Management of pregnancy in women with monogenic diabetes due to mutations in GCK, HNF1A and HNF4A genes.

Women with maturity-onset diabetes of the young (MODY) need tailored antenatal care and monitoring of their offspring. Each MODY subtype has different implications for glycaemic targets, treatment choices and neonatal management. Hyperglycaemia of MODY is often first diagnosed in adolescence or early adulthood and therefore is clinically relevant to pregnant women. MODY remains an under-recognised and undiagnosed condition. Pregnancy represents an opportune time to make a genetic diagnosis of MODY and provide precision treatment. This review describes the nuance of antenatal care in women with MODY and the implications for pregnancies affected by a positive paternal genotype. Mutations in hepatic nuclear factor 1-alpha (HNF1A) and 4-alpha (HNF4A) genes are associated with progressive ß-cell dysfunction resulting in early onset diabetes. Patients are largely managed with sulphonylureas outside of pregnancy. Macrosomia and persistent neonatal hypoglycaemia are reported in 54% and 15% of HNF4A genotype positive offspring respectively with a median increase in birthweight of 790 g. Close observation of foetal growth in utero allows optimal timing of delivery to minimise peri- and postpartum materno-foetal complications. Glucokinase (GCK)-MODY causes mild fasting hyperglycaemia which does not require treatment outside of pregnancy. Birthweight of offspring of maternal carriers is dependent on foetal genotype; heterozygous mutation carriers are usually normal weight while genotype negative offspring are large for gestational age (600 g heavier). Affected offspring of paternal carriers may be small for gestational age (500 g lighter). Serial growth scans with measurement of the abdominal circumference indirectly differentiate foetal genotype. Measurement of cell free foetal DNA in maternal blood from the late first trimester is superior to traditionally used ultrasound to distinguish foetal genotype. Cost and accessibility may limit its use.

A retrospective cohort study evaluating pregnancy outcomes in women with MIDD.

AIMS: The most common pathogenic mitochondrial mutation associated with mitochondrial disease is m.3243A>G. Increased obstetric complications, such as spontaneous abortion, gestational diabetes (GDM), preterm delivery, and preeclampsia, have been reported in women carrying this mutation. We aimed to determine the fetal and maternal outcomes in pregnant women with mitochondrial disease. METHODS: We retrospectively studied the obstetric and perinatal outcomes in 88 pregnancies of 26 women with genetically confirmed mitochondrial disease (m.3243A>G in the MTTL1 gene (n = 25); m.12258C>A in the MT-TS2 gene (n = 1)). Outcomes included pregnancy related complications, mode of delivery, gestational age at delivery and birthweight. RESULTS: Mean heteroplasmy rate was 18%. The miscarriage rate was higher than background at 25%. 21 pregnancies (24%) were complicated by GDM; 9 pregnancies (13.6%) had a preterm delivery and 2 of them (3%) an extreme premature delivery < 32 weeks. One woman had preeclampsia and one had a postpartum hemorrhage. The caesarean section (CS) rate was 20%. For every unit increase in maternal heteroplasmy levels there was a 26% increased risk of undergoing an assisted operative vaginal delivery (OR 1.26, 95% CI 1.04-1.53, P = 0.002, Bonferroni corrected P = 0.005) and an 18% increased risk of undergoing a CS (OR 1.18, 95% CI 1.01-1.39, P = 0.01, Bonferroni corrected P = 0.03) compared to a spontaneous vaginal delivery. There was a statistical significant correlation between maternal and offspring heteroplasmy levels. Spearman correlation rho = 0.96, 95% CI 0.78-0.99, P = 0.0002. CONCLUSION: Women with mitochondrial disease appear to have more frequent obstetric complications including miscarriage and GDM. Pre-pregnancy diagnosis of m.3243A>G will enable the counseling of women and increase awareness of possible obstetric complications.

tRNA-derived fragments are altered in diabetes.

