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He J, Zhou X. Association between 24-h urine sodium and proteinuria among hospitalized patients with type 2 diabetes. J Diabetes Complications 2020; 34:107498. [PMID: 31813771 DOI: 10.1016/j.jdiacomp.2019.107498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 02/08/2023]
Abstract
AIMS This study used estimated sodium intake from 24-h urine sodium (24hUNa) to explore the relationship of sodium intake with proteinuria among hospitalized patients with type 2 diabetes and with renal tubular injury markers [retinol-binding protein (RBP), beta 2-microglobulin (β2-MG), N-acetyl-beta-D-glucosaminidase (NAG)]. METHODS Hospitalized patients with type 2 diabetes (N = 269) were divided into two groups according to the median (0.08 g/day) 24-h urinary protein (24hUpro) level. Logistic regression was used to analyze the association between 24hUNa and 24hUpro ≥ 0.08 g/L; scatter plots were used to analyze the association of RBP, β2-MG, and NAG with 24hUNa. RESULTS Overall, 269 patients with type 2 diabetes mellitus were enrolled (average age, 56 ± 12 years; men, 61.3%). Multivariate logistic regression analysis revealed a positive correlation between 24hUNa and 24hUpro ≥ 0.08 g/L; every 10 mmol of 24hUNa had an increased risk of 24hUpro elevation [odds ratio (OR) (95% confidence interval [CI]: 1.06 (1.01-1.11)]. Compared with the lowest quartile of 24hUNa, the highest quartile had an increased risk of 24hUpro elevation [OR (95% CI): 2.76 (1.25-6.05)]; 24hUNa did not correlate with RBP, β2-MG, or NAG. CONCLUSIONS In hospitalized patients with type 2 diabetes, 24hUNa was independently related to 24hUpro ≥ 0.08 g/day. However, no correlation of 24hUNa with RBP, β2-MG, or NAG was found.
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Affiliation(s)
- Jinhua He
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing 100044, China; Shijiazhuang Second Hospital, Hebei, Shijiazhuang 050000, China
| | - Xianghai Zhou
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Beijing 100044, China.
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2
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Afolabi OA, Alagbonsi AI, Oyinloye RT, Salahdeen HM, Salman TM, Olatunji LA. High-fat diet reduces weight gain but increases other cardio-metabolic indices in offspring of normotensive and hypertensive rats. Arch Physiol Biochem 2018; 124:218-225. [PMID: 28952789 DOI: 10.1080/13813455.2017.1383441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study investigated the effect of post-natal consumption of high-fat diet (HFD) on cardio-metabolic indices in male offspring of hypertensive female rats. There were neither significant differences in body weight gain either in pups from normotensive or hypertensive dams that received normal diet during the post-weaning periods (except at 7th and 9th weeks), nor in both pup groups that received HFD. However, both pup groups that received HFD had reduced body weight gain when compared to their counterparts that received normal diet. Post-weaning administration of HFD to pups of hypertensive and normotensive dams significantly increased their blood glucose, pressure and lipid profiles when compared to those weaned to normal diet. It was concluded that male offspring consumption of HFD diet elicits cardio-metabolic disturbance that slightly depended of maternal cardiovascular status but majorly depended on post-weaning weight gain, while that elicited by maternal hypertension is not related to post-weaning weight gain.
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Affiliation(s)
- Oladele Ayobami Afolabi
- a Department of Physiology, College of Health Sciences , Ladoke Akintola University of Technology , Ogbosomo , Oyo , Nigeria
| | - Abdullateef Isiaka Alagbonsi
- b Department of Physiology, Faculty of Medicine and Health Sciences , University of Gitwe , Gitwe , Republic of Rwanda
| | - Roseline Toyosi Oyinloye
- a Department of Physiology, College of Health Sciences , Ladoke Akintola University of Technology , Ogbosomo , Oyo , Nigeria
| | | | - Toyin Mohammed Salman
- d Department of Physiology, College of Health Sciences , University of Ilorin , Ilorin , Kwara , Nigeria
| | - Lawrence Aderemi Olatunji
- d Department of Physiology, College of Health Sciences , University of Ilorin , Ilorin , Kwara , Nigeria
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3
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Abstract
Chronic kidney disease affects more than 10% of the population. Programming studies have examined the interrelationship between environmental factors in early life and differences in morbidity and mortality between individuals. A number of important principles has been identified, namely permanent structural modifications of organs and cells, long-lasting adjustments of endocrine regulatory circuits, as well as altered gene transcription. Risk factors include intrauterine deficiencies by disturbed placental function or maternal malnutrition, prematurity, intrauterine and postnatal stress, intrauterine and postnatal overnutrition, as well as dietary dysbalances in postnatal life. This mini-review discusses critical developmental periods and long-term sequelae of renal programming in humans and presents studies examining the underlying mechanisms as well as interventional approaches to "re-program" renal susceptibility toward disease. Clinical manifestations of programmed kidney disease include arterial hypertension, proteinuria, aggravation of inflammatory glomerular disease, and loss of kidney function. Nephron number, regulation of the renin-angiotensin-aldosterone system, renal sodium transport, vasomotor and endothelial function, myogenic response, and tubuloglomerular feedback have been identified as being vulnerable to environmental factors. Oxidative stress levels, metabolic pathways, including insulin, leptin, steroids, and arachidonic acid, DNA methylation, and histone configuration may be significantly altered by adverse environmental conditions. Studies on re-programming interventions focused on dietary or anti-oxidative approaches so far. Further studies that broaden our understanding of renal programming mechanisms are needed to ultimately develop preventive strategies. Targeted re-programming interventions in animal models focusing on known mechanisms will contribute to new concepts which finally will have to be translated to human application. Early nutritional concepts with specific modifications in macro- or micronutrients are among the most promising approaches to improve future renal health.
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Affiliation(s)
- Eva Nüsken
- Pediatric Nephrology, Department of Pediatrics, Medical Faculty, University of Cologne, Cologne, Germany
| | - Jörg Dötsch
- Pediatric Nephrology, Department of Pediatrics, Medical Faculty, University of Cologne, Cologne, Germany
| | - Lutz T Weber
- Pediatric Nephrology, Department of Pediatrics, Medical Faculty, University of Cologne, Cologne, Germany
| | - Kai-Dietrich Nüsken
- Pediatric Nephrology, Department of Pediatrics, Medical Faculty, University of Cologne, Cologne, Germany
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4
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Brophy P. Maternal determinants of renal mass and function in the fetus and neonate. Semin Fetal Neonatal Med 2017; 22:67-70. [PMID: 28347404 DOI: 10.1016/j.siny.2017.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The impact of adverse maternal and early gestational issues, ranging from maternal-fetal interactions all the way through to premature birth, are recognized as having influence on the subsequent development of chronic diseases later in life. The development of chronic kidney disease (CKD) as a direct result of early life renal injury or a sequela of diseases such as hypertension or diabetes is a good model example of the potential impact that early life events may have on renal development and lifelong function. The global monetary and human resource cost of CKD is exorbitant. Socio-economic factors, along with other factors (genetic and environmental) may significantly influence the timing and display of phenotypic expression in fetuses and neonates at risk for developing CKD, yet very few of these factors are studied or well understood. In general our focus has been directed at treatment once CKD is established. This strategy has been and remains short-sighted and costly. Earlier understanding of the intrauterine determinants of renal mass development (i.e. environmental "biomes", poor maternal-fetal health, socio-economic factors impacting early life events, diet, access to value based health care and educational opportunities on disease evolution) may allow us an opportunity for earlier intervention. This article aims to provide some foundation for improved understanding of the maternal determinants of renal mass and function in the fetus and neonate.
