Dialysis vintage time has the strongest correlation to psychosocial pattern of oral health-related quality of life - a multicentre cross-sectional study.

BACKGROUND: Aim of this cross-sectional, multicentre study was to investigate associations of dialysis vintage time in haemodialysis (CKD5D) patients with oral health-related quality of life (OHRQoL) and dental and periodontal treatment need. MATERIAL AND METHODS: CKD5D patients were divided into subgroups according to dialysis vintage time in different dialysis centres in Germany. OHRQoL was assessed with oral health impact profile (OHIP-G14). Dental treatment need was classified as presence of carious lesions. Periodontal treatment need was defined as periodontal screening index score (PSI) 3-4. RESULTS: In total, 190 participants were divided into the subgroups according to the time on CKD5D: 0 - 2 (n = 29), 3 - 5 (n = 35), 6 - 8 (n = 34), 9 - 12 (n = 29), 13 - 20 (n = 34) and >20 years (n = 29). The overall treatment need in the total cohort was 92% (dental 56%, periodontal 88%) with a total OHIP-G14 sum score of 4.17 [2; 0-5] without a significant correlation. Time on CKD5D was inversely correlated with the OHIP G14 score (p<0.01, R = -0.201). The pattern psychosocial impact was significantly associated with the dialysis duration (p<0.01) and showed a negative correlation to the OHIP-G14 (R = -0.283, Spearman's rho test p<0.01). For oral function also a negative correlation with OHIP-G14 was detected (Spearman's rho: -0.183). CONCLUSIONS: Patients with a prolonged dialysis vintage time show an improved OHRQoL, which might be mainly caused by the positive development of psychosocial pattern of OHRQoL. The oral health situation of HD patients seems unsatisfying, independently of dialysis vintage time and OHRQoL. Accordingly, an improvement in oral health situation of CKD5D patients is mandatory necessary. Thereby, consideration of psychosocial aspects especially at the beginning of CKD5D therapy and a sensitization regarding oral health issues with increasing vintage time might be recommendable.

[Acute renal failure: pathophysiology and clinical management]. / Akutes Nierenversagen: Pathophysiologie und klinisches Management.

The main pathomechanism of acute renal failure (ARF) is acute tubular necrosis (ATN) due to reduced perfusion of renal cortex resulting in ischemic injury. ATN has the potential for complete restitution. However, acute renal failure is often complicated by pre-existing renal disease, ongoing toxic injury or non-recovery of systemic circulation. From a clinical point of view, the reason of tubular injury may be based on pre-renal causes, glomerular- and/or interstitial disorders or obstructive nephropathy. Therapy must be specifically targeted on the underlying causes to overcome ARF. If kidney function is not reconstituted in an appropriate time period, renal replacement therapy has to be initiated. Recent evidence for improved patient survival supports an augmented dialysis dose to achieve a maximum of metabolic, volume and electrolyte control. To reach these goals, daily intermittent or continuous forms of hemodialysis or hemofiltration are appropriate measures.

Impaired renal allograft function is associated with increased arterial stiffness in renal transplant recipients.

It is important whether impairment of renal allograft function may deteriorate arterial stiffness in renal transplant recipients. In a cross-sectional study, arterial vascular characteristics were non-invasively determined in 48 patients with renal allograft using applanation tonometry and digital photoplethysmography. Mean age was 51 +/- 2 years (mean +/- SEM), and studies were performed 17 +/- 1 months after transplantation. The stage of chronic kidney disease was based on the glomerular filtration rate. We observed a significant association between the stage of chronic kidney disease and arterial stiffness of large arteries S1 and small arteries S2 in renal transplant recipients (each p < 0.05 by non-parametric Kruskal-Wallis test between groups). Multivariate linear regression analysis showed that male gender of patients with renal allograft (p < 0.01) reduced glomerular filtration rate (p = 0.01), and older age of kidney donor (p = 0.04) were independently associated with an increase of large artery stiffness S1. Furthermore, a significant association between the stage of chronic kidney disease and arterial vascular reactivity during reactive hyperemia was observed (p < 0.05 by non-parametric Kruskal-Wallis test between groups). It is concluded that impairment of renal allograft function is associated with an increased arterial stiffness in renal transplant recipients.

