Las hormonas femeninas en fisiología renal: Sensibilidad a la sal y regulación de la proliferación epitelial / Female hormones in renal physiology. Salt sensitivity and regulation of epithelial proliferation

Un tercio de la población mundial tiene niveles anormalmente altos de presión arterial, hipertensión, responsable de casi el 50% de las muertes por accidente cerebrovascular y enfermedad coronaria. La sensibilidad a la sal es un factor de riesgo para la morbilidad y mortalidad cardiovascular y también para otras enfermedades. En estudios previos describimos un modelo de hipertensión sal sensible (HSS) en ratas Wistar ovariectomizadas (oVx) adultas. Las ratas oVx son normotensas con ingesta normal de sal (NS, 0.24% de NaCl), pero desarrollan un perfil de HSS con una ingesta elevada de sal (HS, 1% de NaCl). En los estudios en riñón encontramos que el circuito receptor D1 de dopamina, citocromo P450 4A y Na+, K+-ATPasa está alterado por la ausencia de hormonas ováricas, lo que se asocia a menor excreción de sodio e hipertensión arterial. La ingesta HS en ratas oVx también promueve cambios en la expresión de proteínas relacionadas con el transporte de sodio en células mononucleares de sangre periférica, principalmente linfocitos periféricos. Por lo tanto, el transporte de sodio se modifica en varios niveles de la fisiología normal. En estudios recientes observamos que el estradiol aumenta la proliferación y diferenciación de células epiteliales en cultivos de corteza renal humana. Sensibilidad a la sal, inmunidad adaptativa, presión arterial y proliferación de células epiteliales en riñón son fenómenos de gran importancia biológica regulados por estradiol.

Female sex hormones participate in the regulation of blood pressure and renal epithelial proliferation, effects not related to their reproductive function. About one-third of the world's population has abnormally high levels of blood pressure, hypertension, which is responsible for almost 50% of deaths from stroke and coronary heart disease. Salt sensitivity is a risk factor for cardiovascular morbidity and mortality and other diseases as well. We reported a model of salt sensitive hypertension in adult ovariectomized (oVx) Wistar rats. oVx rats are normotensive under normal salt intake (NS, 0.24% NaCl), but upon a high salt intake (HS, 1% NaCl) oVx rats developed a blood pressure profile of salt-sensitive hypertension. Our studies on kidney molecules related to sodium balance found that the circuit dopamine D1-like receptor, cytochrome P450 4A and Na+, K+-ATPase is altered by the absence of ovary hormones which is accompanied by a reduced ability to excrete sodium. In oVx rats HS intake also promotes changes in the expression of proteins related to sodium transport in peripheral blood mononuclear cells, mainly peripheral lymphocytes. Therefore, sodium transport is modified at several levels of normal physiology. Lately, we described that estradiol increases the rate of renal epithelial cell proliferation in primary cultures developed from human renal cortex. Thus, salt sensitivity, adaptive immunity, blood pressure and renal cell proliferation are complex biological responses regulated by female sex hormones.

Study on the mechanism of PSGL-1 in salt-sensitive hypertension via inflammation in mice / 中国比较医学杂志

Objective To investigate the role and mechanism of PSGL-1 in development of salt-sensitive hypertension in mice. Methods PSGL-1 knockout(PSGL-1 -/-)and wild type(PSGL-1 +/ +)mice were fed a high salt (6% NaCl)or normal salt(0.4% NaCl)diet for three months. Blood pressure was measured under anesthesia via the carotid artery. The status of tissue inflammation and kidney injury was tested by flow cytometry, immunohistochemistry, and western blotting. Results Compared with mice fed a normal salt diet, PSGL-1 +/ +mice fed a high salt diet for three months showed high blood pressure, increased inflammatory cell infiltration in the aorta and skin, and increased inflammatory cytokine expression(interleukin-6, interleukin-1β, and tumor necrosis factor-α)in the kidney, as well as elevated expression of the kidney injury marker, connective tissue growth factor. In contrast, inflammation and kidney injury were not found in PSGL-1 -/-mice fed a high-salt diet. Conclusions In mice,PSGL-1 via inflammation plays a key role in development of hypertension and kidney injury caused by high salt intake.