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Affiliation(s)
- Patrick Brophy
- University of Iowa Stead Family Children's Hospital, University of Iowa, Iowa City, IA, USA.
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Paauw ND, van Rijn BB, Lely AT, Joles JA. Pregnancy as a critical window for blood pressure regulation in mother and child: programming and reprogramming. Acta Physiol (Oxf) 2017; 219:241-259. [PMID: 27124608 DOI: 10.1111/apha.12702] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/06/2016] [Accepted: 04/25/2016] [Indexed: 12/13/2022]
Abstract
Pregnancy is a critical time for long-term blood pressure regulation in both mother and child. Pregnancies complicated by placental insufficiency, resulting in pre-eclampsia and intrauterine growth restriction, are associated with a threefold increased risk of the mother to develop hypertension later in life. In addition, these complications create an adverse intrauterine environment, which programmes the foetus and the second generation to develop hypertension in adult life. Female offspring born to a pregnancy complicated by placental insufficiency are at risk for pregnancy complications during their own pregnancies as well, resulting in a vicious circle with programmed risk for hypertension passing from generation to generation. Here, we review the epidemiology and mechanisms leading to the altered programming of blood pressure trajectories after pregnancies complicated by placental insufficiency. Although the underlying mechanisms leading to hypertension remain the subject of investigation, several abnormalities in angiotensin sensitivity, sodium handling, sympathetic activity, endothelial function and metabolic pathways are found in the mother after exposure to placental insufficiency. In the child, epigenetic modifications and disrupted organ development play a crucial role in programming of hypertension. We emphasize that pregnancy can be viewed as a window of opportunity to improve long-term cardiovascular health of both mother and child, and outline potential gains expected of improved preconceptional, perinatal and post-natal care to reduce the development of hypertension and the burden of cardiovascular disease later in life. Perinatal therapies aimed at reprogramming hypertension are a promising strategy to break the vicious circle of intergenerational programming of hypertension.
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Affiliation(s)
- N. D. Paauw
- Department of Obstetrics; Wilhelmina Children's Hospital Birth Center; University Medical Center Utrecht; Utrecht the Netherlands
| | - B. B. van Rijn
- Department of Obstetrics; Wilhelmina Children's Hospital Birth Center; University Medical Center Utrecht; Utrecht the Netherlands
- Academic Unit of Human Development and Health; University of Southampton; Southampton UK
| | - A. T. Lely
- Department of Obstetrics; Wilhelmina Children's Hospital Birth Center; University Medical Center Utrecht; Utrecht the Netherlands
| | - J. A. Joles
- Department of Nephrology and Hypertension; University Medical Center Utrecht; Utrecht the Netherlands
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Eshkoor SA, Hamid TA, Shahar S, Ng CK, Mun CY. Factors Affecting Hypertension among the Malaysian Elderly. J Cardiovasc Dev Dis 2016; 3:E8. [PMID: 29367559 PMCID: PMC5715699 DOI: 10.3390/jcdd3010008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/24/2016] [Accepted: 02/26/2016] [Indexed: 02/07/2023] Open
Abstract
Hypertension is a common chronic disease in the elderly. This study aimed to determine the effects of age, ethnicity, gender, education, marital status, nutritional parameters, and blood elements on the risk of high blood pressure in the Malaysian elderly. This research was conducted on a group of 2322 non-institutionalized Malaysian elderly. The hierarchy binary logistic regression analysis was applied to estimate the risk of hypertension in respondents. Approximately, 45.61% of subjects had hypertension. The findings indicated that the female gender (Odds ratio (OR) = 1.54), an increase in body weight (OR = 1.61), and an increase in the blood levels of albumin (OR = 1.51), glucose (OR = 1.92), and triglycerides (OR = 1.27) significantly increased the risk of hypertension in subjects (p < 0.05). Conversely, an increase in both dietary carbohydrates (OR = 0.74), and blood cholesterol level (OR = 0.42) significantly reduced the risk of hypertension in samples (p < 0.05). Furthermore, the results showed that ethnicity was a non-relevant factor to increase the risk of hypertension in subjects. It was concluded that female gender, an increase in body weight, and an increase in the blood levels of glucose, triglycerides, and albumin enhanced the risk of high blood pressure in the Malaysian elderly. In addition, an increase in both dietary carbohydrates and blood cholesterol level decreased hypertension in subjects.
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Affiliation(s)
- Sima Ataollahi Eshkoor
- Malaysian Research on Aging (MyAging), University Putra Malaysia, Serdang 43400, Malaysia.
- Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran 1985713834, Iran.
| | - Tengku Aizan Hamid
- Malaysian Research on Aging (MyAging), University Putra Malaysia, Serdang 43400, Malaysia.
| | - Suzana Shahar
- Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia.
| | - Chee Kyun Ng
- Malaysian Research on Aging (MyAging), University Putra Malaysia, Serdang 43400, Malaysia.
| | - Chan Yoke Mun
- Malaysian Research on Aging (MyAging), University Putra Malaysia, Serdang 43400, Malaysia.
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Chen L, Yue J, Wu H, Yang J, Han X, Li J, Hu Y. Ouabain Attenuates Cardiac Hypertrophy of Male Rat Offspring Exposed to Intrauterine Growth Restriction Following High-Salt Diet Challenge. Reprod Sci 2015; 22:1587-96. [PMID: 26071389 DOI: 10.1177/1933719115589412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Ouabain can normalize the blood pressure of the adult intrauterine growth restriction (IUGR) offspring through retaining the number of glomeruli of the IUGR newborn. However, the melioration of hemodynamic features coinciding with the improvement in cardiac structure and function is poorly understood. Intrauterine growth restriction was induced in pregnant rats with protein intake restriction, and ouabain was administrated using osmotic mini pumps from the second gestational day. The male offspring of the mothers with normal diet, low-protein diet, and low-protein diet added with ouabain treatment were randomly divided into 2 groups, one of which received normal diet and the other was treated with isocaloric 8% high-salt diet. We found that maternal malnutrition caused fetal growth retardation. At the end of a 40-week research, the offspring of the IUGR group presented high blood pressure and deteriorative cardiac performance and even worse in the offspring fed with 8% high-salt diet. Ouabain can normalize the blood pressure and improve the cardiac performance, even if following 8% high-salt diet challenge. Pathological and molecular analyses showed IUGR following 8% high-salt diet significantly increased the cardiac hypertrophy, whereas the unfavorable effects were ameliorated in the offspring treated with ouabain. Results suggest that the effects of ouabain on restoration of glomerular number in newborn and normalization of blood pressure during adulthood in IUGR male offspring can benefit the cardiac structure and function, especially under high-salt diet challenge.
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Affiliation(s)
- Liang Chen
- Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Jing Yue
- Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Han Wu
- Department of Cardiology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Jun Yang
- Department of Pathology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Xiaojuan Han
- Department of Endocrinology, Yancheng Hospital of Traditional Chinese Medicine Affiliated to Nanjing University of Chinese Medicine, Yancheng, China
| | - Juan Li
- Department of Hematology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yali Hu
- Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
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8
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Zohdi V, Lim K, Pearson JT, Black MJ. Developmental programming of cardiovascular disease following intrauterine growth restriction: findings utilising a rat model of maternal protein restriction. Nutrients 2014; 7:119-52. [PMID: 25551250 PMCID: PMC4303830 DOI: 10.3390/nu7010119] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 12/08/2014] [Indexed: 12/11/2022] Open
Abstract
Over recent years, studies have demonstrated links between risk of cardiovascular disease in adulthood and adverse events that occurred very early in life during fetal development. The concept that there are embryonic and fetal adaptive responses to a sub-optimal intrauterine environment often brought about by poor maternal diet that result in permanent adverse consequences to life-long health is consistent with the definition of "programming". The purpose of this review is to provide an overview of the current knowledge of the effects of intrauterine growth restriction (IUGR) on long-term cardiac structure and function, with particular emphasis on the effects of maternal protein restriction. Much of our recent knowledge has been derived from animal models. We review the current literature of one of the most commonly used models of IUGR (maternal protein restriction in rats), in relation to birth weight and postnatal growth, blood pressure and cardiac structure and function. In doing so, we highlight the complexity of developmental programming, with regards to timing, degree of severity of the insult, genotype and the subsequent postnatal phenotype.