AIMS: Maternally inherited diabetes and deafness (MIDD) is a rare form of adult-onset diabetes that can be difficult to diagnose due to its variable clinical phenotype. Transfer RNA-derived small fragments are a novel, emerging class of small non-coding RNAs (sncRNAs) that have significant potential as serum biomarkers due to their stress-induced generation, abundance, stability and ease of detection. METHODS: We investigated the levels of tiRNA 5'ValCAC (alone and in combination with miR-23b-3p) identified from small RNA sequencing studies in serum samples from healthy controls, type 1 diabetes, type 2 diabetes and MIDD subjects. RESULTS: Serum levels of 5'ValCAC were reduced in MIDD and type 2 diabetes subjects compared to controls. Type 2 diabetes subjects had higher serum levels of miR-23b-3p compared to all other subjects. Receiver Operating Characteristic analysis showed the potential of 5'ValCAC and miR-23b-3p as MIDD biomarkers, with the combination showing excellent separation from type 2 diabetes subjects. CONCLUSIONS: This is the first report showing altered serum levels of tiRNAs in diabetes subjects. The combined use of 5'ValCAC and miR-23b-3p as serum biomarkers could potentially differentiate between MIDD subjects and type 2 diabetes subjects.

Phenotype, genotype and glycaemic variability in people with activating mutations in the ABCC8 gene: response to appropriate therapy.

AIMS: To examine the phenotypic features of people identified with ABCC8-maturity-onset diabetes of the young (MODY) who were included in the adult 'Mater MODY' cohort and to establish their response to sulfonylurea therapy. METHODS: Ten participants with activating ABCC8 mutations were phenotyped in detail. A 2-hour oral glucose tolerance test was performed to establish glycaemic tolerance, with glucose, insulin and C-peptide measurements taken at baseline and 30-min intervals. Insulin was discontinued and sulfonylurea therapy initiated after genetic diagnosis of ABCC8-MODY. A blinded continuous glucose monitoring sensor was used to establish glycaemic control on insulin vs a sulfonylurea. RESULTS: The mean age at diagnosis of diabetes was 33.8 ± 11.1 years, with fasting glucose of 18.9 ± 11.5 mmol/l and a mean (range) HbA1c of 86 (51,126) mmol/mol [10.0 (6.8,13.7)%]. Following a genetic diagnosis of ABCC8-MODY three out of four participants discontinued insulin (mean duration 10.6 ± 1.69 years) and started sulfonylurea treatment. The mean (range) HbA1c prior to genetic diagnosis was 52 (43,74) mmol/mol (6.9%) and the post-treatment change was 44 (30,57) mmol/mol (6.2%; P=0.16). Retinopathy was the most common microvascular complication in this cohort, occurring in five out of 10 participants. CONCLUSIONS: Low-dose sulfonylurea therapy resulted in stable glycaemic control and the elimination of hypoglycaemic episodes attributable to insulin therapy. The use of appropriate therapy at the early stages of diabetes may decrease the incidence of complications and reduce the risks of hypoglycaemia associated with insulin therapy.

Prolonged episodes of hypoglycaemia in HNF4A-MODY mutation carriers with IGT. Evidence of persistent hyperinsulinism into early adulthood.

AIMS: HNF4A is an established cause of maturity onset diabetes of the young (MODY). Congenital hyperinsulinism can also be associated with mutations in the HNF4A gene. A dual phenotype is observed in HNF4A-MODY with hyperinsulinaemic hypoglycaemia in the neonatal period progressing to diabetes in adulthood. The nature and timing of the transition remain poorly defined. We performed an observational study to establish changes in glycaemia and insulin secretion over a 6-year period. We investigated glycaemic variability and hypoglycaemia in HNF4A-MODY using a continuous glucose monitoring system (CGMS). METHODS: An OGTT with measurement of glucose, insulin and C-peptide was performed in HNF4A participants with diabetes mellitus (DM) (n = 14), HNF4A-IGT (n = 7) and age- and BMI-matched MODY negative family members (n = 10). Serial assessment was performed in the HNF4A-IGT cohort. In a subset of HNF4A-MODY mutation carriers (n = 10), CGMS was applied over a 72-h period. RESULTS: There was no deterioration in glycaemic control in the HNF4A-IGT cohort. The fasting glucose-to-insulin ratio was significantly lower in the HNF4A-IGT cohort when compared to the normal control group (0.13 vs. 0.24, p = 0.03). CGMS profiling demonstrated prolonged periods of hypoglycaemia in the HNF4A-IGT group when compared to the HNF4A-DM group (432 vs. 138 min p = 0.04). CONCLUSIONS: In a young adult HNF4A-IGT cohort, we demonstrate preserved glucose, insulin and C-peptide secretory responses to oral glucose. Utilising CGMS, prolonged periods of hypoglycaemia are evident despite a median age of 21 years. We propose a prolonged hyperinsulinaemic phase into adulthood is responsible for the notable hypoglycaemic episodes.