Clinical Study of Androgen Receptor (CAG) Gene Polymorphism and Androgen in Male with Salt Sensitive Hypertension / 现代检验医学杂志

Objective To investigate the relationship between androgen receptor CAG-gene polymorphism and androgen in male with salt sensitive hypertension.Methods Through the oral saline loading test and furosemide volume method male hypertension group were divided into salt-sensitive (SS group) and salt-insensitive (SR group).The samples from 161 males were selected in the study,including salt sensitive hypertension patients (SS group,61/161),salt-insensitive hypertension patients (SR group,40/161) and age-matched healthy samples (control group,60/161).All samples were sequenced with an analysis method (CAG) n repeated polymorphism,and determinated of total testosterone (TT) and free testosterone (FT) level in serum by electrochemiluminescence immunoassay.Results The number of CAG repeats was 14～34,average 22.4± 2.7.The CAG repeats of SS,SR and control group were 23.5±3.75,22.3±3.17 and 21.8±2.95,respectively.There were significant differences among the three groups (t=2.627～ 3.257,all P＜0.05).The level of TT and FT in SS and SR group were decreased compared with that of control group.At the same time,the level of SS group was lower,and there were significant differences among the three groups (t=2.524～ 3.826,all P＜0.05).Conclusion The androgen receptor gene repeat length and androgen levels are associated with male hypertension,especially salt-sensitive hypertension.Long (CAG) n repeat polymorphism maybe a genetic factor in the pathogenesis of hypertension.Plasma androgen levels may be used as a predictor of male salt sensitive hypertension.

The study on the mechanism of platelet in the development of salt-sensitive hypertension via inflammation / 中国比较医学杂志

Objective To investigate the role and mechanism of platelet in the development of salt-sensitive hypertension.Methods 25 Dahl salt-sensitive rats (Dahl SS) were divided into three groups: low-salt diet (0.12% NaCl, LS), high-salt diet (8%NaCl, HS) and high-salt diet + platelet inhibitor (8%NaCl+busulfan, HS+bus).Blood pressures were measured by tail-cuff method.After six weeks, animals were sacrificed.Platelet p-selectin expression, platelet cytosolic Ca2+ concentration, platelet-leukocyte aggregation (PLA) in peripheral blood, and immune cells infiltrated on aortic walls were assessed by flow cytometry, and serum IL-6 level was tested by ELISA in vivo.Platelets purified from SD rats were treated with normal salt (0.9%NaCl) and high salt (1.3%NaCl), then the cytosolic Ca2+ concentration and p-selectin expression of platelet were detected.Results We found that Dahl SS rats with high-salt diet, relative to low-salt diet, presented with high blood pressure and increased the ratio of platelet p-selectin expression, Ca2+ concentration.IL-6 level and PLA in peripheral blood, and the number of infiltrated immune cells on aortic walls were also significantly elevated in high-salt diet group.The whole events were ameliorated by the platelet inhibitor busulfan.Cytosolic Ca2+ concentration and p-selectin expression were also increased in purified platelets treated with high salt than those treated with low salt (P < 0.05).Conclusions Our findings suggest that high salt induced platelet activation with increased Ca2+ concentration may play an important role in the development of salt-sensitive hypertension via vascular inflammation.However, the detailed mechanisms of platelet activation and development of high blood pressure via inflammation induced by high salt intake remain to be determined.

Influence of Different Dietary Salt Concentration on the Renal Fibrosis and Macrophages Infiltration in Salt Sensitive Hypertension / 现代生物医学进展

