Effects of mixed meal tolerance test on gastric emptying, glucose and lipid homeostasis in obese nonhuman primates.

Meal ingestion elicits a variety of neuronal, physiological and hormonal responses that differ in healthy, obese or diabetic individuals. The mixed meal tolerance test (MMTT) is a well-established method to evaluate pancreatic ß-cell reserve and glucose homeostasis in both preclinical and clinical research in response to calorically defined meal. Nonhuman primates (NHPs) are highly valuable for diabetic research as they can naturally develop type 2 diabetes mellitus (T2DM) in a way similar to the onset and progression of human T2DM. The purpose of this study was to investigate the reproducibility and effects of a MMTT containing acetaminophen on plasma glucose, insulin, C-peptide, incretin hormones, lipids, acetaminophen appearance (a surrogate marker for gastric emptying) in 16 conscious obese cynomolgus monkeys (Macaca fascicularis). Plasma insulin, C-peptide, TG, aGLP-1, tGIP, PYY and acetaminophen significantly increased after meal/acetaminophen administration. A subsequent study in 6 animals showed that the changes of plasma glucose, insulin, C-peptide, lipids and acetaminophen were reproducible. There were no significant differences in responses to the MMTT among the obese NHPs with (n = 11) or without (n = 5) hyperglycemia. Our results demonstrate that mixed meal administration induces significant secretion of several incretins which are critical for maintaining glucose homeostasis. In addition, the responses to the MMTTs are reproducible in NHPs, which is important when the MMTT is used for evaluating post-meal glucose homeostasis in research.

Pancreatic islet hepatocyte growth factor and vascular endothelial growth factor A signaling in growth restricted fetuses.

Placental insufficiency leads to intrauterine growth restriction (IUGR) and a lifelong risk of developing type 2 diabetes. Impaired islet development in the growth restricted fetus, including decreased ß-cell replication, mass, and insulin secretion, is strongly implicated in the pathogenesis of later life type 2 diabetes. Currently, standard medical management of a woman with a pregnancy complicated by placental insufficiency and fetal IUGR is increased fetal surveillance and indicated preterm delivery. This leads to the dual complications of IUGR and preterm birth - both of which may increase the lifelong risk for type 2 diabetes. In order to develop therapeutic interventions in IUGR pregnancies complicated by placental insufficiency and decrease the risk of later development of type 2 diabetes in the offspring, the mechanisms responsible for impaired islet development in these cases must be determined. This review focuses on current investigations testing the hypothesis that decreased nutrient supply to the IUGR fetus inhibits an intra-islet hepatocyte growth factor - vascular endothelial growth factor A (HGF - VEGFA) feed forward signaling pathway and that this is responsible for developmental islet defects.

Early Life Nutrition and Energy Balance Disorders in Offspring in Later Life.

The global pandemic of obesity and type 2 diabetes is often causally linked to changes in diet and lifestyle; namely increased intake of calorically dense foods and concomitant reductions in physical activity. Epidemiological studies in humans and controlled animal intervention studies have now shown that nutritional programming in early periods of life is a phenomenon that affects metabolic and physiological functions throughout life. This link is conceptualised as the developmental programming hypothesis whereby environmental influences during critical periods of developmental plasticity can elicit lifelong effects on the health and well-being of the offspring. The mechanisms by which early environmental insults can have long-term effects on offspring remain poorly defined. However there is evidence from intervention studies which indicate altered wiring of the hypothalamic circuits that regulate energy balance and epigenetic effects including altered DNA methylation of key adipokines including leptin. Studies that elucidate the mechanisms behind these associations will have a positive impact on the health of future populations and adopting a life course perspective will allow identification of phenotype and markers of risk earlier, with the possibility of nutritional and other lifestyle interventions that have obvious implications for prevention of non-communicable diseases.

GLUT12 deficiency during early development results in heart failure and a diabetic phenotype in zebrafish.

Cardiomyopathies-associated metabolic pathologies (e.g., type 2 diabetes and insulin resistance) are a leading cause of mortality. It is known that the association between these pathologies works in both directions, for which heart failure can lead to metabolic derangements such as insulin resistance. This intricate crosstalk exemplifies the importance of a fine coordination between one of the most energy-demanding organs and an equilibrated carbohydrate metabolism. In this light, to assist in the understanding of the role of insulin-regulated glucose transporters (GLUTs) and the development of cardiomyopathies, we have developed a model for glut12 deficiency in zebrafish. GLUT12 is a novel insulin-regulated GLUT expressed in the main insulin-sensitive tissues, such as cardiac muscle, skeletal muscle, and adipose tissue. In this study, we show that glut12 knockdown impacts the development of the embryonic heart resulting in abnormal valve formation. Moreover, glut12-deficient embryos also exhibited poor glycemic control. Glucose measurements showed that these larvae were hyperglycemic and resistant to insulin administration. Transcriptome analysis demonstrated that a number of genes known to be important in cardiac development and function as well as metabolic mediators were dysregulated in these larvae. These results indicate that glut12 is an essential GLUT in the heart where the reduction in glucose uptake due to glut12 deficiency leads to heart failure presumably due to the lack of glucose as energy substrate. In addition, the diabetic phenotype displayed by these larvae after glut12 abrogation highlights the importance of this GLUT during early developmental stages.

