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1.
Nephrol Dial Transplant ; 32(10): 1617-1627, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27448672

RESUMO

BACKGROUND: Hyperphosphataemia is an independent risk factor for accelerated cardiovascular disease in chronic kidney disease (CKD), although the mechanism for this is poorly understood. We investigated the effects of sustained exposure to a high-phosphate environment on endothelial function in cellular and preclinical models, as well as in human subjects. METHODS: Resistance vessels from rats and humans (± CKD) were incubated in a normal (1.18 mM) or high (2.5 mM) phosphate concentration solution and cells were cultured in normal- (0.5 mM) or high-phosphate (3 mM) concentration media. A single-blind crossover study was performed in healthy volunteers, receiving phosphate supplements or a phosphate binder (lanthanum), and endothelial function measured was by flow-mediated dilatation. RESULTS: Endothelium-dependent vasodilatation was impaired when resistance vessels were exposed to high phosphate; this could be reversed in the presence of a phosphodiesterase-5-inhibitor. Vessels from patients with CKD relaxed normally when incubated in normal-phosphate conditions, suggesting that the detrimental effects of phosphate may be reversible. Exposure to high-phosphate disrupted the whole nitric oxide pathway with reduced nitric oxide and cyclic guanosine monophosphate production and total and phospho endothelial nitric oxide synthase expression. In humans, endothelial function was reduced by chronic phosphate loading independent of serum phosphate, but was associated with higher urinary phosphate excretion and serum fibroblast growth factor 23. CONCLUSIONS: These directly detrimental effects of phosphate, independent of other factors in the uraemic environment, may explain the increased cardiovascular risk associated with phosphate in CKD.


Assuntos
Doenças Cardiovasculares/etiologia , Hiperfosfatemia/complicações , Óxido Nítrico/fisiologia , Insuficiência Renal Crônica/complicações , Animais , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/patologia , Células Cultivadas , Estudos Cross-Over , GMP Cíclico/metabolismo , Células Endoteliais/enzimologia , Endotélio Vascular/metabolismo , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos/sangue , Humanos , Hiperfosfatemia/sangue , Hiperfosfatemia/patologia , Masculino , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfatos/fisiologia , Fosfatos/toxicidade , Ratos , Ratos Endogâmicos WKY , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/patologia , Fatores de Risco , Transdução de Sinais , Método Simples-Cego , Vasodilatação/efeitos dos fármacos
2.
Lancet ; 385 Suppl 1: S10, 2015 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-26312829

RESUMO

BACKGROUND: Hyperphosphataemia is a risk factor for accelerated cardiovascular disease in chronic kidney disease. The mechanism is poorly understood; it is unclear whether phosphate has direct effects or effects mediated via calcification or FGF23. We investigated direct effects of phosphate on endothelial function using myography to study rat and human blood vessels. In addition we assessed the effects of phosphate loading on endothelial function in a clinical study. METHODS: Resistance vessels from patients with (n=12) and without (n=13) chronic kidney disease were incubated in normal or high phosphate. Vasoconstrictor and vasorelaxation responses were measured. Concentration-response curves were constructed and comparisons made. Identical experiments were performed in rat mesenteric vessels with and without phosphodiesterase type 5 inhibitor. A cross-over study was done in 19 healthy volunteers receiving phosphate supplements or binders and endothelial function measured by flow mediated dilatation (FMD). Primary outcome was percent change in FMD from baseline. FINDINGS: Nine to 13 vessels were used in each group. Endothelium-dependent vasodilatation was impaired in high compared with normal phosphate in rat (mean maximum vasodilatation 64% [SE 9] vs 95 [1], p<0·001) and human vessels with (25·3 [11·1] vs 75·7 [13·6], p<0·001) and without chronic kidney disease (42·9 [12] vs 79·4 [8·2], p=0·003). In rat vessels, these effects were reversed by a phosphodiesterase type 5 inhibitor. In vivo in volunteers, endothelial function was reduced by phosphate loading (median maximum vasodilatation 3·38% [IQR 2·57-5·26] vs 8·4 [6·2-11·6], p<0·001); this effect was independent of serum phosphate concentration but associated with urinary phosphate excretion and serum FGF23 concentrations. INTERPRETATION: Prolonged exposure to phosphate is associated with endothelial dysfunction, a direct effect of phosphate, which might contribute to cardiovascular risk in chronic kidney disease. In a high phosphate environment, endothelial and vascular dysfunction is evident in blood vessels and in man exposed to prolonged oral phosphate loading. These effects might be mediated by disruption of the NO pathway. FUNDING: British Heart Foundation, Darlinda's Charity for Renal Research.

