Istvan Mucsi - Academia.edu (original) (raw)
Papers by Istvan Mucsi
Seminars in Nephrology, 2015
Insomnia and poor self-perceived sleep are very common in patients with chronic kidney disease (C... more Insomnia and poor self-perceived sleep are very common in patients with chronic kidney disease (CKD). Poor sleep is associated with fatigue, sleepiness, impaired daytime functioning, impaired health-related quality of life, and increased morbidity and mortality. Many illness- and treatment-related factors (metabolic changes, inflammation, altered sleep regulatory mechanisms, symptoms and complications of CKD, comorbid conditions, medications, and renal replacement therapies) may disturb sleep and contribute to the high prevalence of insomnia in this patient population. Accordingly, the approach to both diagnosing and treating this condition is quite complex. Although sleep-related problems are very important for patients with CKD, they largely are under-recognized and undertreated. Very few intervention trials provide an evidence base to support treatment decisions in this particular patient population. With this review we hope to increase awareness of insomnia among professionals involved in the management of patients with CKD and to provide guidance in recognizing and treating this important condition.
Canadian journal of psychiatry. Revue canadienne de psychiatrie
OBJECTIVE: Despite being a common and potentially serious condition, nephrogenic diabetes insipid... more OBJECTIVE: Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) remains poorly understood in older lithium users. Our main objective was to compare the prevalence of NDI symptoms and decreased urine osmolality ([UOsm] < 300 milli-Osmoles [mOsm/kg]) among geriatric and adult lithium users. We also assessed NDI symptoms, serum sodium (Na+), and urine specific gravity (USG) as possible surrogate measures of decreased UOsm, and ascertained whether potential etiologic factors independently correlated with decreased UOsm. METHOD: This was a cross-sectional study of 100 consecutive outpatients treated with lithium from 6 tertiary care clinics, of which 45 were geriatric (aged 65 years and older) and 55 adult (aged 18 to 64 years). Patients completed a symptom questionnaire and underwent laboratory tests, including UOsm, serum Na+, and USG. RESULTS: Geriatric and adult lithium users had similar rates of decreased UOsm (12.5%, compared with 17.9%,...
Thorax, Jan 2, 2015
There is a paucity of large cohort studies examining the association of obstructive sleep apnoea ... more There is a paucity of large cohort studies examining the association of obstructive sleep apnoea (OSA) with clinical outcomes including all-cause mortality, coronary heart disease (CHD), strokes and chronic kidney disease (CKD). We hypothesised that a diagnosis of incident OSA is associated with higher risks of these adverse clinical outcomes. In a nationally representative cohort of over 3 million (n=3 079 514) US veterans (93% male) with baseline estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m(2), we examined the association between the diagnosis of incident OSA, treated and untreated with CPAP, and: (1) all-cause mortality, (2) incident CHD, (3) incident strokes, (4)incident CKD defined as eGFR<60 mL/min/1.73 m(2), and (5) slopes of eGFR. Compared with OSA-negative patients, untreated and treated OSA was associated with 86% higher mortality risk, (adjusted HR and 95% CI 1.86 (1.81 to 1.91) and 35% (1.35 (1.21 to 1.51)), respectively. Similarly, untreated and treat...
International urology and nephrology, 2015
Protein-energy wasting (PEW) is a common condition in patients with chronic kidney disease (CKD) ... more Protein-energy wasting (PEW) is a common condition in patients with chronic kidney disease (CKD) including dialysis and kidney transplant recipients (TX) and frequently assessed with malnutrition-inflammation score (MIS). We hypothesized that (1) the MIS and PEW parameters are correlated with kidney function and (2) the MIS and PEW parameters are more severe in TX than in non-dialysis (ND) CKD patients with similar eGFR. In this study, we matched 203 ND-CKD and 203 TX patients from two independently assembled cohorts of patients based on estimated glomerular filtration rate (eGFR) and compared various PEW parameters between the two groups using unadjusted and case-mix adjusted linear regression and conditional logistic regression analysis models. In the combined cohort (n = 406) of patients, the mean ± SD age was 57 ± 12 years; included 55 % men and 35 % diabetics; and demonstrated a mean ± SD baseline eGFR of 29 ± 11 ml/min/1.73 m(2). The eGFR correlated positively with serum album...
Medical hypotheses, Jan 6, 2015
Drugs & aging, 2015
Lithium is an important medication in the treatment of mood disorders. However, clinicians are he... more Lithium is an important medication in the treatment of mood disorders. However, clinicians are hesitant to use lithium in older adults for fear of its medical effects, particularly kidney disease. This review describes the current understanding of the epidemiology and mechanisms underlying chronic kidney disease (CKD) in older lithium users, with recommendations for using lithium safely in late life. Prevalence estimates of CKD in older lithium users range from 42-50%, which does not differ greatly from the 37.8% rates seen in community-dwelling non-lithium using, non-psychiatric populations. Clinical and pre-clinical data suggest a variety of synergistic mechanisms contributing to CKD in older lithium users, including aging, cardiovascular factors, oxidative stress, inflammation, nephrogenic diabetes insipidus, acute kidney injury, and medication interactions. With regards to CKD, lithium can be used safely in many older adults with mood disorders. Compared to patients with pre-exi...