Prematurity and programming of cardiovascular disease risk: a future challenge for public health?

There is substantial epidemiological evidence linking low birth weight with adult cardiometabolic disease risk factors. This has led to the concept of 'early life programming' or the 'developmental origins of disease' which proposes that exposure to adverse conditions during critical stages of early development results in compensatory mechanisms predicted to aid survival. There is growing evidence that preterm infants, many of whom are of low birth weight, are also at increased risk of adult cardiometabolic disease. In this article, we provide a broad overview of the evidence linking preterm birth and cardiovascular disease risk and discuss potential consequences for public health.

[Developmental programming of metabolic diseases--a review of studies on experimental animal models]. / Programowanie rozwojowe chorób metabolicznych--przeglad wyników badan na zwierzecych modelach doswiadczalnych.

Growth and development in utero is a complex and dynamic process that requires interaction between the mother organism and the fetus. The delivery of macro--and micronutrients, oxygen and endocrine signals has crucial importance for providing a high level of proliferation, growth and differentiation of cells, and a disruption in food intake not only has an influence on the growth of the fetus, but also has negative consequences for the offspring's health in the future. Diseases that traditionally are linked to inappropriate life style of adults, such as type 2 diabetes, obesity, and arterial hypertension, can be "programmed" in the early stage of life and the disturbed growth of the fetus leads to the symptoms of the metabolic syndrome. The structural changes of some organs, such as the brain, pancreas and kidney, modifications of the signaling and metabolic pathways in skeletal muscles and in fatty tissue, epigenetic mechanisms and mitochondrial dysfunction are the basis of the metabolic disruptions. The programming of the metabolic disturbances is connected with the disruption in the intrauterine environment experienced in the early and late gestation period. It causes the changes in deposition of triglycerides, activation of the hormonal "stress axis" and disturbances in the offspring's glucose tolerance. The present review summarizes experimental results that led to the identification of the above-mentioned links and it underlines the role of animal models in the studies of this important concept.

Obstructive sleep apnea and diabetic nephropathy: a cohort study.

OBJECTIVE: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease (ESRD). Obstructive sleep apnea (OSA) is common in type 2 diabetes and increases oxidative stress. Hence, OSA could promote the development and progression of DN. RESEARCH DESIGN AND METHODS: This was a cohort study in adults with type 2 diabetes. Patients with known OSA or ESRD were excluded. DN was defined as the presence of albuminuria or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. DN progression was based on eGFR measurements. OSA was defined as apnea hypopnea index (AHI) ≥5 events/h. Serum nitrotyrosine abundance (a marker of nitrosative stress) was measured by ELISA. RESULTS: A total of 224 patients were included. OSA and DN prevalence was 64.3 and 40.2, respectively. DN prevalence was higher in patients with OSA (OSA+) compared with those without OSA (OSA-) (49.3% vs. 23.8%, P < 0.001). After adjustment, OSA (odds ratio 2.64 [95% CI 1.13-6.16], P = 0.02) remained independently associated with DN. After an average follow-up of 2.5 (0.7) years, eGFR decline was greater in OSA+ compared with OSA- patients (median -6.8% [interquartile range -16.1 to 2.2] vs. -1.6% [-7.7 to 5.3%], P = 0.002). After adjusting, both baseline OSA (B = -3.8, P = 0.044) and AHI (B = -4.6, P = 0.02) remained independent predictors of study-end eGFR. Baseline serum nitrotyrosine abundance (B = -0.24, P = 0.015) was an independent predictor of study-end eGFR after adjustment. CONCLUSIONS: OSA is independently associated with DN in type 2 diabetes. eGFR declined faster in patients with OSA. Nitrosative stress may provide a pathogenetic link between OSA and DN. Interventional studies assessing the impact of OSA treatment on DN are needed.

Prenatal programming of insulin secretion in intrauterine growth restriction.