3.
Clin Transplant ; 30(8): 918-24, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27218240

RESUMO

Stroke incidence is high in end-stage renal disease, and risk factors differ between the dialysis and general populations. However, risk factors and outcomes following renal transplantation remain unclear. We analyzed all adult patients with a functioning renal transplant from 01/01/2007 to 12/31/2012. Data were extracted from the electronic patient record. Variables associated with stroke were identified by survival analyses; demographic, clinical, and imaging and laboratory variables were assessed and case fatality determined. Follow-up was until 05/12/2013. A total of 956 patients were identified (median age 40.1 years, 59.9% male). Atrial fibrillation (AF) prevalence was 9.2%, and 38.2% received a transplant during follow-up. A total of 26 (2.7%) experienced a stroke during 4409 patient-years of follow-up (84.6% ischemic). Stroke incidence was 5.96/1000 patient-years. Factors associated with stroke on regression analysis were prior stroke, diabetes, age, systolic hypertension, and hemoglobin. Atrial fibrillation was associated with time to stroke (P<0.001). Warfarin did not associate with ischemic stroke risk in those with AF. Fatality was 19.2% at 7, 23.1% at 28, and 42.3% at 365 days after stroke. Patients with a functioning renal transplant have a high stroke incidence and case fatality. Unlike those on hemodialysis, risk factors are similar to the general population. We did not demonstrate benefit from warfarin use in those with AF.


Assuntos
Falência Renal Crônica/cirurgia , Transplante de Rim/efeitos adversos , Complicações Pós-Operatórias , Medição de Risco , Acidente Vascular Cerebral/epidemiologia , Transplantados/estatística & dados numéricos , Adulto , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Acidente Vascular Cerebral/etiologia , Taxa de Sobrevida/tendências , Reino Unido/epidemiologia
4.
Stroke ; 46(9): 2477-81, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26230856

RESUMO

BACKGROUND AND PURPOSE: End-stage renal disease (ESRD) requiring hemodialysis carries up to a 10-fold greater risk of stroke than normal renal function. Knowledge on risk factors and management strategies derived from the general population may not be applicable to those with ESRD. We studied a large ESRD population to identify risk factors and outcomes for stroke. METHODS: All adult patients receiving hemodialysis for ESRD from January 1, 2007, to December 31, 2012, were extracted from the electronic patient record. Variables associated with stroke were identified by survival analysis; demographic, clinical, imaging, and dialysis-related variables were assessed, and case-fatality was determined. Follow-up was until December 31, 2013. RESULTS: A total of 1382 patients were identified (mean age, 60.5 years; 58.5% men). The prevalence of atrial fibrillation was 21.2%, and 59.4% were incident hemodialysis patients. One hundred and sixty patients (11.6%) experienced a stroke during 3471 patient-years of follow-up (95% ischemic). Stroke incidence was 41.5/1000 patient-years in prevalent and 50.1/1000 patient-years in incident hemodialysis patients. Factors associated with stroke on regression analysis were prior stroke, diabetes mellitus, and age at starting renal replacement therapy. Atrial fibrillation was not significantly associated with stroke, and warfarin did not affect stroke risk in warfarin-treated patients. Fatality was 18.8% at 7 days, 26.9% at 28 days, and 56.3% at 365 days after stroke. CONCLUSIONS: Incidence of stroke is high in patients with ESRD on hemodialysis with high case-fatality. Incident hemodialysis patients had the highest stroke incidence. Many, but not all, important risk factors commonly associated with stroke in the general population were not associated with stroke in patients receiving hemodialysis.


