No abstract

The importance of the intrauterine and neonatal metabolic environment as possible teratogenic determinants of predispositions to diabetes, obesity and cardiovascular diseases is discussed. Epidemiological, clinical and experimental results suggest that gestational diabetes or even slightly impaired glucose tolerance during pregnancy are important risk factors for the development of an increased Type II- and even Type I diabetes susceptibility in the offspring. In addition, early prenatal undernutrition might also predispose to enhanced risk of Type II diabetes, whereas perinatal overnutrition seems to enhance predominantly Type I diabetes susceptibility. In this context, fetal and/or neonatal hyperinsulinism occurring during a critical period of brain development and leading to permanent malorganization of hypothalamic regulation centres for metabolism and hence to malprogramming of the hypothalamo-pancreatic system, is discussed as a possible reason for lifelong enhanced diabetes susceptibility. In view of epidemiological and experimental findings, an epigenetic maternofetal transmission of such acquired persistent modifications can run over several generations, mediated by gestational hyperglycaemia and fetal or neonatal hyperinsulinism. In conclusion, a partial prophylaxis of diabetes mellitus, obesity and cardiovascular diseases appears to be possible by prevention of gestational diabetes--even mild forms of impaired glucose tolerance during pregnancy--as well as early prenatal undernutrition and perinatal overnutrition.

Early postnatal overnutrition is a risk factor for obesity in juvenile and adult life. Underlying pathophysiological mechanisms are still unclear. Hypothalamic neuropeptides are decisively involved in the regulation of body weight and food intake. In this study, we investigated consequences of early postnatal overnutrition, as compared to normo-and undernutrition, on NPY within the arcuate nucleus and paraventricular nucleus (PVN). The normal litter size of Wistar rats was adjusted on the third day of life from 10 pups (normal litters, NL; normonutrition) to only three newborns (small litters, SL; overnutrition) or 18 pups per mother (large litters, LL; undernutrition). SL rats developed clear overweight until the day 21 of life (P<0.0001), as well as hyperleptinaemia (P<0.001), and hyperinsulinaemia (P<0.01). LL rats were underweight and had decreased leptin and insulin concentrations. Using radioimmunoassay, NPY contents were determined in hypothalamic micropunches, and immunocytochemistry for NPY was performed in serial hypothalamic sections on day 21 of life. While in the underweight, hypoleptinaemic, and hypoinsulinaemic LL rats increased concentrations of NPY in the arcuate nucleus and PVN were observed, no decrease in NPY content was found in the overweight, hyperleptinaemic, and hyperinsulinaemic SL rats. Moreover, the percentage of NPY-immunopositive neurones per total number of neurones was increased not only in the LL rats, but also in the SL rats. Since the NPY system is functionally mature already at this age, these findings might indicate an acquired resistance of the hypothalamic NPY system to increased levels of insulin and/or leptin in early postnatally overfed SL rats.