Canadian journal of psychiatry. Revue canadienne de psychiatrie, 2014
Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) re... more Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) remains poorly understood in older lithium users. Our main objective was to compare the prevalence of NDI symptoms and decreased urine osmolality ([UOsm] < 300 milli-Osmoles [mOsm/kg]) among geriatric and adult lithium users. We also assessed NDI symptoms, serum sodium (Na+), and urine specific gravity (USG) as possible surrogate measures of decreased UOsm, and ascertained whether potential etiologic factors independently correlated with decreased UOsm. This was a cross-sectional study of 100 consecutive outpatients treated with lithium from 6 tertiary care clinics, of which 45 were geriatric (aged 65 years and older) and 55 adult (aged 18 to 64 years). Patients completed a symptom questionnaire and underwent laboratory tests, including UOsm, serum Na+, and USG. Geriatric and adult lithium users had similar rates of decreased UOsm (12.5%, compared with 17.9%, P = 0.74), but geriatric pa...
Orvosi hetilap, Jan 25, 2003
Over the past ten-fifteen years there has been a continuous increase in the interest in quality o... more Over the past ten-fifteen years there has been a continuous increase in the interest in quality of life research. There is a huge increase in the number of clinical trials applying quality of life as an outcome measure and also in the number of studies where assessment of quality of life is the main focus of the research. During the last decades the resources of health care has increasingly been directed towards the care of chronically ill patients. In these conditions several symptoms persist or may even worsen even with effective therapy. This provides an explanation why quality of life has become an important and useful outcome measure complementing the traditional "hard outcomes" such as morbidity and mortality. Assessment of quality of life is also an important component of cost-effectiveness studies and health-technology assessment. Recently, the overall quality of quality of life research has improved significantly. In the early days, several instruments were used w...
Human Psychopharmacology: Clinical and Experimental, 2014
Lithium continues to be an important mood disorder treatment. Although patients exposed to higher... more Lithium continues to be an important mood disorder treatment. Although patients exposed to higher environmental temperatures may have serum lithium level elevations due to dehydration, there is conflicting data in the literature. In addition, no study has assessed the association between temperature and other renal laboratory tests and symptoms in lithium users. This is a cross-sectional analysis of 63 current lithium users who participated in the McGill Geriatric Lithium-induced Diabetes Insipidus Clinical Study. The relationship between mean daily temperature with diabetes insipidus symptoms, glomerular filtration rate, urine osmolality, serum sodium, lithium level, and lithium dose-level ratio was assessed. Although a higher temperature on the day of laboratory testing trended toward being independently associated with a lower lithium dose-level ratio (Beta = -0.17, p = 0.08), this was not found when using a dichotomous measure of temperature (T &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 20°C). No association was observed between temperature and other renal parameters. The association of temperature with lithium levels, renal symptoms, and laboratory tests appears to be of relatively little clinical importance in lithium users in temperate climates. However, future research should re-examine patients living in climates with extreme temperatures (e.g., &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;40°C), who may theoretically be at higher risk.
Scientific Reports, 2014
Obstructive sleep apnea(OSA) is one of the most common sleep disorders in kidney transplant recip... more Obstructive sleep apnea(OSA) is one of the most common sleep disorders in kidney transplant recipients, however its long-term consequences have only rarely been investigated. Here, we hypothesized that the presence of OSA would be associated with higher risk of mortality and faster decline of graft function in kidney transplant recipients. In a prospective cohort study 100 prevalent kidney transplant recipients who underwent one-night polysomnography at baseline and were followed for a median 75 months. Generalized linear mixed-effects models and Cox regression models were used to assess the association between OSA and the rate of progression of chronic kidney disease(CKD) and mortality. The estimated slopes of estimated glomerular filtration rate(eGFR) in patients with and without OSA were compared using a two-stage model of eGFR change including only OSA as a variable. In this model patients with OSA (eGFR versus time was -0.93 ml/min/1.73 m(2)/yr(95%CI:-1.75 to-0.11) had a similar slope as compared to patients without OSA(eGFR versus time was -1.24 ml/min/1.73 m(2)/yr(95%CI: -1.67 to -0.81). In unadjusted Cox proportional regression analyses OSA was not associated with higher all-cause mortality risk (Hazard Ratio(HR) = 1.20; 95% Confidence Interval(CI): 0.50-2.85). No association was found between the presence of OSA and the rate of progression of CKD or all-cause mortality in prevalent kidney transplant recipients.
Drugs & Aging, 2014
Little is known about how lithium should be dosed to achieve therapeutic but safe serum concentra... more Little is known about how lithium should be dosed to achieve therapeutic but safe serum concentrations in older adults. In this paper, we investigate how the lithium dose-concentration ratio changes across the lifespan. This was a cross-sectional analysis of 63 current lithium users aged 20-95 years using data from McGLIDICS (the McGill Geriatric Lithium-Induced Diabetes Insipidus Clinical Study). Participants underwent blood and urine tests, including serum lithium concentrations. Multivariate analyses were conducted to evaluate potential correlates of the lithium dose-concentration ratio. We found that between the ages of 40-95 years, the total daily dose of lithium required to achieve a given serum concentration decreases threefold (500 vs. 1,500 mg for 1.0 mmol/L). Greater age, once-daily dosing, and lower renal function (estimated glomerular filtration rate) were independently associated with a lower lithium dose-concentration ratio. The lithium dose required to achieve a given serum lithium concentration decreases threefold from middle to old age, with this trend continuing into the ninth and tenth decades of life. In order to avoid lithium toxicity in aging patients, continued serum concentration monitoring and judicious dose reduction may be required, particularly in those patients with reduced renal function.