Objective:To investigate the influence of different salt concentration on the renal fibrosis and macrophages infiltration in salt sensitive hypertension.Methods:Dahl salt sensitive rats were randomly divided into the normal salt (0.3 ％ nacl) group,4 ％ high salt,8 ％ high salt groups at six weeks continuously feeding for 8 weeks,each group contained 15 rats.Tail-cuffmethod was used to value rat blood pressure at 8 weeks,Masson trichromatic method was used to detect renal fibrosis of the three groups at 8 week.Immunohistochemistry and Western blot method were used to depict the renal macrophage infiltration at 8 week.Results:1) The blood pressure of 4 ％ salt and 8％ high salt group rats were significantly higher than those of the normal salt group at 8week,meanwhile the blood pressure of 8 ％ high salt was further increased than that of 4 ％ high salt group at 8 week.2) The relative kidney weight and renal fibrosis of 4 ％ salt and 8 ％ high salt group rats were obviously higher than that of normal salt group at 8week,meanwhile the relative kidney weight and renal fibrosis of 8 ％ high salt were further increased than those of 4 ％ high salt group at 8 week.3) The macrophage infiltration of 4 ％ salt and 8％ high salt group rats were higher than that of the normal salt group at 8week,meanwhile the macrophage infiltration of 8 ％ high salt was further increased than that of 4 ％ high salt group at 8 week.Conclusion:Different high salt concentrations had different effect on the renal fibrosis and macrophage infiltration in the salt sensitive hypertension,high salt concentration could exacerbate the renal fibrosis and macrophage infiltration.

Papel de la inflamación renal en la fisiopatología de la hipertensión sensible a sal / Role of renal inflammation in the physiopathology of salt-sensitive hypertension

La hipertensión sensible a sal es el aumento de la presión arterial luego de una sobrecarga salina, como consecuencia esencialmente de una disminución en la excreción renal de sodio. En los últimos años, ha sido desarrollada una teoría para explicar su origen que tiene como base la inflamación del tejido renal. El proceso inicia con la producción en los riñones de radicales libres derivados del metabolismo oxidativo. Luego se desarrolla un mecanismo de inflamación del intersticio renal por infiltración de linfocitos T, y otras células inmunológicas. Fundamentalmente los linfocitos T incrementan la producción de angiotensina II que estimula la retención de sodio y agua a este nivel, favoreciendo el desarrollo de hipertensión sensible a sal. La relación entre infiltración renal por células del sistema inmune e hipertensión sensible a sal permite, en parte, explicar la asociación entre enfermedades autoinmunes y la hipertensión arterial. El uso de antioxidantes y el diseño de nuevos fármacos pueden ser una alternativa adicional al tratamiento de los pacientes afectados.

Salt-sensitive hypertension is produced by a decrease in salt renal excretion after a salt overload. Over the last few years, a new theory has been developed to explain this condition based on renal tissue inflammation. This process begins with free radicals production in renal tissue due to oxidative metabolism. Then they favor a renal inflammation mechanism with T-lymphocytes infiltration and other immune cells. Essentially, T-lymphocytes determine an increase in angiotensin II production which raises sodium and water retention. Association among autoimmune diseases and hypertension may be explained, in part, by the relationship between salt-sensitive hypertension and renal inflammation. The use of antioxidant drugs and the development of new medicaments may be a choice for treating patients affected with this condition.

Partial baroreceptor dysfunction and low plasma nitric oxide bioavailability as determinants of salt-sensitive hypertension: a reverse translational rat study

This study determined whether clinical salt-sensitive hypertension (cSSHT) results from the interaction between partial arterial baroreceptor impairment and a high-sodium (HNa) diet. In three series (S-I, S-II, S-III), mean arterial pressure (MAP) of conscious male Wistar ChR003 rats was measured once before (pdMAP) and twice after either sham (SHM) or bilateral aortic denervation (AD), following 7 days on a low-sodium (LNa) diet (LNaMAP) and then 21 days on a HNa diet (HNaMAP). The roles of plasma nitric oxide bioavailability (pNOB), renal medullary superoxide anion production (RMSAP), and mRNA expression of NAD(P)H oxidase and superoxide dismutase were also assessed. In SHM (n=11) and AD (n=15) groups of S-I, LNaMAP-pdMAP was 10.5±2.1 vs 23±2.1 mmHg (P<0.001), and the salt-sensitivity index (SSi; HNaMAP−LNaMAP) was 6.0±1.9 vs 12.7±1.9 mmHg (P=0.03), respectively. In the SHM group, all rats were normotensive, and 36% were salt sensitive (SSi≥10 mmHg), whereas in the AD group ∼50% showed cSSHT. A 45% reduction in pNOB (P≤0.004) was observed in both groups in dietary transit. RMSAP increased in the AD group on both diets but more so on the HNa diet (S-II, P<0.03) than on the LNa diet (S-III, P<0.04). MAP modeling in rats without a renal hypertensive genotype indicated that the AD*HNa diet interaction (P=0.008) increases the likelihood of developing cSSHT. Translationally, these findings help to explain why subjects with clinical salt-sensitive normotension may transition to cSSHT.

