control. Nine healthy volunteers (25 ± 4 years old, BMI: 24.6 ± 4.7 kg/m(2)) were examined with intravenous infusion of GLP-1 (0.8 pmol · kg(-1) · min(-1)) or placebo over 8.5 h. Two liquid mixed meals were administered at a 4-h interval. Gastric emptying was determined, and blood samples were drawn frequently. GLP-1 decelerated gastric emptying significantly more after the first meal compared with the second meal (P = 0.01). This was associated with reductions in pancreatic polypeptide levels (marker of vagal activation) after the first but not the second meal (P < 0.05). With GLP-1, glucose concentrations declined after the first meal but increased after the second meal (P < 0.05). The GLP-1-induced reductions in postprandial insulin and C-peptide levels were stronger during the first meal course (P < 0.05). Likewise, glucagon levels were lowered by GLP-1 after the first meal but increased after the second test meal (P < 0.05). The GLP-1-induced delay in gastric emptying is subject to rapid tachyphylaxis at the level of vagal nervous activation. As a consequence, postprandial glucose control by GLP-1 is attenuated after its chronic administration.

• Pharmacotherapy: GLP-1 analogues and insulin: sound the wedding bells?

  Authors: Michael A Nauck, Juris J Meier

  Nature reviews. Endocrinology. 02/2011; 7(4):193-5.

• Diminished glucagon suppression after β-cell reduction is due to impaired α-cell function rather than an expansion of α-cell mass.

  Authors: Juris J Meier, Sandra Ueberberg, Simone Korbas, Stephan Schneider

  American journal of physiology. Endocrinology and metabolism. 02/2011; 300(4):E717-23.

  Impaired suppression of glucagon levels after oral glucose or meal ingestion is a hallmark of type 2 diabetes. Whether hyperglucagonemia after a β-cell loss results from a functional upregulation ofImpaired suppression of glucagon levels after oral glucose or meal ingestion is a hallmark of type 2 diabetes. Whether hyperglucagonemia after a β-cell loss results from a functional upregulation of glucagon secretion or an increase in α-cell mass is yet unclear. CD-1 mice were treated with streptozotocin (STZ) or saline. Pancreatic tissue was collected after 14, 21, and 28 days and examined for α- and β-cell mass and turnover. Intraperitoneal (ip) glucose tolerance tests were performed at day 28 as well as after 12 days of subcutaneous insulin treatment, and glucose, insulin, and glucagon levels were determined. STZ treatment led to fasting and post-challenge hyperglycemia (P < 0.001 vs. controls). Insulin levels increased after glucose injection in controls (P < 0.001) but were unchanged in STZ mice (P = 0.36). Intraperitoneal glucose elicited a 63.1 ± 4.1% glucagon suppression in control mice (P < 0.001), whereas the glucagon suppression was absent in STZ mice (P = 0.47). Insulin treatment failed to normalize glucagon levels. There was a significant inverse association between insulin and glucagon levels after ip glucose ingestion (r(2) = 0.99). β-Cell mass was reduced by ∼75% in STZ mice compared with controls (P < 0.001), whereas α-cell mass remained unchanged (P > 0.05). α-Cell apoptosis (TUNEL) and replication (Ki67) were rather infrequently noticed, with no significant differences between the groups. These studies underline the importance of endogenous insulin for the glucose-induced suppression of glucagon secretion and suggest that the insufficient decline in glucagon levels after glucose administration in diabetes is primarily due to a functional loss of intraislet inhibition of α-cell function rather than an expansion of α-cell mass.

• Cell cycle regulation and proliferation in lichen sclerosus.

  Authors: Thilo Gambichler, Sara Kammann, Christian Tigges, Stephan Kobus, Marina Skrygan, Juris J Meier, Christina U Köhler, Nina Scola, Markus Stücker, Falk G Bechara, Peter Altmeyer, Alexander Kreuter

  Regulatory peptides. 02/2011; 167(2-3):209-14.