Assuntos
Isquemia Encefálica/epidemiologia , Falência Renal Crônica/epidemiologia , Diálise Renal/estatística & dados numéricos , Acidente Vascular Cerebral/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/etiologia , Isquemia Encefálica/mortalidade , Comorbidade , Feminino , Seguimentos , Humanos , Incidência , Falência Renal Crônica/terapia , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Escócia/epidemiologia , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/mortalidade
5.
BMC Nephrol ; 16: 194, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26627078

RESUMO

BACKGROUND: Hyperphosphataemia is linked to cardiovascular disease and mortality in chronic kidney disease (CKD). Outcome in CKD is also affected by socioeconomic status. The objective of this study was to assess the associations between serum phosphate, multiple deprivation and outcome in CKD patients. METHODS: All adult patients currently not on renal replacement therapy (RRT), with first time attendance to the renal outpatient clinics in the Glasgow area between July 2010 and June 2014, were included in this prospective study. Area socioeconomic status was assessed as quintiles of the Scottish Index of Multiple Deprivation (SIMD). Outcomes were all-cause and cardiovascular mortality and commencement of RRT. RESULTS: The cohort included 2950 patients with a median (interquartile range) age 67.6 (53.6-76.9) years. Median (interquartile range) eGFR was 38.1 (26.3-63.5) ml/min/1.73 m(2), mean (± standard deviation) phosphate was 1.13 (± 0.24) mmol/L and 31.6 % belonged to the most deprived quintile (SIMD quintile I). During follow-up 375 patients died and 98 commenced RRT. Phosphate ≥ 1.50 mmol/L was associated with all-cause (hazard ratio (HR) 2.51; 95 % confidence interval (CI) 1.63-3.89) and cardiovascular (HR 5.05; 95 % CI 1.90-13.46) mortality when compared to phosphate 0.90-1.09 mmol/L in multivariable analyses. SIMD quintile I was independently associated with all-cause mortality. Phosphate did not weaken the association between deprivation index and mortality, and there was no interaction between phosphate and SIMD quintiles. Neither phosphate nor SIMD predicted commencement of RRT. CONCLUSIONS: Multiple deprivation and serum phosphate were strong, independent predictors of all-cause mortality in CKD and showed no interaction. Phosphate also predicted cardiovascular mortality. The results suggest that phosphate lowering should be pursued regardless of socioeconomic status.


Assuntos
Hiperfosfatemia/diagnóstico , Hiperfosfatemia/mortalidade , Fosfatos/sangue , Insuficiência Renal Crônica/mortalidade , Insuficiência Renal Crônica/psicologia , Isolamento Social/psicologia , Idoso , Biomarcadores/sangue , Estudos de Coortes , Comorbidade , Feminino , Humanos , Hiperfosfatemia/psicologia , Incidência , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/sangue , Reprodutibilidade dos Testes , Medição de Risco/métodos , Escócia/epidemiologia , Sensibilidade e Especificidade , Análise de Sobrevida
6.
Am J Nephrol ; 39(6): 491-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24854664

RESUMO

BACKGROUND: Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria. METHODS: 1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions. RESULTS: 52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use. CONCLUSION: Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.


Assuntos
Derivação Arteriovenosa Cirúrgica/estatística & dados numéricos , Falência Renal Crônica/terapia , Transplante de Rim , Diálise Renal/métodos , Adolescente , Adulto , Fatores Etários , Idoso , Cateterismo Venoso Central , Comorbidade , Diabetes Mellitus/epidemiologia , Progressão da Doença , Feminino , Taxa de Filtração Glomerular , Humanos , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/metabolismo , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/epidemiologia , Doenças Vasculares Periféricas/epidemiologia , Guias de Prática Clínica como Assunto , Proteinúria , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/terapia , Estudos Retrospectivos , Índice de Gravidade de Doença , Fatores Sexuais , Fatores de Tempo , Adulto Jovem
7.
Nephrol Dial Transplant ; 27(6): 2446-51, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22241795

