Fetal growth retardation and increased placental weight in the spontaneously hypertensive rat

1995 ◽  
Vol 7 (3) ◽  
pp. 639 ◽  
Author(s):  
BM Johnston

Epidemiological studies have linked low birth weight and increased placental weight with increased risk of hypertension in adult life. It has been proposed that the cardiovascular changes which lead to hypertension are initiated in utero by processes associated with intrauterine growth retardation. The alternative possibility, that hypertension may result from genetic influences which also determine fetal and placental size, has had less support because birth weight is not determined genetically in humans. However, in the spontaneously hypertensive rat (SHR) essential hypertension is known to be transmitted genetically. Fetal and placental weights were, therefore, measured at Day 20 gestation in SHRs and compared with those in the normotensive Wistar Kyoto (WKY) control strain. Fetal weight (1.93 +/- 0.04 g) was significantly (P < 0.001) reduced in SHRs compared with WKY fetuses (2.23 +/- 0.01 g) but placental weight was heavier (P < 0.001) in SHRs (0.347 +/- 0.005 g) than in WKY rats (0.300 +/- 0.006 g) although litter size was not different. As expected, maternal blood pressure recorded under 1% halothane anaesthesia was higher (126 +/- 2.7 mm Hg) in SHR than WKY rats (100 +/- 2.1 mm Hg; 1 mm Hg = 133 Pa). In addition the concentration of maternal blood glucose in SHR was significantly (P < 0.001) higher (4.8 +/- 0.32 mM v. 3.7 +/- 0.11 mM) and the concentration of plasma insulin was significantly (P < 0.05) lower in SHRs (18.8 +/- 3.0 ng mL-1) than in WKY dams (29.4 +/- 3.1 ng mL-1). Thus, the data support human population studies which show an association between adult hypertension and a reduced fetal:placental weight ratio at birth. However, because hypertension in the SHR is genetically determined, these data suggest that fetal growth retardation and increased placental weight may also be determined genetically.

2008 ◽  
Vol 295 (4) ◽  
pp. F1239-F1247 ◽  
Author(s):  
Alaa E. S. Abdel-Razik ◽  
Richard J. Balment ◽  
Nick Ashton

Urotensin II (UII) has been implicated widely in cardiovascular disease. The mechanism(s) through which it contributes to elevated blood pressure is unknown, but its emerging role as a regulator of mammalian renal function suggests that the kidney might be involved. The aim of this study was to determine the effect of UII on renal function in the spontaneously hypertensive rat (SHR). UII infusion (6 pmol·min−1·100 g body wt−1) in anesthetized SHR and control Wistar-Kyoto (WKY) rats produced marked reductions in glomerular filtration rate (ΔGFR WKY, n = 7, −0.3 ± 0.1 vs. SHR, n = 7, −0.6 ± 0.1 ml·min−1·100 g body wt−1, P = 0.03), urine flow, and sodium excretion rates, which were greater in SHR by comparison with WKY rats. WKY rats also showed an increase in fractional excretion of sodium (ΔFENa; +0.6 ± 0.1%, P = 0.02) in contrast to SHR in which no such change was observed (ΔFENa −0.6 ± 0.2%). Blockade of the UII receptor (UT), and thus endogenous UII activity, with urantide evoked an increase in GFR which was greater in SHR (+0.3 ± 0.1) compared with WKY rats (+0.1 ± 0.1 ml·min−1·100 g body wt−1, P = 0.04) and was accompanied by a diuresis and natriuresis. UII and UT mRNA expression were greater in the renal medulla than the cortex of both strains; however, expression levels were up to threefold higher in SHR tissue. SHR are more sensitive than WKY to UII, which acts primarily to lower GFR thus favoring salt retention in this model of hypertension.


PEDIATRICS ◽  
1978 ◽  
Vol 62 (4) ◽  
pp. 446-453
Author(s):  
Alistair G.S. Philip

Sixty-three term newborn infants with fetal growth retardation were evaluated within three days of birth. They were classified by length and head circumference. In group 1, both length and head circumference were less than the tenth percentile; in group 2, either length or head circumference was less than the tenth percentile; and in group 3, both length and head circumference were greater than the tenth percentile. Ponderal index (weight/length ratio), anterior fontanel size, and amount of epiphyseal ossification were also determined. Significantly lower birth weights and decreased ossification were found when groups 1 or 2 were compared separately with group 3. These differences were most marked when the weight/length ratio was less than 2.25. When the ponderal index was less than 2.0, epiphyseal ossification was usually absent (suggesting a chronic process). Epiphyseal ossification was positively correlated with birth weight and length but was unrelated to anterior fontanel size. Ossification was more often absent in males than in females. There was a negative (inverse) correlation between birth weight and anterior fontanel size. Follow-up of 32 of these infants at age 1 year showed marked individual variations, but there were significant differences in incremental linear growth between groups 1 and 3, a finding which supports results of animal studies showing that catch-up growth may be related to skeletal immaturity. Physical measurements at birth in the individual baby with fetal growth retardation do not reliably predict subsequent growth.


