The kidney structure was assessed at postnatal weeks 1 and 12, and the expression of proteins known to be involved in kidney development were examined at birth and 1 week of age. Blood pressure was measured by telemetry in male offspring between the ages of two and nine months.
The researchers found that the number of glomeruli (the main structural unit of the kidney) during weeks 1-12 were significantly lower, and the measured blood pressure for males after the fifth month was higher in offspring of mothers on high- or low- compared with intermediate-sodium diet. High salt diet was paralleled by higher concentrations of marinobufagenin in the amniotic fluid and an increase in the expression of both GDNF and its inhibitor, sprouty-1 in the offspring's kidney. The expression of FGF-10, a genetic signal responsible for kidney development, was lower in offspring of mothers on low-sodium diet and the expression of Pax-2 and FGF-2, tissue-specific genes that determine cell lineages, tissue patterning, and cellular proliferation was lower in offspring of mothers on high-sodium diet.
Importance of the Findings
Taken together the above findings indicate that both too low and too high maternal salt intakes retard development of new glomeruli, resulting in a nephron deficit. If the findings in the animals in this study can be extrapolated to humans, both too low and too high salt intake during pregnancy would be a risk factor for hypertension and renal damage in the offspring.
In women, each mother-to-be has specific health issues and conditions that require guidance from a health provider. This study sheds light on the issue of salt intake during pregnancy
|Contact: Donna Krupa|
American Physiological Society