RESUMO

BACKGROUND: Premature sudden cardiovascular death is the commonest cause of death in end-stage renal disease (ESRD) patients and is associated with uraemic cardiomyopathy [left ventricular hypertrophy (LVH), systolic dysfunction (LVSD) or LV dilation]. High-energy phosphates (HEP), quantified using phosphorus-31 magnetic resonance spectroscopy, are reduced in patients with diabetes, heart failure and uraemia. Phosphocreatine:ß adenosine triphosphate (PCr:ATP) ratio is an index of metabolic activity. We compared resting HEPs in ESRD patients and hypertensive patients (with and without LVH) who had normal renal function (LVH-only or normal myocardia). We also assessed associations of HEP levels with abnormalities of uraemic cardiomyopathy. METHODS: Fifty-three ESRD and 30 hypertensive patients (18 with LVH, 12 with normal myocardia) underwent phosphorus magnetic resonance spectroscopy of their left ventricle. PCr:ATP ratios were calculated from (31)P-MR spectra obtained from long-axis views of the left ventricle. RESULTS: There were no significant differences in age, LV mass, chamber sizes and ejection fraction between patient groups. PCr:ATP was significantly lower in ESRD patients compared to hypertensive patients, irrespective of the presence or absence of LVH (P = 0.01). In the ESRD group, PCr:ATP was significantly lower in patients with LVSD (P = 0.05) and LV dilation (P = 0.01). LVH was not associated with significant difference in PCr:ATP. CONCLUSIONS: ESRD patients have lower HEP levels compared to hypertensive patients. Lower PCr:ATP ratio, indicating altered myocardial metabolic function in ESRD patients, is associated with features of uraemic cardiomyopathy.


Assuntos
Cardiomiopatias/diagnóstico , Cardiomiopatias/etiologia , Falência Renal Crônica/complicações , Espectroscopia de Ressonância Magnética , Fosfatos/análise , Uremia/complicações , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Hipertensão/complicações , Hipertrofia Ventricular Esquerda/diagnóstico , Hipertrofia Ventricular Esquerda/etiologia , Masculino , Pessoa de Meia-Idade , Isótopos de Fósforo/metabolismo , Prognóstico
8.
Nephrol Dial Transplant ; 26(7): 2382-6, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21310742

RESUMO

BACKGROUND: Increasing numbers of older patients are developing established renal failure and considering kidney transplant as a renal replacement therapy (RRT) option. The probability of older patients actually receiving a deceased donor kidney transplant is unclear, preventing informed choice about pursuing the option of transplantation. We sought to analyse our RRT population to determine the probability of receiving a deceased donor kidney transplant in patients commencing RRT categorized by age and for whom there was no suitable living kidney donor. METHODS: Patients commencing dialysis in our centre between 1992 and 2009 were identified. Time to listing on the deceased donor transplant waiting list and time to first deceased donor transplant were determined by Kaplan-Meier analysis for patients, categorized by age, with censoring at the date of first living donor kidney transplant, death or last dialysis. RESULTS: One-thousand-five-hundred-and-thirteen patients were categorized into groups by age in years [1: <35 (n = 134), 2: 35-49.9 (n = 207), 3: 50-64.9 (n = 415), 4: >65-74.9 (n = 438) and 5: ≥ 75 (n = 319)]. The probability of being listed for deceased donor transplant within 1 year of commencing RRT was 75, 54, 27, 4 and 0.8% in Groups 1-5, respectively. If listed, the probability of receiving a deceased donor transplant within 5 years of starting RRT was 81, 48, 26, 8 and 0% in Groups 1-5, respectively. In Groups 1-4, 93% (n = 63), 87% (n = 65), 76% (n = 45) and 100% (n = 7) of the patients, respectively, who received a deceased donor transplant were alive and off dialysis 1 year after transplant. The reason patients who were listed did not receive a transplant was usually death on the waiting list. CONCLUSIONS: The likelihood of being listed for transplant falls with increasing age at the time of starting RRT. Even for patients listed for transplant, the probability of older patients actually receiving a transplant is much lower than for younger patients, with only 8% of listed patients aged 65-74.9 years being transplanted within 5 years. This is partly the result of death on the waiting list but may also be related to organ allocation policies. Assessment for possible deceased donor transplantation involves a considerable investment in time and effort for the patient, as well as in health care resources, and a patient's decision whether to proceed with assessment should be informed by the kind of information we have produced. As there may be regional and national variations in practice, each centre should generate such data for use locally.


