Parental recovered acute kidney injury causes prenatal renal dysfunction and fetal growth restriction with sexually dimorphic implications for adult offspring

Abstract

Introduction: Acute kidney injury (AKI) is rapidly increasing in global incidence and a healthcare burden. Prior maternal AKI diagnosis correlates with later pregnancy complications. As pregnancy influences developmental programming, we hypothesized that recovered parental AKI results in poor pregnancy outcomes, impaired fetal growth, and adult offspring disease. Methods: Using a well-characterized model of rhabdomyolysis-induced acute kidney injury (RIAKI), a form of AKI commonly observed in young people, we confirmed functional renal recovery by assessing glomerular filtration rate (GFR) 2 weeks following RIAKI. We bred sham and recovered RIAKI sires and dams in timed, matched matings for gestational day (GD) 16.5 and offspring (birth-12 weeks, 6 months) study. Results: Despite a normal GFR pre-pregnancy, recovered RIAKI dams at GD16.5 had impaired renal function, resulting in reduced fetoplacental ratios and offspring survival. Pregnant RIAKI dams also had albuminuria and less renal megalin in the proximal tubule brush border than shams, with renal subcapsular fibrosis and higher diastolic blood pressure. Growth-restricted offspring had a reduced GFR as older adults, with evidence of metabolic inefficiency in male offspring; this correlated with reduced renal AngII levels in female offspring from recovered RIAKI pairings. However, the blood pressures of 6-month-old offspring were unaffected by parental RIAKI. Conclusions: Our mouse model demonstrated a causal relationship among RIAKI, gestational risk, and developmental programming of the adult-onset offspring GFR and metabolic dysregulation despite parental recovery.

Keywords: acute kidney injury; developmental programming; pregnancy; renal function; rhabdomyolysis.

FIGURE 1

The glycerol injection model of rhabdomyolysis-induced acute kidney injury (RIAKI) caused transient renal functional impairment, which was reversed by 2 weeks. (A) Glomerular filtration rate (GFR; uL/min/100 g body weight [BW]) of the control versus RIAKI male (left) and female (right) mice. The GFR is significantly reduced after rhabdomyolysis but recovers 2 weeks post-injury. (B) High levels of blood urea nitrogen (BUN) and (C) urinary albumin were observed following RIAKI. BUN and urinary albumin levels returned to baseline by 2 weeks. (D) The urinary retinol-binding protein 4 (RBP4) level, a marker of proximal tubule dysfunction, was increased significantly 24 h following RIAKI. One-way ANOVA with post hoc tests for multiple-group analyses and the t-test for two-group analyses were conducted. *: p < 0.05. **: p < 0.01.

FIGURE 2

Recovered parental RIAKI causes fetal growth restriction but does not affect fertility. RIAKI did not affect fertility, as measured by (A) the number of days from pair introduction to birth and (B) litter sites. (C) More pups from RIAKI pairings died in the perinatal period than pups from sham pairings. Neither (D) fetal nor (E) placental weight was significantly different, but (F) placental sufficiency (fetal weight/placental weight) decreased in pups from RIAKI pairings. (G) Pups from RIAKI pairs were born smaller and remained smaller in the first week than pups from shams. By 2 weeks, the weights of the pups were not different between groups. (H) Fetal sex was not a factor in differences. Litters: n = 4. (D–F) Presented as the average per litter. (A–G) T-test for two-group analyses. (H) One-way ANOVA with post hoc tests. *: p < 0.05. **: p < 0.01.

FIGURE 3

Exposure to recovered RIAKI results in intrapregnancy renal functional and histological derangement at gestational day (GD) 16.5. (A) The GFR was selectively induced in recovered RIAKI-exposed dams, accompanied by (B) new subcapsular fibrosis (see insets). (C) RIAKI dams also exhibited low-molecular weight proteinuria in urine gels. The marked band was suspected to be albumin; we confirmed that the total urinary excretion of albumin over 24 h was elevated (D). Urine excretion amounts were not different between groups over 24 h (E). Assessment of (F) tubular megalin confirms that recovered RIAKI was correlated with the reduction in tubular megalin levels. (G) The ratio of urine to tissue ACE2 activity is reduced, confirming a change in renal renin–angiotensin system (RAS) components. No change was observed in (H) systolic blood pressure during late-term pregnancy, but (I) diastolic blood pressure was higher in recovered RIAKI dams. T-test for two groups. *: p < 0.05. **: p < 0.01.

FIGURE 4

Adult offspring of recovered RIAKI parents develop renal dysfunction with age. (A) The GFR of 12-week-old offspring was not significantly different, nor was (B) sex a factor. (C) By 6 months old, the GFR was reduced in all RIAKI offspring, (D) regardless of sex. (E) Between young (12 weeks) and middle (6 months) adulthood, males from RIAKI pairings gained significantly more weight than sham males, (F) with significantly steeper weight gain slopes (male slopes p = 0.005). T-test for two groups and one-way ANOVA with post hoc tests for multiple comparisons. *: p < 0.05. **: p < 0.01.

FIGURE 5

RAS but not blood pressure is affected in adult offspring of sham and RIAKI parents. (A) In 12-week-old offspring, AngII kidney tissue content varied by breeding pairing and (B) offspring sex. Females from sham pairings had higher AngII levels than males; female offspring of RIAKI had lower AngII levels than sham females. However, (C) systolic and (D) diastolic blood pressures of 6-month-old offspring were not significantly different. T-test for two groups and one-way ANOVA with post hoc tests. *: p < 0.05.