1
|
Impact of long-term high-fat diet intake gestational protein-restricted offspring on kidney morphology and function. J Dev Orig Health Dis 2017; 8:89-100. [PMID: 28051762 DOI: 10.1017/s2040174416000398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Emerging evidence highlights the far-reaching consequences of high-fat diet (HFD) and obesity on kidney morphological and functional disorders. In the present study, we aim to evaluate the effects of early HFD intake on renal function and morphology in maternal protein-restricted offspring (LP). LP and normal protein-intake offspring (NP) were fed HFD (LPH and NPH, respectively) or standard rodent (LPN and NPN) diet from the 8th to 13th week of age. Blood pressure, kidney function, immunohistochemistry and scanning electron microscopy were analyzed. Increased total cholesterol and low-density lipoprotein serum levels were observed in LPH offspring. The adiposity index was reduced in the (LPN) group and, conversely, increased in the NPH and LPH groups. Blood pressure was higher beyond the 10th week of age in the LPH group compared with the other groups. Decreased urinary sodium excretion was observed in LP offspring, whereas the HFD-treated groups presented a decreased urine pH in a time-dependent fashion. The LPN, NPH and LPH groups showed increased expression of type 1 angiotensin II (AngII) receptor (AT1R), TGF-β1, collagen and fibronectin in the kidneys. Moreover, the adult fetal-programmed offspring showed pronounced effacement of the podocyte foot process associated with the rupture of cell membranes and striking urinary protein excretion, exacerbated by HFD treatment. To the best of our knowledge, this is the first study demonstrating that young fetal-programmed offspring submitted to long-term HFD intake have increased susceptibility to renal structural and functional disorders associated with an accentuated stage of fibrosis and tubular dysfunction.
Collapse
|
2
|
Roza NAV, Possignolo LF, Palanch AC, Gontijo JAR. Effect of long-term high-fat diet intake on peripheral insulin sensibility, blood pressure, and renal function in female rats. Food Nutr Res 2016; 60:28536. [PMID: 26880072 PMCID: PMC4754019 DOI: 10.3402/fnr.v60.28536] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 01/16/2016] [Accepted: 01/16/2016] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND This study determines whether 8-week high-fat diet (HFD) consumption alters insulin sensitivity, kidney function, and blood pressure (BP) in female rats when compared with standard rodent diet (ND) intake in gender- and age-matched rats. METHODS The present study investigates, in female Wistar HanUnib rats, the effect of long-term high-fat fed group (HFD) compared with standard chow on BP by an indirect tail-cuff method using an electrosphygmomanometer, insulin and glucose function, and kidney function by creatinine and lithium clearances. RESULTS The current study shows glucose tolerance impairment, as demonstrated by increased fasting blood glucose (ND: 78±2.8 vs. HFD: 87±3.8 mg/dL) associated with reduced insulin secretion (ND: 0.58±0.07 vs. HFD: 0.40±0.03 ng/mL) in 8-week female HFD-treated rats. The incremental area under the curve (AUC, ND: 1,4558.0±536.0 vs. HFD: 1,6507.8±661.9), homeostasis model assessment of insulin resistance (HOMA-IR) index, and the first-order rate constant for the disappearance of glucose (Kitt) were significantly enhanced in 8-week HFD-treated rats compared with age-matched ND group (respectively, P=0.03, P=0.002, and P<0.0001). The current study also shows a significantly higher systolic BP measured in 5 and 8 weeks posttreatment in HFD (5-week HFD-treated: 155.25±10.54 mmHg and 8-week HFD-treated: 165±5.8 mmHg) (P=0.0001), when compared to BP values in 5-week ND, 137±4.24 mmHg and 8-week ND, 131.75±5.8 mmHg age-matched group. Otherwise, the glomerular filtration rate and renal sodium handling evaluated by FENa, FEPNa and FEPPNa, were unchanged in both groups. CONCLUSION We may conclude that 8-week female HFD-fed rats compared with ND group stimulate harmful effects, such as BP rise and peripheral glucose intolerance. The increased BP occurs through insulin resistance and supposedly decreased vasodilatation response without any change on renal function.