Different combination of drugs regarding the damage on organs targeting salt sensitivity or non-salt-sensitive hypertension / 中华流行病学杂志

Objective To study the damage on organs from salt sensitivity hypertension or non-salt-sensitive hypertension and the selection of drug combination.Methods 120 hypertensive patiems including 60 cases salt-sensitive (SS) and 60 non-salt-sensitive (NSS) groups were selected in our hospital and their salt load tested.These two groups were randomly divided into two groups,each group with 30 patients,one was given felodipine and perindopril and the others were given indapamide sustained release tablets and peridopril to facilitate the 12-week treatment.Before and after the treatment,patients were tested for physiological indicators,such as sitting blood pressure,24-hour ambulatory blood pressure,insulin resistance index,comparing changes of various sub-index etc.Results Significantly different were seen in indices as fasting blood glucose and serum creatinine (P＜ 0.01),fasting insulin,left ventricular mass index,urinary albumin,body mass index,insulin resistance indices,while between the SS group and the NSS group(P＜0.05).In the SS group,when patients with various sub-indicators were using perindopril combined with indapamide treatment,the related detected indicators tended to be normal and with statistically significant differences (P＜0.05).In the NSS group,those related indexes also tended to be more normal when using felodipine combined with perindopril.However,there were statistically significant differences between the two groups (P＜0.05).Conclusion On SS hypertensive patients with target organ damages,perindopril and indapamide seemed to be more effective in NSS patients,indicating that the use of perindopril and felodipine combination,seemed to be more suitable.

Prostaglandin E receptors in regulation of blood pressure / 中国药理学通报

Prostaglandin E_2(PGE_2)is one of the major metabolic products of arachidonic acid.PGE_2 plays important roles in various important physiological processes by binding to its G protein-coupled receptors designated EP1,EP2,EP3,and EP4,respectively.EP receptors are highly expressed in the kidney and cardiovascular system,and PGE2-mediated activation of EP receptors plays important roles in the regulation of blood pressure.The abnormal expression of EP receptors in the kidney and cardiovascular system is associated with some blood pressure disease such as salt-sensitive hypertension,renal hypertension,and myocardial hypertrophy.

Altered Regulation of Renal Sodium Transporters in Salt-Sensitive Hypertensive Rats Induced by Uninephrectomy

Uninephrectomy (uNx) in young rats causes salt-sensitive hypertension (SSH). Alterations of sodium handling in residual nephrons may play a role in the pathogenesis. Therefore, we evaluated the adaptive alterations of renal sodium transporters according to salt intake in uNx-SSH rats. uNx or sham operations were performed in male Sprague-Dawley rats, and normal-salt diet was fed for 4 weeks. Four experimental groups were used: sham-operated rats raised on a high-salt diet for 2 weeks (CHH) or on a low-salt diet for 1 week after 1 week's high-salt diet (CHL) and uNx rats fed on the same diet (NHH, NHL) as the sham-operated rats were fed. Expression of major renal sodium transporters were determined by semiquantitative immunoblotting. Systolic blood pressure was increased in NHH and NHL groups, compared with CHH and CHL, respectively. Protein abundances of Na+/K+/2Cl- cotransporter (NKCC2) and Na+/Cl- cotransporter (NCC) in the CHH group were lower than the CHL group. Expression of epithelial sodium channel (ENaC)-gamma increased in the CHH group. In contrast, expressions of NKCC2 and NCC in the NHH group didn't show any significant alterations, compared to the NHL group. Expressions of ENaC-alpha and ENaC-beta in the NHH group were higher than the CHH group. Adaptive alterations of NKCC2 and NCC to changes of salt intake were different in the uNx group, and changes in ENaC-alpha and ENaC-beta were also different. These altered regulations of sodium transporters may be involved in the pathogenesis of SSH in the uNx rat model.