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Black MJ. Filtering the good from the bad: A focus on kidney development and disease to celebrate John Bertram's long‐standing career in anatomy and renal research. Anat Rec (Hoboken) 2020. [DOI: 10.1002/ar.24484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Mary Jane Black
- Department of Anatomy and Developmental Biology, Biomedicine Discovery InstituteMonash University Clayton Victoria Australia
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Lumbers ER, Kandasamy Y, Delforce SJ, Boyce AC, Gibson KJ, Pringle KG. Programming of Renal Development and Chronic Disease in Adult Life. Front Physiol 2020; 11:757. [PMID: 32765290 PMCID: PMC7378775 DOI: 10.3389/fphys.2020.00757] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/11/2020] [Indexed: 12/18/2022] Open
Abstract
Chronic kidney disease (CKD) can have an insidious onset because there is a gradual decline in nephron number throughout life. There may be no overt symptoms of renal dysfunction until about two thirds or more of the nephrons have been destroyed and glomerular filtration rate (GFR) falls to below 25% of normal (often in mid-late life) (Martinez-Maldonaldo et al., 1992). Once End Stage Renal Disease (ESRD) has been reached, survival depends on renal replacement therapy (RRT). CKD causes hypertension and cardiovascular disease; and hypertension causes CKD. Albuminuria is also a risk factor for cardiovascular disease. The age of onset of CKD is partly determined during fetal life. This review describes the mechanisms underlying the development of CKD in adult life that results from abnormal renal development caused by an adverse intrauterine environment. The basis of this form of CKD is thought to be mainly due to a reduction in the number of nephrons formed in utero which impacts on the age dependent decline in glomerular function. Factors that affect the risk of reduced nephron formation during intrauterine life are discussed and include maternal nutrition (malnutrition and obesity, micronutrients), smoking and alcohol, use of drugs that block the maternal renin-angiotensin system, glucocorticoid excess and maternal renal dysfunction and prematurity. Since CKD, hypertension and cardiovascular disease add to the disease burden in the community we recommend that kidney size at birth should be recorded using ultrasound and those individuals who are born premature or who have small kidneys at this time should be monitored regularly by determining GFR and albumin:creatinine clearance ratio. Furthermore, public health measures aimed at limiting the prevalence of obesity and diabetes mellitus as well as providing advice on limiting the amount of protein ingested during a single meal, because they are all associated with increased glomerular hyperfiltration and subsequent glomerulosclerosis would be beneficial.
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Affiliation(s)
- Eugenie R Lumbers
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Yoga Kandasamy
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Newcastle, NSW, Australia.,Department of Neonatology, Townsville University Hospital, Douglas, QLD, Australia
| | - Sarah J Delforce
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Amanda C Boyce
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Karen J Gibson
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Kirsty G Pringle
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Newcastle, NSW, Australia
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Briffa JF, Wlodek ME, Moritz KM. Transgenerational programming of nephron deficits and hypertension. Semin Cell Dev Biol 2018; 103:94-103. [PMID: 29859996 DOI: 10.1016/j.semcdb.2018.05.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 01/16/2023]
Abstract
Exposure to a sub-optimal environment in the womb can result in poor fetal growth and impair the normal development of organs. The kidney, specifically the process of nephrogenesis, has been shown to be impacted by many common pregnancy exposures including an inadequate diet, poor placental function, maternal stress as well as maternal smoking and alcohol consumption. This can result in offspring being born with a reduced nephron endowment, which places these individuals at increased risk of hypertension and chronic kidney disease (CKD). Of recent interest is whether this disease risk can be passed on to subsequent generations and, if so, what are the mechanisms and pathways involved. In this review, we highlight the growing body of evidence that a low birth weight and hypertension, which are both major risk factors for cardiovascular and CKD, can be transmitted across generations. However, as yet there is little data as to whether a low nephron endowment contributes to this disease transmission. The emerging data suggests transmission can occur both through both the maternal and paternal lines, which likely involves epigenetic mechanisms such chromatin remodelling (DNA methylation and histone modification) and non-coding RNA modifications. In addition, females who were born small and/or have a low nephron endowment are at an increased risk for pregnancy complications, which can influence the growth and development of the next generation. Future animal studies in this area should include examining nephron endowment across multiple generations and determining adult renal function. Clinically, long term follow-up studies of large birth cohorts need to be undertaken to more clearly determine the impact a sub-optimal environment in one generation has on the health outcomes in the second, and subsequent, generation.
