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Older patients with chronic kidney disease (CKD) undergoing maintenance hemodialysis are at a higher risk of falling. However, there is no standard method to screen patients at higher risk. We have evaluated whether calf circumference (CC) measurement would be able to predict falls in this population.This is a prospective study that enrolled patients aged ≥65 years on conventional hemodialysis, followed for 6 months. The presence of falls was associated with demographical, clinical, and biochemical data. Reduced CC was set at34 cm for men and33 cm for women. We evaluated physical status using Duke activity status index (DASI) and hand grip strength (HGS).Ninety-one patients were included (age 73.7 ± 5.4 years, 69.2% men, 56% with diabetes). Mean CC was 32.6 ± 3.7 cm, with a high prevalence of reduced CC (61.5%). During the follow-up, 13 falls were identified (1 had a fracture and died). These patients were older and heavier (P = .017 and P = .025, respectively). Most falls occurred in patients with sarcopenic obesity (BMI27 kg/mCC measurement, an easy and nonexpensive tool, was able to predict falls in older patients on HD. Further studies should test the inclusion of CC in a fall risk assessment in older patients on hemodialysis.

Resumo Introdução: Há discordância entre os dados sobre duração do sono obtidos a partir de questionários e medições objetivas. Não se sabe se isto também é verdade para indivíduos com DRC. Aqui comparamos a duração do sono autorrelatada com a duração do sono obtida por meio de actigrafia. Métodos: Este estudo prospectivo incluiu indivíduos adultos com DRC estadio 3 recrutados entre Setembro/2016 e Fevereiro/2019. Avaliamos a duração subjetiva do sono, fazendo a seguinte questão: “Quantas horas de sono real você teve à noite?” Resultados: Os pacientes (N=34) eram relativamente jovens (51 ± 13 anos). A duração do sono autorrelatada e mensurada foi de 7,1 ± 1,7 e 6,9 ± 1,6 horas, respectivamente, sem correlação entre elas (p=0,165). Embora a diferença média entre as medições tenha sido de 0,21 h, os limites de concordância variaram de -3,7 a 4,1 h. Conclusão: Pacientes com DRC que não estão em diálise apresentam uma percepção equivocada do sono. Dados sobre a duração do sono devem ser obtidos preferencialmente a partir de medições objetivas em pacientes com DRC.

There is a paucity of data on the prognosis for patients returning to peritoneal dialysis (PD) after a failed transplant. PD has an advantage over hemodialysis in preserving residual renal function, which is associated with better outcomes. We have reviewed the electronic charts of patients on PD in a tertiary academic hospital for the last 8 years. We have compared technique survival, peritonitis-free survival, and residual diuresis in two groups: patients with graft failure which returned to PD (PD-KTx, N = 18) and patients starting PD for other causes (PD-not KTx, N = 163). The median follow-up was similar between groups [42(16,71) in PD-not KTx vs. 48(22,90) months in PD-KTx, p = 0.293]. Kaplan–Meier survival comparing PD-KTx and PD-not KTx showed no difference in technique survival (p = 0.196), and peritonitis-free survival (log-rank 0.238), which were confirmed in a fully adjusted Cox regression. Diuresis at baseline and at the end of the first year was similar between groups (p = 0.799 and p = 0.354, respectively). Six out of 18 patients from the PD-KTx group had the immunosuppression maintained and none of those had peritonitis. The reduction of diuresis across the first year of PD was significant for all patients, except for those on continued immunosuppressive therapy. PD is a worthy dialysis alternative after a failed kidney transplant, providing similar outcomes when compared to patients who started PD for other reasons.