Upregulation of the vascular NAD(P)H-oxidase isoforms Nox1 and Nox4 by the renin-angiotensin system in vitro and in vivo.

In different cardiovascular disease states, oxidative stress decreases the bioavailability of endothelial NO, resulting in endothelial dysfunction. An important molecular source of reactive oxygen species is the enzyme family of NAD(P)H oxidases (Nox). Here we provide evidence that the vascular Nox isoforms Nox1 and Nox4 appear to be involved in vascular oxidative stress in response to risk factors like angiotensin II (Ang II) in vitro as well as in vivo. Nox mRNA and protein levels were quantified by real-time RT-PCR and Western blotting, respectively. Nox1 and Nox4 were expressed in the vascular smooth muscle cell (VSMC) line A7r5 and aortas and kidneys of rats. Upon exposure of A7r5 cells to Ang II (1 microM, 4 h), Nox1 and Nox4 mRNA levels were increased 6-fold and 4-fold, respectively. Neither the vasoconstrictor endothelin 1 (up to 500 nM, 1-24 h) nor lipopolysaccharide (up to 100 ng/ml, 1-24 h) had any effect on Nox1 and Nox4 expression in these cells. Consistent with these observations made in vitro, aortas and kidneys of transgenic hypertensive rats overexpressing the Ren2 gene [TGR(mRen2)27] had significantly higher amounts of Nox1 and Nox4 mRNA and of Nox4 protein compared to tissues from normotensive wild-type animals. In conclusion, Nox4 and Nox1 are upregulated by the renin-angiotensin system. Increased superoxide production by upregulated vascular Nox isoforms may diminish the effectiveness of NO and thus contribute to the development of vascular diseases. Nox1 and Nox4 could be targeted therapeutically to reduce vascular reactive oxygen species production and thereby increase the bioavailability of NO.

Effects of angiotensin II subtype 1 receptor blockade on cardiac fibrosis and sarcoplasmic reticulum Ca2+ handling in hypertensive transgenic rats overexpressing the Ren2 gene.

OBJECTIVE: We evaluated the effects of angiotensin II subtype 1 (AT1) receptor antagonism on cardiac fibrosis and sarcoplasmic (SR) Ca2+ handling in a transgenic rat model of renin-dependent left ventricular (LV) hypertrophy (LVH). METHODS: Hypertensive transgenic rats overexpressing the Ren2 gene (TGR(mRen2)27) were treated between 10 and 30 weeks of age with the angiotensin II subtype 1 (AT1) receptor antagonist, eprosartan, in an antihypertensive (Ren2-E60, 60 mg/kg per day) and a non-antihypertensive (Ren2-E6, 6 mg/kg per day) dose applied intraperitoneally via osmotic-mini-pumps. They were compared to age-matched Ren2 and Sprague-Dawley (SD) control rats receiving 0.9% NaCl as vehicle via osmotic mini-pumps (Ren2-Vehicle, SD-Vehicle, respectively). RESULTS: Systolic blood pressure (SBP), LV weight, LV end-diastolic pressure (LVEDP), and cardiac fibrosis were elevated in Ren2-Vehicle, while diastolic function (-dP/dt(max)) and sarcoplasmic reticulum (SR) Ca2+ uptake were decreased in Ren2-Vehicle compared to SD-Vehicle (P < 0.05, respectively). SBP was not altered in Ren2-E6, but reduced to normotensive levels in Ren2-E60 compared to Ren2-Vehicle and SD-Vehicle (P < 0.0001). In both Ren2-E6 and Ren2-E60, LV weights were reduced and LVEDP and -dP/dt(max)normalized compared to Ren2-Vehicle (P < 0.05). SR Ca2+ uptake was normalized in both Ren2-E6 and Ren2-E60. Cardiac fibrosis did not change in Ren2-E6, but perivascular LV fibrosis and hydroxyprolin content were reduced in Ren2-E60 compared to Ren2-Vehicle (P < 0.05, respectively). CONCLUSIONS: Normalization of LV SR Ca2+ uptake is an important mechanism by which AT1 receptor antagonism improves LV diastolic dysfunction independent from a reduction of SBP and cardiac fibrosis in the TGR (mRen2)27 model.