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Affiliation(s)
- Jessica F Briffa
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Mary E Wlodek
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Karen M Moritz
- Child Health Research Centre and School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD, Australia.
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Kandasamy Y, Rudd D, Smith R, Lumbers ER, Wright IMR. Extra uterine development of preterm kidneys. Pediatr Nephrol 2018; 33:1007-1012. [PMID: 29500630 PMCID: PMC5943378 DOI: 10.1007/s00467-018-3899-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 01/19/2018] [Accepted: 01/19/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We carried out a study to determine the impact of prematurity on renal development. The primary outcomes measured were nephrinuria and albuminuria; renal volume and glomerular filtration rate were the secondary outcomes. METHODS Preterm neonates born at less than 28 weeks of gestation, with birth weight between 10th and 90th centile (appropriate for gestational age), were recruited and underwent assessments at 28, 32 and 37 weeks postmenstrual age (PMA). RESULTS Fifty-three premature neonates and 31 term neonates (control) were recruited. The median gestational age of the premature neonates was 26.4 [24.7-27.4] weeks, with a mean birth weight of 886 (179) g. The mean gestational age of term neonates was 39.1 (1.2) weeks and the mean birth weight was 3406 (406) g. The median age of the term neonates was 6.5 [3.0-12.5] days. The total kidney volume (TKV) almost doubled from 10.3 (2.9) cm3 at 28 weeks PMA to 19.2 (3.7) cm3 at 37 weeks PMA (P = 0.0001). TKV at 37 weeks PMA was significantly smaller compared to term neonates (19.2 (3.7) vs 26.3 (7.0) cm3; P = 0.0001). However, there was no significant difference in estimated glomerular filtration rate (eGFR) between premature neonates (at 37 weeks PMA) and term neonates (control) (43.5 [39.7-48.9] vs. 42.0 [38.2-50.0] mL/min/1.73 m2; P = 0.75). There was a statistically significant decline in nephrin-creatinine ratio and albumin-creatinine ratio from 32 to 37 weeks PMA. CONCLUSIONS Despite having a smaller renal volume (and fewer nephrons), extremely premature neonates achieve similar eGFRs at corrected term as term-born neonates, likely through single nephron hyperfiltration. Extremely premature neonates also show evidence of glomerular injury.
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Affiliation(s)
- Yogavijayan Kandasamy
- Department of Neonatology, The Townsville Hospital, 100 Angus Smith Drive, Douglas, QLD, 4814, Australia. .,Mothers and Babies Research Centre, Hunter Medical Research Institute, The University of Newcastle, Callaghan, NSW, 2308, Australia. .,College of Public Health, Medical and Veterinary Sciences, The James Cook University, Douglas, QLD, 4814, Australia.