Since Pedersen's fundamental work [1] the metabolic situation in infants of mothers with diabetes mellitus during pregnancy has been investigated in a number of studies [2][3][4]. While most authors focussed on altered glucose homeostasis during neonatal life, it remains unclear if these alterations do persist or resolve in later life. Clinical investigations during childhood indicated elevated frequencies of impaired glucose tolerance (IGT) in the offspring of mothers with diabetes during pregnancy [5,6]. Some authors reported alterations of insulin secretion such as hyperinsulinaemia [6,7] which is known to play a key role in the development of metabolic and cardiovascular disturbances in adulthood [8]. Experimental studies in rats displayed long-term alterations of glucose tolerance and insulin secretion due to the induction of maternal gestational hyperglycaemia which leads to fetal and neonatal hyperinsulinism [9][10][11][12][13].However, only a very small number of studies are available which compared glucose metabolism and Diabetologia (1997Diabetologia ( ) 40: 1094Diabetologia ( -1100 Glucose tolerance and insulin secretion in children of mothers with pregestational IDDM or gestational diabetes Summary The offspring of mothers with diabetes mellitus during pregnancy are presumed to develop altered glucose homeostasis. We analysed metabolic parameters at birth and glucose tolerance and insulin secretion during oral glucose tolerance tests at 1-9 years of age in 129 children born to mothers with pregestational insulin-dependent diabetes (IDDM) and 69 infants of gestational diabetic mothers. Newborns of IDDM mothers displayed higher insulin (p < 0.001), glucose (p < 0.05), and insulin/glucose ratios (p < 0.002) than newborns of gestational diabetic mothers. During childhood, frequencies of impaired glucose tolerance (IGT) rose in infants of IDDM mothers from 9.4 % at 1-4 years to 17.4 % at 5-9 years of age, while in children of gestational diabetic mothers an increase from 11.1 % up to 20.0 % was observed. Offspring of gestational diabetic mothers displayed higher stimulated blood glucose (p < 0.025) than infants of IDDM mothers, while children of IDDM mothers showed higher stimulated insulin (p < 0.025), accompanied by increased fasting and stimulated insulin/glucose ratios (p < 0.05 and p < 0.02, respectively). Stimulated insulin in childhood was positively correlated to insulin at birth (p < 0.05). Furthermore, insulin/glucose ratio in childhood showed a positive correlation to insulin (p < 0.01) and insulin/glucose ratio at birth (p < 0.005). In conclusion, a pathogenetic role of fetal and neonatal hyperinsulinism for the development of IGT in both groups of infants of diabetic mothers is suggested, in particular for early induction of insulin resistance in the offspring of mothers with pregestational IDDM. [Diabetologia (1997)

Maternal low protein malnutrition during gestation and lactation (LP) is an animal model frequently used for the investigation of long-term deleterious consequences of perinatal growth retardation. Both perinatal malnutrition and growth retardation at birth are risk factors for diabetic and cardiovascular disturbances in later life. The pathophysiologic mechanisms responsible are unknown. Hypothalamic nuclei are decisively involved in the central nervous regulation of food intake, body weight and metabolism. We investigated effects of a low protein diet (8% protein; control diet, 17% protein) during gestation and lactation in rat dams on the organization of hypothalamic regulators of body weight and metabolism in the offspring at weaning (d 20 of life). LP offspring had significantly lower body weight than control offspring (CO; P: < 0.001), associated with hypoglycemia and hypoinsulinemia (P: < 0. 005) on d 20 of life. This was accompanied by a greater relative volume of the ventromedial hypothalamic nucleus (P: < 0.01) and a greater numerical density of Nissl-stained neurons in this nucleus (P: < 0.01) as well as in the paraventricular hypothalamic nucleus (PVN; P: < 0.001). In contrast, no significant differences in neuronal densities were observed generally in the lateral hypothalamic area, arcuate hypothalamic nucleus (ARC), and dorsomedial hypothalamic nucleus between LP offspring and CO offspring. On the other hand, LP offspring displayed fewer neurons immunopositive for neuropeptide Y in the ARC (P: < 0.05), whereas in the PVN, lower neuronal densities of neurons immunopositive for galanin were found in LP offspring compared with CO offspring (P: < 0.001). On the contrary, in the PVN, no significant group difference in the numerical density of cholecystokinin-8S-positive neurons was present. A long-term effect of these specific hypothalamic alterations on body weight and metabolism in LP offspring during later life is suggested.