Intrauterine growth restriction (IUGR) impairs insulin secretion in humans and in animal models of IUGR. Several underlying mechanisms have been implicated, including decreased expression of molecular regulators of ß-cell mass and function, in some cases shown to be due to epigenetic changes initiated by an adverse fetal environment. Alterations in cell cycle progression contribute to loss of ß-cell mass, whereas decreased islet vascularity and mitochondrial dysfunction impair ß-cell function in IUGR rodents. Animal models of IUGR sharing similar insulin secretion outcomes as the IUGR human are allowing underlying mechanisms to be identified. This review will focus on models of uteroplacental insufficiency.

Gestational diabetes, maternal obesity, and the NCD burden.

A greater proportion of women of reproductive age are now overweight or obese. Gestational diabetes mellitus and maternal obesity are associated with long-term adverse consequences in the offspring and subsequent generations, and are important drivers of the escalating global burden of diabetes and cardiovascular disease. We review the evidence linking gestational diabetes mellitus and maternal obesity with a greater risk of metabolic compromise in the offspring. We use an evolutionary perspective to elucidate the origins of gestational diabetes. Focusing efforts on maternal health is an important approach to combating the growing burden of diabetes and other noncommunicable diseases.

The obstetric origins of health for a lifetime.

There is a new "developmental" model for the origins of a wide range of chronic diseases. Under this model the causes to be identified are linked to normal variations in fetoplacental development. These variations are thought to lead to variations in the supply of nutrients to the baby that permanently alter gene expression, a process known as "programming." According to the developmental model variations in the processes of development program the function of a few key systems that are linked to disease, including the immune system, antioxidant defenses, inflammatory responses, and the number and quality of stem cells.

Role of placental nutrient sensing in developmental programming.

Altered maternal nutrition and metabolism, restricted utero-placental blood flow, and other perturbations in the maternal compartment may disturb critical periods of fetal development resulting in increased susceptibility to develop disease in childhood and adult life. In response to these perturbations, changes in placental structure and function occur, which influence the supply of nutrients, oxygen, and methyl donors and alter the secretion of hormones and other signaling molecules into the fetal circulation. Thus, the placenta plays a critical role in modulating maternal-fetal resource allocation, thereby affecting fetal growth and the long-term health of the offspring.

A euglycaemic/non-diabetic perinatal environment does not alleviate early beta cell maldevelopment and type 2 diabetes risk in the GK/Par rat model.

AIMS/HYPOTHESIS: We used the GK/Par rat, a spontaneous model of type 2 diabetes with early defective beta cell neogenesis, to determine whether the development of GK/Par offspring in a non-diabetic intrauterine/postnatal environment would prevent the alteration of fetal beta cell mass (BCM) and ultimately decrease the risk of diabetes later in adult life. METHODS: We used an embryo-transfer approach, with fertilised GK/Par ovocytes (oGK) being transferred into pregnant Wistar (W) or GK/Par females (pW and pGK). Offspring were phenotyped at fetal age E18.5 and at 10 weeks of age, for BCM, expression of genes of pancreatic progenitor cell regulators (Igf2, Igf1r, Sox9, Pdx1 and Ngn3), glucose tolerance and insulin secretion. RESULTS: (1) Alterations in neogenesis markers/regulators and BCM were as severe in the oGK/pW E18.5 fetuses as in the oGK/pGK group. (2) Adult offspring from oGK transfers into GK (oGK/pGK/sGK) had the expected diabetic phenotype compared with unmanipulated GK rats. (3) Adult offspring from oGK reared in pW mothers and milked by GK foster mothers had reduced BCM, basal hyperglycaemia, glucose intolerance and low insulin, to an extent similar to that of oGK/pGK/sGK offspring. (4) In adult offspring from oGK transferred into pW mothers and milked by their W mothers (oGK/pW/sW), the phenotype was similar to that in oGK/pGK/sGK or oGK/pW/sGK offspring. CONCLUSIONS/INTERPRETATION: These data support the conclusion that early BCM alteration and subsequent diabetes risk in the GK/Par model are not removed despite normalisation of the prenatal and postnatal environments, either isolated or combined.

Fetal programming of the neuroendocrine-immune system and metabolic disease.

Adverse uterine environments experienced during fetal development can alter the projected growth pattern of various organs and systems of the body, leaving the offspring at an increased risk of metabolic disease. The thrifty phenotype hypothesis has been demonstrated as an alteration to the growth trajectory to improve the survival and reproductive fitness of the individual. However, when the intrauterine environment does not match the extrauterine environment problems can arise. With the increase in metabolic diseases in both Westernized and developing countries, it is becoming apparent that there is an environmental disconnect with the extrauterine environment. Therefore, the focus of this paper will be to explore the effects of maternal malnutrition on the offspring's susceptibility to metabolic disorders such as obesity, cardiovascular disease, and diabetes with emphasis on programming of the neuroendocrine-immune system.