The American Journal of Geriatric Psychiatry, 2015
ABSTRACT
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, Jan 3, 2014
Transplant glomerulopathy (TG) is generally accepted to result from repeated episodes of endothel... more Transplant glomerulopathy (TG) is generally accepted to result from repeated episodes of endothelial activation, injury and repair, leading to pathological abnormalities of double contouring or multi-layering of the glomerular basement membrane. TG is a major sequel of chronic active antibody-mediated rejection (cABMR), from pre-existing or de novo anti-HLA antibodies. Hepatitis C infection, thrombotic microangiopathy or other factors may also contribute to TG development. TG prevalence is 5-20% in most series, reaching 55%, in some high-risk cohorts, and is associated with worse allograft outcomes. Despite its prevalence and clinical significance, few well-studied treatment options have been proposed. Similar to desensitization protocols, plasmapheresis with or without immunoabsorption, high-dose intravenous immunoglobulin, rituximab, bortezomib and eculizumab have been proposed in the treatment of TG due to cABMR individually or in various combinations. Robust clinical trials are ...
Transplantation, 2011
Anemia and mineral and bone disorders (MBD) are both important and common complications in kidney... more Anemia and mineral and bone disorders (MBD) are both important and common complications in kidney transplant recipients. Studies in patients with chronic kidney disease indicated a possible independent association of higher serum phosphorus with anemia, but similar associations have not been examined in kidney transplant recipients. We hypothesized that higher serum phosphorus is associated with anemia independent of other components of MBD. We examined the association of serum phosphorus with hemoglobin level and the prevalence of anemia in a prevalent cohort of 992 kidney transplant recipients in a single outpatient transplant center. Associations were examined in linear and logistic regression models with adjustment for demographic and comorbid conditions for various known risk factors of anemia, including measures of iron deficiency, inflammation, and components of MBD including serum levels of 25(OH) vitamin D, parathyroid hormone, and fibroblast growth factor 23. In multivariable adjusted regression models, a 1 standard deviation (0.8 mg/dL) higher serum phosphorus level was associated with 0.26 g/dL lower blood hemoglobin concentration (95% confidence intervals -0.36 to -0.15, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) and with an odds ratio for anemia of 1.77 (95% confidence intervals 1.33-2.37, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). These associations were consistent across the entire spectrum of the physiologic serum phosphorus concentration and were more accentuated in patients with lower estimated glomerular filtration rate. Higher serum phosphorus is independently associated with anemia in kidney transplant recipients.
Nephron Clinical Practice, 2011
Although it is a known predictor of mortality, there is a relative lack of recent information abo... more Although it is a known predictor of mortality, there is a relative lack of recent information about anaemia in kidney transplant recipients. Thus, we now report data about the prevalence and management of post-transplant anaemia (PTA) in Europe 5 years after the TRansplant European Survey on Anemia Management (TRESAM) study. In a cross-sectional study enrolling the largest number of patients to date, data were obtained from 5,834 patients followed at 10 outpatient transplant clinics in four European countries using the American Society of Transplantation anaemia guideline. More than one third (42%) of the patients were anaemic. The haemoglobin (Hb) concentration was significantly correlated with the estimated glomerular filtration rate (eGFR) (r = 0.4, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). In multivariate analysis, eGFR, serum ferritin, age, gender, time since transplantation and centres were independently and significantly associated with Hb. Only 24% of the patients who had a Hb concentration &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;110 g/l were treated with an erythropoiesis-stimulating agent. The prevalence of anaemia and also the use of erythropoiesis-stimulating agents were significantly different across the different centres, suggesting substantial practice variations. PTA is still common and under-treated. The prevalence and management of PTA have not changed substantially since the TRESAM survey.
Nephron Clinical Practice, 2011
Elevated parathyroid hormone (PTH) is used to diagnose high turnover bone disease in chronic kidn... more Elevated parathyroid hormone (PTH) is used to diagnose high turnover bone disease in chronic kidney disease (CKD). The diagnostic accuracy of PTH in kidney transplant recipients with CKD is unknown. We examined kidney transplant recipients with CKD stages 3 (n = 498) and 4 (n = 141) to determine the sensitivity and specificity of the Kidney/Dialysis Outcome Quality Initiative (K/DOQI)-recommended PTH levels in detecting elevated serum β-CrossLaps (CTX) or osteocalcin (OC) levels. We performed receiver-operator curve analyses to determine CKD stage-specific PTH levels that provide optimal diagnostic accuracy. PTH below the lower limits of the K/DOQI ranges (35 and 70 pg/ml in CKD stages 3 and 4, respectively) showed sensitivity of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;90% in diagnosing increases in biochemical markers. The upper limits (70 and 110 pg/ml), however, showed poor specificity. A specificity of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;90% for detecting increased biochemical markers was seen with PTH of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;140 and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;240 pg/ml in CKD stages 3 and 4, respectively. Currently applied cutoffs for PTH in kidney transplant recipients with CKD stages 3 and 4 do not appear to adequately detect increased biochemical markers of bone turnover. Diagnostic uncertainty exists in patients with CKD stage 3 and PTH between 35 and 140 pg/ml, and CKD stage 4 and PTH between 70 and 240 pg/ml.