Successful maintenance on sulphonylurea therapy and low diabetes complication rates in a HNF1A-MODY cohort.

AIMS: HNF1A gene mutations are the most common cause of maturity-onset diabetes of the young (MODY) in the UK. Persons with HNF1A-MODY display sensitivity to sulphonylurea therapy; however, the long-term efficacy is not established. There is limited literature as to the prevalence of micro- and macrovascular complications in this unique cohort. The aim of this study was to determine the natural progression and clinical management of HNF1A-MODY diabetes in a dedicated MODY clinic. METHODS: Sixty patients with HNF1A-MODY and a cohort of 60 BMI-, age-, ethnicity- and diabetes duration-matched patients with Type 1 diabetes mellitus participated in the study. All patients were phenotyped in detail. Clinical follow-up of the HNF1A-MODY cohort occurred on a bi-annual basis. RESULTS: Following a genetic diagnosis of MODY, the majority of the cohort treated with sulphonylurea therapy remained insulin independent at 84-month follow-up (80%). The HbA1c in the HNF1A-MODY group treated with sulphonylurea therapy alone improved significantly over the study period [from 49 (44-63) mmol/mol, 6.6 (6.2-7.9)% to 41 (31-50) mmol/mol, 5.9 (5-6.7)%; P = 0.003]. The rate of retinopathy was significantly lower than that noted in the Type 1 diabetes mellitus group (13.6 vs. 50%; P = 0.0001).There was also a lower rate of microalbuminuria and cardiovascular disease in the HNF1A-MODY group compared with the Type 1 diabetes mellitus group. CONCLUSIONS: This study demonstrates that the majority of patients with HNF1A-MODY can be maintained successfully on sulphonylurea therapy with good glycaemic control. We note a significantly lower rate of micro- and macrovascular complications than reported previously. The use of appropriate therapy at early stages of the disorder may decrease the incidence of complications.

BH3-Only protein bmf is required for the maintenance of glucose homeostasis in an in vivo model of HNF1α-MODY diabetes.

Heterozygous loss-of-function mutations in the hepatocyte nuclear factor 1α (HNF-1α) gene can lead to diminished amounts of functional HNF-1α, resulting in the onset of a particularly severe form of maturity-onset diabetes of the young (MODY). We have previously shown that induction of a dominant-negative mutant of HNF-1α (DNHNF-1α) results in the activation of the bioenergetic stress sensor AMP-activated protein kinase (AMPK), preceding the onset of apoptosis and the induction of pro-apoptotic Bcl-2 homology domain-3-only protein Bmf (Bcl-2-modifying factor) as a mediator of DNHNF-1α-induced apoptosis. Through the knockout of bmf in a transgenic mouse model with DNHNF-1α suppression of HNF-1α function in pancreatic beta-cells, this study aimed to examine the effect of loss-of-function of this BH3-only protein on the disease pathology and progression, and further elucidate the role of Bmf in mediating DNHNF-1α-induced beta-cell loss. Morphological analysis revealed an attenuation in beta-cell loss in bmf-deficient diabetic male mice and preserved insulin content. Surprisingly, bmf deficiency was found to exacerbate hyperglycemia in both diabetic male and hyperglycemic female mice, and ultimately resulted in a decreased glucose-stimulated insulin response, implicating a role for Bmf in glucose homeostasis regulation independent of an effect on beta-cell loss. Collectively, our data demonstrate that Bmf contributes to the decline in beta-cells in a mouse model of HNF1A-MODY but is also required for the maintenance of glucose homeostasis in vivo.

