Fetal kidney programming by maternal smoking exposure: effects on kidney structure, blood pressure and urinary sodium excretion in adult offspring.

INTRODUCTION: Fetal programming by different insults results in low birth weight and reduction in nephron number increasing the risk for adult development of cardiovascular and renal diseases. Maternal smoking is an important modifiable adverse fetal exposure worldwide and leads to a decrease in the offspring's birth weight. Thus far, the specific adverse fetal smoking exposures and mechanisms underlying these associations on renal development and functional disorder are unclear. METHODS: The present study investigates, in adult male rats, the effect of smoking exposure (Sk) in uteri on blood pressure (BP) by an indirect tail-cuff method using an electrosphygmomanometer, and its association with nephron structure by stereological estimation, immunohistochemical and histological techniques, in parallel with kidney function creatinine and lithium clearance. RESULTS: The current study showed in a 16-week old Sk offspring enhanced arterial blood pressure associated with, reduced urinary sodium excretion and higher TGF-ß1 glomerular expression. Sk glomeruli also presented an upregulated collagen and fibronectin deposition intrinsically related to fibrotic process as compared to age-matched control group. CONCLUSION: Here, we demonstrate that fetal-programmed Sk offspring present pronounced glomerular TGF-ß1 and fibrotic marker expression that may, subsequently, promote a glomerular epithelial-mesenchymal transition activated process in an Sk offspring. Although the precise mechanism responsible for the subsequently renal morphological and functional response in Sk offspring is incompletely known, the current data suggest that changes in renal function are conducive to excess sodium tubule reabsorption that is associated with enhanced TGF-ß1, fibronectin and collagen deposition, intrinsically related to fibrotic process, might potentiate the programming of adult hypertension.