| | - Donna Rudd
- 0000 0004 0474 1797grid.1011.1College of Public Health, Medical and Veterinary Sciences, The James Cook University, Douglas, QLD 4814 Australia
| | - Roger Smith
- 0000 0000 8831 109Xgrid.266842.cMothers and Babies Research Centre, Hunter Medical Research Institute, The University of Newcastle, Callaghan, NSW 2308 Australia
| | - Eugenie R Lumbers
- 0000 0000 8831 109Xgrid.266842.cMothers and Babies Research Centre, Hunter Medical Research Institute, The University of Newcastle, Callaghan, NSW 2308 Australia ,0000 0000 8831 109Xgrid.266842.cSchool of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308 Australia
| | - Ian MR Wright
- 0000 0000 8831 109Xgrid.266842.cMothers and Babies Research Centre, Hunter Medical Research Institute, The University of Newcastle, Callaghan, NSW 2308 Australia ,0000 0004 0486 528Xgrid.1007.6Illawarra Health and Medical Research Institute and Graduate Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
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5
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Turner AJ, Brown RD, Brandon AE, Persson AEG, Gibson KJ. Tubuloglomerular feedback responses in offspring of dexamethasone-treated ewes. Am J Physiol Renal Physiol 2017; 313:F864-F873. [PMID: 28679594 DOI: 10.1152/ajprenal.00538.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 06/21/2017] [Accepted: 06/29/2017] [Indexed: 11/22/2022] Open
Abstract
Via developmental programming, prenatal perturbations, such as exposure to glucocorticoids and maternal malnutrition alter kidney development and contribute to the development of hypertension. To examine the possibility that alterations in tubuloglomerular feedback (TGF) contribute to the development of hypertension in offspring following maternal dexamethasone treatment (Dex) in early gestation, studies were conducted in fetal sheep and lambs. Pregnant ewes were infused with dexamethasone (0.48 mg/h) at 26-28 days gestation. No differences were observed in mean arterial pressure, glomerular filtration rate. or electrolyte excretion rates between the Dex and Untreated fetuses or lambs. Gestational exposure to Dex markedly enhanced TGF sensitivity, as the turning point in Dex-treated fetuses was significantly lower (12.9 ± 0.9 nl/min; P < 0.05) compared with Untreated fetuses (17.0 ± 1.0 nl/min). This resetting of TGF sensitivity persisted after birth (P < 0.01). TGF reactivity did not differ between the groups in fetuses or lambs. In response to nitric oxide inhibition, TGF sensitivity increased (the turning point decreased) and reactivity increased in Untreated fetuses and lambs, but these effects were blunted in the Dex-treated fetuses and lambs. Our data suggest that an altered TGF response may be an underlying renal mechanism contributing to the development of hypertension in the Dex model of fetal programming. The lower tonic level of NO production in these dexamethasone-exposed offspring may contribute to the development of hypertension as adults.
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Affiliation(s)
- Anita J Turner
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia; .,Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia; and
| | - Russell D Brown
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia; and.,Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Amanda E Brandon
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia; and
| | - A Erik G Persson
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia; and.,Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Karen J Gibson
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia; and
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Turner AJ, Brown RD, Boyce A, Gibson KJ, Persson AEG. Fetal tubuloglomerular feedback in an ovine model of mild maternal renal disease. Physiol Rep 2015; 3:3/7/e12448. [PMID: 26169542 PMCID: PMC4552528 DOI: 10.14814/phy2.12448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Fetuses of pregnant ewes, which were subtotally nephrectomized prior to mating, were studied to assess whether mild maternal renal impairment would affect fetal tubuloglomerular feedback (TGF) under control conditions and after the inhibition of macula densa-derived nitric oxide (NO). Based on previous observations we hypothesized that, the TGF curve of fetuses of subtotally nephrectomized (STNx) ewes would resemble that of a volume expanded fetus with a high production rate of NO and that inhibition of neuronal nitric oxide synthase (nNOS) would increase the sensitivity of the TGF system in these fetuses. Renal function studies were performed on anaesthetized fetal sheep (133–140 days gestation; term ∼150 days; Isoflurane 2–4% in oxygen). Fetuses were removed from the uterus and placed in a water bath (39.5°C) while maintaining umbilical blood flow. Glomerular filtration rate (GFR) and urine flow rate were markedly increased in fetuses of STNx ewes compared to fetuses of untreated ewes. Interestingly, and contrary to our hypothesis, the fetuses of STNx ewes exhibited no difference in TGF sensitivity in the presence or absence of 7-nitroindazole (7NI; nNOS inhibitor), compared to fetuses of untreated ewes, although sensitivity and reactivity increased in both groups after 7NI. There was however, a decrease in the stop flow pressure and net filtration pressure with an increase in the filtration coefficient (Kf). These factors suggest that maternal renal impairment drives the glomerular hypertrophy which has previously been found to be present in the neonatal period. Thus, we conclude that at ∼138 days gestation, the fetal kidney has matured functionally and fetuses of STNx ewes are able to maintain fluid and electrolyte homeostasis even in the presence of increased transplacental flux.