  Genital lichen sclerosus (LS) is considered a potential precursor lesion of squamous cell carcinoma. We aimed to investigate the expression pattern of cell cycle regulators, tumour suppressorGenital lichen sclerosus (LS) is considered a potential precursor lesion of squamous cell carcinoma. We aimed to investigate the expression pattern of cell cycle regulators, tumour suppressor proteins and proliferation markers in genital LS as compared to extragenital LS (ELS) and healthy controls (HC). In order to assess the expression of minichromosome maintenance protein 3 (MCM3), MCM7, Ki-67, cyclin D1, cyclin E, p16, p21, and p53, immunohistochemistry and immunofluorescence were performed on skin specimens obtained from the genital region of LS patients (short-standing LS, n=19; long-standing LS, n=15), patients with ELS (n=10), and HC (n=8). Median protein expression of MCM3 and Ki-67 was significantly higher in LS when compared to ELS and HC. In patients with long-standing LS, the expression profiles of MCM3 and Ki-67 significantly correlated. Moreover, long-standing LS lesions showed significantly increased expression of p53 when compared to short-standing LS, ELS, and HS. Immunoreactivity of MCM7, p16, p21, cyclin D1 and cyclin E did not significantly differ between the groups. Tumour suppressor proteins such as p53 are significantly overexpressed in genital LS when compared to extragenital disease and healthy skin. The significant p53 overexpression, particularly in long-standing genital lesions, may reflect the increased risk of malignant transformation and/or oxidative stress associated with LS. Moreover, we have demonstrated that proliferation markers such as Ki-67 and MCM3 are significantly up-regulated in genital LS as compared to controls. With regard to cell cycle regulation and proliferation rates, ELS significantly differs from its genital counterpart.

• GIP does not potentiate the antidiabetic effects of GLP-1 in hyperglycemic patients with type 2 diabetes.

  Authors: Nikolaos Mentis, Irfan Vardarli, Lars D Köthe, Jens J Holst, Carolyn F Deacon, Michael Theodorakis, Juris J Meier, Michael A Nauck

  Diabetes. 02/2011; 60(4):1270-6.

  The incretin glucagon-like peptide 1 (GLP-1) exerts insulinotropic activity in type 2 diabetic patients, whereas glucose-dependent insulinotropic polypeptide (GIP) no longer does. We studied whetherThe incretin glucagon-like peptide 1 (GLP-1) exerts insulinotropic activity in type 2 diabetic patients, whereas glucose-dependent insulinotropic polypeptide (GIP) no longer does. We studied whether GIP can alter the insulinotropic or glucagonostatic activity of GLP-1 in type 2 diabetic patients. Twelve patients with type 2 diabetes (nine men and three women; 61 ± 10 years; BMI 30.0 ± 3.7 kg/m²; HbA(1c) 7.3 ± 1.5%) were studied. In randomized order, intravenous infusions of GLP-1(7-36)-amide (1.2 pmol · kg⁻¹ · min⁻¹), GIP (4 pmol · kg⁻¹ · min⁻¹), GLP-1 plus GIP, and placebo were administered over 360 min after an overnight fast (≥ 1 day wash-out period between experiments). Capillary blood glucose, plasma insulin, C-peptide, glucagon, GIP, GLP-1, and free fatty acids (FFA) were determined. Exogenous GLP-1 alone reduced glycemia from 10.3 to 5.1 ± 0.2 mmol/L. Insulin secretion was stimulated (insulin, C-peptide, P < 0.0001), and glucagon was suppressed (P = 0.009). With GIP alone, glucose was lowered slightly (P = 0.0021); insulin and C-peptide were stimulated to a lesser degree than with GLP-1 (P < 0.001). Adding GIP to GLP-1 did not further enhance the insulinotropic activity of GLP-1 (insulin, P = 0.90; C-peptide, P = 0.85). Rather, the suppression of glucagon elicited by GLP-1 was antagonized by the addition of GIP (P = 0.008). FFA were suppressed by GLP-1 (P < 0.0001) and hardly affected by GIP (P = 0.07). GIP is unable to further amplify the insulinotropic and glucose-lowering effects of GLP-1 in type 2 diabetes. Rather, the suppression of glucagon by GLP-1 is antagonized by GIP.

• Gastrin stimulates the VEGF-A promotor in a human colon cancer cell line.

  Authors: Mark Ellrichmann, Peter R Ritter, Henning Schrader, Wolfgang E Schmidt, Juris J Meier, Frank Schmitz

  Regulatory peptides. 12/2010; 165(2-3):146-50.