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Affiliation(s)
- Vladislava Zohdi
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia.
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Institute, P.O. Box 6492 St Kilda Rd Central, Melbourne 8008, Australia.
| | - James T Pearson
- Department of Physiology, Monash University, Melbourne, VIC 3800, Australia.
| | - M Jane Black
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia.
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9
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Han SY, Hong JW, Noh JH, Kim DJ. Association of the estimated 24-h urinary sodium excretion with albuminuria in adult koreans: the 2011 Korea National Health and Nutrition Examination Survey. PLoS One 2014; 9:e109073. [PMID: 25313865 PMCID: PMC4196757 DOI: 10.1371/journal.pone.0109073] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 09/08/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Sodium intake and albuminuria have important roles in blood pressure and renal progression. Although their relationship has been reported, the results have not been consistent and all studies have examined small populations. OBJECTIVE This study investigated the role of the estimated 24-h urinary sodium excretion as a marker of sodium intake and albuminuria. DESIGN This investigation included 5,187 individuals age 19 years and older from a cross-sectional, nationally representative, stratified survey: The Korea National Health and Nutrition Examination Survey (KNHANES V-2), in 2011. Albuminuria was defined as a urinary albumin/creatinine ratio ≥30 mg/g. The 24-h urinary sodium excretion was estimated from a spot urine. RESULTS On classifying our participants into quartiles based on the estimated 24-h urinary sodium excretion, the prevalence of albuminuria increased with the 24-h urinary sodium excretion (5.3, 5.7, 7.5, and 11.8% in the first through fourth quartiles, respectively, p for trend <0.001). Even after adjusting for age, sex, diabetes, obesity, and hypertension, the significance persisted. In a multiple logistic regression analysis, the second and third quartiles of the estimated 24-h urinary sodium excretion were not associated with the presence of albuminuria with the first quartile as a control. However, the fourth quartile was significantly associated with the presence of albuminuria (odds ratio 1.61 [95% confidence interval 1.71-2.21], p = 0.003) after adjusting for age, sex, diabetes, obesity, and hypertension. CONCLUSIONS These findings suggest that salt intake is associated with the presence of albuminuria in the general Korean adult population.
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Affiliation(s)
- Sang Youb Han
- Department of Internal Medicine, Ilsan-Paik Hospital, College of Medicine, Inje University, Goyang, Republic of Korea
| | - Jae Won Hong
- Department of Internal Medicine, Ilsan-Paik Hospital, College of Medicine, Inje University, Goyang, Republic of Korea
| | - Jung Hyun Noh
- Department of Internal Medicine, Ilsan-Paik Hospital, College of Medicine, Inje University, Goyang, Republic of Korea
| | - Dong-Jun Kim
- Department of Internal Medicine, Ilsan-Paik Hospital, College of Medicine, Inje University, Goyang, Republic of Korea
- * E-mail:
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Association between Salt Intake and Albuminuria in Normotensive and Hypertensive Individuals. Int J Hypertens 2013; 2013:523682. [PMID: 24171109 PMCID: PMC3793292 DOI: 10.1155/2013/523682] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/04/2013] [Accepted: 08/07/2013] [Indexed: 11/23/2022] Open
Abstract
Background. There is a little published data regarding the association between salt intake and albuminuria as an important alarm for progression of cardiovascular and renal dysfunction. We aimed to assess this relationship to emphasize the major role of restricting salt intake to minimize albuminuria and prevent these life-threatening events. Methods. The study population comprised 820 individuals. Participants were assigned to groups as follows: normal albuminuria, slight albuminuria, and clinical albuminuria. Daily salt intake was assessed on the basis of 24-hour urinary sodium excretion, since urinary sodium excretion largely equals sodium intake. Results. In normotensive participants, the mean level of urine albumin was higher in those who had higher amounts of salt intake with a significantly upward trend (the mean urinary albumin level in low-salt-diet group, in medium-salt-intake group, and in high-salt-intake group was 42.70 ± 36.42, 46.89 ± 38.91, and 53.38 ± 48.23, resp., (P = 0.017)). There was a significant positive correlation between 24-hour urinary sodium secretion and the level of urine albumin (beta = 0.130, P < 0.001). The amount of salt intake was significantly associated with urine albumin concentration (beta = 3.969, SE = 1.671, P = 0.018). Conclusion. High salt intake was shown to be associated with higher level of microalbuminuria even adjusted for potential underlying risk factors.
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Gurusinghe S, Brown RD, Cai X, Samuel CS, Ricardo SD, Thomas MC, Kett MM. Does a nephron deficit exacerbate the renal and cardiovascular effects of obesity? PLoS One 2013; 8:e73095. [PMID: 24019901 PMCID: PMC3760915 DOI: 10.1371/journal.pone.0073095] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 07/19/2013] [Indexed: 12/30/2022] Open
Abstract
It has been hypothesized that a reduced nephron endowment exacerbates the hypertensive and renal effects of obesity. We therefore examined the impact of diet-induced obesity on renal structure and function, and arterial pressure in a genetic model of reduced nephron endowment, the GDNF Heterozygous (HET) mouse. 6wk-old male GDNF WT and HET mice were placed on control or high fat (HFF) diet for 20 weeks. 24 hr arterial pressure, heart rate and activity (radiotelemetry), creatinine clearance and albumin excretion were measured, and kidneys collected (histopathology, collagen content). Bodyweights of HFF WT (50.6±1.2 g) and HET (48.8±1.4 g) mice were ∼14 g greater than control mice (37.3±1.3 g, 36.4±1.1 g respectively; Pdiet<0.001). Obesity led to significantly greater 24 hr MAP (Pdiet<0.001), heart rate (Pdiet<0.01) and lower locomotor activity (Pdiet<0.01) in HET and WT mice. Whilst there was no significant impact of genotype on 24 hr MAP response to obesity, night-time MAP of obese HET mice was significantly greater than obese WT mice (122.3±1.6 vs 116.9±1.3 mmHg; P<0.05). 24 hr creatinine clearance was 50%, and albumin excretion 180% greater in obese WT and HET mice compared to controls (Pdiet<0.05) but this response did not differ between genotypes. Obesity induced glomerulomegaly, glomerulosclerosis, tubulointerstitial expansion and increased collagen accumulation (total, collagen I, V and IV; Pdiet<0.001). Obese GDNF HET mice had exacerbated total renal collagen (P<0.01), and greater levels of the collagen I subtype compared to kidneys of obese WT mice. In summary, obese nephron-deficient GDNF HET mice were able to maintain the high creatinine clearances of obese WT mice but at the expense of higher MAP and greater renal fibrosis. Whilst modest, our findings support the hypothesis that a reduced nephron endowment increases the susceptibility to obesity-induced kidney disease and hypertension.