Assuntos
Envelhecimento , Rejeição de Enxerto/diagnóstico , Falência Renal Crônica/terapia , Transplante de Rim , Complicações Pós-Operatórias , Adolescente , Adulto , Idoso , Cadáver , Função Retardada do Enxerto , Feminino , Seguimentos , Taxa de Filtração Glomerular , Sobrevivência de Enxerto , Humanos , Falência Renal Crônica/mortalidade , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Prognóstico , Estudos Prospectivos , Fatores de Risco , Taxa de Sobrevida , Obtenção de Tecidos e Órgãos , Adulto Jovem
9.
Transpl Immunol ; 69: 101474, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34582968

RESUMO

INTRODUCTION: End stage renal disease (ESRD) is the irreversible deterioration of renal function requiring renal replacement therapy by dialysis or transplant. Human leucocyte antigens (HLA) have been well examined however research still is required into the non-HLA antibodies. Antibody mediated rejection (AMR) can be seen in the absence of HLA antibodies on biopsies of patients who have received identical transplants; anti-endothelial cell antibodies may explain this. Investigation into endothelial cell antigens on donor and recipient endothelium may elucidate and stratify the degree of risk of any given transplant and may guide towards the best matched donor. METHODS: Protein array analysis was carried out on 8 patient pairs using nitro-cellulose membranes and biotinylated detection antibodies. The fluorescence emitted was captured by X-Ray film and results were recorded with ImageJ software. A fold increase of more than 2 was considered to be positive. RESULTS: 11 proteins identified had a fold increase of increase ≥2 and were present in ≥2 patient pairs which may point to potential clinical utility. Nectin2/CD112 may be measured in order analyse graft survival time in transplant recipients. Prognosticating renal failure has clinical importance and potential markers that have been identified to aid which include MEPE, CRELD2, and TIMP-4. Novel pharmacological therapies for specific biomarkers identified in this study include JAM-A, E-Selectin, CD147, Galectin-3, JAM-C, PAR-1, and TNFR2. CONCLUSION: Protein analysis showed differences in expression of antigens between patients with and without Chronic Kidney Disease (CKD). This information could be used at the matching stage of renal transplantation and also in the treatment of rejection episodes. The results highlight biomarkers that potentially prognosticate and pharmacological therapies that may ameliorate kidney disease and rejection in ESRD and transplant recipients.


Assuntos
Transplante de Rim , Rejeição de Enxerto , Sobrevivência de Enxerto , Antígenos HLA , Humanos , Rim/fisiologia , Diálise Renal , Transplantados
10.
Am J Kidney Dis ; 55(6): 1088-96, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20346559

RESUMO

BACKGROUND: Left ventricular hypertrophy (LVH) is common in patients with end-stage renal disease (ESRD) and an independent risk factor for premature cardiovascular death. Left atrial volume (LAV), measured using echocardiography, predicts death in patients with ESRD. Cardiovascular magnetic resonance (CMR) imaging is a volume-independent method of accurately assessing cardiac structure and function in patients with ESRD. STUDY DESIGN: Single-center prospective observational study to assess the determinants of all-cause mortality, particularly LAV, in a cohort of ESRD patients with LVH, defined using CMR imaging. SETTING & PARTICIPANTS: 201 consecutive ESRD patients with LVH (72.1% men; mean age, 51.6 +/- 11.7 years) who had undergone pretransplant cardiovascular assessment were identified using CMR imaging between 2002-2008. LVH was defined as left ventricular mass index >84.1 g/m(2) (men) or >74.6 g/m(2) (women) based on published normal left ventricle dimensions for CMR imaging. Maximal LAV was calculated using the biplane area-length method at the end of left ventricle systole and corrected for body surface area. PREDICTORS: CMR abnormalities, including LAV. OUTCOME: All-cause mortality. RESULTS: 54 patients died (11 after transplant) during a median follow-up of 3.62 years. Median LAV was 30.4 mL/m(2) (interquartile range, 26.2-58.1). Patients were grouped into high (median or higher) or low (less than median) LAV. There were no significant differences in heart rate and mitral valve Doppler early to late atrial peak velocity ratio. Increased LAV was associated with higher mortality. Kaplan-Meier survival analysis showed poorer survival in patients with higher LAV (log rank P = 0.01). High LAV and left ventricular systolic dysfunction conferred similar risk and were independent predictors of death using multivariate analysis. LIMITATIONS: Only patients undergoing pretransplant cardiac assessment are included. Limited assessment of left ventricular diastolic function. CONCLUSIONS: Higher LAV and left ventricular systolic dysfunction are independent predictors of death in ESRD patients with LVH.