  Hypergastrinemia has been observed in patients suffering from colorectal cancer. Vascular endothelial growth factor (VEGF) is known to play a pivotal role in tumour growth. Therefore, we addressedHypergastrinemia has been observed in patients suffering from colorectal cancer. Vascular endothelial growth factor (VEGF) is known to play a pivotal role in tumour growth. Therefore, we addressed whether gastrin-17-gly and gastrin-17-amide regulate VEGF-A-gene and protein expression. Colo-320-cells were stably transfected with a VEGF-Luciferase-reporter gene. Luciferase activity was assessed after stimulation with various gastrin concentrations. Relevant promotor elements were identified by deletion analyses. VEGF protein levels in culture supernatants were quantified by ELISA. VEGF-A stimulation with gastrin induced a dose- and time-dependent stimulation of luciferase activity. The greatest activities were found 6h after stimulation at concentrations of 10(-)(6)mmol/l. VEGF-promotor expression resulted in significantly (p<0.05) increased VEGF-A protein secretion. These effects were restricted to gastrin-17-amide. Gastrin-17-amide enhances VEGF-A gene and protein expression in Colo320 cells stably transfected with a wild-type CCK-B/gastrin receptor. The induction of VEGF-A transcription and translation may contribute to the carcinogenic effects of gastrin observed in clinical studies. Therefore, CCK-B receptor antagonists may represent a treatment strategy in patients with colorectal cancer.

• Endogenous hyperinsulinaemia in insulinoma patients is not associated with changes in beta-cell area and turnover in the tumor-adjacent pancreas.

  Authors: Chiara Montemurro, Christina U Köhler, Waldemar Uhl, Andrea Tannapfel, Wolfgang E Schmidt, Enzo Bonora, Juris J Meier

  Regulatory peptides. 12/2010; 165(2-3):180-5.

  Insulin therapy has been suggested to preserve beta-cell mass in patients with diabetes through the mechanisms of beta-cell rest as well as direct effects on beta-cell proliferation. However, dataInsulin therapy has been suggested to preserve beta-cell mass in patients with diabetes through the mechanisms of beta-cell rest as well as direct effects on beta-cell proliferation. However, data about the effects of hyperinsulinism on beta-cell mass and turnover in humans are sparse. Pancreatic tissue specimens from five patients with pancreatic insulinomas and ten non-diabetic control subjects were examined. Pancreatic sections were stained for insulin, Ki67 (replication) and TUNEL (apoptosis), and quantitative morphometric analyses were performed. Fractional beta-cell area was 1.11%±0.67% in the tumor-free pancreatic tissue of the insulinoma patients and 0.78%±0.26% in the control group (p=0.19). There also were no differences in islet size (p=0.62) or beta-cell nuclear diameter (p=0.20). Beta-cell replication and apoptosis were infrequently detected, without any measurable differences between the groups. There were also no differences in percentage of duct cells expressing insulin (p=0.47), a surrogate marker for islet neogenesis. Beta-cell area and turnover are not significantly altered in the proximity of intra-pancreatic insulinomas. Future in vivo studies, ideally employing larger animal models, are warranted to further evaluate the impact of exogenous insulin on beta-cell turnover.

• Cell cycle control of β-cell replication in the prenatal and postnatal human pancreas.

  Authors: Christina U Köhler, Marvin Olewinski, Andrea Tannapfel, Wolfgang E Schmidt, Helga Fritsch, Juris J Meier

  American journal of physiology. Endocrinology and metabolism. 10/2010; 300(1):E221-30.