Pre-pregnancy care and pregnancy outcomes in type 1 diabetes mellitus: a comparison of continuous subcutaneous insulin infusion and multiple daily injection therapy.

BACKGROUND: Pre-pregnancy care improves pregnancy outcomes in type 1 diabetes mellitus (T1DM). Continuous subcutaneous insulin infusion (CSII) therapy and multiple daily injection (MDI) therapy can both be used to achieve glycaemic targets, but few data are available to compare their efficacy in pre-pregnancy care. AIM: To compare MDI and CSII in pre-pregnancy care in T1DM. METHODS: Retrospective database review of women with T1DM attending the Dublin Diabetes in Pregnancy Centre. RESULTS: 464 women with T1DM (40 treated with CSII) were included. Women attending for pre-pregnancy care had lower HbA1c levels at booking to antenatal services [52 ± 10 mmol/mol (6.9 ± 0.9 %) vs. 62 ± 16 mmol/mol (7.8 ± 1.5 %), p < 0.001], and booked at an earlier gestation (6 ± 2 vs. 8 ± 6 weeks, p < 0.001). In those who attended for pre-pregnancy care, the CSII group had lower HbA1c levels at booking than those using MDI [48 ± 8 mmol/mol (6.5 ± 0.7 %) vs. 53 ± 10 mmol/mol (7.0 ± 0.9 %), p = 0.03]. Gestational age at delivery and birth weight did not differ between groups. Caesarean section rates were associated with CSII use (p < 0.001), duration of diabetes (p = 0.002), and parity (p = 0.006). Nulliparous women using CSII with a longer history of diabetes were more likely to deliver by Caesarean section. There was no perinatal mortality. CONCLUSIONS: Pre-pregnancy care delivered by a specialist multi-disciplinary team effectively reduces HbA1c levels peri-conception. CSII use results in lower HbA1c levels in pre-pregnancy care in selected individuals and should be considered in women with T1DM planning pregnancy.

Identification of circulating microRNAs in HNF1A-MODY carriers.

AIMS/HYPOTHESIS: HNF1A-MODY is a monogenic form of diabetes caused by mutations in the HNF1A gene. Here we identify, for the first time, HNF1A-MODY-associated microRNAs (miRNAs) that can be detected in the serum of HNF1A-MODY carriers. METHODS: An miRNA array was carried out in rat INS-1 insulinoma cells inducibly expressing the common human Pro291fsinsC-HNF1A frame shift mutation. Differentially expressed miRNAs were validated by quantitative real-time PCR. Expression of miRNAs in the serum of HNF1A-MODY carriers (n = 31), MODY-negative family members (n = 10) and individuals with type 2 diabetes mellitus (n = 17) was quantified by absolute real-time PCR analysis. RESULTS: Inducible expression of Pro291fsinsC-HNF1A in INS-1 cells caused a significant upregulation of three miRNAs (miR-103, miR-224, miR-292-3p). The differential expression of two miRNAs (miR-103 and miR-224) was validated in vitro. Strongly elevated levels of miR-103 and miR-224 could be detected in the serum of HNF1A-MODY carriers compared with MODY-negative family controls. Serum levels of miR-103 distinguished HNF1A-MODY carriers from HbA1c-matched individuals with type 2 diabetes mellitus. CONCLUSIONS/INTERPRETATION: Our study demonstrates that the pathophysiology of HNF1A-MODY is associated with the overexpression of miR-103 and miR-224. Furthermore, our study demonstrates that these miRNAs can be readily detected in the serum of HNF1A-MODY carriers.

Identification of HNF1A-MODY and HNF4A-MODY in Irish families: phenotypic characteristics and therapeutic implications.