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Affiliation(s)
- Anita J Turner
- Australian School of Advanced Medicine Macquarie University, Sydney, New South Wales, Australia Department of Physiology, School of Medical Sciences University of New South Wales, Sydney, New South Wales, Australia
| | - Russell D Brown
- Department of Physiology, School of Medical Sciences University of New South Wales, Sydney, New South Wales, Australia Department of Medical Cell Biology, Division of Integrative Physiology, University of Uppsala, Uppsala, Sweden
| | - Amanda Boyce
- Department of Physiology, School of Medical Sciences University of New South Wales, Sydney, New South Wales, Australia
| | - Karen J Gibson
- Department of Physiology, School of Medical Sciences University of New South Wales, Sydney, New South Wales, Australia
| | - A Erik G Persson
- Department of Physiology, School of Medical Sciences University of New South Wales, Sydney, New South Wales, Australia Department of Medical Cell Biology, Division of Integrative Physiology, University of Uppsala, Uppsala, Sweden
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Lumbers ER, Pringle KG, Wang Y, Gibson KJ. The renin-angiotensin system from conception to old age: the good, the bad and the ugly. Clin Exp Pharmacol Physiol 2013; 40:743-52. [DOI: 10.1111/1440-1681.12098] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 04/08/2013] [Accepted: 04/12/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Eugenie R Lumbers
- School of Biomedical Sciences and Pharmacy; Hunter Medical Research Institute; University of Newcastle and Mothers and Babies Research Centre; Newcastle NSW Australia
| | - Kirsty G Pringle
- School of Biomedical Sciences and Pharmacy; Hunter Medical Research Institute; University of Newcastle and Mothers and Babies Research Centre; Newcastle NSW Australia
| | - Yu Wang
- School of Biomedical Sciences and Pharmacy; Hunter Medical Research Institute; University of Newcastle and Mothers and Babies Research Centre; Newcastle NSW Australia
| | - Karen J Gibson
- School of Medical Sciences; University of New South Wales; Sydney NSW Australia
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Brandon AE, Boyce AC, Lumbers ER, Kumarasamy V, Gibson KJ. Programming of the renin response to haemorrhage by mild maternal renal impairment in sheep. Clin Exp Pharmacol Physiol 2011; 38:102-8. [PMID: 21182536 DOI: 10.1111/j.1440-1681.2010.05473.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The aim of the present study was to test the hypothesis that the renin response to mechanisms activated by haemorrhage is programmed by exposure to maternal renal dysfunction. 2. In 26-27-day-old lambs born to ewes that had reduced renal function (STNxL, n=10) and lambs born to ewes with normal renal function (ConL, n=6), 1.6 mL/kg per min of blood was removed over 10 min. 3. Under basal conditions, the STNxL group had increased mean arterial pressure (P < 0.05). In response to haemorrhage, mean arterial pressure decreased in the STNxL group (P < 0.001), but there was no significant change in the ConL group. 4. Although plasma renin level increased in both groups (P < 0.05), the peak response was reduced and delayed in the STNxL group. In contrast, the rise in arginine vasopressin (AVP) level was similar in both groups and occurred over the same time course. At 24 h, both plasma renin and AVP level were the same as those measured before haemorrhage in both groups. Kidney renin level was similar in the two groups. 5. The attenuated renin response to haemorrhage in the STNxL group might explain the inability to maintain arterial pressure after haemorrhage. The results of the present study suggest that the renin response of the postnatal kidney to reductions in blood volume can be affected by the intrauterine environment. If these changes persist into adulthood, it suggests that permanent programming has occurred. Thus, the ability of an individual to respond to acute severe reductions in blood volume might be determined during intrauterine life.