Nephron Clinical Practice, 2011
Resistance to erythropoiesis-stimulating agents (ESAs) has been observed in patients with chronic... more Resistance to erythropoiesis-stimulating agents (ESAs) has been observed in patients with chronic kidney disease (CKD) and it is associated with clinical outcomes. The presence of ESA resistance cannot always be explained by the known risk factors of the condition, suggesting that additional factors may be involved. We wanted to test the hypothesis that vitamin D insufficiency is associated with lower hemoglobin (Hb) and ESA resistance in patients on maintenance hemodialysis (HD). Data from patients receiving maintenance HD in a single dialysis center were extracted from the medical records in a retrospective chart review. Basic patient characteristics and laboratory data including Hb, serum albumin, intact parathyroid hormone and serum 25(OH)-cholecalciferol (25(OH)D(3)) levels were collected. ESA dose and Kt/V were extracted from the dialysis charts. Correlation analysis and multivariate linear regression analysis were used to reveal potential independent associations between clinical and laboratory parameters and ESA resistance. Data from 142 patients were analyzed. Serum 25(OH)D(3) concentration was significantly correlated with Hb (ρ = 0.186, p &amp;amp;amp;lt; 0.05) and also with ESA dose/Hb index (ρ = 0.230, p &amp;amp;amp;lt; 0.01). In multivariable regression analyses, serum 25(OH)D(3) concentration remained significantly associated with both Hb and ESA dose/Hb index after controlling for potentially important confounders. Serum 25(OH)D(3) concentration is independently associated with erythropoietin responsiveness in CKD patients on maintenance HD. If this association will be confirmed, treatment trials looking at the effect of vitamin D supplementation on anemia treatment in CKD patients may be warranted.
Nephron Experimental Nephrology, 2001
To study the role of extracellular-signal-regulated kinase (ERK) cascade and the small GTP-ase pr... more To study the role of extracellular-signal-regulated kinase (ERK) cascade and the small GTP-ase proteins in the activation of the c-fos promoter by angiotensin II (AII), transient transfection experiments were performed in CHO cells stably expressing the rat AT(1A) receptor. In this system AII activated ERK in 1 min and also increased the transcriptional activity of the c-fos promoter-luciferase reporter gene construct. The activation of the promoter proved to be dependent on the Ras-Raf-ERK cascade as cotransfection of expression vectors known to specifically inhibit this cascade blocked the effect of AII. Dominant-negative p21Rac1 mutant partially blocked the activation of the c-fos promoter by AII. However, activation of the c-fos promoter was independent of protein kinase C (PKC) as bisindolylmaleimide I, a specific PKC inhibitor did not block the effect of AII. These results suggest that AII activates the transcription of the c-fos through the Ras-Raf-ERK cascade. Furthermore, p21Rac1 is involved in the modulation of the c-fos promoter by AII.
Nephron Experimental Nephrology, 2010
Epithelial-mesenchymal transition of tubular cells into alpha-smooth muscle actin (SMA)-expressin... more Epithelial-mesenchymal transition of tubular cells into alpha-smooth muscle actin (SMA)-expressing myofibroblasts is a central mechanism in tubulointerstitial fibrosis. Previously, a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;two-hit&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; model was proposed for epithelial-mesenchymal transition wherein an initial injury of the intercellular contacts and TGF-beta(1) are both required for SMA protein expression in LLC-PK1 cells. The Rho-Rho kinase-myosin light chain-myocardin-related transcription factor (MRTF)-serum response factor (SRF) pathway and Rac1, p21-activated kinase (PAK) and p38 were described as important regulators of MRTF localization and SMA expression. Cdc42 is another small G protein situated upstream of PAK and p38, and is activated upon cell contact disassembly. Here, we investigated its potential role in the regulation of MRTF nuclear shuttling and in the regulation of the SMA promoter. Transfection of a constitutive active (CA) Cdc42 construct alone induced the activation of the SMA promoter. The dominant negative (DN) Cdc42 construct prevented the activation of the promoter induced by cell contact disassembly, and reduced the combined effect of cell contact disruption and TGF-beta(1). SRF showed a marked nuclear accumulation in CA Cdc42-transfected cells. Cdc42 induced the nuclear translocation of MRTF, while DN Cdc42 inhibited its nuclear translocation induced by cell contact disassembly. Blocking PAK, MRTF and p38 by the corresponding DN constructs blunted the effects of CA Cdc42 on the SMA promoter. Cdc42 is involved in the regulation of SMA promoter activation through PAK, p38, MRTF and SRF. Cdc42 may be an important regulator of MRTF cellular localization.
Sleep Medicine, 2011
Objectives: Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular mor... more Objectives: Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular morbidity in the general population. The clinical significance of OSA among kidney transplant patients is unknown. Our aim was to investigate the association of ''high risk of OSA'' with death-censored graft loss and mortality in a large cohort of kidney transplant recipients. Patients and methods: Using the Berlin questionnaire 1067 prevalent kidney transplant recipients were assessed for risk of OSA. Socio-demographic variables, laboratory parameters and data about graft loss and mortality were obtained from the medical records. Multivariable-adjusted associations of OSA risk with graft loss and with all-cause mortality was assessed in competing-risks regression models. Results: Of the 823 patients who completed the Berlin questionnaire 28% had high risk of OSA (HRO) at baseline. Patients with HRO were older (52 ± 11 vs. 47 ± 13 years, p < 0.001), had a higher prevalence of diabetes (22 vs. 15%, p = 0.018), worse baseline kidney function (estimated glomerular filtration rate: 46 ± 18 vs. 51 ± 19 ml/min/1.73m 2 , p = 0.001) and higher BMI (27 ± 5 vs. 24 ± 4 kg/m 2 , p < 0.001). In multivariate models HRO was an independent predictor of graft loss among females after adjusting for age, comorbidity, hypertension, BMI, kidney function, duration of chronic kidney disease, other laboratory parameters and transplant-related data (HR = 3.05; CI: 1.24-7.51; p = 0.015), while HRO did not predict graft survival among males. HRO at baseline was not independently associated with all-cause mortality in the sample. Conclusion: High risk of OSA is an independent predictor of graft loss among female kidney transplant patients.