Collapse
Affiliation(s)
- Noemi A V Roza
- Laboratório de Metabolismo Hidrossalino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Luiz F Possignolo
- Laboratório de Metabolismo Hidrossalino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Adrianne C Palanch
- Laboratório de Metabolismo Hidrossalino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - José A R Gontijo
- Laboratório de Metabolismo Hidrossalino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil;
| |
Collapse
|
3
|
Block DB, Mesquita FF, de Lima IP, Boer PA, Gontijo JAR. Fetal kidney programming by maternal smoking exposure: effects on kidney structure, blood pressure and urinary sodium excretion in adult offspring. Nephron Clin Pract 2015; 129:283-92. [PMID: 25895625 DOI: 10.1159/000377634] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 02/01/2015] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Fetal programming by different insults results in low birth weight and reduction in nephron number increasing the risk for adult development of cardiovascular and renal diseases. Maternal smoking is an important modifiable adverse fetal exposure worldwide and leads to a decrease in the offspring's birth weight. Thus far, the specific adverse fetal smoking exposures and mechanisms underlying these associations on renal development and functional disorder are unclear. METHODS The present study investigates, in adult male rats, the effect of smoking exposure (Sk) in uteri on blood pressure (BP) by an indirect tail-cuff method using an electrosphygmomanometer, and its association with nephron structure by stereological estimation, immunohistochemical and histological techniques, in parallel with kidney function creatinine and lithium clearance. RESULTS The current study showed in a 16-week old Sk offspring enhanced arterial blood pressure associated with, reduced urinary sodium excretion and higher TGF-β1 glomerular expression. Sk glomeruli also presented an upregulated collagen and fibronectin deposition intrinsically related to fibrotic process as compared to age-matched control group. CONCLUSION Here, we demonstrate that fetal-programmed Sk offspring present pronounced glomerular TGF-β1 and fibrotic marker expression that may, subsequently, promote a glomerular epithelial-mesenchymal transition activated process in an Sk offspring. Although the precise mechanism responsible for the subsequently renal morphological and functional response in Sk offspring is incompletely known, the current data suggest that changes in renal function are conducive to excess sodium tubule reabsorption that is associated with enhanced TGF-β1, fibronectin and collagen deposition, intrinsically related to fibrotic process, might potentiate the programming of adult hypertension.
Collapse
Affiliation(s)
- Daniel B Block
- Department of Internal Medicine School of Medicine, State University of Campinas, Campinas, Brazil
| | | | | | | | | |
Collapse
|
4
|
de Almeida AR, Monte-Alegre S, Zanini MB, Souza AL, Etchebehere M, Gontijo JAR. Association between prehypertension, metabolic and inflammatory markers, decreased adiponectin and enhanced insulinemia in obese subjects. Nutr Metab (Lond) 2014; 11:25. [PMID: 24966877 PMCID: PMC4070164 DOI: 10.1186/1743-7075-11-25] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/20/2014] [Indexed: 01/05/2023] Open
Abstract
Background Obesity is associated with development of the cardiorenal metabolic syndrome, which is a constellation of risk factors, such as insulin resistance, inflammatory response, dyslipidemia, and high blood pressure that predispose affected individuals to well-characterized medical conditions such as diabetes, cardiovascular and kidney chronic disease. The study was designed to establish relationship between metabolic and inflammatory disorder, renal sodium retention and enhanced blood pressure in a group of obese subjects compared with age-matched, lean volunteers. Methods The study was performed after 14 h overnight fast after and before OGTT in 13 lean (BMI 22.92 ± 2.03 kg/m2) and, 27 obese (BMI 36.15 ± 3.84 kg/m2) volunteers. Assessment of HOMA-IR and QUICKI index were calculated and circulating concentrations of TNF-α, IL-6 and C-reactive protein, measured by immunoassay. Results The study shows that a hyperinsulinemic (HI: 10.85 ± 4.09 μg/ml) subgroup of well-characterized metabolic syndrome bearers-obese subjects show higher glycemic and elevated blood pressure levels when compared to lean and normoinsulinemic (NI: 5.51 ± 1.18 μg/ml, P < 0.027) subjects. Here, the combination of hyperinsulinemia, higher HOMA-IR (HI: 2.19 ± 0.70 (n = 12) vs. LS: 0.83 ± 0.23 (n = 12) and NI: 0.98 ± 0.22 (n = 15), P < 0.0001) associated with lower QUICKI in HI obese when compared with LS and NI volunteers (P < 0.0001), suggests the occurrence of insulin resistance and a defect in insulin-stimulated peripheral action. Otherwise, the adiponectin measured in basal period was significantly enhanced in NI subjects when compared to HI groups (P < 0.04). The report also showed a similar insulin-mediated reduction of post-proximal urinary sodium excretion in lean (LS: 9.41 ± 0.68% vs. 6.38 ± 0.92%, P = 0.086), and normoinsulinemic (NI: 8.41 ± 0.72% vs. 5.66 ± 0.53%, P = 0.0025) and hyperinsulinemic obese subjects (HI: 8.82 ± 0.98% vs. 6.32 ± 0.67%, P = 0.0264), after oral glucose load, despite elevated insulinemic levels in hyperinsulinemic obeses. Conclusion In conclusion, this study highlights the importance of adiponectin levels and dysfunctional inflammatory modulation associated with hyperinsulinemia and peripheral insulin resistance, high blood pressure, and renal dysfunction in a particular subgroup of obeses.
