Birthweight and the future risk of cardiovascular disease: does intrauterine malnutrition have a role in fetal programming?

Central Hematocrit Levels in Fetal Malnourished Term Infants

BACKROUND

Fetal malnutrition is especially important for common chronic diseases in adult life. They could potentially be prevented by achieving optimal fetal nutrition.

OBJECTIVE

The aim of this study was to investigate hematocrit levels of malnourished, term, appropriate for gestational age (AGA) neonates.

SUBJECTS AND METHODS

A total of 80 AGA neonates (between 10% and 90% percentiles interval according to birth week), born with spontaneous vaginal delivery between 37 and 42 weeks of gestation, detected by both last menstrual period and ultrasonography measurements, were included in the study. Neonates with fetal malnutrition constituted the study group and the control group consisted of well-nourished neonates. We analyzed central venous hematocrit levels obtained 4 hours after birth and maternal risk factors for both groups.

RESULTS

Although there were no differences in gestational age, head circumference, maternal factors (gravidity, parity, abortions and curettage counts, maternal tobacco use, preeclampsia, hypertension, diabetes mellitus, gestational diabetes mellitus, and history of urinary tract infections), first minute APGAR scores, and sex, Clinical Assessment of Nutritional Status score was lower (29.91±2.87 vs. 21.25±1.65) and hematocrit levels were higher (51.33±2.740 vs. 59.53±5.094) in the fetal malnutrition group (P<0.0001).

CONCLUSIONS

Central hematocrit levels in malnourished term AGA neonates were found significantly higher than well-nourished term AGA newborns.

The long-term effects of perinatal glucocorticoid exposure on the host defence system of the respiratory tract

Glucocorticoids are used to mature the fetal lung at times of threatened premature delivery. These drugs modify leukocyte profiles when administered in adulthood, but their effects on the mature host defence system following administration during the perinatal period are incompletely understood. In this study, the long-term effects of perinatal dexamethasone exposure on rodent host defence cells in the pulmonary airspaces, the perivascular compartment of the lung, and the blood were investigated. Rats were treated prenatally (gestational days 16-19) or neonatally (postnatal days 1-7) by inclusion of dexamethasone in the mothers' drinking water (1 microg/ml). The pups were then allowed to develop to adulthood (P60-80), at which time respiratory tissues were collected for light and electron microscopy and bronchoalveolar lavage (BAL), and blood for cell count and fluorescent activated cell-sorting (FACS) analysis. Prenatal treatment had no effect on any parameter examined. Following neonatal dexamethasone exposure, light microscopy of the lung tissue revealed a significant reduction in the number of cells in the perivascular space in both the central and the peripheral regions of the adult lung, but no differences in the number of cells in the airspaces. Neonatal dexamethasone exposure was also characterized by a significant reduction in the total number of white cells in the peripheral blood in adulthood and in particular, the number of lymphocytes relative to neutrophils was significantly reduced at maturity in these animals. The results show that neonatal, but not prenatal, dexamethasone exposure significantly alters the distribution of host defence cells in the blood and lung at maturity compared with control animals. The early neonatal period is characterized by the stress hyporesponsive period in the rat, when endogenous glucocorticoid levels are very low. Therefore, exogenous glucocorticoids administered during this time are likely to have marked "programming" effects on glucocorticoid-sensitive tissues.

Prenatal stress changes rat arterial adrenergic reactivity in a regionally selective manner

A suboptimal fetal environment has been linked to increased risk of cardiovascular disease in adulthood. We investigated whether intrauterine stress (IUS) alters the development of adrenergic reactivity in different types of rat arteries. Intrauterine stress was induced by ligation of the uterine arteries at day 13 of pregnancy in Wistar rats. First-order mesenteric, renal, femoral and saphenous arteries of the 21-day-old male offspring were studied in a myograph. IUS in the rat changes arterial adrenergic reactivity in a regionally selective manner. Adrenoceptor-mediated responses are altered in the renal artery. Maximal contractile responses to phenylephrine were increased, while sensitivity to the alpha(1)-adrenoceptor agonist was decreased. Intrauterine stress significantly reduced contractile responses to norepinephrine and enhanced relaxing responses to isoproterenol in the renal artery. Adrenergic responses were not modified in mesenteric, femoral and saphenous arteries. In the kidneys the densities of [(3)H]prazosin binding sites, periarterial adrenergic nerves and of the glomeruli were not altered after intrauterine stress at day 13 of gestation. The observed regionally selective alterations in arterial reactivity might link a suboptimal fetal environment to the development of cardiovascular disease in the adult.