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Affiliation(s)
- Seshini Gurusinghe
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Russell D. Brown
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Xiaochu Cai
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Chrishan S. Samuel
- Department of Pharmacology, Clayton, Victoria, Australia
- Howard Florey Institute, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Sharon D. Ricardo
- Department of Anatomy and Cell Biology, Monash University, Clayton, Victoria, Australia
| | - Merlin C. Thomas
- Baker IDI Heart and Diabetes Institute, Prahran, Victoria, Australia
| | - Michelle M. Kett
- Department of Anatomy and Cell Biology, Monash University, Clayton, Victoria, Australia
- * E-mail:
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Mao C, Liu R, Bo L, Chen N, Li S, Xia S, Chen J, Li D, Zhang L, Xu Z. High-salt diets during pregnancy affected fetal and offspring renal renin-angiotensin system. J Endocrinol 2013; 218:61-73. [PMID: 23620529 PMCID: PMC4406098 DOI: 10.1530/joe-13-0139] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intrauterine environments are related to fetal renal development and postnatal health. Influence of salty diets during pregnancy on renal functions and renin-angiotensin system (RAS) was determined in the ovine fetuses and offspring. Pregnant ewes were fed high-salt diet (HSD) or normal-salt diet (NSD) for 2 months during middle-to-late gestation. Fetal renal functions, plasma hormones, and mRNA and protein expressions of the key elements of renal RAS were measured in the fetuses and offspring. Fetal renal excretion of sodium was increased while urine volume decreased in the HSD group. Fetal blood urea nitrogen was increased, while kidney weight:body weight ratio decreased in the HSD group. The altered ratio was also observed in the offspring aged 15 and 90 days. Maternal and fetal plasma antidiuretic hormone was elevated without changes in plasma renin activity and Ang I levels, while plasma Ang II was decreased. The key elements of local renal RAS, including angiotensinogen, angiotensin converting enzyme (ACE), ACE2, AT1, and AT2 receptor expression in both mRNA and protein, except renin, were altered following maternal high salt intake. The results suggest that high intake of salt during pregnancy affected fetal renal development associated with an altered expression of the renal key elements of RAS, some alterations of fetal origins remained after birth as possible risks in developing renal or cardiovascular diseases.
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Affiliation(s)
- Caiping Mao
- Institute for Fetology and Reproductive Medicine Center, First Hospital of Soochow University, Suzhou 215006, People's Republic of China.
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13
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Abstract
Events that occur in the early fetal environment have been linked to long-term health and lifespan consequences in the adult. Intrauterine growth restriction (IUGR), which may occur as a result of nutrient insufficiency, exposure to hormones, or disruptions in placental structure or function, may induce the fetus to alter its developmental program in order to adapt to the new conditions. IUGR may result in a decrease in the expression of genes that are responsible for nephrogenesis as nutrients are rerouted to the development of more essential organs. Fetal survival under these conditions often results in low birth weight and a deficit in nephron endowment, which are associated with hypertension in adults. Interestingly, male IUGR offspring appear to be more severely affected than females, suggesting that sex hormones may be involved. The processes of fetal programming of hypertension are complex, and we are only beginning to understand the underlying mechanisms.
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14
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Nanez A, Ramos IN, Ramos KS. A mutant Ahr allele protects the embryonic kidney from hydrocarbon-induced deficits in fetal programming. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:1745-1753. [PMID: 21803694 PMCID: PMC3261986 DOI: 10.1289/ehp.1103692] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 07/29/2011] [Indexed: 05/27/2023]
Abstract
BACKGROUND The use of experimental model systems has expedited the elucidation of pathogenetic mechanisms of renal developmental disease in humans and the identification of genes that orchestrate developmental programming during nephrogenesis. OBJECTIVES We conducted studies to evaluate the role of AHR polymorphisms in the disruption of renal developmental programming by benzo(a)pyrene (BaP). METHODS We used metanephric cultures of C57BL/6J (C57) mice expressing the Ahr(b-1) allele and B6.D2N-Ahr(d)/J (D2N) mice expressing a mutant allele deficient in ligand binding (Ahr(d)) to investigate molecular mechanisms of renal development. Deficits in fetal programming were evaluated in the offspring of pregnant mice treated with BaP during nephrogenesis. RESULTS Hydrocarbon challenge of metanephri from C57 mice altered Wilms' tumor suppressor gene (Wt1) mRNA splice variant ratios and reduced mRNAs of the Wt1 transcriptional targets syndecan-1 (Sdc1) paired box gene 2 (Pax2), epidermal growth factor receptor (Egfr), and retinoic acid receptor, alpha (Rarα). These changes correlated with down-regulation of effectors of differentiation [secreted frizzled-related sequence protein 1 (Sfrp1), insulin-like growth factor 1 receptor (Igf1r), wingless-related MMTV-integration site 4 (Wnt4), Lim homeobox protein 1 (Lhx1), E-cadherin]. In contrast, metanephri from D2N mice were spared hydrocarbon-induced changes in Wt1 splice variant ratios and deficits of differentiation. We observed similar patterns of dysmorphogenesis and progressive loss of renal function at postnatal weeks 7 and 52 in the offspring of pregnant C57 but not D2N mice gavaged with 0.1 or 0.5 mg/kg BaP on gestation days 10-13. CONCLUSIONS These findings support a functional link between AHR and WT1 in the regulation of renal morphogenesis and raise important questions about the contribution of human AHR polymorphisms to the fetal origins of adult-onset kidney disease.
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Affiliation(s)
- Adrian Nanez
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky 40292, USA
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15
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Koleganova N, Piecha G, Ritz E, Becker LE, Müller A, Weckbach M, Nyengaard JR, Schirmacher P, Gross-Weissmann ML. Both high and low maternal salt intake in pregnancy alter kidney development in the offspring. Am J Physiol Renal Physiol 2011; 301:F344-54. [PMID: 21593188 DOI: 10.1152/ajprenal.00626.2010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In humans, low glomerular numbers are related to hypertension, cardiovascular, and renal disease in adult life. The present study was designed 1) to explore whether above- or below-normal dietary salt intake during pregnancy influences nephron number and blood pressure in the offspring and 2) to identify potential mechanisms in kidney development modified by maternal sodium intake. Sprague-Dawley rats were fed low (0.07%)-, intermediate (0.51%)-, or high (3.0%)-sodium diets during pregnancy and lactation. The offspring were weaned at 4 wk and subsequently kept on a 0.51% sodium diet. The kidney structure was assessed at postnatal weeks 1 and 12 and the expression of proteins of interest at term and at week 1. Blood pressure was measured in male offspring by telemetry from postnatal month 2 to postnatal month 9. The numbers of glomeruli at weeks 1 and 12 were significantly lower and, in males, telemetrically measured mean arterial blood pressure after month 5 was higher in offspring of dams on a high- or low- compared with intermediate-sodium diet. A high-salt diet was paralleled by higher concentrations of marinobufagenin in the amniotic fluid and an increase in the expression of both sprouty-1 and glial cell-derived neutrophic factor in the offspring's kidney. The expression of FGF-10 was lower in offspring of dams on a low-sodium diet, and the expression of Pax-2 and FGF-2 was lower in offspring of dams on a high-sodium diet. Both excessively high and excessively low sodium intakes during pregnancy modify protein expression in offspring kidneys and reduce the final number of glomeruli, predisposing the risk of hypertension later in life.
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16
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Simeoni U, Ligi I, Buffat C, Boubred F. Adverse consequences of accelerated neonatal growth: cardiovascular and renal issues. Pediatr Nephrol 2011; 26:493-508. [PMID: 20938692 DOI: 10.1007/s00467-010-1648-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 07/12/2010] [Accepted: 07/26/2010] [Indexed: 12/13/2022]
Abstract
Epidemiological and experimental studies show that the risk of cardiovascular and metabolic diseases at adulthood is inversely related to the weight at birth. Although with less evidence, low birth weight has been suggested to increase the risk of chronic kidney disease (CKD). It is well established that the developmental programming of arterial hypertension and of renal disease involves in particular renal factors, especially nephron endowment, which is reduced in low birth weight and maternal diabetes situations. Experimental studies, especially in rodents, have demonstrated the long-term influence of postnatal nutrition and/or postnatal growth on cardiovascular, metabolic and renal functions, while human data are scarce on this issue. Vascular and renal diseases appear to have a "multihits" origin, with reduced nephron number the initial hit and rapid postnatal growth the second hit. This review addresses the current understanding of the role of the kidney, both as a mechanism and as a target, in the developmental origins of adult disease theory, with a particular focus on the long-term effects of postnatal growth and nutrition.