Collapse
Affiliation(s)
- Amanda Roberta de Almeida
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidrossalino, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil ; Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil
| | - Sarah Monte-Alegre
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidrossalino, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil ; Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil
| | - Michele Bianca Zanini
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidrossalino, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil ; Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil
| | - Aglécio Luiz Souza
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidrossalino, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil ; Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil
| | - Maurício Etchebehere
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidrossalino, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil ; Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil
| | - José Antonio Rocha Gontijo
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidrossalino, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil ; Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brasil
| |
Collapse
|
5
|
Pinhal CS, Lopes A, Torres DB, Felisbino SL, Rocha Gontijo JA, Boer PA. Time-course morphological and functional disorders of the kidney induced by long-term high-fat diet intake in female rats. Nephrol Dial Transplant 2014; 28:2464-76. [PMID: 24078639 DOI: 10.1093/ndt/gft304] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Evidence is emerging that highlights the far-reaching consequences of a high-fat diet (HFD) on kidney morphology and function disorders. METHODS The present study was performed on 3-, 5-, 7- and 9-week-old HFD female rats compared with the appropriate gender and age-matched animals. We evaluated the kidney expression of angiotensin type II receptor and fibrotic and epithelial-to-mesenchymal transition (EMT) markers, by immunoblotting and immunohistochemical and histological techniques, in parallel with kidney function. RESULTS In the current study, the time-course HFD-treated group showed, by immunoblotting and immunohistochemical analysis, an early time-course increase in the expression of transforming growth factor β-1 (TGFβ-1) in the entire kidney of HFD-treated rats, compared with that observed in the control group. Simultaneously, the study shows a transient increase in the expression of ZEB2 in the HFD whole kidney accompanied by a fall in the E-cadherin expression and increased collagen and fibronectin deposition. A pronounced decrease in fractional urinary sodium excretion was also demonstrated in the long-term HFD-treated rats. The decreased FENa(+) was accompanied by a fall in FEPNa(+) and FEPPNa(+), which occurred in association with significantly decreased CCr and, certainly on the sodium-filtered load. The reduction in the glomerular filtration rate (GFR) occurred in parallel to proteinuria and glomerular desmin overexpression. CONCLUSIONS The results of the current study suggest that podocyte injury in parallel with observed proteinuria and evidence of EMT transformation are associated with long-term loss of kidney function and renal sodium and water retention.
Collapse
Affiliation(s)
- Carolina Staut Pinhal
- Renal Function Laboratory, Campinas State University, UNICAMP, Campinas, São Paulo, Brazil
| | | | | | | | | | | |
Collapse
|
6
|
Lutaif NA, Palazzo R, Gontijo JAR. Early detection of metabolic and energy disorders by thermal time series stochastic complexity analysis. Braz J Med Biol Res 2014; 47:70-9. [PMID: 24519093 PMCID: PMC3932975 DOI: 10.1590/1414-431x20133097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/06/2013] [Indexed: 11/22/2022] Open
Abstract
Maintenance of thermal homeostasis in rats fed a high-fat diet (HFD) is
associated with changes in their thermal balance. The thermodynamic relationship
between heat dissipation and energy storage is altered by the ingestion of
high-energy diet content. Observation of thermal registers of core temperature
behavior, in humans and rodents, permits identification of some characteristics
of time series, such as autoreference and stationarity that fit adequately to a
stochastic analysis. To identify this change, we used, for the first time, a
stochastic autoregressive model, the concepts of which match those associated
with physiological systems involved and applied in male HFD rats compared with
their appropriate standard food intake age-matched male controls (n=7 per
group). By analyzing a recorded temperature time series, we were able to
identify when thermal homeostasis would be affected by a new diet. The
autoregressive time series model (AR model) was used to predict the occurrence
of thermal homeostasis, and this model proved to be very effective in
distinguishing such a physiological disorder. Thus, we infer from the results of
our study that maximum entropy distribution as a means for stochastic
characterization of temperature time series registers may be established as an
important and early tool to aid in the diagnosis and prevention of metabolic
diseases due to their ability to detect small variations in thermal profile.