PEDIATRICS ◽  
1972 ◽  
Vol 50 (4) ◽  
pp. 547-558
Author(s):  
J. Urrusti ◽  
P. Yoshida ◽  
L. Velasco ◽  
S. Frenk ◽  
A. Rosado ◽  
...  

Intrauterine growth was assessed in a series of 128 cases. Thirty-six infants were small for gestational age, and showed the usual signs of intrauterine growth retardation (IUM). The head circumference of these infants was small, with reference to normal term babies (FT) and comparable to premature infants, appropriately sized for a gestational age (ACA) five weeks less than that of the IUM's. There were 12 neonatal deaths, three among IUM infants within 24 hours and nine in the low birth weight AGA group within 72 hours. The mothers of these three groups of infants were similar with respect to age, weight, height, nutritional patterns, and prior pregnancy histories.


1982 ◽  
Vol 52 (3) ◽  
pp. 695-699 ◽  
Author(s):  
L. G. Moore ◽  
S. S. Rounds ◽  
D. Jahnigen ◽  
R. F. Grover ◽  
J. T. Reeves

Infant birth weight is reported to decrease at high altitude as a reulst of fetal growth retardation (McCullough, Reeves, and Liljegren. Arch. Environ, Health. 32: 36--39, 1977) but not all babies born at high altitude are small. We hypothesized that maternal characteristics acting to lower arterial O2 content would contribute to smaller infant birth weight. To test this hypothesis, we measured arterial oxygenation serially during pregnancy and again postpartum in 44 residents of Leadville, CO (elevation 3,100 m). We identified three maternal characteristics--ventilation, hemoglobin concentration, and smoking habits--that were related to the birth weight of the offspring. Mothers of smaller babies (less than 2,900 g) compared to mothers of larger babies (greater than 3,500 g) were characterized by hypoventilation, no change or a decrease in ventilation and arterial O2 saturation from early to late gestation, and a falling hemoglobin concentration that combined to lower arterial O2 content in the 3rd trimester. Maternal smoking at 3,100 m was associated with a two to threefold greater reduction in infant birth weight (-546 g) than reported from sea level. Thus, maternal arterial oxygenation during pregnancy may be important for predicting fetal growth retardation and the process of adaptation to high altitude.


1994 ◽  
Vol 5 (4) ◽  
pp. 1125-1132
Author(s):  
A Debska-Slizien ◽  
P Ho ◽  
R Drangova ◽  
A D Baines

Dopamine's modulatory actions on signal transduction in the spontaneously hypertensive rat (SHR) proximal tubule are blunted; therefore, it was predicted that dopamine does not regulate phosphate (Pi) reabsorption in SHR. To test this hypothesis, dopamine production was inhibited with carbidopa (10 mg/kg ip) 18 h before and during clearance measurements of chronically denervated SHR and Wistar-Kyoto (WKY) rat kidneys. Dopamine excretion decreased 80% from SHR and 85% from WKY rats. Pi excretion decreased 60 to 67%. Plasma Pi and calcium, inulin clearance, and Na excretion did not change. Citrate excretion, which reflects proton secretion by proximal tubules, decreased 72% from WKY rats. Citrate excretion was significantly lower from SHR (5 +/- 10 pmol/min) than from WKY rats (73 +/- 11 pmol/min) and was not altered by carbidopa. Carbidopa, injected 18 and 1 h before kidneys were collected, increased NaK-ATPase in cortical basolateral membranes from WKY rats (27%) but not in membranes from SHR. After the incubation of renal cortical minceates for 15 min with L-DOPA (10(-5) M), there was no change in brush border membrane vesicle uptake of 32Pi, (3H)glucose, or (14C)citrate. Incubation with carbidopa (10(-4) M) increased 32Pi uptake by 11% (P < 0.001) and (3H)glucose uptake by 9% (P = 0.02). (14C)citrate uptake was not increased by carbidopa but was higher in SHR (977 +/- 2 pmol/10 s.mg) than in WKY rats (823 +/- 43 pmol/10 s.mg; P = 0.04). In summary, dopamine produced in WKY rat and SHR proximal tubules decreases Pi uptake by using a signaling process distinct from those that regulate NaK-ATPase and the antiporter.(ABSTRACT TRUNCATED AT 250 WORDS)


2018 ◽  
Vol 5 (2) ◽  
pp. 88-92
Author(s):  
Andrey V. Murashko ◽  
M. S Simonova ◽  
A. G Goryunova ◽  
D. K Chebanov ◽  
A. A Abramov ◽  
...  

MicroRNAs are small non-coding RNAs (20-24 nucleotides) that regulate gene expression through post-transcriptional repression or degradation of the template RNA. The role of microRNA during pregnancy is currently poorly understood. Some studies have identified a microRNA profile associated with pregnancy since it was present in the placenta and maternal blood throughout pregnancy. In this study, we compared individual expression levels of 10 microRNAs in the maternal peripheral blood samples and further estimated their association with adverse pregnancy outcomes including preeclampsia, gestational arterial hypertension, and fetal growth retardation syndrome. MicroRNAs can be used as a non-invasive biomarker to identify an adverse obstetric outcome and with the potent therapeutic target for the prevention or treatment of pathology of pregnancy. Further research with a large sample size in different populations is needed to confirm our results.


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