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Affiliation(s)
- Amanda E Brandon
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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Tang L, Bi J, Valego N, Carey L, Figueroa J, Chappell M, Rose JC. Prenatal betamethasone exposure alters renal function in immature sheep: sex differences in effects. Am J Physiol Regul Integr Comp Physiol 2010; 299:R793-803. [PMID: 20554936 DOI: 10.1152/ajpregu.00590.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Synthetic glucocorticoids are commonly given to pregnant women when premature delivery threatens. Antenatal administration of clinically relevant doses of betamethasone to pregnant sheep causes sex-specific compromises of renal function and increases in blood pressure in adult offspring. However, it is unclear whether such effects are present in immature lambs. Therefore, the aims of the present study were to determine whether antenatal betamethasone at 80-81 days of gestation increases blood pressure and adversely impacts renal function in adolescent ewes and rams. Prenatal steroid exposure increased blood pressure significantly in the young male (84 +/- 2 vs. 74 +/- 3 mmHg) and female sheep (88 +/- 5 vs. 79 +/- 4), but it did not alter basal glomerular filtration rate, renal blood flow (RBF), or sodium excretion in either sex. However, antenatal betamethasone exposure blocked increases in RBF (P = 0.001), and enhanced excretion of an acute Na load (P < 0.05) in response to systemic infusions of angiotensin (ANG)-(1-7) at 10 pmol.kg(-1).min(-1) in males. In females, the natriuretic response to combined ANG-(1-7), and Na load was significantly altered by prenatal betamethasone exposure. These findings indicate that blood pressure is increased in immature animals in response to antenatal steroid exposure and that sex-specific effects on renal function also exist. These changes may reflect greater risk for further loss of renal function with age.
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Affiliation(s)
- Lijun Tang
- Department of Obstetrics and Gynecology and Center of Research for Obstetrics and Gynecology, Wake Forest Univ. School of Medicine, Winston-Salem, NC 27157, USA.
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Zhang J, Massmann GA, Rose JC, Figueroa JP. Differential effects of clinical doses of antenatal betamethasone on nephron endowment and glomerular filtration rate in adult sheep. Reprod Sci 2009; 17:186-95. [PMID: 19897787 DOI: 10.1177/1933719109351098] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Antenatal steroid administration is associated with alterations in fetal kidney development and hypertension. However, a causal relationship between nephron deficit and hypertension has not been established. In this study, we measured nephron number, renal function, and blood pressure in sheep exposed antenataly to betamethasone. Pregnant sheep were given 2 betamethasone doses (0.17 mg/kg) or vehicle at 80 and 81 days gestational age and allowed to deliver at term. Data were obtained from a fetal cohort and 2 adult cohorts and were analyzed by analysis of variance (ANOVA) and/or 2 sample t test. Antenatal betamethasone induced a 26% reduction in the number of nephrons in both males and females in the absence of intrauterine growth restriction and/or prematurity. Adult males presented a reduction in glomerular filtration rate (GFR; 132 +/- 12.7 vs 114 +/- 7.0 mL/min, P < .05). Betamethasone administration was also associated with an increase in arterial blood pressure of similar magnitude in male (mean arterial pressure [MAP] in mm Hg; 98 +/- 2.7 vs 105 +/- 2.4) and female (96 +/- 1.9 vs 105 +/- 2.4) adult sheep and the increase in blood pressure preceded the decrease in GFR in the males. Furthermore, we found no significant association between the magnitude of the decrease in nephron number and the magnitude of the increase in arterial blood pressure. Our data thus support the conclusion that exposure to glucocorticoids at a time of rapid kidney growth is associated with an elevation in blood pressure that does not appear related solely to the reduction in nephron number.