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Affiliation(s)
- Umberto Simeoni
- Division of Neonatology, Hôpital la Conception, Assistance Publique-Hôpitaux de Marseille, 147 Boulevard Baille, 13385, Marseille, France.
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17
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Abstract
Development of the kidney can be altered in utero in response to a suboptimal environment. The intrarenal factors that have been most well characterized as being sensitive to programming events are kidney mass/nephron endowment, the renin-angiotensin system, tubular sodium handling, and the renal sympathetic nerves. Newborns that have been subjected to an adverse intrauterine environment may thus begin life at a distinct disadvantage, in terms of renal function, at a time when the kidney must take over the primary role for extracellular fluid homeostasis from the placenta. A poor beginning, causing renal programming, has been linked to increased risk of hypertension and renal disease in adulthood. However, although a cause for concern, increasingly, evidence demonstrates that renal programming is not a fait accompli in terms of future cardiovascular and renal disease. A greater understanding of postnatal renal maturation and the impact of secondary factors (genes, sex, diet, stress, and disease) on this process is required to predict which babies are at risk of increased cardiovascular and renal disease as adults and to be able to devise preventative measures.
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Affiliation(s)
- Michelle M Kett
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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18
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Abstract
There are many instances in life when the environment plays a critical role in the health outcomes of an individual, yet none more so than those experienced in fetal and neonatal life. One of the most detrimental environmental problems encountered during this critical growth period are changes in nutrition to the growing fetus and newborn. Disturbances in the supply of nutrients and oxygen to the fetus can not only lead to adverse fetal growth patterns, but they have also been associated with the development of features of metabolic syndrome in adult life. This fetal response has been termed developmental programming or the developmental origins of health and disease. The present review focuses on the epidemiological studies that identified this association and the importance that animal models have played in studying this concept. We also address the potential mechanisms that may underpin the developmental programming of future disease. It also highlights (i) how developmental plasticity, although beneficial for short-term survival, can subsequently programme glucose intolerance and insulin resistance in adult life by eliciting changes in key organ structures and the epigenome, and (ii) how aberrant mitochondrial function can potentially lead to the development of Type 2 diabetes and other features of metabolic syndrome.
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Affiliation(s)
- Matthew J Warner
- Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, UK
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19
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Ruta LAM, Dickinson H, Thomas MC, Denton KM, Anderson WP, Kett MM. High-salt diet reveals the hypertensive and renal effects of reduced nephron endowment. Am J Physiol Renal Physiol 2010; 298:F1384-92. [PMID: 20335316 DOI: 10.1152/ajprenal.00049.2010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The extent to which a reduced nephron endowment contributes to hypertension and renal disease is confounded in models created by intrauterine insults that also demonstrate other phenotypes. Furthermore, recent data suggest that a reduced nephron endowment provides the "first hit" and simply increases the susceptibility to injurious stimuli. Thus we examined nephron number, glomerular volume, conscious mean arterial pressure (MAP), and renal function in a genetic model of reduced nephron endowment before and after a high-salt (5%) diet. One-yr-old glial cell line-derived neurotrophic factor wild-type (WT) mice, heterozygous (HET) mice born with two kidneys (HET2K), and HET mice born with one kidney (HET1K) were used. Nephron number was 25% lower in HET2K and 65% lower in HET1K than WT mice. Glomeruli hypertrophied in both HET groups by 33%, resulting in total glomerular volumes that were similar between HET2K and WT mice but remained 50% lower in HET1K mice. On a normal-salt diet, 24-h MAP was not different between WT, HET2K, and HET1K mice (102 +/- 1, 103 +/- 1, and 102 +/- 2 mmHg). On a high-salt diet, MAP increased 9.1 +/- 1.9 mmHg in HET1K mice (P < 0.05) and 5.4 +/- 0.9 mmHg in HET2K mice (P < 0.05) and did not change significantly in WT mice. Creatinine clearance was 60% higher in WT mice but 30% lower in HET2K and HET1K mice fed a high-salt diet than in controls maintained on a normal-salt diet. Thus a reduction in nephron number (or total glomerular volume) alone does not lead to hypertension or kidney disease in aged mice, but exposure to high salt uncovers a hypertensive and renal phenotype.
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Affiliation(s)
- Leah-Anne M Ruta
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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20
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Qin Y, Xu G, Fan J, Witt RE, Da C. High-salt loading exacerbates increased retinal content of aquaporins AQP1 and AQP4 in rats with diabetic retinopathy. Exp Eye Res 2009; 89:741-7. [DOI: 10.1016/j.exer.2009.06.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 06/24/2009] [Accepted: 06/26/2009] [Indexed: 01/19/2023]
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21
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Ramos KS, Nanez A. Genetic regulatory networks of nephrogenesis: deregulation of WT1 splicing by benzo(a)pyrene. ACTA ACUST UNITED AC 2009; 87:192-7. [PMID: 19530133 DOI: 10.1002/bdrc.20148] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Recent studies have identified AHR as a master regulator of Wilms' tumor suppressor gene (WT1) signaling in the developing kidney. Activation of AHR signaling by environmental chemical is associated with proteasome-mediated degradation of AHR protein, disruption of WT1 alternative splicing, and marked alterations in the regulation of genetic programs of developmental progression in the developing kidney. The complexity of genetic regulatory networks of nephrogenesis controlled by AHR-WT1 interactions will be discussed here with particular emphasis given to the biological and medical consequences that may result from deficits in nephrogenesis that compromise reserve capacity and renal function later in life. Understanding the impact of early-life environmental exposures to chemicals that disrupt AHR signaling can help minimize negative health consequences to pregnant women and their offspring.
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Affiliation(s)
- Kenneth S Ramos
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Delia Baxter Building, Room 227, Louisville, KY 40292, USA.
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22
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Boubred F, Daniel L, Buffat C, Feuerstein JM, Tsimaratos M, Oliver C, Dignat-George F, Lelièvre-Pégorier M, Simeoni U. Early postnatal overfeeding induces early chronic renal dysfunction in adult male rats. Am J Physiol Renal Physiol 2009; 297:F943-51. [PMID: 19656908 DOI: 10.1152/ajprenal.90704.2008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Low birth weight is associated with an increased risk of hypertension and renal dysfunction at adulthood. Such an association has been shown to involve a reduction of nephron endowment and to be enhanced by accelerated postnatal growth in humans. However, while low-birth-weight infants often undergo catch-up growth, little is known about the long-term vascular and renal effects of accelerated postnatal growth. We surimposed early postnatal overfeeding (OF; reduction of litter size during the suckling period) to appropriate-birth-weight (NBW+OF) and intrauterine growth restriction (IUGR; IUGR+OF) pups, obtained after a maternal gestational low-protein diet. Blood pressure (systolic blood pressure; SBP) and renal function (glomerular filtration rate; GFR) were measured in young and aging offspring. Glomerulosclerosis and nephron number were determined in aging offspring (22 mo). Nephron number was reduced in both IUGR and IUGR+OF male offspring (by 24 and 26%). GFR was reduced by 40% in 12-mo-old IUGR+OF male offspring, and both NBW+OF and IUGR+OF aging male offspring had sustained hypertension (+25 mmHg) and glomerulosclerosis, while SBP and renal function were unaffected in IUGR aging offspring. Female offspring were unaffected. In conclusion, in this experimental model, early postnatal OF in the neonatal period has major long-lasting effects. Such effects are gender dependent. Reduced nephron number alone, associated with IUGR, may not be sufficient to induce long-lasting physiological alterations, and early postnatal OF acts as a "second hit." Early postnatal OF is a suitable model with which to study the long-term effects of postnatal growth in the pathogenesis of vascular disorders and renal disease.