Glycemic response and attainment of A1C goals following newly initiated insulin therapy for type 2 diabetes.

OBJECTIVE: To identify the characteristics associated with glycemic response to newly initiated insulin therapy. RESEARCH DESIGN AND METHODS: We identified 1,139 type 2 diabetic patients who initiated insulin therapy between 1 January 2009 and 30 June 2010. Outcomes of interest were the proportion of patients achieving A1C <7% and mean change in A1C within 3-9 months. RESULTS: Mean A1C at insulin initiation was 8.2 vs. 9.2% among those who did and did not attain A1C <7% (P < 0.001). Within a mean of 5 months, 464 (40.7%) patients attained A1C <7%. In multivariable analyses controlling for insulin regimen, dose, and oral agent use, preinsulin A1C was responsible for nearly all the explained variance in A1C change. Each one percentage point of preinsulin A1C reduced the probability of attaining <7% by 26% (odds ratio 0.74 [95% CI 0.68-0.80]). CONCLUSIONS: Insulin initiation at lower levels of A1C improves goal attainment and independently increases glycemic response.

Metabolomic profiling of fatty acid and amino acid metabolism in youth with obesity and type 2 diabetes: evidence for enhanced mitochondrial oxidation.

OBJECTIVE: We compared acylcarnitine (AcylCN) species, common amino acid and fat oxidation (FOX) byproducts, and plasma amino acids in normal weight (NW; n = 39), obese (OB; n = 64), and type 2 diabetic (n = 17) adolescents. RESEARCH DESIGN AND METHODS: Fasting plasma was analyzed by tandem mass spectrometry, body composition by dual energy X-ray absorptiometry and computed tomography, and total-body lipolysis and substrate oxidation by [(2)H(5)]glycerol and indirect calorimetry, respectively. In vivo insulin sensitivity (IS) was assessed with a 3-h hyperinsulinemic-euglycemic clamp. RESULTS: Long-chain AcylCNs (C18:2-CN to C14:0-CN) were similar among the three groups. Medium- to short-chain AcylCNs (except C8 and C10) were significantly lower in type 2 diabetes compared with NW, and when compared with OB, C2-, C6-, and C10-CN were lower. Amino acid concentrations were lower in type 2 diabetes compared with NW. Fasting lipolysis and FOX were higher in OB and type 2 diabetes compared with NW, and the negative association of FOX to C10:1 disappeared after controlling for adiposity, Tanner stage, and sex. IS was lower in OB and type 2 diabetes with positive associations between IS and arginine, histidine, and serine after adjusting for adiposity, Tanner stage, and sex. CONCLUSIONS: These metabolomics results, together with the increased rates of in vivo FOX, are not supportive of defective fatty acid or amino acid metabolism in obesity and type 2 diabetes in youth. Such observations are consistent with early adaptive metabolic plasticity in youth, which over time-with continued obesity and aging-may become dysfunctional, as observed in adults.

[Risk of type 2 diabetes mellitus and acute cardiovascular disorders in patients with early disturbances of carbohydrate metabolism].

The aim of this work was to estimate the relative risk (RR) of type 2 diabetes mellitus (DM2) and cardiovascular diseases, total and cardiovascular mortality in patients with disturbances of carbohydrate metabolism revealed in the prospective study carried out in 2009 that included patients found to have disturbances of carbohydrate metabolism in 2006. We analysed the 3-year risk of development of type 2 diabetes mellitus, total and cardiovascular mortality. RR of DM2 was significantly increased in association with practically all early disturbances of carbohydrate metabolism. The most unfavourable combination is fasting glycemia and impaired glucose tolerance. Within 3 years after its determination, 33.3% of the patients developed DM2 while RR of DM2 increased 11-fold. Newly diagnosed DM2 increased RR of total mortality by 2.3 times. Fasting glycemia during 3 years increased RR of cardiovascular mortality by 3.2 times. Results of the study suggest the necessity of not only timely diagnosis of fasting glycemia and impaired glucose tolerance but also further monitoring and correction of carbohydrate metabolism in patients with this pathology as well as of the elaboration and implementation of a comprehensive program for the screening of disturbed carbohydrate metabolism in high-risk groups.

Maternal malnutrition programs the endocrine pancreas in progeny.