Seminars in Nephrology, 2015
Insomnia and poor self-perceived sleep are very common in patients with chronic kidney disease (C... more Insomnia and poor self-perceived sleep are very common in patients with chronic kidney disease (CKD). Poor sleep is associated with fatigue, sleepiness, impaired daytime functioning, impaired health-related quality of life, and increased morbidity and mortality. Many illness- and treatment-related factors (metabolic changes, inflammation, altered sleep regulatory mechanisms, symptoms and complications of CKD, comorbid conditions, medications, and renal replacement therapies) may disturb sleep and contribute to the high prevalence of insomnia in this patient population. Accordingly, the approach to both diagnosing and treating this condition is quite complex. Although sleep-related problems are very important for patients with CKD, they largely are under-recognized and undertreated. Very few intervention trials provide an evidence base to support treatment decisions in this particular patient population. With this review we hope to increase awareness of insomnia among professionals involved in the management of patients with CKD and to provide guidance in recognizing and treating this important condition.
Canadian journal of psychiatry. Revue canadienne de psychiatrie
OBJECTIVE: Despite being a common and potentially serious condition, nephrogenic diabetes insipid... more OBJECTIVE: Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) remains poorly understood in older lithium users. Our main objective was to compare the prevalence of NDI symptoms and decreased urine osmolality ([UOsm] < 300 milli-Osmoles [mOsm/kg]) among geriatric and adult lithium users. We also assessed NDI symptoms, serum sodium (Na+), and urine specific gravity (USG) as possible surrogate measures of decreased UOsm, and ascertained whether potential etiologic factors independently correlated with decreased UOsm. METHOD: This was a cross-sectional study of 100 consecutive outpatients treated with lithium from 6 tertiary care clinics, of which 45 were geriatric (aged 65 years and older) and 55 adult (aged 18 to 64 years). Patients completed a symptom questionnaire and underwent laboratory tests, including UOsm, serum Na+, and USG. RESULTS: Geriatric and adult lithium users had similar rates of decreased UOsm (12.5%, compared with 17.9%,...
Thorax, Jan 2, 2015
There is a paucity of large cohort studies examining the association of obstructive sleep apnoea ... more There is a paucity of large cohort studies examining the association of obstructive sleep apnoea (OSA) with clinical outcomes including all-cause mortality, coronary heart disease (CHD), strokes and chronic kidney disease (CKD). We hypothesised that a diagnosis of incident OSA is associated with higher risks of these adverse clinical outcomes. In a nationally representative cohort of over 3 million (n=3 079 514) US veterans (93% male) with baseline estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m(2), we examined the association between the diagnosis of incident OSA, treated and untreated with CPAP, and: (1) all-cause mortality, (2) incident CHD, (3) incident strokes, (4)incident CKD defined as eGFR<60 mL/min/1.73 m(2), and (5) slopes of eGFR. Compared with OSA-negative patients, untreated and treated OSA was associated with 86% higher mortality risk, (adjusted HR and 95% CI 1.86 (1.81 to 1.91) and 35% (1.35 (1.21 to 1.51)), respectively. Similarly, untreated and treat...
International urology and nephrology, 2015
Protein-energy wasting (PEW) is a common condition in patients with chronic kidney disease (CKD) ... more Protein-energy wasting (PEW) is a common condition in patients with chronic kidney disease (CKD) including dialysis and kidney transplant recipients (TX) and frequently assessed with malnutrition-inflammation score (MIS). We hypothesized that (1) the MIS and PEW parameters are correlated with kidney function and (2) the MIS and PEW parameters are more severe in TX than in non-dialysis (ND) CKD patients with similar eGFR. In this study, we matched 203 ND-CKD and 203 TX patients from two independently assembled cohorts of patients based on estimated glomerular filtration rate (eGFR) and compared various PEW parameters between the two groups using unadjusted and case-mix adjusted linear regression and conditional logistic regression analysis models. In the combined cohort (n = 406) of patients, the mean ± SD age was 57 ± 12 years; included 55 % men and 35 % diabetics; and demonstrated a mean ± SD baseline eGFR of 29 ± 11 ml/min/1.73 m(2). The eGFR correlated positively with serum album...
Medical hypotheses, Jan 6, 2015
Drugs & aging, 2015
Lithium is an important medication in the treatment of mood disorders. However, clinicians are he... more Lithium is an important medication in the treatment of mood disorders. However, clinicians are hesitant to use lithium in older adults for fear of its medical effects, particularly kidney disease. This review describes the current understanding of the epidemiology and mechanisms underlying chronic kidney disease (CKD) in older lithium users, with recommendations for using lithium safely in late life. Prevalence estimates of CKD in older lithium users range from 42-50%, which does not differ greatly from the 37.8% rates seen in community-dwelling non-lithium using, non-psychiatric populations. Clinical and pre-clinical data suggest a variety of synergistic mechanisms contributing to CKD in older lithium users, including aging, cardiovascular factors, oxidative stress, inflammation, nephrogenic diabetes insipidus, acute kidney injury, and medication interactions. With regards to CKD, lithium can be used safely in many older adults with mood disorders. Compared to patients with pre-exi...
