Impaired insulin secretion after intravenous glucose in neonatal rhesus monkeys that had been chronically hyperinsulinemic in utero

Consequences of gestational and pregestational diabetes on placental function and birth weight

Maternal diabetes constitutes an unfavorable environment for embryonic and fetoplacental development. Despite current treatments, pregnant women with pregestational diabetes are at increased risk for congenital malformations, materno-fetal complications, placental abnormalities and intrauterine malprogramming. The complications during pregnancy concern the mother (gravidic hypertension and/or preeclampsia, cesarean section) and the fetus (macrosomia or intrauterine growth restriction, shoulder dystocia, hypoglycemia and respiratory distress). The fetoplacental impairment and intrauterine programming of diseases in the offspring’s later life induced by gestational diabetes are similar to those induced by type 1 and type 2 diabetes mellitus. Despite the existence of several developmental and morphological differences in the placenta from rodents and women, there are similarities in the alterations induced by maternal diabetes in the placenta from diabetic patients and diabetic experimental models. From both human and rodent diabetic experimental models, it has been suggested that the placenta is a compromised target that largely suffers the impact of maternal diabetes. Depending on the maternal metabolic and proinflammatory derangements, macrosomia is explained by an excessive availability of nutrients and an increase in fetal insulin release, a phenotype related to the programming of glucose intolerance. The degree of fetal damage and placental dysfunction and the availability and utilisation of fetal substrates can lead to the induction of macrosomia or intrauterine growth restriction. In maternal diabetes, both the maternal environment and the genetic background are important in the complex and multifactorial processes that induce damage to the embryo, the placenta, the fetus and the offspring. Nevertheless, further research is needed to better understand the mechanisms that govern the early embryo development, the induction of congenital anomalies and fetal overgrowth in maternal diabetes.

Comparison of plasma insulin levels after a mixed-meal challenge in children with and without intrauterine exposure to diabetes

BACKGROUND

The diabetic intrauterine environment is a known risk factor for the development of diabetes in the offspring.

OBJECTIVE

We compared anthropometric and metabolic characteristics of 41 nondiabetic children whose mothers developed diabetes either before (ODM, n = 19, 9.3 +/- 1.1 yr) or after (OPDM, n = 22, 9.5 +/- 1.3 yr) the pregnancy of interest. Maternal diabetes status was established from OGTT results before, during, and after the pregnancy of interest.

DESIGN

After consuming a standardized diet for 2 d, a mixed-meal breakfast was given after an overnight fast. Fasting concentrations and responses of plasma glucose and insulin were evaluated using linear regression analyses to assess potential independent determinants of plasma insulin concentration at each time point.

RESULTS

After adjustment for age and sex, there were no differences between ODM and OPDM children for maternal age at diagnosis, height, weight, body mass index, BMI z score, or percent body fat (dual energy x-ray absorptiometry). After adjusting for age, sex, percent body fat, and the corresponding glucose level at each time point, ODM had a lower plasma insulin level at the 15-min time point during the meal test than OPDM (P = 0.01).

CONCLUSION

A lower initial insulin response to a standard mixed-meal challenge can be detected in nondiabetic ODM compared with OPDM children as early as 9 yr of age. This response may be another indicator for an attenuated early insulin response and explain the increased risk for diabetes in these children.

Perinatal Nutrition and Hormone-Dependent Programming of Food Intake

It is increasingly accepted that alterations of the intrauterine and early postnatal nutritional, metabolic and hormonal environment may predispose individuals to development of diseases in later life. Results from studies of the offspring of diabetic mothers strongly support this hypothesis. It has also been suggested that being light at birth leads to an increased risk of the metabolic syndrome (Syndrome X) in later life (the Barker hypothesis). The pathophysiological mechanisms that underlie this programming are unclear. However, hormones are important environment-dependent organizers of the developing neuroendocrine-immune network, which regulates all the fundamental processes of life. Hormones can act as 'endogenous functional teratogens' when present in non-physiological concentrations, induced by alterations in the intrauterine or neonatal environment during critical periods of perinatal life. Perinatal hyperinsulinism is pathognomic in offspring of diabetic mothers. Early hyperinsulinism also occurs as a result of early postnatal overfeeding. In rats, endogenous hyperinsulinism, as well as peripheral or intrahypothalamic insulin treatment during perinatal development, may lead to 'malprogramming' of the neuroendocrine systems regulating body weight, food intake and metabolism. This results in an increased disposition to become obese and to develop diabetes throughout life. Similar malprogramming may occur due to perinatal hypercortisolism and hyperleptinism. With regard to 'small baby syndrome' and the thrifty phenotype hypothesis, we propose that early postnatal overfeeding of underweight newborns may substantially contribute to their long-term risk of obesity and diabetes. In summary, a complex malprogramming of the central regulation of body weight and metabolism may provide a general aetiopathogenetic concept, explaining perinatally acquired disposition to later disease and, thereby, opening a wide field for primary prevention.