Assuntos
Átrios do Coração/patologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Falência Renal Crônica/mortalidade , Falência Renal Crônica/cirurgia , Transplante de Rim , Adulto , Doenças Cardiovasculares/epidemiologia , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Tamanho do Órgão , Valor Preditivo dos Testes , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Disfunção Ventricular Esquerda/fisiopatologia
12.
Clin Kidney J ; 11(4): 532-539, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30094018

RESUMO

BACKGROUND: Premature cardiovascular disease in patients with chronic kidney disease (CKD) is not explained by traditional risk factors and oxidative stress may contribute via endothelial and vascular dysfunction. We investigated the effect of ascorbic acid on oxidative stress and vascular function in CKD patients compared with controls with hypertension (HTN). METHODS: A crossover study of intravenous saline and ascorbic acid was conducted. Biomarkers of oxidative stress were measured, while pulse wave analysis and brachial flow-mediated dilatation were performed to assess large artery and endothelial function. RESULTS: Twenty HTN and 30 CKD patients Stages 3-5 were recruited. Serum ascorbic acid was significantly lower in patients with CKD. In both groups, ascorbic acid significantly increased total antioxidant potential and superoxide. Asymmetric dimethylarginine (ADMA) was reduced significantly by ascorbic acid in the CKD group and on multivariate regression analysis, age and the presence of CKD were predictors of ADMA response to ascorbic acid. Although no effect on FMD was observed, central blood pressure and augmentation index were reduced significantly in both groups. CONCLUSIONS: Ascorbic acid has pro- and antioxidant effects, reducing central blood pressure and augmentation index in HTN and CKD. Ascorbic acid reduces serum ADMA in CKD, which may have longer-term benefits.

14.
Nephron ; 133(3): 183-92, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27362585

RESUMO

AIMS: Arterial spin labelling (ASL) MRI measures perfusion without administration of contrast agent. While ASL has been validated in animals and healthy volunteers (HVs), application to chronic kidney disease (CKD) has been limited. We investigated the utility of ASL MRI in patients with CKD. METHODS: We studied renal perfusion in 24 HVs and 17 patients with CKD (age 22-77 years, 40% male) using ASL MRI at 3.0T. Kidney function was determined using estimated glomerular filtration rate (eGFR). T1 relaxation time was measured using modified look-locker inversion and xFB02;ow-sensitive alternating inversion recovery true-fast imaging and steady precession was performed to measure cortical and whole kidney perfusion. RESULTS: T1 was higher in CKD within cortex and whole kidney, and there was association between T1 time and eGFR. No association was seen between kidney size and volume and either T1, or ASL perfusion. Perfusion was lower in CKD in cortex (136 ± 37 vs. 279 ± 69 ml/min/100 g; p < 0.001) and whole kidney (146 ± 24 vs. 221 ± 38 ml/min/100 g; p < 0.001). There was significant, negative, association between T1 longitudinal relaxation time and ASL perfusion in both the cortex (r = -0.75, p < 0.001) and whole kidney (r = -0.50, p < 0.001). There was correlation between eGFR and both cortical (r = 0.73, p < 0.01) and whole kidney (r = 0.69, p < 0.01) perfusion. CONCLUSIONS: Significant differences in renal structure and function were demonstrated using ASL MRI. T1 may be representative of structural changes associated with CKD; however, further investigation is required into the pathological correlates of reduced ASL perfusion and increased T1 time in CKD.


Assuntos
Córtex Renal/diagnóstico por imagem , Falência Renal Crônica/diagnóstico por imagem , Medula Renal/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Córtex Renal/fisiologia , Córtex Renal/fisiopatologia , Medula Renal/fisiologia , Medula Renal/fisiopatologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
15.
J Hypertens ; 33(10): 2046-53, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26431193