Regulation of pressure-activated channel in intact vascular endothelium of stroke-prone spontaneously hypertensive rats.

The pressure-activated cation channel (PAC), a novel type of mechanosensitive channel, has been suggested to act as a mechanosensor in aortic endothelium. In experimental hypertension, PAC function was up-regulated in the established phase of high blood pressure. This association of altered PAC function and elevated arterial pressure suggests that PAC function is regulated by alterations in blood pressure. In the present study, we electrophysiologically investigated PAC function in intact endothelium of aorta (EA) and mesenteric artery (EMA) from stroke-prone spontaneously hypertensive rats (SHRSP), SHRSP after 4 weeks of treatment with quinaprilat (10 mg/kg/day), and normotensive Wistar-Kyoto (WKY) rats. In untreated SHRSP and WKY rats, systolic blood pressure (SBP) was 201+/-3 mm Hg and 142+/-3 mm Hg, respectively. In quinaprilat-treated SHRSP, SBP was lowered to 135+/-5 mm Hg. Apparent PAC density (percentage of patches with PAC activity) in EA of untreated SHRSP (63.7%+/-7.3%) was 2.4-fold higher than in WKY rats (26.0%+/-5.0%). In contrast, no significant PAC up-regulation was detected in EMA of SHRSP (15.7%+/-4.2%) compared with WKY rats (12.0%+/-3.9%). In EA of quinaprilat-treated normotensive SHRSP, PAC density (27.1%+/-5.2%) was lowered to levels found in normotensive WKY rats. Unitary conductance and pressure sensitivity of PAC were not altered in either hypertensive or normotensive rats. Taken together, hypertension-induced increases of endothelial PAC density can be completely reversed by antihypertensive therapy. The PAC up-regulation in EA was interpreted as a compensatory mechanism to enhance Ca2+-influx and subsequently the synthesis of vasodilatory factors. This mechanism is missing in EMA of SHRSP, which might contribute to high blood pressure in this rat model of severe genetic hypertension.

Renal endothelin ET(A)/ET(B) receptor imbalance differentiates salt-sensitive from salt-resistant spontaneous hypertension.

It is unclear why a subgroup of patients with essential hypertension develop salt-sensitive hypertension with progression of target organ damage over time. We evaluated the role of the renal endothelin (ET) system in the stroke-prone spontaneously hypertensive rat (SHRSP) model of salt-sensitive spontaneous hypertension (SS-SH) compared with the spontaneously hypertensive rat (SHR) model of salt-resistant spontaneous hypertension (SR-SH). Both strains were studied after either sham-operation on a normal diet (Sham) or after unilateral nephrectomy and high NaCl loading (NX-NaCl) with 4% NaCl in diet for 6 weeks (n=10, respectively). Systolic blood pressure (SBP) increased only in SHRSP-NX-NaCl compared with SHRSP-Sham (250+/-6 versus 172+/-5 mm Hg, P:<0.0001). SBP remained unchanged in SHR-NX-NaCl compared with SHR-Sham. In SHRSP-NX-NaCl animals, urinary albumin and ET-1 excretion, renal ET-1 mRNA expression, glomerulosclerosis index, and tubulointerstitial damage index were elevated compared with SHRSP-Sham (P:<0.05, respectively), whereas no significant changes were found in SHR after NX-NaCl. Urinary sodium excretion (U(Na(+))) was significantly reduced by 38% in SHRSP-NX-NaCl compared with SHR-NX-NaCl (P:<0.005, respectively). SHR animals showed a similar increase in both renal ET(A) and ET(B) receptor densities after NX-NaCl (2.2-fold, P:<0.05). In contrast, SHRSP-NX-NaCl developed a significantly more pronounced increase in ET(A) compared with ET(B) binding (4.7-fold versus 2.4-fold, P:<0.05, compared with SHRSP-Sham, respectively), resulting in a significant 2.1-fold increase in ET(A)/ET(B) receptor ratio only in the SHRSP-NX-NaCl (P:<0.05). Thus, activation of the renal ET system together with an increased ET(A)/ET(B) receptor ratio may contribute to the development and progression of SS-SH.