AIM: The prevalence of hepatocyte nuclear factor (HNF)-1A and HNF4A mutations, and the clinical implications following the genetic diagnosis of maturity-onset diabetes of the young (MODY) in the Irish population, remain unknown. The aim of this study was to establish the occurrence of HNF1A and HNF4A mutations in subjects classified clinically as MODY to identify novel mutations, and to determine the phenotypic features and response to therapy. METHODS: A total of 36 unrelated index cases with a clinical diagnosis of MODY were analyzed for HNF1A/HNF4A mutations. OGTT was performed to determine the degree of glucose tolerance and insulin secretory response. Also, 38 relatives underwent OGTT and were tested for the relevant known mutations. HNF1A-/HNF4A-MODY subjects were compared with nine HNF1A mutation-negative relatives and 20 type 2 diabetic (T2DM) patients. RESULTS: Seven different HNF1A mutations were identified in 11/36 (30.5%) index cases, two of which were novel (S352fsdelG and F426X), as well as two novel HNF4A mutations (M1? and R290C; 6%). Family screening revealed 20 subjects with HNF1A and seven with HNF4A mutations. Only 51.6% of HNF1A mutation carriers were diagnosed with diabetes by age 25 years; 11 of the mutation carriers were overweight and four were obese. Insulin secretory response to glucose was significantly lower in HNF1A-MODY subjects than in T2DM patients and HNF1A mutation-negative relatives (P=0.01). Therapeutic changes occurred in 48% of mutation carriers following genetic diagnosis. CONCLUSION: There was an HNF1A-MODY pick-up rate of 30.5% and an HNF4A-MODY pick-up rate of 6% in Irish MODY families. Genetically confirmed MODY has significant therapeutic implications.

Pessimistic explanatory style: a psychological risk factor for poor pain and functional outcomes two years after knee replacement.

Seligman's theory of causal attribution predicts that patients with a pessimistic explanatory style will have less favourable health outcomes. We identified 702 patients who had undergone 894 primary total knee replacements between 1993 and 2005, who responded to follow-up surveys at two (n = 783 knee replacements) and/or five years (n = 443 knee replacements) and had also completed the Minnesota Multiphasic Personality Inventory long before the joint replacement (median = 16.6 and 14.5 years for two- and five-year cohorts, respectively). Scores from the Minnesota Multiphasic Personality Inventory Optimism-Pessimism scale were used to categorise patients as pessimistic (t-score > 60) or non-pessimistic (t-score < or = 60). Multivariate logistic regression models assessing the effect of pessimistic explanatory style on pain or improvement in knee function were adjusted for gender, age, distance from the place of treatment and depression score. Pessimists reported (a) significantly more moderate or severe pain at two years with odds ratio 2.21 (95% confidence interval (CI) 1.12 to 4.35; p = 0.02), but not at five years when the odds ratio was 1.21 (95% CI 0.51 to 2.83; p = 0.67); and (b) less improvement in knee function at two years when the odds ratio was 0.53 (95% CI 0.30 to 0.96; p = 0.04), but not at five years when the odds ratio was 1.26 (95% CI 0.57 to 2.77; p = 0.57). No significant associations with moderate or severe limitation of activity were seen at two or five years. We conclude that a pessimistic explanatory style is associated with worse pain and functional outcomes two years after total knee replacement.

Early loss of mammalian target of rapamycin complex 1 (mTORC1) signalling and reduction in cell size during dominant-negative suppression of hepatic nuclear factor 1-alpha (HNF1A) function in INS-1 insulinoma cells.