  β-Cell regeneration declines with aging, but the molecular mechanisms controlling β-cell replication in humans are not well understood. We compared the expression of selected cell cycle proteins inβ-Cell regeneration declines with aging, but the molecular mechanisms controlling β-cell replication in humans are not well understood. We compared the expression of selected cell cycle proteins in prenatal and adult tissue and examined the association of these proteins with β-cell replication. Pancreatic tissue from a total of 20 human fetuses and adults was stained for Ki67, cyclin D3, p16 and p27, and insulin. The β-cellular expression of these cell cycle proteins was determined. The frequency of β-cell replication was lower in adult compared with prenatal β-cells (<0.5 vs. 3.4 ± 0.5%, respectively; P < 0.0001). p16 was sporadically expressed in prenatal β-cells (8.0 ± 1.1%) but highly enriched in adult β-cells (63.1 ± 5.2%, P < 0.0001). Likewise, the expression of p27 was much lower in prenatal β-cells (1.7 ± 0.4 vs. 44.1 ± 5.4%, respectively, P < 0.0001), and cyclin D3 expression increased from 24.2 ± 4.1 to 47.25 ± 5.0%, respectively (P < 0.001), with aging. The expression of all three proteins was significantly correlated with each other (P < 0.01 and r > 0.75, respectively). The strong expression of cyclin D3 in adult human β-cells and its correlation to p27 and p16 suggest a positive role in human β-cell cycle regulation. p16 and p27 appear to restrict β-cell replication with aging. The age dependency of cell cycle regulation in human β-cells might explain the reduced β-cell regeneration in adult humans.

• Proinsulin levels in patients with pancreatic diabetes are associated with functional changes in insulin secretion rather than pancreatic beta-cell area.

  Authors: Thomas G K Breuer, Bjoern A Menge, Matthias Banasch, Waldemar Uhl, Andrea Tannapfel, Wolfgang E Schmidt, Michael A Nauck, Juris J Meier

  European journal of endocrinology / European Federation of Endocrine Societies. 10/2010; 163(4):551-8.

  Hyperproinsulinaemia has been reported in patients with type 2 diabetes. It is unclear whether this is due to an intrinsic defect in β-cell function or secondary to the increased demand on theHyperproinsulinaemia has been reported in patients with type 2 diabetes. It is unclear whether this is due to an intrinsic defect in β-cell function or secondary to the increased demand on the β-cells. We investigated whether hyperproinsulinaemia is also present in patients with secondary diabetes, and whether proinsulin levels are associated with impaired β-cell area or function. Thirty-three patients with and without diabetes secondary to pancreatic diseases were studied prior to pancreatic surgery. Intact and total proinsulin levels were compared with the pancreatic β-cell area and measures of insulin secretion and action. Fasting concentrations of total and intact proinsulin were similar in patients with normal, impaired (including two cases of impaired fasting glucose) and diabetic glucose tolerance (P=0.58 and P=0.98 respectively). There were no differences in the total proinsulin/insulin or intact proinsulin/insulin ratio between the groups (P=0.23 and P=0.71 respectively). There was a weak inverse association between the total proinsulin/insulin ratio and pancreatic β-cell area (r(2)=0.14, P=0.032), whereas the intact proinsulin/insulin ratio and the intact and total proinsulin levels were unrelated to β-cell area. However, a strong inverse relationship between homeostasis model assessment index of β-cell function and both the total and the intact proinsulin/insulin ratio was found (r(2)=0.55 and r(2)=0.48 respectively). The association of insulin resistance (IR) with intact proinsulin was much weaker than the correlation with fasting insulin. Hyperproinsulinaemia is associated with defects in insulin secretion rather than a reduction in β-cell area. The weak association between intact proinsulin and IR argues against the usefulness of this parameter in clinical practice.

• Waking up the gut in critically ill patients.

  Authors: Juris J Meier

  Critical care (London, England). 09/2010; 14(5):183.

  Multiorgan failure frequently develops in critically ill patients. While therapeutic efforts in such patients are often focused on the lungs, on the cardiovascular system as well as on the kidneys,Multiorgan failure frequently develops in critically ill patients. While therapeutic efforts in such patients are often focused on the lungs, on the cardiovascular system as well as on the kidneys, it is important to also consider the functional alterations in gut motility and hormone secretion. Given the central regulatory functions of many gut hormones, such as glucagon-like peptide 1, glucagon-like peptide 2, ghrelin and others, exogenous supplementation of some of these factors may be beneficial under conditions of critical illness. From a pragmatic point of view, the most feasible way towards a restoration of gut hormone secretion in critically ill patients is to provide enteral nutritional supply as soon as possible.

• Individualised incretin-based treatment for type 2 diabetes.

  Authors: Michael A Nauck, Juris J Meier

  Lancet. 08/2010; 376(9739):393-4.