RESUMO

OBJECTIVES: Abnormalities of bone mineral parameters are associated with cardiovascular morbidity and mortality in patients with chronic kidney disease and the general population. METHODS: We assessed the impact of baseline serum phosphate and calcium on longitudinal blood pressure (BP) control and survival in hypertensive adults. We studied 9260 hypertensive adults followed for 40 years (151 789 person-years). Changes in BP over initial 5-year follow-up were analysed using generalized estimating equations. Survival analyses were performed using Cox proportional hazards model. RESULTS: Serum phosphate levels were higher in hypertensive women (1.10 mmol/l ±â€Š0.20) than compared to men (1.02 mmol/l ±â€Š0.21). In treated hypertensive patients, higher baseline serum phosphate was significantly associated with poor longitudinal SBP reduction (one standard deviation increase in phosphate was associated with 0.22 and 0.59 mmHg higher SBP at 5 years in men and women, respectively). Higher serum phosphate was significantly associated with all-cause and cardiovascular mortality in men, whereas in men and women, serum calcium significantly predicted all-cause and noncardiovascular mortality. In hypertensive patients with chronic kidney disease, higher phosphate was significantly associated with poorer survival. CONCLUSION: In hypertensive patients, serum phosphate and calcium are significantly associated with reduced all-cause and cardiovascular survival and this appears not to be related to BP control.


Assuntos
Pressão Sanguínea/fisiologia , Cálcio/sangue , Hipertensão/sangue , Hipertensão/mortalidade , Fosfatos/sangue , Adulto , Anti-Hipertensivos/uso terapêutico , Feminino , Seguimentos , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/epidemiologia , Masculino
16.
Transplant Res ; 3(1): 20, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25505546

RESUMO

BACKGROUND: Premature cardiovascular (CV) death is the commonest cause of death in renal transplant recipients. Abnormalities of left ventricular (LV) structure (collectively termed uremic cardiomyopathy) and left atrial (LA) dilation, a marker of fluid status and diastolic function, are risk factors for reduced survival in patients with end stage renal disease (ESRD). In the present analysis, we studied the impact of pre-transplant LA and LV abnormalities on survival after successful renal transplantation (RT). METHODS: One hundred nineteen renal transplant recipients (first transplant, deceased donors) underwent cardiovascular MRI (CMR) as part of CV screening prior to inclusion on the waiting list. Data regarding transplant function and patient survival after transplantation were collected. RESULTS: Median post-transplant follow-up was 4.3 years (interquartile range (IQR) 1.9, 6.2). During the post-transplant period, 13 patients returned to dialysis after graft failure and 23 patients died with a functioning graft. Survival analyses, censoring for patients returning to dialysis, showed that pre-transplant LV hypertrophy and elevated LA volume were significantly associated with reduced survival after transplantation. Multivariate Cox regression analyses demonstrated that longer waiting time, poorer transplant function, presence of LV hypertrophy and higher LA volume on screening CMR and female sex were independent predictors of death in patients with a functioning transplant. CONCLUSIONS: Presence of LVH and higher LA volume are significant, independent predictors of death in patients who are wait-listed and proceed with renal transplantation.

17.
Transplantation ; 96(1): 65-9, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23715051

RESUMO

BACKGROUND: Proteinuria is associated with poorer outcomes in renal transplant recipients. Fractional excretion of total protein (FEPR) may better reflect kidney damage than urine protein-to-creatinine ratio (PCR). METHODS: We assessed FEPR (FEPR = [serum creatinine × urine protein] / [serum protein × urine creatinine], %) and PCR ([urinary protein/urinary creatinine] × 1000, mg/mM) 1 year after first renal transplantation as predictors of transplant failure. The primary endpoints were transplant failure and death. The use of the tests was analyzed by constructing receiver operator characteristic curves and comparing the area under the curve. Using receiver operator characteristic analysis, patients were stratified into high- and low-risk groups. RESULTS: Two hundred nineteen recipients were followed up for a median of 4.9 years. At a median of 2.7 years, 11.4% (n=25) of the transplants failed. Eight percent (n=17) of the patients died. The area under the curve was higher for FEPR than PCR (0.92 vs. 0.84). Patients with an FEPR of 0.019% or higher had a 3.4-fold (P=0.003) increased risk of transplant failure and a 2.3-fold (P=0.02) increased risk of death compared with those with an FEPR of less than 0.019%. Patients with a PCR of 97 mg/mM or greater had a 2.1-fold (P=0.04) increased risk of transplant failure and a 1.6-fold (P=0.04) increased risk of death compared with those with a PCR of less than 97 mg/mM (P=0.04). In multivariate analysis with time to transplant failure as the dependent variable, FEPR and PCR were independent predictors of transplant failure (hazards ratio, 1.07 [P=0.013] and 1.03 [P=0.03], respectively). CONCLUSIONS: FEPR and PCR at 1 year are independent predictors of transplant failure, but FEPR may be superior.