Left ventricular hypertrophy is a risk factor for cardiovascular mortality in patients on peritoneal dialysis (PD). Because icodextrin has a greater ultrafiltration power compared with glucose-based solutions for long dwell, it could improve left ventricular mass by reducing fluid overload. This was a randomized clinical trial that included patients on PD recruited from 2 teaching hospitals, in Sao Paulo—Brazil. Patients were allocated to the control glucose group (GLU) or the intervention icodextrin (ICO) group. Clinical and cardiac magnetic resonance image (MRI) parameters were evaluated at baseline and 6 months after randomization. The primary outcome was the change in left ventricular mass adjusted by surface area (ΔLVMI), measured by cardiac MRI. A total of 22 patients completed the study (GLU, N = 12 and ICO, N = 10). Baseline characteristics such as age, sex, underlying disease, and time on dialysis were similar in both groups. At baseline, 17 patients (77.3%) presented with left ventricular hypertrophy with no difference between groups (p = 0.748). According to the total body water (TBW)/extracellular water (ECW) ratio, 36.8% and 80% of patients from GLU and ICO groups, respectively, were considered hypervolemic (p = 0.044). During follow-up, ΔLVMI was 3.9 g/m (− 10.7, 2.2) in GLU and 5.2 (− 26.8, 16.8) in ICO group (p = 0.651). ΔLVMI correlated with change in brain natriuretic peptide (r = 0.566, p = 0.044), which remained significant in a multiple regression analysis. The use of the icodextrin-based solution in prevalent patients on PD compared with a glucose-based solution was not able to improve LMV. A larger randomized trial with a longer follow-up period may be needed to show changes in LVM in this patient population.Trial registration: this study has been registered at ReBEC (Registro Brasileiro de Ensaios Clinicos) under the identification #RBR-2mzhmj2, available at: https://ensaiosclinicos.gov.br/pesquisador.

In the last decades, improvements in the average life expectancy in the world population have been associated with a significant increase in the proportion of elderly people, in parallel with a higher prevalence of non-communicable diseases, such as hypertension and diabetes. As the kidney is a common target organ of a variety of diseases, an adequate evaluation of renal function in the approach of this population is of special relevance. It is also known that the kidneys undergo aging-related changes expressed by a decline in the glomerular filtration rate (GFR), reflecting the loss of kidney function, either by a natural senescence process associated with healthy aging or by the length of exposure to diseases with potential kidney damage. Accurate assessment of renal function in the older population is of particular importance to evaluate the degree of kidney function loss, enabling tailored therapeutic interventions. The present review addresses a relevant topic, which is the effects of aging on renal function. In order to do that, we analyze and discuss age-related structural and functional changes. The text also examines the different options for evaluating GFR, from the use of direct methods to the implementation of several estimating equations. Finally, this manuscript supports clinicians in the interpretation of GFR changes associated with age and the management of the older patients with decreased kidney function.

Peritoneal equilibration test (PET) is the gold standard for evaluating peritoneal transport, and measurement of the drain volume after 4-h dwell time with glucose 4.25% is a simple means of evaluating failure of ultrafiltration. The study objective was to verify if the measurement of the volume drained after 4 h dwell of icodextrin at 7.5% (ICO), has a better correlation with the parameters of PET. Patients in a peritoneal dialysis program (N = 35) underwent three procedures: PET; determination of the drain volume after a 4-h dwell with glucose 4.25%; and determination of the drain volume after a 4-h dwell with ICO. Among patients who were classified as high transporters, the ultrafiltration volume was greater after ICO use. The ICO ultrafiltration volume correlated negatively with the ratio between the 4- and 0-h dialysate glucose concentrations (D4/D0 ratio, r = -0.579; P = 0.002), correlating positively with the dialysate-to-plasma ratio for creatinine (D/PCr ratio, r = 0.474; P = 0.002). For ICO, the area under the receiver operating characteristic curve was 0.867 and 0.792 for the D/PCr and D4/D0 ratios (P

Objective to explore the status of concentration of klotho and fibroblast growth factor 23 (FGF23) in cerebrospinal fluid (CSF) of patients with narcolepsy. Patients/methods 59 patients with narcolepsy and 17 control individuals were enrolled. We used radioimmunoassay, human klotho enzyme-linked immunosorbent assay (ELISA), human intact FGF23 ELISA and spectrophotometry to measure hypocretin-1, klotho, FGF-23 and phosphorus, respectively. T-Student Test was used to compare klotho and phosphate concentrations, Mann–Whitney U Test were used to compare FGF-23 levels between groups. ANOVA Test was used to compare klotho and phosphate CSF concentrations among narcolepsy patients with CSF hypocretin-1 110 pg/ml (HCRT+) versus control subjects. Results Klotho and phosphorus CSF levels were lower in narcoleptic patients than in control (908.18 ± 405.51 versus 1265.78 ± 523.26 pg/ml; p = 0.004 and 1.34 ± 0.25 versus 1.58 ± 0.23 mg/dl; p = 0.001, respectively). We found higher FGF-23 levels in narcoleptic patients (5.51 versus 4.00 pg/mL; p = 0.001). Klotho and phosphorus CSF levels were lower in both HCRT- and HCRT+ than controls. Moreover, there were higher FGF-23 levels in both HCRT-/HCRT+ groups versus controls. However, we did not find differences comparing HCRT- and HCRT+ groups, analyzing CSF klotho, FGF-23 or phosphorus levels. Conclusions Patients with narcolepsy have decreased CSF concentration of klotho and increased CSF levels of FGF-23. These findings may play a role in understanding the pathogenesis of narcolepsy.