AIMS/HYPOTHESIS: Mutations in the HNF1A (previously known as TCF1) gene encoding hepatocyte nuclear factor-1alpha (HNF1A) lead to the development of maturity-onset diabetes of the young, type 3 (HNF1A-MODY), characterised by impaired insulin secretion and a reduction in beta cell mass. HNF1A plays an important role in pancreatic beta cell differentiation and survival. The mammalian target of rapamycin (mTOR) is a central growth factor- and nutrient-activated protein kinase controlling cell metabolism, growth and survival. We investigated the role of mTOR inactivation in the decline in beta cell mass in a cellular model of HNF1A-MODY. METHODS: Previously we showed that suppression of HNF1A function via expression of a dominant-negative mutant (DN-HNF1A) decreases insulin gene transcription in insulinoma (INS-1) cells. We investigated the signalling of two distinct mTOR protein complexes, mTORC1 and mTORC2, in response to DN-HNF1A induction. RESULTS: We observed delayed inactivation of mTORC2 48 h after DN-HNF1A induction, evidenced by a reduction in serine 473 phosphorylation of thymoma viral proto-oncogene 1 (AKT1). We also observed an early inactivation of mTORC1 24 h after DN-HNF1A induction, which was detected by decreases in threonine 389 phosphorylation of p70 ribosomal protein S6 kinase (S6K1) and serine 65 phosphorylation of translational inhibitor eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1). Flow cytometry and gene expression analysis demonstrated a pre-apoptotic decrease in INS-1 cell size in response to DN-HNF1A induction, and an increase in the level of the mTORC1-regulated cell-cycle inhibitor, cyclin-dependent kinase inhibitor 1B p27. CONCLUSIONS/INTERPRETATION: Our data suggest that mTOR kinase and signalling through mTORC1 are highly sensitive to suppression of HNF1A function, and may contribute to disturbance of cell-size regulation and cell-cycle progression in HNF1A-MODY.

Clinical trial: alvimopan for the management of post-operative ileus after abdominal surgery: results of an international randomized, double-blind, multicentre, placebo-controlled clinical study.

BACKGROUND: Post-operative ileus (POI) affects most patients undergoing abdominal surgery. AIM: To evaluate the effect of alvimopan, a peripherally acting mu-opioid receptor antagonist, on POI by negating the impact of opioids on gastrointestinal (GI) motility without affecting analgesia in patients outside North America. METHODS: Adult subjects undergoing open abdominal surgery (n = 911) randomly received oral alvimopan 6 or 12 mg, or placebo, 2 h before, and twice daily following surgery. Opioids were administered as intravenous patient-controlled analgesia (PCA) or bolus injection. Time to recovery of GI function was assessed principally using composite endpoints in subjects undergoing bowel resection (n = 738). RESULTS: A nonsignificant reduction in mean time to tolerate solid food and either first flatus or bowel movement (primary endpoint) was observed for both alvimopan 6 and 12 mg; 8.5 h (95% CI: 0.9, 16.0) and 4.8 h (95% CI: -3.2, 12.8), respectively. However, an exploratory post hoc analysis showed that alvimopan was more effective in the PCA (n = 317) group than in the non-PCA (n = 318) group. Alvimopan was well tolerated and did not reverse analgesia. CONCLUSION: Although the significant clinical effect of alvimopan on reducing POI observed in previous trials was not reproduced, this trial suggests potential benefit in bowel resection patients who received PCA.

Ivor Lewis approach is superior to transhiatal approach in retrieval of lymph nodes at esophagectomy.

Lymph node involvement may impact postoperative therapeutic decision-making and prognosis in patients undergoing esophagectomy. This study evaluates which surgical approach yields the most lymph nodes. We undertook a retrospective chart review of esophagectomies performed by six surgeons from April 1994 to February 2004 using a prospective general thoracic surgery database at Mayo Clinic, Rochester, Minnesota, US. Lymph nodes were categorized into one of 17 regions per the American Joint Committee on Cancer, with the total number of lymph nodes, summed over each region, used as the primary outcome. A total of 517 esophagectomies were performed: 68 transhiatal, 392 Ivor Lewis, and 57 extended Ivor Lewis. A mean of 18.7 (SD 8.5) lymph nodes were retrieved with the Ivor Lewis approach as compared to 17.4 (SD 9.2) with the extended Ivor Lewis approach (P = 0.30). Since there was no statistical difference between the number of nodes collected in either Ivor Lewis approach, they were collapsed into one group for comparison with the transhiatal cases. Significantly more lymph nodes were collected with an Ivor Lewis approach (mean 18.5, SD 8.6) than with a transhiatal approach (mean 9.0, SD 5.0, P < 0.001). As expected, more thoracic lymph nodes were retrieved with the Ivor Lewis approach [mean 12.4 (SD 7.0) vs. 4.7 (SD 5.3), P < 0.001]. The Ivor Lewis approach was also superior for retrieval of abdominal nodes [mean 6.1 (SD 5.6) versus 4.3 (SD 4.4), P = 0.01]. More lymph nodes are obtained at esophagectomy with an Ivor Lewis than a transhiatal approach.