• Impact of exogenous hyperglucagonemia on postprandial concentrations of gastric inhibitory polypeptide and glucagon-like peptide-1 in humans.

  Authors: Juris J Meier, Peter R Ritter, Alexandra Jacob, Bjoern A Menge, Carolyn F Deacon, Wolfgang E Schmidt, Michael A Nauck, Jens J Holst

  The Journal of clinical endocrinology and metabolism. 08/2010; 95(8):4061-5.

  Postprandial secretion of glucagon-like peptide 1 (GLP-1) has been found diminished in some patients with type 2 diabetes mellitus (T2DM) and high glucagon concentrations. We examined the effects ofPostprandial secretion of glucagon-like peptide 1 (GLP-1) has been found diminished in some patients with type 2 diabetes mellitus (T2DM) and high glucagon concentrations. We examined the effects of exogenous glucagon on the release of incretin hormones. Ten patients with T2DM and 10 healthy controls were examined with a meal test during the iv administration of glucagon 0.65 ng/kg.min and placebo. GLP-1 plasma concentration increased after meal ingestion in both groups (P<0.0001), but postprandial GLP-1 plasma levels were not affected by glucagon administration. However, immediately after cessation of the glucagon infusion, GLP-1 levels increased by about 2-fold to levels of 51.8+/-14.6 pmol/liter in the T2DM patients and 58.9+/-20.0 pmol/liter in controls (P<0.05). The time courses of glucose-dependent insulinotropic peptide glucose-dependent insulinotropic peptide and GLP-1 concentrations were not different between T2DM patients and controls during the placebo experiments (P=0.33 and P=0.13, respectively). Glucose concentrations were increased by glucagon administration in controls (P<0.05, respectively), but insulin and C-peptide levels were not affected. Gastric emptying was slightly delayed by glucagon administration in controls (P<0.05) but not in T2DM patients (P=0.77). Exogenous glucagon does not directly inhibit incretin secretion. However, a decline in circulating glucagon levels may exert a permissive effect on GLP-1 release. This might contribute to the reduction in GLP-1 concentrations found in some patients with T2DM.

• Validation of different replication markers for the detection of beta-cell proliferation in human pancreatic tissue.

  Authors: Christina U Köhler, Alexander Kreuter, Martha C Rozynkowski, Tim Rahmel, Waldemar Uhl, Andrea Tannapfel, Wolfgang E Schmidt, Juris J Meier

  Regulatory peptides. 06/2010; 162(1-3):115-21.

  Beta-cell-regeneration is considered as a future option for the therapy of diabetes, but the detection of beta-cell replication in human pancreas is still challenging. Therefore, the expression ofBeta-cell-regeneration is considered as a future option for the therapy of diabetes, but the detection of beta-cell replication in human pancreas is still challenging. Therefore, the expression of Ki67, PCNA and MCM-7 in human pancreatic tissue was quantified in order to validate their use as beta-cell replication markers. Human pancreatic tissue samples were stained for Ki67, PCNA, MCM7, insulin and nuclei, and the expression of replication markers was quantified. Co-expression of the markers was assessed by four-colour fluorescence-staining. All three markers could be detected in endocrine and exocrine tissue. There was a significant correlation between the expression frequencies of all three markers in the exocrine tissue (r>0.49, respectively) and in beta-cells (r>0.95, respectively). A subset of beta-cells with differential expression of the three replication markers was identified. Quantitative analyses revealed that only 36-55% of all exocrine cells expressed two markers at the same time. The expression of Ki67, MCM-7 and PCNA in adult human pancreas is highly correlated, but the labelling of individual cells differs between the markers. The analysis of a combination of markers, preferably MCM7 and Ki67, appears to yield the most reliable results for the determination of beta-cell replication and may allow for a differentiation of cell cycle stages.

• Is the diminished incretin effect in type 2 diabetes just an epi-phenomenon of impaired beta-cell function?

  Authors: Juris J Meier, Michael A Nauck

  Diabetes. 05/2010; 59(5):1117-25.

• [GLP-1: a new therapeutic principle for the treatment of type 2 diabetes mellitus].

  Authors: Björn A Menge, Juris J Meier, Wolfgang E Schmidt

  Medizinische Klinik (Munich, Germany : 1983). 03/2010; 105(3):163-75.