In patients with chronic kidney disease (CKD), hyperphosphatemia is associated with several adverse outcomes, including bone fragility and progression of kidney and cardiovascular disease. However, there is a knowledge gap regarding phosphate balance in CKD. This review explores its current state, depending on the stage of CKD, dialysis modalities, and the influence of kidney transplantation.Adequate phosphate control is one of the goals of treatment for CKD-mineral and bone disorder. However, ongoing studies are challenging the benefits of phosphate-lowering treatment. Nevertheless, the current therapy is based on dietary restriction, phosphate binders, and optimal removal by dialysis. In the face of limited adherence, due to the high pill burden, adjuvant options are under investigation. The recent discovery that intestinal absorption of phosphate is mostly paracellular when the intraluminal concentration is adequate might help explain why phosphate is still well absorbed in CKD, despite the lower levels of calcitriol.Future studies could confirm the benefits of phosphate control. Greater understanding of the complex distribution of phosphate among the body compartments will help us define a better therapeutic strategy in patients with CKD.

BackgroundRenal replacement therapy (RRT) is usually indicated for patients with chronic kidney disease (CKD) with glomerular filtration rate below 10 ml/ml/min/1.73m2. However, the need for RRT and timing of dialysis initiation are debatable for patients aged 70 years or older. We here describe the study design and methodology of the Aging Nephropathy Study (AGNES) protocol that aims at evaluating to what extent geriatric-related conditions such as frailty, cognitive dysfunction, and presence of comorbidities have an impact on survival and RRT initiation in this group of patients. In this manuscript we provide detailed information about the AGNES study design and methodology.MethodsAGNES is a prospective observational cohort that aim to investigate clinical, biochemical and demographic factors associated with RRT initiation and mortality of patients with CKD stage 4 or 5 who are aged 70 years and older. We plan to include 200 patients over 5 years. Clinically stable outpatients on conservative management for at least 6 months will be recruited from the Nephrogeriatric Clinic at theHospital das Clinicas da Universidade de Sao Paulo, Brazil. Eligible patients are submitted to a full clinical examination, geriatric assessment, and blood test at baseline. Following the baseline visit the patients are being monitored during an observational follow up period of at least 12 months during which patients will be contacted in the clinic at their regular follow up or by phone until either RRT initiation or death occurs. This cohort includes evaluation of cognition by the education-adjusted 10-point Cognitive Screener (10-CS), frailty by Fried index score, a complete nutritional assessment (by body composition assessment, global subjective assessment and dietary intake), comorbidities by Charlson comorbidity index and biochemical markers including FGF-23 and Klotho.DiscussionThe AGNES cohort, a real-world study of current clinical practice in elderly patients with advanced CKD prior to dialysis initiation, will shed light into progression of CKD and its complications, indications of RRT and factors determining survival. This investigation will elucidate to what extent geriatric conditions, nutritional status and clinical factors are associated with survival, quality of life and RRT initiation in elderly CKD patients not yet on dialysis.Trial registrationRegistered onClinicalTrials.govon 18 October 2019 (NCT04132492).