Collapse
Affiliation(s)
- N A Lutaif
- Universidade Estadual de Campinas, Faculdade de Ciências Médicas, Departamento de Clínica Médica, CampinasSP, Brasil
| | - R Palazzo
- Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e Computação, Departamento de Telemática, CampinasSP, Brasil
| | - J A R Gontijo
- Universidade Estadual de Campinas, Faculdade de Ciências Médicas, Departamento de Clínica Médica, CampinasSP, Brasil
| |
Collapse
|
7
|
Vaccari B, Mesquita FF, Gontijo JAR, Boer PA. Fetal kidney programming by severe food restriction: effects on structure, hormonal receptor expression and urinary sodium excretion in rats. J Renin Angiotensin Aldosterone Syst 2013; 16:33-46. [PMID: 23482371 DOI: 10.1177/1470320313481081] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 11/01/2013] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION The present study investigates, in 23-day-old and adult male rats, the effect of severe food restriction in utero on blood pressure (BP), and its association with nephron structure and function changes, angiotensin II (AT1R/AT2R), glucocorticoid (GR) and mineralocorticoid (MR) receptor expression. MATERIALS AND METHODS The daily food supply to pregnant rats was measured and one group (n=15) received normal quantity of food (NF) while the other received 50% of that (FR50%) (n=15). Kidneys were processed to AT1R, AT2R, MR, and GR immunolocalization and for western blotting analysis. The renal function was estimated by creatinine and lithium clearances in 12-week-old offspring. RESULTS By stereological analyses, FR50% offspring present a reduction of nephron numbers (35%) with unchanged renal volume. Expression of AT1R and AT2R was significantly decreased in FR50% while the expression of GR and MR increased in FR50%. We also verified a pronounced decrease in urinary sodium excretion accompanied by increased BP in 12-week-old FR50% offspring. CONCLUSION The current data suggest that changes in renal function are conducive to excess sodium tubule reabsorption, and this might potentiate the programming of adult hypertension. It is plausible to arise in the current study an association between decreasing natriuresis, reciprocal changes in renal AngII and steroid receptors with the hypertension development found in FR50% compared with age-matched NF offspring.
Collapse
Affiliation(s)
- Barbara Vaccari
- Department of Morphology, São Paulo State University, Botucatu, SP, Brazil
| | - Flavia F Mesquita
- Department of Internal Medicine School of Medicine, State University of Campinas, Campinas, SP, Brazil
| | - Jose A R Gontijo
- Department of Internal Medicine School of Medicine, State University of Campinas, Campinas, SP, Brazil
| | - Patricia A Boer
- Department of Morphology, São Paulo State University, Botucatu, SP, Brazil
| |
Collapse
|
8
|
Scabora JE, de Lima MC, Lopes A, de Lima IP, Mesquita FF, Torres DB, Boer PA, Gontijo JAR. Impact of taurine supplementation on blood pressure in gestational protein-restricted offspring: Effect on the medial solitary tract nucleus cell numbers, angiotensin receptors, and renal sodium handling. J Renin Angiotensin Aldosterone Syst 2013; 16:47-58. [PMID: 23468165 DOI: 10.1177/1470320313481255] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/12/2013] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The current study considers changes of the postnatal brainstem cell number and angiotensin receptors by maternal protein restriction (LP) and LP taurine supplementation (LPT), and its impact on arterial hypertension development in adult life. METHODS AND RESULTS The brain tissue studies were performed by immunoblotting, immunohistochemistry, and isotropic fractionator analysis. The current study shows that elevated blood pressure associated with decreased fractional urinary sodium excretion (FENa) in adult LP offspring was reverted by diet taurine supplementation. Also, that 12-day-old LP pups present a reduction of 21% of brainstem neuron counts, and, immunohistochemistry demonstrates a decreased expression of type 1 angiotensin II receptors (AT1R) in the entire medial solitary tract nuclei (nTS) of 16-week-old LP rats compared to age-matched NP and LPT offspring. Conversely, the immunostained type 2 AngII (AT2R) receptors in 16-week-old LP nTS were unchanged. CONCLUSION The present investigation shows a decreased FENa that occurs despite unchanged creatinine clearance. It is plausible to hypothesize an association of decreased postnatal nTS cell number, AT1R/AT2R ratio and FENa with the higher blood pressure levels found in taurine-deficient progeny (LP) compared with age-matched NP and LPT offspring.