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Affiliation(s)
- Farid Boubred
- INSERM UMR608, Faculté de Pharmacie, Université de la Méditerranée, Marseille, France
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Qin Y, Fan J, Ye X, Xu G, Liu W, Da C. High salt loading alters the expression and localization of glial aquaporins in rat retina. Exp Eye Res 2009; 89:88-94. [PMID: 19268466 DOI: 10.1016/j.exer.2009.02.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/20/2009] [Accepted: 02/24/2009] [Indexed: 10/21/2022]
Abstract
In the neural retina, glial cells control the ionic concentrations in part by mediation of transmembrane water fluxes through aquaporin (AQP) water channels. The expression and immunolocalization of two water channels, AQP1 and AQP4, in the rat retina during experimental high salt loading were investigated in this study. Six-week-old Wistar rats were allowed free access to rat chow with 8% NaCl concentration. Of these rats, 6 were killed after 2, 6, 10 and 20 weeks. Twelve-week-old and 26-week-old Wistar rats with a normal diet (0.5% NaCl concentration) were used as controls. Retinal tissues were collected. Ultrathin sections stained with uranyl acetate and lead citrate were photographed using a transmission electron microscope (TEM). Retinal whole mounts and cryosections were immunostained with AQP1 and AQP4 antibodies to detect the immunolocalization changes by confocal microscopy. The AQP1 and AQP4 contents were evaluated by western blot analysis. In control tissues, no intracellular edema and mitochondria swelling were observed by TEM. The immunoreactive AQP4 was expressed by glial cells (Müller cells and astrocytes) predominantly in the inner retina, and AQP1 was expressed in the outer retina. In the retinas of high salt loading animals, obvious intracellular edema was observed by TEM in retinal ganglion cell (RGC) and mitochondria swelling was observed in glial cells. Strong expression of AQP1 was found in glial cells located in the innermost retinal layers, mainly in astrocytes. The superficial retinal vessels were surrounded by AQP4 in control retinas, but by both AQP4 and AQP1 in retina of high salt loading animals. A similar alteration in the localization of AQP1 has been described in the rat retina after transient ischemia and diabetes. Western blot results supported the conclusion that the AQP1 expression increased during high salt diet. Our findings indicate that high salt loading may induce neural retina edema, and that altered glial cell-mediated water transport via AQP channels in the retina may be one of the reasons for intracellular edema in the neural retina.
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Affiliation(s)
- Yaowu Qin
- EENT Hospital, Eye Institute, Fudan University, Fenyang Road 83, Shanghai, China
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24
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Ritz E, Mehls O. Salt restriction in kidney disease--a missed therapeutic opportunity? Pediatr Nephrol 2009; 24:9-17. [PMID: 18535843 PMCID: PMC2644745 DOI: 10.1007/s00467-008-0856-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Revised: 04/09/2008] [Accepted: 04/10/2008] [Indexed: 11/24/2022]
Abstract
The importance of salt restriction in the treatment of patients with renal disease has remained highly controversial. In the following we marshal the current evidence that salt plays a definite role in the genesis of hypertension and target organ damage, point to practical problems of salt restriction, and report on novel pathomechanisms of how salt affects blood pressure and causes target organ damage.
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Affiliation(s)
- Eberhard Ritz
- Department of Internal Medicine, Ruperto Carola University of Heidelberg, Nierenzentrum, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany.
| | - Otto Mehls
- Division of Pediatric Nephrology, University Children’s Hospital of Heidelberg, Heidelberg, Germany
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25
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Obih P, Oyekan AO. Regulation of blood pressure, natriuresis and renal thiazide/amiloride sensitivity in PPARalpha null mice. Blood Press 2008; 17:55-63. [PMID: 18568693 DOI: 10.1080/08037050701789278] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
This study evaluated the role of PPARalpha in renal function and whether PPARalpha knockout (KO) mice are hypertensive or salt-sensitive. We hypothesize that PPARalpha modulation of ion transport defines the capacity for sodium excretion (U(Na)V). PPARalpha KO and wild-type (WT) mice were placed on a normal salt (NS, 0.5% NaCl) or high salt (8% NaCl, HS) diet for 28 days and mean arterial blood pressure (MABP) and heart rate (HR) determined. In a group of anesthetized animals on NS diet, pressure natriuresis (P/N) was determined and in another group, acute sodium load (0.9% NaCl) was administered and U(Na)V compared in mice pretreated with amiloride (200 microg/kg) or hydrochlorothiazide (3 mg/kg), in vivo measurements of sodium hydrogen exchanger or Na-Cl-cotransporter activity, respectively. MABP and HR were similar in PPARalpha KO and WT mice placed on a NS diet (116+/-6 mmHg, 587+/-40 beats/min, KO; 116+/-4 mmHg, 551+/-20 beats/min, WT). HS diet increased MABP to a greater extent in KO mice (Delta = 29+/-3 vs 14+/-3 mmHg, p<0.05) as did proteinuria (8- vs 2.5-fold, p<0.05). P/N was blunted in untreated KO mice. In response to an acute NaCl-load, U(Na)V was faster in PPARalpha KO mice (4.31+/-1.11 vs 0.77+/-0.31 micromol, p<0.05). However, U(Na)V was unchanged in hydrochlorothiazide-treated KO mice but increased 6.9-fold in WT mice. Similarly, U(Na)V was less in amiloride-treated KO mice (3.4- vs 15.5-fold). These data suggest that PPARalpha participates in pressure natriuresis and affects Na transport via amiloride- and thiazide-sensitive mechanisms. Thus, despite defective fatty acid oxidation, PPARalpha null mice are not hypertensive but develop salt-sensitive hypertension.
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Affiliation(s)
- Patience Obih
- College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana, USA
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26
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Abstract
Few controversies in medicine have such a long history as that of whether salt is identifiably dangerous or not dangerous. The most common reported association between excess dietary salt intake and clinical outcome has been in the field of hypertension, but dietary sodium intake mediates effects that go far beyond, and are independent of, extracellular fluid expansion and elevation in blood pressure. For nephrologists, clinical trials that demonstrate no negative outcome of a high salt diet in the general population are thus not particularly assuasive, because patients with chronic kidney disease (CKD) represent an entity that is by no means comparable to the general population. This review takes a look at the challenges associated with salt balance in CKD patients (particularly at K/DOQI stage 5), followed by a summary of current concepts believed to play a part in salt-mediated pathophysiology, and the conclusion, based on the present state of scientific knowledge, that it appears advisable to advocate low dietary salt intake in this patient population.
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27
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Baumann M, Stehouwer C, Scheijen J, Heemann U, Struijker Boudier H, Schalkwijk C. N epsilon-(carboxymethyl)lysine during the early development of hypertension. Ann N Y Acad Sci 2007; 1126:201-4. [PMID: 18079484 DOI: 10.1196/annals.1433.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Advanced glycation end products (AGEs) are associated with hypertension. Whether N(epsilon)-(carboxymethyl)lysine (CML) contributes to the development of hypertension in young spontaneously hypertensive rats (SHR) remains to be established compared to WKY. We determined blood pressure, renal function, marker for oxidative stress (OS), and CML in young WKY rats and SHR. We found blood pressure was increased in SHR with no difference in renal function and OS compared to WKY. CML was elevated in plasma (2.3 +/- 0.3 vs. 1.3 +/- 0.2 micromol/L) and kidney (1.0 +/- 0.1 vs. 0.5 +/- 0.1 micromol/L) compared to WKY. Early CML accumulation may contribute to the development of hypertension potentially by inducing early renal inflammation independent of glomerular dysfunction or oxidative stress.