Patients on hemodialysis are exposed to calcium via the dialysate at least three times a week. Changes in serum calcium vary according to calcium mass transfer during dialysis, which is dependent on the gradient between serum and dialysate calcium concentration (d[Ca]) and the skeleton turnover status that alters the ability of bone to incorporate calcium. Although underappreciated, the d[Ca] can potentially cause positive calcium balance that leads to systemic organ damage, including associations with mortality, myocardial dysfunction, hemodynamic tolerability, vascular calcification, and arrhythmias. The pathophysiology of these adverse effects includes serum calcium changes, parathyroid hormone suppression, and vascular calcification through indirect and direct effects. Some organs are more susceptible to alterations in calcium homeostasis. In this review, we discuss the existing data and potential mechanisms linking the d[Ca] to calcium balance with consequent dysfunction of the skeleton, myocardium, and arteries. Resumo Pacientes em hemodiálise são expostos ao cálcio, por meio do dialisato, pelo menos três vezes por semana. As alterações no cálcio sérico variam de acordo com a transferência de massa de cálcio durante a diálise, que é dependente do gradiente entre a concentração de cálcio no plasma e no dialisato (d [Ca]) e o estado de renovação do esqueleto que altera a capacidade do osso de incorporar cálcio. Embora subestimado, o d [Ca] pode potencialmente causar balanço positivo de cálcio que leva a danos em órgãos sistêmicos, incluindo associações com mortalidade, disfunção miocárdica, tolerabilidade hemodinâmica, calcificação vascular e arritmias. A fisiopatologia desses efeitos adversos inclui alterações do cálcio sérico, supressão do hormônio da paratireóide e calcificação vascular por meio de efeitos diretos e indiretos. Alguns órgãos são mais suscetíveis a alterações na homeostase do cálcio. Nesta revisão, discutimos os dados existentes e os mecanismos potenciais que ligam o d [Ca] ao equilíbrio do cálcio com a consequente disfunção no esqueleto, miocárdio e artérias.

Studies investigating bone histology in children with chronic kidney disease (CKD) are scarce.Forty-two patients, mean age 11.3 ± 4.3 years with stage 5 CKD on dialysis, underwent double tetracycline labeling bone biopsy and the relationship between clinical features, biochemical markers, and bone densitometry (DXA) was investigated.Low bone turnover was present in 59% of patients, abnormal mineralization in 29%, and low bone volume in 7%. Higher bone formation rate was found in non-Caucasian patients, whereas abnormal mineralization occurred in older and shorter children. We found no impact of gender and etiology of renal disease in our population. Parathormone (PTH) and alkaline phosphatase (AP) showed positive associations with bone turnover. ROC curve analysis showed a fair performance of biomarkers to predict TMV status. PTH 2 times ULN independently associated with low bone turnover (RR 5.62, 95% CI 1.01-31.24; p = 0.049), in a model adjusted for race, calcitriol dosage, and calcium. It was also associated with abnormal mineralization (RR 1.35, 95% CI 1.04-1.75; p = 0.025), in a model adjusted for BMD scores, AP, age, and calcitriol. PTH and AP significantly predicted turnover and mineralization defect, although with low specificity and sensitivity, reaching a maximum value of 64% and 67%, respectively.While PTH and AP were associated with turnover and mineralization, we recognize the limitation of their performance to clearly distinguish high from low/normal bone turnover and normal from abnormal mineralization. Our results reinforce the need to expand knowledge about renal osteodystrophy in pediatric population through prospective bone biopsy studies. Graphical abstract.

Hypokalemia is a well-described electrolyte disturbance in patients on peritoneal dialysis (PD). Hyperkalemia, however, is still overlooked, although it also represents a risk factor for mortality. Angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers (ACE/ARB), diuretics, and proton pump inhibitor (PPI) can interfere with potassium levels in these patients. This is a retrospective study that evaluated monthly serum potassium in a 5-year period. Serum potassium disturbances were evaluated as time-average and number of hypo- and hyperkalemia episodes per patient. Prescribed medication such as ACE/ARB, diuretics, and omeprazole were recorded. We evaluated 2025 potassium measurements obtained from 146 patients on PD. Serum potassium ranged from 2.5 to 8.3 mEq/L with an average of 4.72 ± 0.74 mEq/L. Hypokalemia was found in 59 measurements (2.9%) obtained from 35 patients (23.9%) whereas hyperkalemia was demonstrated in 269 (13.3%) measurements obtained from 74 patients (50.7%). Hypokalemia was associated with low albumin (p = 0.022), and omeprazole use (p = 0.024). Black race was a protector factor (p = 0.031). Omeprazole-associated hypokalemia was seen only in non-anuric patients and remained an independent risk factor even after adjustments. Patients who had hyperkalemia were more likely to be anuric (p = 0.001) and in use of furosemide (p = 0.0001). Hyperkalemia and hypokalemia are very frequent in patients on PD and should be closely monitored. Interventional studies should address the impact of discontinuing omeprazole in the levels of potassium.