Canadian journal of psychiatry. Revue canadienne de psychiatrie, 2014
Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) re... more Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) remains poorly understood in older lithium users. Our main objective was to compare the prevalence of NDI symptoms and decreased urine osmolality ([UOsm] < 300 milli-Osmoles [mOsm/kg]) among geriatric and adult lithium users. We also assessed NDI symptoms, serum sodium (Na+), and urine specific gravity (USG) as possible surrogate measures of decreased UOsm, and ascertained whether potential etiologic factors independently correlated with decreased UOsm. This was a cross-sectional study of 100 consecutive outpatients treated with lithium from 6 tertiary care clinics, of which 45 were geriatric (aged 65 years and older) and 55 adult (aged 18 to 64 years). Patients completed a symptom questionnaire and underwent laboratory tests, including UOsm, serum Na+, and USG. Geriatric and adult lithium users had similar rates of decreased UOsm (12.5%, compared with 17.9%, P = 0.74), but geriatric pa...
Orvosi hetilap, Jan 25, 2003
Over the past ten-fifteen years there has been a continuous increase in the interest in quality o... more Over the past ten-fifteen years there has been a continuous increase in the interest in quality of life research. There is a huge increase in the number of clinical trials applying quality of life as an outcome measure and also in the number of studies where assessment of quality of life is the main focus of the research. During the last decades the resources of health care has increasingly been directed towards the care of chronically ill patients. In these conditions several symptoms persist or may even worsen even with effective therapy. This provides an explanation why quality of life has become an important and useful outcome measure complementing the traditional "hard outcomes" such as morbidity and mortality. Assessment of quality of life is also an important component of cost-effectiveness studies and health-technology assessment. Recently, the overall quality of quality of life research has improved significantly. In the early days, several instruments were used w...
Human Psychopharmacology: Clinical and Experimental, 2014
Lithium continues to be an important mood disorder treatment. Although patients exposed to higher... more Lithium continues to be an important mood disorder treatment. Although patients exposed to higher environmental temperatures may have serum lithium level elevations due to dehydration, there is conflicting data in the literature. In addition, no study has assessed the association between temperature and other renal laboratory tests and symptoms in lithium users. This is a cross-sectional analysis of 63 current lithium users who participated in the McGill Geriatric Lithium-induced Diabetes Insipidus Clinical Study. The relationship between mean daily temperature with diabetes insipidus symptoms, glomerular filtration rate, urine osmolality, serum sodium, lithium level, and lithium dose-level ratio was assessed. Although a higher temperature on the day of laboratory testing trended toward being independently associated with a lower lithium dose-level ratio (Beta = -0.17, p = 0.08), this was not found when using a dichotomous measure of temperature (T &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 20°C). No association was observed between temperature and other renal parameters. The association of temperature with lithium levels, renal symptoms, and laboratory tests appears to be of relatively little clinical importance in lithium users in temperate climates. However, future research should re-examine patients living in climates with extreme temperatures (e.g., &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;40°C), who may theoretically be at higher risk.
Scientific Reports, 2014
Obstructive sleep apnea(OSA) is one of the most common sleep disorders in kidney transplant recip... more Obstructive sleep apnea(OSA) is one of the most common sleep disorders in kidney transplant recipients, however its long-term consequences have only rarely been investigated. Here, we hypothesized that the presence of OSA would be associated with higher risk of mortality and faster decline of graft function in kidney transplant recipients. In a prospective cohort study 100 prevalent kidney transplant recipients who underwent one-night polysomnography at baseline and were followed for a median 75 months. Generalized linear mixed-effects models and Cox regression models were used to assess the association between OSA and the rate of progression of chronic kidney disease(CKD) and mortality. The estimated slopes of estimated glomerular filtration rate(eGFR) in patients with and without OSA were compared using a two-stage model of eGFR change including only OSA as a variable. In this model patients with OSA (eGFR versus time was -0.93 ml/min/1.73 m(2)/yr(95%CI:-1.75 to-0.11) had a similar slope as compared to patients without OSA(eGFR versus time was -1.24 ml/min/1.73 m(2)/yr(95%CI: -1.67 to -0.81). In unadjusted Cox proportional regression analyses OSA was not associated with higher all-cause mortality risk (Hazard Ratio(HR) = 1.20; 95% Confidence Interval(CI): 0.50-2.85). No association was found between the presence of OSA and the rate of progression of CKD or all-cause mortality in prevalent kidney transplant recipients.
Drugs & Aging, 2014
Little is known about how lithium should be dosed to achieve therapeutic but safe serum concentra... more Little is known about how lithium should be dosed to achieve therapeutic but safe serum concentrations in older adults. In this paper, we investigate how the lithium dose-concentration ratio changes across the lifespan. This was a cross-sectional analysis of 63 current lithium users aged 20-95 years using data from McGLIDICS (the McGill Geriatric Lithium-Induced Diabetes Insipidus Clinical Study). Participants underwent blood and urine tests, including serum lithium concentrations. Multivariate analyses were conducted to evaluate potential correlates of the lithium dose-concentration ratio. We found that between the ages of 40-95 years, the total daily dose of lithium required to achieve a given serum concentration decreases threefold (500 vs. 1,500 mg for 1.0 mmol/L). Greater age, once-daily dosing, and lower renal function (estimated glomerular filtration rate) were independently associated with a lower lithium dose-concentration ratio. The lithium dose required to achieve a given serum lithium concentration decreases threefold from middle to old age, with this trend continuing into the ninth and tenth decades of life. In order to avoid lithium toxicity in aging patients, continued serum concentration monitoring and judicious dose reduction may be required, particularly in those patients with reduced renal function.