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Affiliation(s)
- Marcus Baumann
- Department of Pharmacology and Toxicology, University Maastricht, Maastricht, the Netherlands.
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Porter JP, King SH, Honeycutt AD. Prenatal high-salt diet in the Sprague-Dawley rat programs blood pressure and heart rate hyperresponsiveness to stress in adult female offspring. Am J Physiol Regul Integr Comp Physiol 2007; 293:R334-42. [PMID: 17491116 DOI: 10.1152/ajpregu.00887.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several animal models have been developed to study fetal programming of hypertension. One model involves feeding high-salt (HS) diet to rats before and during pregnancy, during lactation, and after weaning for 10 days. In the present investigation, we limited HS diet to the prenatal period in an attempt to find a narrower critical window for fetal programming. The HS diet did not result in low-birth weight offspring. In the adult offspring, radiotelemetry was used to assess blood pressure and heart rate in the conscious unstressed state. As adults, the HS offspring were not hypertensive compared with normal-salt (NS) control animals. However, the pressor and tachycardic responses to 1-h of restraint were significantly enhanced in HS female offspring, and recovery after restraint was delayed. This was accompanied by an increase in relative expression of corticotropin-releasing hormone (CRH) mRNA in the paraventricular nucleus of the hypothalamus during basal and stressed conditions. There was no augmented stress response or relative increase in CRH mRNA in adult HS male offspring. When challenged with 1 wk of 8% NaCl diet as adults, neither HS male nor female offspring exhibited salt sensitivity compared with NS groups. These data show that a high-salt diet limited to the prenatal period is not sufficient to program hypertension in adult offspring. However, this narrower critical period is sufficient to imprint a lasting hyperresponsiveness to stress, at least in adult female offspring. These data indicate that excessive maternal salt intake during pregnancy can adversely affect the cardiovascular health of adult offspring.
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Affiliation(s)
- James P Porter
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
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29
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Bagby SP. Maternal nutrition, low nephron number, and hypertension in later life: pathways of nutritional programming. J Nutr 2007; 137:1066-72. [PMID: 17374679 DOI: 10.1093/jn/137.4.1066] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A large body of epidemiologic literature supports an inverse relation between birth weight and both systolic blood pressure and prevalence of hypertension, but mechanisms through which lower birth weight increases risk for hypertension are not established. This article advances the view that 1) permanently reduced nephron number is essential but not alone sufficient to mediate nutritionally induced hypertension; and 2) fetally programmed propensity for increased appetite and accelerated postnatal growth, thus generating inappropriately increased body mass, is a necessary "second hit" to actualize hypertension vulnerability. Based on decades of nephrologic research, this increased ratio of body mass (excretory load) to nephron number (excretory capacity) induces intrarenal compensations (tubular and glomerular hypertrophy with single-nephron hyperfiltration and intrarenal renin-angiotensin II activation), which maintain normal glomerular filtration rate at the expense of systemic and glomerular hypertension and at the risk of progressive renal disease. The vigor of the intrarenal compensatory responses is markedly greater in the immature than in the mature kidney, potentially explaining the greater risk of nephron deficits being present early in life as compared with the minimal risk in adult kidney donors. Effective interventions have not yet been defined. Suboptimal maternal nutrition, pervasive in both developed and developing countries, offers a window of opportunity to enhance the cardiovascular and renal health of future generations.
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Affiliation(s)
- Susan P Bagby
- OHSU Heart Research Center and Division of Nephrology and Hypertension, Department of Medicine and Research Service, Oregon Health and Science University and Portland Veterans Administration Medical Center, Portland, OR 97239, USA.
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Barker DJP, Bagby SP, Hanson MA. Mechanisms of Disease: in utero programming in the pathogenesis of hypertension. ACTA ACUST UNITED AC 2006; 2:700-7. [PMID: 17124527 DOI: 10.1038/ncpneph0344] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Accepted: 08/25/2006] [Indexed: 01/08/2023]
Abstract
Nutritional and other environmental cues during development can permanently alter the structure, homeostatic systems, and functions of the body. This phenomenon has been referred to as 'programming'. Epidemiological and animal studies show that programmed effects operate within the normal range of growth and development, and influence the risk of chronic disease in adult life. We review the evidence that these effects include reduced nephron number and compensatory adaptations, which might lead to hypertension, and perhaps accelerate the decline in renal function that accompanies aging. These processes might be exacerbated by programmed changes in vascular structure and function, and alterations in endocrine and metabolic homeostasis. Programmed effects might be initiated as early as the periconceptual phase of development, and could involve epigenetic changes in gene expression or altered stem cell allocation. Better understanding of these processes could lead to the development of novel diagnostic and preventive measures, and to early detection of at-risk individuals. By monitoring blood pressure, weight, and renal function in children, it might be possible to reduce the risk of cardiovascular and renal disease in later life.
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Affiliation(s)
- David J P Barker
- Developmental Origins of Health and Disease Division (MP 887), University of Southampton, Princess Anne Hospital, Southampton SO16 5YA, UK.
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31
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Matavelli LC, Zhou X, Varagic J, Susic D, Frohlich ED. Salt loading produces severe renal hemodynamic dysfunction independent of arterial pressure in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 2006; 292:H814-9. [PMID: 16997890 DOI: 10.1152/ajpheart.00671.2006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We have previously shown that salt excess has adverse cardiac effects in spontaneously hypertensive rats (SHR), independent of its increased arterial pressure; however, the renal effects have not been reported. In the present study we evaluated the role of three levels of salt loading in SHR on renal function, systemic and renal hemodynamics, and glomerular dynamics. At 8 wk of age, rats were given a 4% (n = 11), 6% (n = 9), or 8% (n = 11) salt-load diet for the ensuing 8 wk; control rats (n = 11) received standard chow (0.6% NaCl). Rats had weekly 24-h proteinuria and albuminuria quantified. At the end of salt loading, all rats had systemic and renal hemodynamics measured; glomerular dynamics were specially studied by renal micropuncture in the control, 4% and 6% salt-loaded rats. Proteinuria and albuminuria progressively increased by the second week of salt loading in the 6% and 8% salt-loaded rats. Mean arterial pressure increased minimally, and glomerular filtration rate decreased in all salt-loaded rats. The 6% and 8% salt-loaded rats demonstrated decreased renal plasma flow and increased renal vascular resistance and serum creatinine concentration. Furthermore, 4% and 6% salt-loaded rats had diminished single-nephron plasma flow and increased afferent and efferent arteriolar resistances; glomerular hydrostatic pressure also increased in the 6% salt-loaded rats. In conclusion, dietary salt loading as low as 4% dramatically deteriorated renal function, renal hemodynamics, and glomerular dynamics in SHR independent of a minimal further increase in arterial pressure. These findings support the concept of a strong independent causal relationship between salt excess and cardiovascular and renal injury.