Activation of the hepatic endothelin-system in rats with biliary liver fibrosis.

Circulating plasma endothelin-1 (ET-1) is elevated in liver cirrhosis, in a disease-stage-dependent manner. However, ET-1 exerts its effects mainly via paracrine and autocrine pathways. Therefore, the aim of the present study was to analyze the hepatic endothelin (ET) system in liver cirrhosis resulting from bile duct obstruction (BDO). Wistar rats were subjected for 6 weeks to either sham operation (control) or BDO. Thereafter, hepatic ET-1 concentrations were elevated 7.2-fold in BDO compared to control (p <0.001), whereas big ET-1 was unchanged. The density of both ET receptor subtypes was upregulated in BDO (ETA: 7.4-fold and ETB: 4.9-fold vs control, p < 0.001, respectively). The affinity of both receptor subtypes was significantly reduced in BDO. In conclusion, our data demonstrated for the first time that the hepatic ET system in liver cirrhosis is characterized by a simultaneous upregulation of both ET-1 tissue concentration as well as the density of hepatic ETA- and ETB-receptors, suggesting a synergistic activation of the hepatic ET system in rats with BDO. The increased ET-1 tissue concentration is not a result of an altered big ET-1 synthesis in biliary liver fibrosis, suggesting an increased activity of endothelin-converting enzyme (ECE) in liver cirrhosis.

Regulation of the hepatic endothelin system in advanced biliary fibrosis in rats.

The aim of the present study was to analyze the hepatic endothelin system and its regulation in liver cirrhosis due to bile duct obstruction. Wistar rats were subjected for 6 weeks to: 1) sham operation; 2) bile duct obstruction; 3) bile duct obstruction and the selective oral endothelin A receptor antagonist LU 135252; 4) bile duct obstruction and oral silymarin, a hepatoprotective and antifibrotic compound. We determined tissue concentrations of endothelin-1 and big-endothelin-1 by ELISA and the density of both endothelin receptor subtypes in plasma membrane fractions by Scatchard analysis. The hepatic endothelin system in liver cirrhosis due to chronic bile duct obstruction is characterized by a simultaneous up-regulation of both endothelin-1 tissue concentration (7.2 fold compared to sham operation; p<0.001) as well as the density of both endothelin receptor subtypes (ET(A) 7.4-fold, ET(B) 4.9-fold, p<0.001, respectively) suggesting a synergistic activation of the hepatic endothelin system in this rat model of non-inflammatory cirrhosis. Treatment with proven antifibrotic agents such as silymarin or a selective endothelin-A-receptor blocker (LU 135252) did not reduce the activity of the hepatic endothelin system, suggesting that the hepatic endothelin system is not activated by the fibrotic process itself.

Cardiac endothelin system impairs left ventricular function in renin-dependent hypertension via decreased sarcoplasmic reticulum Ca(2+) uptake.