Assuntos
Transplante de Rim/mortalidade , Complicações Pós-Operatórias/mortalidade , Complicações Pós-Operatórias/fisiopatologia , Proteinúria/mortalidade , Proteinúria/fisiopatologia , Adulto , Creatinina/sangue , Creatinina/urina , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Rim/fisiopatologia , Transplante de Rim/efeitos adversos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Curva ROC , Fatores de Risco
18.
J Ren Care ; 38 Suppl 1: 125-37, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22348372

RESUMO

New-onset diabetes after transplantation (NODAT) has serious consequences for the patient in terms of overall survival, graft function and graft survival. The incidence of NODAT and impaired glucose tolerance has probably been underestimated previously because of lack of a universal diagnostic definition. Many risk factors have been identified, a proportion of which are modifiable. Early identification of those who are at high risk of NODAT and strategies to reduce risk will help to reduce the morbidity and mortality resulting from this condition. Where prevention is not possible, stringent management strategies are essential. Although, this article focuses on NODAT in the renal transplant recipient and considers the scale of the problem, impact on patient and transplant survival, determinants and risk factors for, and the management of, impaired glucose tolerance and NODAT, much of it will also be applicable to other types of solid organ transplantation.


Assuntos
Diabetes Mellitus , Imunossupressores/efeitos adversos , Transplante de Rim , Complicações Pós-Operatórias/diagnóstico , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/etiologia , Diabetes Mellitus/terapia , Intolerância à Glucose/diagnóstico , Intolerância à Glucose/etiologia , Intolerância à Glucose/terapia , Sobrevivência de Enxerto , Humanos , Complicações Pós-Operatórias/terapia , Fatores de Risco
19.
Int J Nephrol ; 2011: 297070, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21860794

RESUMO

Elevated FGF-23 is a predictor of mortality and is associated with LVH in CKD. It may be a biomarker or a direct toxin. We assessed the relationship between FGF-23 and LVH in CKD using CMRI. In vitro we studied the effect of phosphate, FGF-23, and Klotho on E-selectin and VCAM production in HUVECs. FGF-23 concentration correlates negatively with eGFR and positively with LVMI. FGF-23 was an independent predictor of LVH in CKD. E-selectin and VCAM production was elevated in HUVECs cultured in high phosphate with FGF-23 or Klotho. This effect was attenuated in cells exposed to both FGF-23 and Klotho. FGF-23 is an independent predictor of LVH as measured by CMRI. We show preliminary data which supports that FGF-23 is toxic resulting in activation of the vascular endothelium. We do not prove causality with elevated FGF-23 and LVH. Further research should ascertain if lowering levels of FGF-23 translates to improved clinical outcomes.

20.
Transplantation ; 89(6): 707-9, 2010 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-20010330

RESUMO

BACKGROUND: Activation of the renin angiotensin system may contribute to the development of delayed graft function after renal transplantation. We, therefore, examined the impact of pretransplant treatment with blockers of the renin angiotensin system on early graft function after renal transplantation. METHOD: The case records of all patients who received a live donor transplant between January 2001 and August 2008 were reviewed. RESULTS: Serum creatinine measurements were recorded for the first nine posttransplant days, in 94 recipients of live donor kidneys, where there were neither surgical nor hemodynamic complications and no documented rejection or infection. Forty patients (43%) were treated with a blocker of the renin-angiotensin-aldosterone system before transplantation. Serum creatinine levels fell more slowly in these patients (P=0.02). Two patients required hemodialysis after transplantation; both were on an angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker. CONCLUSION: Live donor renal transplant recipients who are taking a renin-angiotensin-aldosterone system blocker at the time of transplantation are more likely to have impaired graft function postoperatively in the absence of other explanations. This observation requires further exploration in live and deceased donor renal transplantation.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/efeitos adversos , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Função Retardada do Enxerto/etiologia , Transplante de Rim/efeitos adversos , Doadores Vivos , Sistema Renina-Angiotensina/efeitos dos fármacos , Adolescente , Adulto , Idoso , Biomarcadores/sangue , Creatinina/sangue , Função Retardada do Enxerto/metabolismo , Função Retardada do Enxerto/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Diálise Renal , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
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