Collapse
Affiliation(s)
- José Eduardo Scabora
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Marcelo Cardoso de Lima
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Agnes Lopes
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Ize Penhas de Lima
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Flávia Fernandes Mesquita
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Daniele Bráz Torres
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Patrícia Aline Boer
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - José Antonio Rocha Gontijo
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| |
Collapse
|
9
|
Ciampone S, Borges R, de Lima IP, Mesquita FF, Cambiucci EC, Gontijo JAR. Long-term exercise attenuates blood pressure responsiveness and modulates kidney angiotensin II signalling and urinary sodium excretion in SHR. J Renin Angiotensin Aldosterone Syst 2011; 12:394-403. [PMID: 21628355 DOI: 10.1177/1470320311408750] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Observations have been made regarding the effects of long-term exercise training on blood pressure, renal sodium handling and renal renin-angiotensin-aldosterone (RAS) intracellular pathways in conscious, trained Okamoto-Aoki spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKy) normotensive rats, compared with appropriate age-matched sedentary SHR and WKy. To evaluate the influence of exercise training on renal function and RAS, receptors and intracellular angiotensin II (AngII) pathway compounds were used respectively, and lithium clearance and western blot methods were utilised. The current study demonstrated that increased blood pressure in SHR was blunted and significantly reduced by long-term swim training between the ages of 6 and 16 weeks. Additionally, the investigators observed an increased fractional urinary sodium excretion in trained SHR (SHR(T)) rats, compared with sedentary SHR (SHR(S)), despite a significantly decreased creatinine clearance (C(Cr)). Furthermore, immunoblotting analysis demonstrated a decreased expression of AT1(R) in the entire kidney of T(SHR) rats, compared with S(SHR). Conversely, the expression of the AT2(R), in both sedentary and trained SHR, was unchanged. The present study may indicate that, in the kidney, long-term exercise exerts a modulating effect on AngII receptor expression. In fact, the present study indicates an association of increasing natriuresis, reciprocal changes in renal AngII receptors and intracellular pathway proteins with the fall in blood pressure levels observed in T(SHR) rats compared with age-matched S(SHR) rats.
Collapse
Affiliation(s)
- Silmara Ciampone
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, São Paulo, Brazil
| | | | | | | | | | | |
Collapse
|
10
|
Zapparoli A, Figueiredo JF, Boer PA, Rocha Gontijo JA. Impaired dipsogenic and renal response to repetitive intracerebroventricular angiotensin II (AngII) injections in rats. J Renin Angiotensin Aldosterone Syst 2011; 12:161-8. [PMID: 21393358 DOI: 10.1177/1470320310392617] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The role of the central nervous system (CNS) in the control of blood pressure and hydrosaline homeostasis has been demonstrated by several studies. While circulating angiotensin II (AngII) tends to retain sodium by a direct renal action as well as through aldosterone release, stimulation of brain AngII receptors has been reported to induce natriuresis. Repetitive intracerebroventricular AngII injection was recently demonstrated to be capable of leading to desensitisation of the dipsogenic effect of AngII stimuli. The aim of the current study was to investigate a possible central desensitisation to AngII stimuli by observing the effects of a low-concentration solution of AngII on the dipsogenic and natriuretic mechanisms in conscious rats, compared with appropriate age-matched 0.15 M NaCl-injected subjects, as evaluated by lithium clearance. The present report confirmed earlier reports on the potent natriuretic and dipsogenic effects of central AngII receptor stimulation. Natriuresis is mediated by a decrease in sodium reabsorption in the proximal and post-proximal tubule segments of the nephron. The current findings lend further support to the idea that AngII, in the CNS, is instrumental in the regulation of body fluid homeostasis. The magnitude of the dipsogenic and renal response to AngII was significantly decreased by repetitive stimulus.