'Fetal programming' and 'functional teratogenesis': on epigenetic mechanisms and prevention of perinatally acquired lasting health risks

Alterations of the intrauterine and early postnatal nutritional, metabolic, and hormonal environment may cause predispositions to the development of disorders and diseases in later life. Mechanisms responsible for this perinatally acquired 'malprogramming' still remain unclear. It has long been known, however, that hormones are environment-dependent organizers of the developing 'neuroendocrine-immune network', which regulates all fundamental processes of life. When present in nonphysiological concentrations during critical ontogenetic periods, hormones can therefore also act as 'endogenous functional teratogens'. Fetal and neonatal hyperinsulinism is a pathognomic feature in the offspring of diabetic mothers. Perinatal hyperinsulinism also occurs due to early postnatal overfeeding. Data obtained by our group indicate that elevated insulin concentrations during critical periods of perinatal life may induce a lasting 'malprogramming' of neuroendocrine systems regulating body weight, food intake, and metabolism. Similar characteristics may occur due to perinatal hyperleptinism, hypercortisolism etc. Since mechanisms of early 'programming' of obesity, diabetes, and the metabolic syndrome X are unclear, a complex 'neuroendocrine malprogramming' of the regulation of body weight and metabolism may provide a general etiopathogenetic concept in this context, exemplarily revealing critical new implications for chances and challenges of perinatal preventive medicine in the future.

Long-term consequences for offspring of diabetes during pregnancy

There is evidence that the diabetic intra-uterine environment has consequences for later life. Maternal diabetes mainly results in asymmetric macrosomia. This macrosomia is associated with an increased insulin secretion and overstimulation of the insulin producing B-cells during fetal life. In later life, a reduced insulin secretion is found. Intra-uterine growth restriction is present in severe maternal diabetes associated with vasculopathy. Intra-uterine growth restriction is associated with low insulin secretion and reduced development of the insulin receptors. In later life, these alterations can induce insulin resistance. The long-term consequences of an abnormal intra-uterine environment are of primary importance world-wide. Concentrated efforts are needed to explore how these long-term effects can be prevented.

Infant mortality: The role of the macaque as a model for human disease

Factors which have been identified as the leading causes of infant mortality include birth defects, hemoglobinopathies, prematurity, and Sudden Infant Death Syndrome (SIDS). In order to further our understanding of the specific causes of infant mortality and the mechanisms by which they occur, suitable animal models will be required. Studies with nonhuman primates (specifically the macaque) have addressed malformation/functional deficit syndromes such as those associated with Fetal Alcohol Syndrome (FAS), nutritional deficiencies, and retinoid teratogenicity. These studies have provided critical information for further basic and preventive research. In addition, efforts to evaluate the safety of diagnostic ultrasound continue to aid in identifying safe methods for exposure. From a prenatal perspective, cellular transplantation has been shown to be a feasible method for treating individuals with inherited defects in utero, thereby avoiding postnatal transplantation and the associated risks. Longterm complications of prematurity have also been pursued with growth factors (i.e., epidermal growth factor) noted to play an important role in both pre- and postnatal development of the gastrointestinal tract and lung. As one of the most distressing causes of death in infancy, SIDS will require a concentrated effort to understand the basic mechanism(s) responsible for the characteristic respiratory complications. The nonhuman primate will continue to provide critical information as the model of choice for the human in determining the causes, mechanisms, and treatments for these significant causes of infant death. © 1994 Wiley-Liss, Inc.