OBJECTIVES: To analyse the development of body weight and frequencies of overweight and obesity in infants of long-term insulin-dependent diabetic mothers as compared to those of gestational diabetic mothers. DESIGN: Retrospective study. SUBJECTS: Two hundred infants of mothers with pregestational insulin-dependent diabetes mellitus (IDM) and 117 infants of gestational diabetic mothers (IGDM) born between 1980 and 1990 at the Clinic of Obstetrics and Gynaecology, Berlin-Kaulsdorf, Germany. MEASUREMENTS: Birth weight, birth length, plasma insulin, interscapular skinfold, symmetry index (SI) and body mass index (BMI) at birth; SI and BMI in childhood (1±9 y of age). RESULTS: Neonatally, mean relative weight (SI) was found to be increased in both groups of infants. It was positively correlated to interscapular skinfold (P`0.001) and insulin (P`0.005). However, IDM had higher insulin levels (P`0.001) and a higher frequency of obesity (P`0.05) than IGDM at birth. Throughout childhood frequencies of overweight (SI b 1.1) were elevated in both IDM as well as IGDM. In IDM the percentage of obesity (SI b 1.2) displayed a signi®cant increase from 11.2% in children 1±4 y old up to 25.8% at 5±9 y (P`0.05). Similar frequencies and a highly signi®cant increase of overweight during childhood of IDM (P`0.005) were observed when BMI ! 95th percentile was used to determine overweight. Relative weight in childhood was positively correlated to relative weight at birth (P`0.05). Large-for-gestational-age infants displayed a signi®cantly higher percentage of overweight (SI b 1.1) in childhood than appropriate-for-gestational-age infants (P`0.05). CONCLUSIONS: Infants of mothers with diabetes during pregnancy are predisposed to develop overweight and obesity during childhood. These alterations seem to be related to insulin and relative body weight at birth. Pathophysiological mechanisms which might be involved into the development of these changes are discussed. Prophylactic measures are recommended to reduce morbidity in infants of diabetic mothers.

We recently reported on an elevation of neurons expressing the main orexigenic peptide neuropeptide Y (NPY) in the arcuate hypothalamic nucleus (ARC) of neonatally hyperinsulinaemic offspring of gestational diabetic mother rats (GD) at weaning. To investigate possible consequences, the long-term outcome of those animals was examined. At adult age, GD offspring showed hyperphagia (p < 0.001), basal hyperinsulinaemia (p < 0.05) and impaired glucose tolerance (p < 0.05), and were overweight (p < 0.01). This was accompanied by an elevated number of NPY neurons (p < 0.001) and galanin neurons (p < 0.001) in the ARC in adult GD offspring under basal conditions. These findings support our hypothesis on perinatally acquired, persisting malformation and/or malprogramming of peptidergic hypothalamic neurons in the offspring of GD mothers, possibly promoting the development of overweight and diabetogenic disturbances during life.

Insulin is a potent modulator of central nervous development and is suggested to influence the differentiation and maturation of hypothalamic structures involved in the regulation of body weight and metabolism. Hyperinsulinemic offspring of mothers with impaired glucose tolerance during pregnancy (gestational diabetes, GD) have an increased risk to develop overweight and diabetes mellitus during life, while the underlying pathophysiological mechanisms are still unknown. To investigate the effects of perinatal hyperinsulinism on the organization of hypothalamic regulators of body weight and metabolism, GD was induced in rats by application of streptozotocin on the day of conception (25 mg/kg, i.p.). On the 21st day of life, offspring of GD rats were overweight (p < 0.05) and hyperinsulinemic (p < 0.01). Using computer-assisted morphometric measurements, significantly decreased mean areas of neuronal nuclei and neuronal cytoplasm within the paraventricular hypothalamic nucleus (PVN; p < 0.01) and the ventromedial hypothalamic nucleus (VMN; p < 0.05) were observed in GD offspring. Analysis of topographically distinct parts revealed that these alterations particularly occurred in the parvocellular part of the PVN, as well as in the anterior, central, and dorsomedial part of the VMN. No morphometric alterations were found within the lateral hypothalamic area and the dorsomedial hypothalamic nucleus. In the arcuate hypothalamic nucleus, the mean area of neuronal cytoplasm was decreased (p < 0.05), while the number of neurons expressing tyrosine hydroxylase was clearly elevated (p < 0.002). For astrocytes, a tendency towards an increased glia/neuron ratio was observed in the periventricular hypothalamic area. These observations suggest disturbed differentiation and organization of distinct hypothalamic nuclei and subnuclei, respectively, in hyperinsulinemic offspring of GD rats, possibly leading to dysfunctions of hypothalamic regulators of body weight and metabolism which might contribute to the lifelong increased risk to develop overweight and diabetogenic disturbances.