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Affiliation(s)
- Luis C Matavelli
- Hypertension Research Laboratory, Division of Research, Ochsner Clinic Foundation, New Orleans, Louisiana 70121, USA
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Bursztyn M, Gross ML, Goltser-Dubner T, Koleganova N, Birman T, Smith Y, Ariel I. Adult hypertension in intrauterine growth-restricted offspring of hyperinsulinemic rats: evidence of subtle renal damage. Hypertension 2006; 48:717-23. [PMID: 16923994 DOI: 10.1161/01.hyp.0000237973.64711.e2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In humans, intrauterine growth-restricted newborns are prone to develop hypertension as adults. We studied a rat model of pregnancy-induced hypertension associated with intrauterine growth restriction (IUGR) produced by chronic administration of insulin. Fetuses of hyperinsulinemic dams (HDs) were smaller than those of normal dams (5.1+/-0.4 g versus 5.6+/-0.1 g, respectively; P<0.05). At 16 weeks of age, tail-cuff systolic blood pressure was measured, the rats were placed in metabolic cages and euthanized, and the kidneys were examined. Male but not female offspring of HDs (n=9) had higher blood pressure than normal-pregnancy offspring (n=12; 148+/-11 mm Hg versus 118+/-14 mm Hg; P<0.004). In contrast to other models, there was no difference in ours in the number and volume of glomeruli. However, there were significantly greater glomerular, tubulointerstitial, and vascular damage indices in the kidneys of male HD offspring versus controls (2.01+/-0.34 versus 1.08+/-0.16, 1.80+/-0.34 versus 0.76+/-0.12, and 2.13+/-0.81 versus 0.78+/-0.16, respectively; P<0.0001), with similar tubulointerstitial findings in females. Increased expression of collagen type IV, a kidney damage marker indicating fibrosis, was found in the tubulointerstitium. This may be associated with downregulation of bone morphogenetic protein 6, a presumptive antifibrogenic agent, at the end of gestation. In conclusion, male offspring of HDs displayed IUGR and adult hypertension accompanied by several indices of renal fibrosing damage, mainly in the renal tubulointerstitium. Our findings suggest that there is >1 pathway of fetal programming leading from IUGR to development of hypertension in later life.
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Affiliation(s)
- Michael Bursztyn
- Department of Medicine, Hadassah-Hebrew University Medical Center, Mount-Scopus, Jerusalem, Israel.
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Schreuder M, Delemarre-van de Waal H, van Wijk A. Consequences of Intrauterine Growth Restriction for the Kidney. Kidney Blood Press Res 2006; 29:108-25. [PMID: 16837795 DOI: 10.1159/000094538] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Low birth weight due to intrauterine growth restriction is associated with various diseases in adulthood, such as hypertension, cardiovascular disease, insulin resistance and end-stage renal disease. The purpose of this review is to describe the effects of intrauterine growth restriction on the kidney. Nephrogenesis requires a fine balance of many factors that can be disturbed by intrauterine growth restriction, leading to a low nephron endowment. The compensatory hyperfiltration in the remaining nephrons results in glomerular and systemic hypertension. Hyperfiltration is attributed to several factors, including the renin-angiotensin system (RAS), insulin-like growth factor (IGF-I) and nitric oxide. Data from human and animal studies are presented, and suggest a faltering IGF-I and an inhibited RAS in intrauterine growth restriction. Hyperfiltration makes the kidney more vulnerable during additional kidney disease, and is associated with glomerular damage and kidney failure in the long run. Animal studies have provided a possible therapy with blockage of the RAS at an early stage in order to prevent the compensatory glomerular hyperfiltration, but this is far from being applicable to humans. Research is needed to further unravel the effect of intrauterine growth restriction on the kidney.
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Affiliation(s)
- Michiel Schreuder
- Department of Pediatric Nephrology, VU University Medical Center, Amsterdam, The Netherlands.
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Magalhães JCG, da Silveira AB, Mota DL, Paixão ADO. Renal function in juvenile rats subjected to prenatal malnutrition and chronic salt overload. Exp Physiol 2006; 91:611-9. [PMID: 16513822 DOI: 10.1113/expphysiol.2005.032995] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Dietary sodium may contribute to hypertension and to cardiovascular and renal disease if a primary deficiency of the kidney to excrete sodium exists. In order to investigate whether chronic 1% NaCl in the drinking water changes blood pressure and renal haemodynamics in juvenile Wistar rats subjected to prenatal malnutrition, an evaluation of plasma volume, oxidative stress in the kidney, proteinuria and renal haemodynamics was carried out. Malnutrition was induced by a multideficient diet. Mean arterial pressure, renal blood flow and glomerular filtration rate (GFR) were measured using a blood pressure transducer, a flow probe and inulin clearance, respectively. Plasma volume and oxidative stress were measured by means of the Evans Blue method and by monitoring thiobarbituric acid reactive substances (TBARS) in the kidneys, respectively. Urinary protein was measured by precipitation with 3% sulphosalicylic acid. It was observed that prenatally malnourished rats presented higher values of plasma volume (26%, P < 0.05), kidney TBARS (43%, P < 0.01) and blood pressure (10%, P < 0.01) when compared with the control group. However, they showed no change in renal haemodynamics or proteinuria. Neither prenatally malnourished nor control rats treated with sodium overload presented plasma volume or blood pressure values different from their respective control groups, but both groups presented elevated proteinuria (P < 0.01). The prenatally malnourished group treated with sodium overload presented higher values of kidney TBARS, GFR and filtration fraction (58, 87 and 72% higher, respectively, P < 0.01) than its respective control group. In summary, sodium overload did not exacerbate the hypertension in juvenile prenatally malnourished rats, but induced renal haemodynamic adjustments compatible with the development of renal disease.
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Affiliation(s)
- João Carlos G Magalhães
- Departamento de Fisiologia e Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Avenue Prof. Moraes Rego, s/n, Cidade Universitária, 50670-901 Recife, PE, Brazil
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Abstract
It has been known for decades that salt (NaCl) determines extracellular volume as well as blood pressure and is one cause of hypertension. The difficulty to control the NaCl balance and thus treat sodium overload and hypertension in patients on dialysis has been recognized by Scribner in the early days of dialysis. In recent years, an impressive body of evidence has accumulated indicating that in essential hypertension, NaCl--blood pressure independently--causes target organ damage such as left ventricular hypertrophy, microalbuminuria, and increased aortic stiffness. It has further been recognized that NaCl increases oxidative stress and, again blood pressure independently, amplifies tissue injury induced by aldosterone. In renal damage models, progression is dramatically accelerated by high NaCl intake. Sodium as a potential culprit in progression to target organ damage in terminal renal failure has not been well investigated so far. However, it is possible, and indeed likely, that sodium plays an adverse role in the genesis of target organ damage in terminal renal failure.
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Affiliation(s)
- Eberhard Ritz
- Department of Internal Medicine, Ruperto Carola University Heidelberg, Heidelberg, Germany.
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Abstract
Hypertension (HTN) and chronic kidney disease are highly prevalent diseases that tend to occur more frequently among disadvantaged populations, in whom prenatal care also tends to be poor. More and more evidence is emerging highlighting the important role of fetal programming in the development of adult disease, suggesting a possible common pathophysiologic denominator in the development of these disorders. Epidemiologic evidence accumulated over the past 2 decades has demonstrated an association between low birth weight and subsequent adult HTN, diabetes, and cardiovascular disease. More recently, a similar association has been found with chronic kidney disease. Animal studies and indirect evidence from human studies support the hypothesis that low birth weight, as a marker of adverse intrauterine circumstances, is associated with a congenital deficit in nephron number. The precise mechanism of the reduction in nephron number has not been established, but several hypotheses have been put forward, including changes in DNA methylation, increased apoptosis in the developing kidney, alterations in renal renin-angiotensin system activity, and increased fetal glucocorticoid exposure. A reduction in nephron number is associated with compensatory glomerular hypertrophy and an increased susceptibility to renal disease progression. HTN in low birth weight individuals also appears to be mediated in part through a reduction in nephron number. Increased awareness of the implications of low birth weight and inadequate prenatal care should lead to public health policies that may have long-term benefits in curbing the epidemics of HTN, diabetes, and kidney disease in generations to come.
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Affiliation(s)
- Kambiz Zandi-Nejad
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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