Collapse
Affiliation(s)
- Adriana Zapparoli
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Sao Paolo, Brazil
| | | | | | | |
Collapse
|
11
|
Rocha Gontijo JA, Gui DC, Boer PA, Dos Santos AR, Ferreira-filho CP, Nery Aguiar AR, Da Silva BB. Evaluation of Arterial Blood Pressure and Renal Sodium Handling in a Model of Female Rats in Persistent Estrus. Clin Exp Hypertens 2010; 32:385-9. [DOI: 10.3109/10641961003628536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
12
|
Mesquita FF, Gontijo JAR, Boer PA. Expression of renin-angiotensin system signalling compounds in maternal protein-restricted rats: effect on renal sodium excretion and blood pressure. Nephrol Dial Transplant 2009; 25:380-8. [DOI: 10.1093/ndt/gfp505] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
13
|
Lutaif NA, Rocha EM, Veloso LA, Bento LM, Gontijo JAR. Renal contribution to thermolability in rats: role of renal nerves. Nephrol Dial Transplant 2008; 23:3798-805. [PMID: 18593740 DOI: 10.1093/ndt/gfn368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Body temperature is closely regulated via the integration of a number of mechanisms, the study of which has been greatly assisted by the exploitation of comparative physiology. Previous studies have demonstrated that chronic renal failure patients have significantly lower body temperatures than healthy subjects when artifacts from circadian changes were taken into consideration. We hypothesize that the blunting of renal sensory neurons after kidney partial ablation may contribute to the lack of suppression of sympathetic efferent outflow towards BAT, modifying the glucose metabolism signaling pathway, UCP 1 expression and liver mitocondrial respiratory chain activity. METHODS To evaluate the influence of renal mass reduction, renal denervation and chronic deafferentation by capsaicin on thermoregulation, glucose metabolism, UCP1 expression and liver mitocondrial respiration, was used respectively, the blocking of heat dissipation by thermoneutral body water immersion, the oxygen consumption by Clark-type electrode, and western blot method. RESULTS The study confirmed that, following 5/6 nephrectomy, the basal core temperature of rats was significantly lower than that of control animals when maintained in a thermoneutral body water immersion recipient, as compared to controls. Additionally, we demonstrated that exposure of bilateral renal denervated or of renal chronic capsaicin-treated rats to a similar experimental protocol results in a fast and high rise in rectal temperature response, and this is associated with a significant increase in the basal serine phosphorylation and protein levels of Akt and protein levels of UCP1. This was observed despite unchanged liver mitochondria respiratory control and ADP/O ratios in 5/6 Nx, as well as DNx, when compared to control mitochondria. CONCLUSIONS Speculatively, it may be suggested that one of the renal sensory nerve signal defects associated with decreased kidney energy generation, induced by kidney ablation, may result in an inability to control the body temperature.
Collapse
Affiliation(s)
- Nelson A Lutaif
- Departamento de Clínica Médica, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brazil
| | | | | | | | | |
Collapse
|
14
|
Menegon LF, Zaparolli A, Boer PA, de Almeida AR, Gontijo JAR. Long-term effects of intracerebroventricular insulin microinjection on renal sodium handling and arterial blood pressure in rats. Brain Res Bull 2008; 76:344-8. [PMID: 18502308 DOI: 10.1016/j.brainresbull.2008.02.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 02/11/2008] [Accepted: 02/16/2008] [Indexed: 11/28/2022]
Abstract
The role of the central nervous system (CNS) in the control of hydrosaline homeostasis has been strikingly demonstrated by several studies. Our laboratory recently showed that centrally administered insulin produced a dose-related increase in the urinary output of sodium, which was abolished by bilateral renal denervation, nitric oxide synthase inhibition and cerebroventricular streptozotocin administration in rats. Recent studies have shown that hyperinsulinemia induces subtle derangements of intracellular insulin-insulin receptor trafficking and insulin metabolism, which are associated with an impairment of insulin signaling. The long-term effect of high insulin levels on the periventricular region could alter insulin signaling, which in turn, may modify the central natriuretic and cardiovascular effects of this peptide. In order to evaluate this hypothesis, we investigated the effects of 7-day i.c.v. insulin administration on tubular handling and blood pressure in conscious, unrestrained rats and their controls, randomly assigned to one of two separate groups: (a) i.c.v. 0.15M NaCl-injected (n=7) and (b) i.c.v. 126.0 ng insulin-injected rats (n=7). In the current study, there were no significant differences between the blood pressure, daily tap water intake and serum sodium, potassium, lithium and creatinine levels in control i.c.v. 0.15M NaCl-injected rats, compared with the insulin-treated group. Conversely, there was a significant decrease in the daily solid rat chow intake (Co: 16.4+/-3.5 g vs. Ins: 10.3+/-2.6g, P=0.003) in 7-day long-term insulin-treated rats, compared with the control group. We confirmed that centrally administered insulin produced a substantial increase in the urinary output of Na+, Li+ and K+, and that the response was significantly enhanced in long-term i.c.v. insulin pre-treated animals, when compared with controls (fractional sodium excretion (FE(Na)) from basal: 0.047+/-0.18% to Ins-treated: 0.111+/-0.035%, P=0.001). Additionally, we demonstrated that insulin-induced natriuresis occurred by increasing fractional proximal (FEP(Na)) from basal (16.8+/-2.6% to Ins-treated: 26.7+/-2.8%, P=0.001) and post-proximal sodium excretion (FEPP(Na)) from basal (0.37+/-0.03% to Ins-treated: 0.42+/-0.05%, P=0.043), despite a decreased Na(+) filtered load and rat food intake. The current data suggest that centrally injected insulin maintain its CNS ability to amplify neuronal hypotensive and natriuretic pathways that counteract the known peripheral antinatriuretic effects of insulin.
