Adenosine Concentration in Umbilical Cord Blood of Newborn Infants after Vaginal Delivery and Cesarean Section

Abstract

ABSTRACT. Umbilical blood was collected immediatelyat birth (<30 s) in full-term infants after vaginal deliveries (n = 33) and elective cesarean sections (n = 11). Blood gases, plasma adenosine, hypoxanthine, and catecholamine concentrations were determined. In vaginally born infants the median arterial adenosine concentration was found to be 0.46 pM (range 0.13-2.06) and the venous 0.48 pM (0.09-1.62). These levels were significantly higher ( p < 0.01) than in infants delivered by elective cesarean section; 0.16 pM (0.04-0.42) in the artery and 0.17 FM (0.02-0.56) in the vein. Vaginally born infants showed about a 4-fold higher level of umbilical arterial catecholamines than infants born by elective cesarean section. There was a strong inverse correlation between arterial hypoxanthine concentration and pH (r = -0,81, p < 0.01). It is suggested that increased adenosint: release at vaginal delivery modulates the stress response elicited by the strong catecholamine surge and may furthermore exert protective effects in perinatal asphyxia. (Pediatr Res 26:106-108, 1989) The adenosine metabolite hypoxanthine has been found to be released in high concentrations during perinatal asphyxia and is suggested to be an indicator of the severity of hypoxemia (1-4). During hypoxemia increased hypoxanthine production may also be due to an increased adenine nucleotide degradation in skeletal muscle through the route from inosine monophosphate to inosine (cf. 5). The fetus may, however, sustain short periods of moderate hypoxemia also in normal vaginal delivery during uterine contractions (6). It is at present unclear whether this degree of intermittent physiologic fetal hypoxemia during normal delivery is associated with release of adenosine, hypoxanthine, or other purines. The production and release of adenosine seem also to be closely linked to the balance between substrate supply and demand, and therefore increased formation of adenosine may occur during increased metabolic activity (7).Adenosine is a potent vasodilator (8) and exerts inhibitory influence on metabolic processes such as lipolysis (9). It also effectively counteracts myocardial stimulatory effects of catecholamines (10). Furthermore, adenosine or its analogues have been demonstrated to depress breathing particularly in the neonate (1 1, 12). Thus, enhanced formation of adenosine during fetal hypoxia could theroretically be involved in a physiologic defense against hypoxia through its action on metabolism, respiration, and hemodynamics.

High expression levels of macrophage migration inhibitory factor sustain the innate immune responses of neonates

“…This parallels the postnatal fall in circulating concentrations of cortisol, placental steroids, prostaglandins, and adenosine, which are potent inhibitors of neonatal innate immune responses (9)(10)(11)(12)46). The expression pattern of MIF in newborns is unique in the sense that MIF reaches blood levels that are at least 10-fold higher than those measured in healthy children and adults, an observation that has no antecedent for a proinflammatory cytokine or mediator (7,13).…”

“…During pregnancy, the placenta and the fetal adrenal gland produce mediators that influence fetal and neonatal immune responses. Adenosine plasma concentrations at birth range between 0.02 and 2 μM, which is threefold higher than levels measured in adults (9,46). Concentrations of PGE 2 range between 0.4 and 10 nM at birth and decrease by fourfold during the first week of life (12, 59).…”

Effect of mode of birth on purine and malondialdehyde in umbilical arterial plasma in normal term newborns

“…Only Irestedt et al 10 investigated the effect of mode of birth on hypoxanthine. In this study, hypoxanthine levels were shown to be significantly higher in infants born vaginally, but no measures of xanthine, uric acid or MDA levels were performed.…”

“…Although umbilical cord uric acid levels [7][8][9] and hypoxanthine levels 10 have been reported in normal term newborns, there are currently no published baseline levels of all three breakdown products of ATP as well as MDA in the cord blood of normal term infants immediately after birth. In addition, the specific effects of oxytocin-augmentation on purine and MDA levels have not been measured.…”

Advantages of human umbilical vein scaffolds derived from cesarean section vs. vaginal delivery for vascular tissue engineering

“…In general, PCS are considered less stressful for the fetus as compared to VD due to lower cord blood levels of the stress indicators cortisol, catecholamines, and β-endorphin [17][18][19][20][21][22]. There is also evidence that vaginal deliveries are associated with an increased oxidative stress [10] compared to c-sections.…”