Downregulation of protein kinase B/Akt-1 mediates INS-1 insulinoma cell apoptosis induced by dominant-negative suppression of hepatocyte nuclear factor-1alpha function.

AIMS/HYPOTHESIS: Inactivating mutations in Tcf1, which encodes the transcription factor hepatocyte nuclear factor (HNF)-1alpha, cause maturity-onset diabetes of the young-3. We have previously shown that a dominant-negative mutant (DN-HNF-1alpha) renders INS-1 insulinoma cells sensitive to the mitochondrial apoptosis pathway, but the underlying alterations in signal transduction remain unknown. MATERIALS AND METHODS: Using a reverse tetracycline-dependent transactivator system, DN-HNF-1alpha-induced apoptosis was assessed by immunoblotting and caspase assays. Alterations in AKT1 kinase/protein kinase B (AKT1) survival signalling during DN-HNF-1alpha-induced apoptosis were investigated by phospho-specific immunodetection and transient transfection experiments. RESULTS: Induction of DN-HNF-1alpha caused significant changes in the activation-specific phosphorylation status of AKT1 that were preceded by a downregulation of Ins1 gene transcription. Phosphorylation of AKT1 at Ser473 was dramatically reduced after 36 to 48 h of DN-HNF-1alpha induction and coincided with maximal apoptosis activation. Overexpression of a constitutively active mutant of Akt1 rescued INS-1 cells from DN-HNF-1alpha-induced apoptosis, while ectopic expression of a dominant-negative mutant mimicked the effect of DN-HNF-1alpha on apoptosis activation. Pharmacological suppression of growth factor survival signalling through administration of the phosphatidylinositol-3 kinase (PI-3K) inhibitor wortmannin accelerated the induction of apoptosis by DN-HNF-1alpha. CONCLUSIONS/INTERPRETATION: These data suggest that a decrease in PI-3K/AKT1 survival signalling mediates DN-HNF-1alpha-induced apoptosis in insulin-secreting cells.

Glucagon-like peptide-1 reduces the pulsatile component of testosterone secretion in healthy males.

BACKGROUND: Glucagon-like-peptide-1 (7-36) amide (GLP-1), a potent regulator of glucose homeostasis, has been implicated in the control of hypothalamic-pituitary function. In vivo it is a relevant neuroendocrine modulator of gonadotropin-releasing hormone release, suggesting its possible role as a metabolic signal to the reproductive system. The present study was undertaken to establish its effect on luteinizing hormone (LH) and testosterone secretion in nine healthy male volunteers. MATERIALS AND METHODS: Each subject underwent an oral glucose tolerance test to establish LH, testosterone, and GLP-1 responses to glucose. Euglycaemic clamp experiments (6 h) were performed on two occasions with saline or with a constant infusion of GLP-1 (0.4 pmol kg(-1) min (-1)). Blood samples were drawn at 10-min intervals to measure the pulsatile pattern of LH and testosterone secretion. RESULTS: Ingestion of oral glucose resulted in a reduction in plasma testosterone levels at 30 min compared with baseline (P < 0.004) despite unaltered LH levels (P = 0.5). Constant GLP-1 infusion resulted in no change in LH (P = 0.83), testosterone (P = 0.96), follicle stimulating hormone (FSH) (P = 0.86) and leptin levels (P = 0.3). Pulse analysis revealed no significant difference in the number (P = 0.1) or median absolute amplitude (P = 0.3) of the LH pulses. However, there was a significant decrease in the number (3.0 +/- 0.6 vs. 1.3 +/- 0.4; P < 0.05) and a tendency for increased duration of testosterone pulses (97.4 +/- 16.7 vs. 170 +/- 27.1 min; P = 0.06). CONCLUSION: Oral glucose ingestion and intravenous GLP-1 infusion reduce the pulsatile component of testosterone secretion by a mechanism independent of LH release.

Maternal recall bias, obstetric history and schizophrenia.