Collapse
Affiliation(s)
- Leonardo F Menegon
- Disciplina de Medicina Interna, Departamento de Clínica Médica, Laboratório Balanço Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-592 Campinas, SP, Brazil
| | | | | | | | | |
Collapse
|
15
|
Guadagnini D, Gontijo JAR. Altered renal sodium handling in spontaneously hypertensive rats (SHR) after hypertonic saline intracerebroventricular injection: role of renal nerves. Life Sci 2006; 79:1666-73. [PMID: 16806279 DOI: 10.1016/j.lfs.2006.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 05/25/2006] [Accepted: 06/02/2006] [Indexed: 11/21/2022]
Abstract
The mechanism by which blood pressure rises in the SHR strain remains to be elucidated. Also, there is a surprising lack of experimental data on the natriuretic mechanisms induced by intracerebroventricular (ICV) injection of hyperosmotic saline (HoS) in SHR. In normotensive animals ICV injection of HoS causes coordinated responses including natriuresis and inhibition of renal sympathetic nerve activity. In the present study, we hypothesized that presumable blunting of the sympathoinhibitory response to centrally injected HoS may contribute to a lack of suppression of efferent renal nerve outflow in SHR. To test this hypothesis, the present study evaluates the influence of renal denervation after central HoS injection at increasing concentration on urinary sodium handling in SHR compared with age-matched normotensive WKy rats. The study confirmed previous data showing pronounced natriuretic response to centrally HoS stimuli but also demonstrated that the creatinine clearance (C(Cr)) and fractional sodium excretion responses diminished as graded NaCl concentrations were increased in WKy rats but not in SHR. In SHR, increased FE(Na) obtained by central administration of 0.90 M NaCl was produced by increases in proximal (FEP(Na)) and post-proximal fractional urinary sodium rejection without changes in C(Cr), indicating a direct tubular effect. Renal denervation caused significant antinatriuresis by decreased C(Cr) and increased FEP(Na) reabsorption in WKy but not in SHR. This study suggests that natriuresis observed only after higher centrally HoS stimuli with a rightward shift of dose-response curve provides evidence of a down-regulation of target organ responsiveness of periventricular areas of genetic hypertensive rats.