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Affiliation(s)
- Jie Zhang
- Perinatal Research Laboratory, Department of Obstetrics and Gynecology, Center for Research in Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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Tang L, Carey LC, Bi J, Valego N, Sun X, Deibel P, Perrott J, Figueroa JP, Chappell MC, Rose JC. Gender differences in the effects of antenatal betamethasone exposure on renal function in adult sheep. Am J Physiol Regul Integr Comp Physiol 2009; 296:R309-17. [PMID: 19036827 PMCID: PMC2643986 DOI: 10.1152/ajpregu.90645.2008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Accepted: 11/20/2008] [Indexed: 11/22/2022]
Abstract
Exposure to clinically relevant doses of glucocorticoids during fetal life increases blood pressure in adult male and female sheep. The purpose of this study was to evaluate the effects of prenatal exposure to betamethasone at 80-81 days of gestation on renal function in ewes and rams at 1.5 yr of age. In prenatal betamethasone-exposed males, compared with the vehicle-exposed animals, basal glomerular filtration rate (GFR) (1.93 +/- 0.08 vs. 2.27 +/- 0.10 ml.min(-1).kg body wt(-1)) and the ability to excrete an acute Na+ load (37.1 +/- 4.4 vs. 53.7 +/- 9.7%) were reduced. (P < 0.03 and P = 0.03, respectively). In contrast, prenatal betamethasone exposure had no effect on basal GFR, Na+ excretion, or the percentage of the Na+ load excreted during the experiment in females. Systemic infusions of ANG-(1-7) at 9 ng.min(-1).kg(-1) for 2 h had minimal effects on basal GFR, renal plasma flow, and Na+ excretion in males but increased Na+ excretion in females. However, the percentage of Na+ load excreted during ANG-(1-7) infusion did not change in prenatal betamethasone-exposed females (113.1 +/- 14.2 vs. 98.1 +/- 12.2%) compared with the significant increase in vehicle females (139.2 +/- 22.3 vs. 92.2 +/- 7.5%) (P = 0.01). The data indicate that antenatal betamethasone exposure produces gender-specific alternations in renal function and thus suggest that different mechanisms underlie the antenatal steroid-induced elevations in blood pressure in male and female offspring.
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Affiliation(s)
- Lijun Tang
- Department of Obstetrics and Gynecology and Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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12
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Brandon AE, Boyce AC, Lumbers ER, Gibson KJ. Maternal renal dysfunction in sheep is associated with salt insensitivity in female offspring. J Physiol 2008; 587:261-70. [PMID: 19001051 DOI: 10.1113/jphysiol.2008.158808] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
To examine the programming effects of maternal renal dysfunction (created by subtotal nephrectomy in ewes prior to mating; STNx), renal and cardiovascular function were studied in 6-month-old male and female offspring of STNx and control pregnancies. After studies were conducted on a low salt diet (LSD) some female offspring underwent salt loading (0.17 M NaCl in the drinking water for 5-7 days; HSD). On LSD both male and female offspring of STNx had similar mean arterial pressures (MAP), heart rates, cardiac outputs and renal function to those measured in offspring of control ewes. In female STNx offspring on a HSD, plasma sodium levels increased and haematocrits fell, indicating volume expansion (P < 0.05). Plasma renin levels were not suppressed despite the increases in plasma sodium concentrations, but aldosterone levels were reduced. In control animals plasma renin levels fell (P < 0.05) but there was no change in plasma aldosterone concentrations. There was a positive relationship between GFR and MAP which was present only in female STNx offspring. In conclusion, in STNx offspring there was an impaired ability to regulate glomerular filtration independent of arterial pressure, renin release was insensitive to a high salt intake and control of aldosterone secretion was abnormal. This study provides evidence of abnormal programming of the renin-angiotensin system and glomerular function in offspring of pregnancies in which there is impaired maternal renal function.
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Affiliation(s)
- A E Brandon
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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