BACKGROUND: This study sought to clarify the role of obstetric complications (OCs) and maternal recall bias for patients with first episodes of schizophrenia and those at increased risk of the disorder. METHOD: Subjects at high risk of schizophrenia were compared with people with first-episode schizophrenia and with healthy volunteers. Consenting mothers of subjects were interviewed using a standardised questionnaire for the recall of OCs, and OCs were also measured from records collected at the time of pregnancy and delivery. RESULTS: High-risk subjects and first-episode patients had higher rates of OCs recalled by their mother than controls, but hospital records showed no differences in OCs between groups. The number of OCs recalled by mothers of the high-risk group was not related to whether the mother had schizophrenia or not, but was related to the maternally rated abnormal childhood behaviour as measured by the Child Behaviour Checklist. CONCLUSIONS: These results suggest that studies that rely on maternal recall alone are susceptible to bias. The excess of OCs recalled by the mother could be related to abnormal behaviour in their child rather than maternal illness, family history or psychotic symptoms.

A psychometric analysis of the measurement level of the rating scale, time trade-off, and standard gamble.

A fundamental assumption of utility-based analyses is that patient utilities for health states can be measured on an equal-interval scale. This assumption, however, has not been widely examined. The objective of this study was to assess whether the rating scale (RS), standard gamble (SG), and time trade-off (TTO) utility elicitation methods function as equal-interval level scales. We wrote descriptions of eight prostate-cancer-related health states. In interviews with patients who had newly diagnosed, advanced prostate cancer, utilities for the health states were elicited using the RS, SG, and TTO methods. At the time of the study, 77 initial and 73 follow-up interviews had. been conducted with a consecutive sample of 77 participants. Using a Rasch model, the boundaries (Thurstone Thresholds) between four equal score sub-ranges of the raw utilities were mapped onto an equal-interval logit scale. The distance between adjacent thresholds in logit units was calculated to determine whether the raw utilities were equal-interval. None of the utility scales functioned as interval-level scales in our sample. Therefore, since interval-level estimates are assumed in utility-based analyses, doubt is raised regarding the validity of findings from previous analyses based on these scales. Our findings need to be replicated in other contexts, and the practical impact of non-interval measurement on utility-based analyses should be explored. If cost-effectiveness analyses are not found to be robust to violations of the assumption that utilities are interval, serious doubt will be cast upon findings from utility-based analyses and upon the wisdom of expending millions in research dollars on utility-based studies.

GLP-1-induced alterations in the glucose-stimulated insulin secretory dose-response curve.

The present study was undertaken to establish in normal volunteers the alterations in beta-cell responsiveness to glucose associated with a constant infusion of glucagon-like peptide-1 (GLP-1) or a pretreatment infusion for 60 min. A high-dose graded glucose infusion protocol was used to explore the dose-response relationship between glucose and insulin secretion. Studies were performed in 10 normal volunteers, and insulin secretion rates (ISR) were calculated by deconvolution of peripheral C-peptide levels by use of a two-compartmental model that utilized mean kinetic parameters. During the saline study, from 5 to 15 mM glucose, the relationship between glucose and ISR was linear. Constant GLP-1 infusion (0.4 pmol x kg(-1) x min(-1)) shifted the dose-response curve to the left, with an increase in the slope of this curve from 5 to 9 mM glucose from 71.0 +/- 12.4 pmol x min(-1) x mM(-1) during the saline study to 241.7 +/- 36.6 pmol x min(-1) x mM(-1) during the constant GLP-1 infusion (P < 0.0001). GLP-1 consistently stimulated a >200% increase in ISR at each 1 mM glucose interval, maintaining plasma glucose at <10 mM (P < 0.0007). Pretreatment with GLP-1 for 60 min resulted in no significant priming of the beta-cell response to glucose (P = 0.2). Insulin clearance rates were similar in all three studies at corresponding insulin levels. These studies demonstrate that physiological levels of GLP-1 stimulate glucose-induced insulin secretion in a linear manner, with a consistent increase in ISR at each 1 mM glucose interval, and that they have no independent effect on insulin clearance and no priming effect on subsequent insulin secretory response to glucose.