Type 2 diabetes arises when the endocrine pancreas fails to secrete sufficient insulin to cope with metabolic demands resulting from ß cell secretory dysfunction, decreased ß cell mass, or both. Epidemiologic studies have shown strong relations between poor fetal and early postnatal nutrition and susceptibility to diabetes later in life. Animal models have been established, and studies have shown that a reduction in the availability of nutrients during fetal development programs the endocrine pancreas and insulin-sensitive tissues. We investigated several modes of early malnutrition in rats. Regardless of the type of diet investigated, whether there was a deficit in calories or protein in food or even in the presence of a high-fat diet, malnourished pups were born with a defect in their ß cell population, with fewer ß cells that did not secrete enough insulin and that were more vulnerable to oxidative stress; such populations of ß cells will never completely recover. Despite the similar endpoint, the cellular and physiologic mechanisms that contribute to alterations in ß cell mass differ depending on the nature of the nutritional insult. Hormones that are operative during fetal life, such as insulin, insulin-like growth factors, and glucocorticoids; specific molecules, such as taurine; and islet vascularization have been implicated as possible factors in amplifying this defect. The molecular mechanisms responsible for intrauterine programming of ß cells are still elusive, but among them the programming of mitochondria may be a strong central candidate.

Genetic variant in the IGF2BP2 gene may interact with fetal malnutrition to affect glucose metabolism.

OBJECTIVE: Fetal malnutrition may predispose to type 2 diabetes through gene programming and developmental changes. Previous studies showed that these effects may be modulated by genetic variation. Genome-wide association studies discovered and replicated a number of type 2 diabetes-associated genes. We investigated the effects of such well-studied polymorphisms and their interactions with fetal malnutrition on type 2 diabetes risk and related phenotypes in the Dutch Famine Birth Cohort. RESEARCH DESIGN AND METHODS: The rs7754840 (CDKAL1), rs10811661 (CDKN2AB), rs1111875 (HHEX), rs4402960 (IGF2BP2), rs5219 (KCNJ11), rs13266634 (SLC30A8), and rs7903146 (TCF7L2) polymorphisms were genotyped in 772 participants of the Dutch Famine Birth Cohort Study (n = 328 exposed, n = 444 unexposed). Logistic and linear regression models served to analyze their interactions with prenatal exposure to famine on type 2 diabetes, impaired glucose tolerance (IGT), and area under the curves (AUCs) for glucose and insulin during oral glucose tolerance testing (OGTT). RESULTS: In the total population, the TCF7L2 and IGF2BP2 variants most strongly associated with increased risk for type 2 diabetes/IGT and increased AUC for glucose, while the CDKAL1 polymorphism associated with decreased AUC for insulin. The IGF2BP2 polymorphism showed an interaction with prenatal exposure to famine on AUC for glucose (beta = -9.2 [95% CI -16.2 to -2.1], P = 0.009). CONCLUSIONS: The IGF2BP2 variant showed a nominal interaction with exposure to famine in utero, decreasing OGTT AUCs for glucose. This may provide a clue that modulation of the consequences of fetal environment depends on an individual's genetic background.

A fingerprint marker from early gestation associated with diabetes in middle age: the Dutch Hunger Winter Families Study.

BACKGROUND: Fetal programming of diabetes might originate in early pregnancy when fingerprints are permanently established. The mean dermatoglyphic ridge count difference between fingertips 1 and 5 ('Md15') varies with the early prenatal environment. We hypothesized that Md15 would be associated with adult-onset diabetes. METHODS: We obtained Md15 from 577 Dutch adults (aged 58.9 years, SD 1.1) whose births in 1943-47 were documented in maternity records and from 260 of their same-sex siblings for whom birth weights were not available. Of these 837 participants, complete anthropometry and diabetes status (from history or glucose tolerance test) were obtained for 819. RESULTS: After adjustment for age, sex, parental diabetes and adult anthropometry, fingerprint Md15 was associated with prevalent diabetes [odds ratio (OR) = 1.37 per 1 SD (95% confidence interval 1.02-1.84)]. This relationship held [OR = 1.40 (1.03-1.92)] for diabetic cases restricted to those recently diagnosed (within 7 years). In the birth series restricted to recently diagnosed cases, the mutually adjusted ORs were 1.34 (1.00-1.79) per SD of Md15 and 0.83 (0.62-1.10) per SD of birth weight. Further adjustments for maternal smoking, conception season or prenatal famine exposure in 1944-45 did not alter these estimates. Among 42 sibling pairs discordant for diabetes, the diabetic sibling had higher Md15 by 3.5 (0.6-6.3) after multivariable adjustment. CONCLUSIONS: Diabetes diagnosed at age 50+ years was associated with a fingerprint marker established in early gestation, irrespective of birth weight. Fingerprints may provide a useful tool to investigate prenatal developmental plasticity.