The American Journal of Geriatric Psychiatry, 2015
ABSTRACT
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, Jan 3, 2014
Transplant glomerulopathy (TG) is generally accepted to result from repeated episodes of endothel... more Transplant glomerulopathy (TG) is generally accepted to result from repeated episodes of endothelial activation, injury and repair, leading to pathological abnormalities of double contouring or multi-layering of the glomerular basement membrane. TG is a major sequel of chronic active antibody-mediated rejection (cABMR), from pre-existing or de novo anti-HLA antibodies. Hepatitis C infection, thrombotic microangiopathy or other factors may also contribute to TG development. TG prevalence is 5-20% in most series, reaching 55%, in some high-risk cohorts, and is associated with worse allograft outcomes. Despite its prevalence and clinical significance, few well-studied treatment options have been proposed. Similar to desensitization protocols, plasmapheresis with or without immunoabsorption, high-dose intravenous immunoglobulin, rituximab, bortezomib and eculizumab have been proposed in the treatment of TG due to cABMR individually or in various combinations. Robust clinical trials are ...
Transplantation, 2011
Anemia and mineral and bone disorders (MBD) are both important and common complications in kidney... more Anemia and mineral and bone disorders (MBD) are both important and common complications in kidney transplant recipients. Studies in patients with chronic kidney disease indicated a possible independent association of higher serum phosphorus with anemia, but similar associations have not been examined in kidney transplant recipients. We hypothesized that higher serum phosphorus is associated with anemia independent of other components of MBD. We examined the association of serum phosphorus with hemoglobin level and the prevalence of anemia in a prevalent cohort of 992 kidney transplant recipients in a single outpatient transplant center. Associations were examined in linear and logistic regression models with adjustment for demographic and comorbid conditions for various known risk factors of anemia, including measures of iron deficiency, inflammation, and components of MBD including serum levels of 25(OH) vitamin D, parathyroid hormone, and fibroblast growth factor 23. In multivariable adjusted regression models, a 1 standard deviation (0.8 mg/dL) higher serum phosphorus level was associated with 0.26 g/dL lower blood hemoglobin concentration (95% confidence intervals -0.36 to -0.15, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) and with an odds ratio for anemia of 1.77 (95% confidence intervals 1.33-2.37, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). These associations were consistent across the entire spectrum of the physiologic serum phosphorus concentration and were more accentuated in patients with lower estimated glomerular filtration rate. Higher serum phosphorus is independently associated with anemia in kidney transplant recipients.
Nephron Clinical Practice, 2011
Although it is a known predictor of mortality, there is a relative lack of recent information abo... more Although it is a known predictor of mortality, there is a relative lack of recent information about anaemia in kidney transplant recipients. Thus, we now report data about the prevalence and management of post-transplant anaemia (PTA) in Europe 5 years after the TRansplant European Survey on Anemia Management (TRESAM) study. In a cross-sectional study enrolling the largest number of patients to date, data were obtained from 5,834 patients followed at 10 outpatient transplant clinics in four European countries using the American Society of Transplantation anaemia guideline. More than one third (42%) of the patients were anaemic. The haemoglobin (Hb) concentration was significantly correlated with the estimated glomerular filtration rate (eGFR) (r = 0.4, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). In multivariate analysis, eGFR, serum ferritin, age, gender, time since transplantation and centres were independently and significantly associated with Hb. Only 24% of the patients who had a Hb concentration &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;110 g/l were treated with an erythropoiesis-stimulating agent. The prevalence of anaemia and also the use of erythropoiesis-stimulating agents were significantly different across the different centres, suggesting substantial practice variations. PTA is still common and under-treated. The prevalence and management of PTA have not changed substantially since the TRESAM survey.
Nephron Clinical Practice, 2011
Elevated parathyroid hormone (PTH) is used to diagnose high turnover bone disease in chronic kidn... more Elevated parathyroid hormone (PTH) is used to diagnose high turnover bone disease in chronic kidney disease (CKD). The diagnostic accuracy of PTH in kidney transplant recipients with CKD is unknown. We examined kidney transplant recipients with CKD stages 3 (n = 498) and 4 (n = 141) to determine the sensitivity and specificity of the Kidney/Dialysis Outcome Quality Initiative (K/DOQI)-recommended PTH levels in detecting elevated serum β-CrossLaps (CTX) or osteocalcin (OC) levels. We performed receiver-operator curve analyses to determine CKD stage-specific PTH levels that provide optimal diagnostic accuracy. PTH below the lower limits of the K/DOQI ranges (35 and 70 pg/ml in CKD stages 3 and 4, respectively) showed sensitivity of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;90% in diagnosing increases in biochemical markers. The upper limits (70 and 110 pg/ml), however, showed poor specificity. A specificity of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;90% for detecting increased biochemical markers was seen with PTH of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;140 and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;240 pg/ml in CKD stages 3 and 4, respectively. Currently applied cutoffs for PTH in kidney transplant recipients with CKD stages 3 and 4 do not appear to adequately detect increased biochemical markers of bone turnover. Diagnostic uncertainty exists in patients with CKD stage 3 and PTH between 35 and 140 pg/ml, and CKD stage 4 and PTH between 70 and 240 pg/ml.