BACKGROUND: We evaluated the role of the cardiac endothelin (ET) system in compensated hypertensive left ventricular (LV) hypertrophy (LVH) and after the transition toward LV dysfunction. METHODS AND RESULTS: Hypertensive transgenic rats overexpressing the Ren2 gene (Ren2 rats) were investigated between the ages of 10 and 30 weeks (Ren2-10 and Ren2-30 groups, respectively) and compared with age-matched normotensive Sprague-Dawley (SD) rats (SD-10 and SD-30 groups, respectively). Systolic blood pressure and LV weight were elevated in both Ren2 groups compared with their age-matched SD control groups (P:<0.0001). In Ren2-30 rats, LV end-diastolic pressure increased and -dP/dt(max) decreased compared with the values in SD-30 and Ren2-10 rats (P:<0.05). This was paralleled by an activation of LV mRNA expression of preproET-1 and ET-converting enzyme-1 and ET subtype A (ETA) receptor binding in Ren2-30 compared with Ren2-10 rats (P:<0.001). Cardiac fibrosis was increased and sarcoplasmic reticulum (SR) Ca(2+) reuptake was reduced in Ren2-30 compared with SD-30 and Ren2-10 rats (P:<0.05). Treatment of Ren2 rats with the selective ETA receptor antagonist Lu135252 between 10 and 30 weeks of age did not lower systolic blood pressure, heart weight, or cardiac fibrosis but completely prevented the deterioration of LV end-diastolic pressure and abolished alterations in -dP/dt(max) and SR Ca(2+) reuptake compared with no treatment in Ren2-30 and SD-30 rats (P:<0.05). CONCLUSIONS: Activation of the cardiac ET system accounts at least in part for the LV dysfunction that gradually develops in LVH. The protective effect of ETA antagonism can be attributed to the improvement of diastolic LV function that is due to normalization of impaired SR Ca(2+) uptake.

Effect of high NaCl diet on spontaneous hypertension in a genetic rat model with reduced nephron number.

OBJECTIVE: An inherited reduction in nephron number has been implicated in the development of salt-sensitive hypertension and end stage renal disease. The Munich Wistar Frömter (MWF) rat represents a genetic model with a 30-50% reduction of nephrons compared with normal rats. MWF rats develop spontaneous hypertension and increased urinary albumin excretion (UAE). We addressed the question whether the inherited defect in this model leads to salt-sensitive hypertension. METHODS: At the age of 6 weeks, we started male and female MWF/Fub rats and salt-resistant Lewis (Lew) reference rats on either a normal NaCl (0.2%) or a high NaCl (8%) diet (n = 8, each group). Systolic blood pressure (SBP) and UAE were measured at 14 weeks. RESULTS: Under a normal diet, MWF/Fub rats demonstrated significantly elevated SBP compared to Lew rats both in male (165 +/- 2 versus 133 +/- 3 mmHg, P < 0.0001) and female (156 +/- 3 versus 134 +/- 3 mmHg, P < 0.0001) rats. After high NaCl treatment, SBP was significantly higher in both male and female MWF/Fub rats (+55 mmHg and +36 mmHg, P < 0.0001, respectively) compared with MWF/ Fub under a normal diet UAE was also significantly higher in male and female MWF/Fub rats after high NaCl excess (P < 0.0005, respectively). In contrast, both SBP and UAE remained unchanged in response to high NaCl in Lew rats. CONCLUSIONS: Our findings demonstrate that both the hypertension and UAE are sensitive to high NaCl loading in female and male MWF/Fub rats. Thus, an inborn nephron deficit may lead to salt-sensitive hypertension and renal dysfunction.

Acute blood pressure effects of YC-1-induced activation of soluble guanylyl cyclase in normotensive and hypertensive rats.

We used YC-1 as a pharmacological tool to investigate the short-term blood pressure effects of NO-independent activation of sGC in normotensive and hypertensive rats. Four groups of normotensive Wistar-Kyoto rats were treated by i.v. injection with vehicle (V), YC-1 (YC-1), sodium nitroprusside (SNP), or YC-1 and SNP (YC-1+SNP). Hypertension was induced in four additional groups of WKY rats by 3 weeks of oral treatment with L-NAME. These animals were investigated with the same protocol as the normotensive animals: L-NAME/V, L-NAME/YC-1, L-NAME/SNP, L-NAME/YC-1+SNP. YC-1 lowered mean arterial blood pressure (MAP) in normotensive and hypertensive animals similarly to SNP alone (P<0.05, respectively). The combination of YC-1 with SNP caused a strong decrease of MAP in both the hypertensive and normotensive animals (P<0.05, respectively). SNP with YC-1 also induced a pronounced cyclic GMP increase in the aorta. This study shows for the first time the blood pressure lowering potential of bimodal targeting of the NO-sGC-system.