Collapse
Affiliation(s)
- Dioze Guadagnini
- Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-100 Campinas, SP, Brazil
| | | |
Collapse
|
16
|
Costa EL, Almeida AR, Netto FM, Gontijo JAR. Effect of intraperitoneally administered hydrolyzed whey protein on blood pressure and renal sodium handling in awake spontaneously hypertensive rats. Braz J Med Biol Res 2005; 38:1817-24. [PMID: 16302096 DOI: 10.1590/s0100-879x2005001200010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study evaluated the acute effect of the intraperitoneal (ip) administration of a whey protein hydrolysate (WPH) on systolic arterial blood pressure (SBP) and renal sodium handling by conscious spontaneously hypertensive rats (SHR). The ip administration of WPH in a volume of 1 ml dose-dependently lowered the SBP in SHR 2 h after administration at doses of 0.5 g/kg (0.15 M NaCl: 188.5 +/- 9.3 mmHg vs WPH: 176.6 +/- 4.9 mmHg, N = 8, P = 0.001) and 1.0 g/kg (0.15 M NaCl: 188.5 +/- 9.3 mmHg vs WPH: 163.8 +/- 5.9 mmHg, N = 8, P = 0.0018). Creatinine clearance decreased significantly (P = 0.0084) in the WPH-treated group (326 +/- 67 microL min-1 100 g body weight-1) compared to 0.15 M NaCl-treated (890 +/- 26 microL min-1 100 g body weight-1) and captopril-treated (903 +/- 72 microL min-1 100 g body weight-1) rats. The ip administration of 1.0 g WPH/kg also decreased fractional sodium excretion to 0.021 +/- 0.019% compared to 0.126 +/- 0.041 and 0.66 +/- 0.015% in 0.15 M NaCl and captopril-treated rats, respectively (P = 0.033). Similarly, the fractional potassium excretion in WPH-treated rats (0.25 +/- 0.05%) was significantly lower (P = 0.0063) than in control (0.91 +/- 0.15%) and captopril-treated rats (1.24 +/- 0.30%), respectively. The present study shows a decreased SBP in SHR after the administration of WPH associated with a rise in tubule sodium reabsorption despite an angiotensin I-converting enzyme (ACE)-inhibiting in vitro activity (IC50 = 0.68 mg/mL). The present findings suggest a pathway involving ACE inhibition but measurements of plasma ACE activity and angiotensin II levels are needed to support this suggestion.
Collapse
Affiliation(s)
- E L Costa
- Departamento de Planejamento Alimentar e Nutrição, Faculdade de Engenharia de Alimentos, Universidade Estadual de Campinas, 13083-970 Campinas, SP, Brazil
| | | | | | | |
Collapse
|
17
|
Boer PA, Morelli JM, Figueiredo JF, Gontijo JAR. Early altered renal sodium handling determined by lithium clearance in spontaneously hypertensive rats (SHR): Role of renal nerves. Life Sci 2005; 76:1805-15. [PMID: 15698858 DOI: 10.1016/j.lfs.2004.09.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Accepted: 09/13/2004] [Indexed: 10/25/2022]
Abstract
The mechanism by which blood pressure rises in the SHR strain remains to be elucidated. Since the long-term changes in renal sodium tubule handling associated with genetic hypertension have not been examined in detail, we hypothesized that SHR hypertension development may result from sustained renal sympathetic nerve overactivity and consequently decreased urinary sodium excretion. To test this hypothesis, we assessed renal sodium handling and cumulative sodium balance for 10 consecutive weeks in unanesthetized renal-denervated SHR, performed prior to the start of the entire 10-week metabolic studies, and their age-matched normotensive and hypertensive controls. The present investigation shows that SHR excreted less sodium than Wistar-Kyoto (WKy) rats during the initial 3-week observation period (p <0.05). This tendency was reversed when SHR were 10-wk old. Fractional urinary sodium excretion (FENa+) was significantly lower in 3 and 6-wk-old SHR when compared with the WKy age-matched group, as follows: SHR3-wk-old: 0.33 +/- 0.09% and WKy3-wk-old: 0.75 +/- 0.1% (P <0.05); SHR(6-wk-old): 0.52 +/- 0.12% and WKy6-wk-old: 0.83 +/- 0.11%. The decreased FENa+ in young SHR was accompanied by a significant increase in proximal sodium reabsorption (FEPNa+) compared with the normotensive age-matched control group (P <0.01). This increase occurred despite unchanged creatinine clearance (CCr) and fractional post-proximal sodium excretion (FEPPNa+)in all groups studied. The decreased urinary sodium excretion response in SHR up to the age of 6 weeks was significantly eradicated by bilateral renal denervation of SHR3-wk-old: 0.33 +/- 0.09% and SHR6-wk-old: 0.52 +/- 0.12% to DxSHR 3-wk-old: 1.02 +/- 0.2% and DxSHR 6-wk-old: 0.94 +/- 0.2% (P <0.01), in renal denervated rats. The current data suggest that neural pathways may play an instrumental role on renal sodium reabsorption as result of sustained sympathetic nervous system overexcitability.
Collapse
Affiliation(s)
- Patrícia Aline Boer
- Disciplina de Medicina Interna, Laboratório Balanço Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-100 Campinas, SP, Brazil
| | | | | | | |
Collapse
|