Nephron Clinical Practice, 2011
Resistance to erythropoiesis-stimulating agents (ESAs) has been observed in patients with chronic... more Resistance to erythropoiesis-stimulating agents (ESAs) has been observed in patients with chronic kidney disease (CKD) and it is associated with clinical outcomes. The presence of ESA resistance cannot always be explained by the known risk factors of the condition, suggesting that additional factors may be involved. We wanted to test the hypothesis that vitamin D insufficiency is associated with lower hemoglobin (Hb) and ESA resistance in patients on maintenance hemodialysis (HD). Data from patients receiving maintenance HD in a single dialysis center were extracted from the medical records in a retrospective chart review. Basic patient characteristics and laboratory data including Hb, serum albumin, intact parathyroid hormone and serum 25(OH)-cholecalciferol (25(OH)D(3)) levels were collected. ESA dose and Kt/V were extracted from the dialysis charts. Correlation analysis and multivariate linear regression analysis were used to reveal potential independent associations between clinical and laboratory parameters and ESA resistance. Data from 142 patients were analyzed. Serum 25(OH)D(3) concentration was significantly correlated with Hb (ρ = 0.186, p &amp;amp;amp;lt; 0.05) and also with ESA dose/Hb index (ρ = 0.230, p &amp;amp;amp;lt; 0.01). In multivariable regression analyses, serum 25(OH)D(3) concentration remained significantly associated with both Hb and ESA dose/Hb index after controlling for potentially important confounders. Serum 25(OH)D(3) concentration is independently associated with erythropoietin responsiveness in CKD patients on maintenance HD. If this association will be confirmed, treatment trials looking at the effect of vitamin D supplementation on anemia treatment in CKD patients may be warranted.
Nephron Experimental Nephrology, 2001
To study the role of extracellular-signal-regulated kinase (ERK) cascade and the small GTP-ase pr... more To study the role of extracellular-signal-regulated kinase (ERK) cascade and the small GTP-ase proteins in the activation of the c-fos promoter by angiotensin II (AII), transient transfection experiments were performed in CHO cells stably expressing the rat AT(1A) receptor. In this system AII activated ERK in 1 min and also increased the transcriptional activity of the c-fos promoter-luciferase reporter gene construct. The activation of the promoter proved to be dependent on the Ras-Raf-ERK cascade as cotransfection of expression vectors known to specifically inhibit this cascade blocked the effect of AII. Dominant-negative p21Rac1 mutant partially blocked the activation of the c-fos promoter by AII. However, activation of the c-fos promoter was independent of protein kinase C (PKC) as bisindolylmaleimide I, a specific PKC inhibitor did not block the effect of AII. These results suggest that AII activates the transcription of the c-fos through the Ras-Raf-ERK cascade. Furthermore, p21Rac1 is involved in the modulation of the c-fos promoter by AII.
Nephron Experimental Nephrology, 2010
Epithelial-mesenchymal transition of tubular cells into alpha-smooth muscle actin (SMA)-expressin... more Epithelial-mesenchymal transition of tubular cells into alpha-smooth muscle actin (SMA)-expressing myofibroblasts is a central mechanism in tubulointerstitial fibrosis. Previously, a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;two-hit&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; model was proposed for epithelial-mesenchymal transition wherein an initial injury of the intercellular contacts and TGF-beta(1) are both required for SMA protein expression in LLC-PK1 cells. The Rho-Rho kinase-myosin light chain-myocardin-related transcription factor (MRTF)-serum response factor (SRF) pathway and Rac1, p21-activated kinase (PAK) and p38 were described as important regulators of MRTF localization and SMA expression. Cdc42 is another small G protein situated upstream of PAK and p38, and is activated upon cell contact disassembly. Here, we investigated its potential role in the regulation of MRTF nuclear shuttling and in the regulation of the SMA promoter. Transfection of a constitutive active (CA) Cdc42 construct alone induced the activation of the SMA promoter. The dominant negative (DN) Cdc42 construct prevented the activation of the promoter induced by cell contact disassembly, and reduced the combined effect of cell contact disruption and TGF-beta(1). SRF showed a marked nuclear accumulation in CA Cdc42-transfected cells. Cdc42 induced the nuclear translocation of MRTF, while DN Cdc42 inhibited its nuclear translocation induced by cell contact disassembly. Blocking PAK, MRTF and p38 by the corresponding DN constructs blunted the effects of CA Cdc42 on the SMA promoter. Cdc42 is involved in the regulation of SMA promoter activation through PAK, p38, MRTF and SRF. Cdc42 may be an important regulator of MRTF cellular localization.
Sleep Medicine, 2011
Objectives: Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular mor... more Objectives: Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular morbidity in the general population. The clinical significance of OSA among kidney transplant patients is unknown. Our aim was to investigate the association of ''high risk of OSA'' with death-censored graft loss and mortality in a large cohort of kidney transplant recipients. Patients and methods: Using the Berlin questionnaire 1067 prevalent kidney transplant recipients were assessed for risk of OSA. Socio-demographic variables, laboratory parameters and data about graft loss and mortality were obtained from the medical records. Multivariable-adjusted associations of OSA risk with graft loss and with all-cause mortality was assessed in competing-risks regression models. Results: Of the 823 patients who completed the Berlin questionnaire 28% had high risk of OSA (HRO) at baseline. Patients with HRO were older (52 ± 11 vs. 47 ± 13 years, p < 0.001), had a higher prevalence of diabetes (22 vs. 15%, p = 0.018), worse baseline kidney function (estimated glomerular filtration rate: 46 ± 18 vs. 51 ± 19 ml/min/1.73m 2 , p = 0.001) and higher BMI (27 ± 5 vs. 24 ± 4 kg/m 2 , p < 0.001). In multivariate models HRO was an independent predictor of graft loss among females after adjusting for age, comorbidity, hypertension, BMI, kidney function, duration of chronic kidney disease, other laboratory parameters and transplant-related data (HR = 3.05; CI: 1.24-7.51; p = 0.015), while HRO did not predict graft survival among males. HRO at baseline was not independently associated with all-cause mortality in the sample. Conclusion: High risk of OSA is an independent predictor of graft loss among female kidney transplant patients.