Hypertension and the renin-angiotensin system--evidence from genetic and transgenic studies.

The renin-angiotensin system (RAS) has been extensively studied in the past decades as an important mediator of hypertension and hypertensive end-organ damage. Originally, the RAS was described as an endocrine system that exerts its action through the effector peptide angiotensin II (ANG II). Recently, tissue-based renin-angiotensin systems which act through paracrine-autocrine mechanisms have been suggested as the more important pathway. After all, genes of the RAS have been cloned transgenic animals overexpressing different components of the RAS were constructed. Furthermore, gene polymorphisms were investigated as genetic markers for hypertension and cardiovascular disease. Finally, very effective substances interacting on different levels of the RAS cascade were developed.

The role of endothelin in hypertension.

The endothelins are 21-amino-acid peptides which may play a role in the pathogenesis of hypertension. There is increasing evidence that the endothelins have a central function in mediating end-organ damage in hypertension, and that important effects of endothelin in the pathogenesis of hypertension may be based on the interactions of the endothelins and the renin-angiotensin and the nitric oxide systems.

ACE inhibition prevents Na and water retention and MABP increase during reduction of renal perfusion pressure.

Two groups of six dogs were studied during 4 control days and 4 days of reduced renal perfusion pressure (rRPP) servo controlled at 20% below the individual dog's 24-h mean arterial blood pressure (MABP) during control days, i.e., below the threshold for renin release. On rRPP days, endogenous activation of plasma aldosterone and angiotensin II was inhibited by the angiotensin-converting enzyme inhibitor captopril. The dogs were kept on a high-Na and high-water intake. Unlike studies during rRPP alone, there was no Na and water retention during rRPP+captopril. Glomerular filtration rate dropped by approximately 9%, and MABP remained in the range of control days. Plasma renin activity rose to values 14 times greater than control, whereas plasma aldosterone decreased by approximately 60%. Atrial natriuretic peptide remained in the range of controls. In conclusion, angiotensin-converting enzyme inhibition can prevent the otherwise obligatory Na and water retention and systemic MABP increase during a 20% reduction in renal perfusion pressure. This is achieved most likely via the captopril-induced fall in angiotensin II and plasma aldosterone levels.

Resetting of 24-h sodium and water balance during 4 days of servo-controlled reduction of renal perfusion pressure.

This study examines whether an increase in renal perfusion pressure (RPP) is necessary to escape endogenously stimulated Na- and water-retaining mechanisms. In seven dogs stimulation was accomplished by a servo-controlled reduction of RPP (rRPP) below the threshold for pressure-dependent renin release for 4 days. Oral intake was standardized. Plasma renin activity (PRA) rose from 2.5 in controls to approximately 5 ng ANG I.ml-1 x h-1 during rRPP days. Plasma aldosterone concentration (PAC) increased by approximately 50% only on day 1 of rRPP but fell at or below control levels thereafter. The PAC-to-PRA ratio decreased during rRPP days. Atrial natriuretic factor (ANF) rose to values three times higher than in controls. Mean systemic blood pressure (MABP) rose from 111 +/- 12 in controls to 142 +/- 14 mmHg on day 4 of rRPP. On day 1 of rRPP 60% of the Na and 24% of the water intake were retained. However, after 2-3 days the input-output balance was restored but on a higher level of total body Na and total body water (new "set point"). Because elevated systemic MABP could not exert direct pressure effects on the kidneys due to servo control of rRPP, there must be other factors, e.g., fall in PAC, increase in ANF, and changes in intrarenal hemodynamics and physical factors that may have contributed to the resetting of input-output balances during rRPP.