Introduction: Iron deficiency (ID) is the most common nutritional deficiency worldwide, with pregnant women most at risk. ID during gestation can alter developmental trajectories making offspring more susceptible to adult disease. We have shown that adult offspring exposed to perinatal ID exhibit altered renal structure and function. Here, we sought to assess how perinatal ID impairs kidney development through cellular senescence, autophagy, and apoptosis.
Methods: Six-week-old Sprague Dawley dams were fed an iron-restricted (3-10 mg/kg) or iron-replete (37 mg/kg) diet two weeks prior to and throughout gestation. Following birth, offspring were maintained on an iron-replete diet. Offspring were euthanized on postnatal days (PD)1 and PD28, and tissues were cryopreserved for biochemical analyses. Apoptosis was assessed by TUNEL and Caspase 3 & 9 activity assays; cellular senescence was assessed via senescence-associated β-galactosidase (SA-βGal) activity; autophagy was assessed by western blot for conjugated and unconjugated forms of microtubule-associated protein 1 light chain 3B (LC3-I and LC3-II).
Results: ID resulted in anemia and decreased birth weight on PD1 (P<0.05). By PD28, perinatal ID offspring remained growth restricted (P<0.05) despite Hb values reaching values comparable to controls. On PD1, TUNEL staining and caspase 3, but not caspase 9 activity was increased in male (P=0.01), but not female perinatal ID offspring. The ratio of LC3-II to LC3-I was increased in male (P=0.01), but not female perinatal ID offspring on PD1. Perinatal ID offspring, irrespective of sex, exhibited reduced SA-βGal activity on PD1 (P<0.01), however on PD28 perinatal ID offspring exhibited increased activity (P<0.01). On PD28, no differences were observed in apoptosis or autophagy measurements.
Conclusion: Perinatal ID causes alterations in cellular health and survival in the developing kidney, particularly in males, despite iron repletion by PD28. These mechanisms may be implicated in the long-term programming of renal function.
Andrew Woodman– MD-PhD Candidate, University of Alberta
Ronan Noble– Graduate Student, University of Alberta
Ferrante Gragasin– Clinical Professor, University of Alberta
Stephane Bourque– Assistant Professor, University of Alberta