Background: Left ventricular hypertrophy (LVH) is a risk factor for cardiovascular mortality in patients on peritoneal dialysis (PD). Icodextrin has a greater ultrafiltration power and could improve left ventricular mass by treating fluid overload. Findings from cardiac magnetic resonance imaging (MRI), however, are scarce. Methods: This is a randomized cohort that included prevalent patients on PD recruited from 2 tertiary hospitals. Patients were allocated to the glucose (GLU) or icodextrin (ICO) group. Clinical, demographic, biochemical, bioimpedance (extracellular water/total body water ratio – AEC/ACT) data, and cardiac MRI were evaluated at baseline and after 6 months. The outcome was a change in left ventricular mass adjusted by surface area (ΔLVMI). Results: 22 completed the study (GLU, N=12 and ICO, N=10). Patients from GLU and ICO groups had similar age, sex, underlying disease, and time on dialysis. At baseline, LVH was found in 17 patients (77.3%), with no difference between groups (p=0.748). According to ECW/TBW, 36.8% and 80% of patients from GLU and ICO groups, respectively, were considered hypervolemic (p=0.044). During follow-up, ΔLVMI was 3.9 (-10.7, 2.2)g/m in GLU and 5.2 (-26.8, 16.8) in ICO group (p=0.651). ΔLVMI correlated with change in ΔBNP (r=0.566, p=0.044), and remained significant in a multiple regression analysis. Conclusion: We found no superiority of icodextrin to glucose-based solution in improving LMVI in prevalent patients on PD. Whether icodextrin would improve LVMI in long-term follow-up deserver further evaluation.

Introduction: There is disagreement between data on sleep duration obtained from questionnaires and objective measurements. Whether this is also true for individuals with CKD is unknown. Here we compared self-reported sleep duration with sleep duration obtained by actigraphy. Methods: This prospective study included adult individuals with stage 3 CKD recruited between September/2016 and February/2019. We evaluated subjective sleep duration by asking the following question: “How many hours of actual sleep did you get at night?” Results: Patients (N=34) were relatively young (51 ± 13 years). Self-reported and measured sleep duration were 7.1 ± 1.7 and 6.9 ± 1.6 hours, respectively, with no correlation between them (p=0.165). Although the mean difference between measurements was 0.21 h, the limits of agreement ranged from -3.7 to 4.1 h. Conclusion: Patients with CKD who are not on dialysis have an erroneous sleep perception. Data on sleep duration should be preferentially obtained from objective measurements in patients with CKD. Resumo Introdução: Há discordância entre os dados sobre duração do sono obtidos a partir de questionários e medições objetivas. Não se sabe se isto também é verdade para indivíduos com DRC. Aqui comparamos a duração do sono autorrelatada com a duração do sono obtida por meio de actigrafia. Métodos: Este estudo prospectivo incluiu indivíduos adultos com DRC estadio 3 recrutados entre Setembro/2016 e Fevereiro/2019. Avaliamos a duração subjetiva do sono, fazendo a seguinte questão: “Quantas horas de sono real você teve à noite?” Resultados: Os pacientes (N=34) eram relativamente jovens (51 ± 13 anos). A duração do sono autorrelatada e mensurada foi de 7,1 ± 1,7 e 6,9 ± 1,6 horas, respectivamente, sem correlação entre elas (p=0,165). Embora a diferença média entre as medições tenha sido de 0,21 h, os limites de concordância variaram de -3,7 a 4,1 h. Conclusão: Pacientes com DRC que não estão em diálise apresentam uma percepção equivocada do sono. Dados sobre a duração do sono devem ser obtidos preferencialmente a partir de medições objetivas em pacientes com DRC.

Hyperuricemia is common among patients with chronic kidney disease (CKD). In the general population, hyperuricemia is associated with secondary hyperparathyroidism (SHPT), in a mechanism that involves vitamin D metabolism. Data for patients with CKD, however, are scarce. We aimed to evaluate the relationship between hyperuricemia and mineral and bone metabolism, particularly hyperparathyroidism.This is a retrospective study that included 922 adult patients with stages 3, 4, or 5 CKD, not on dialysis. Clinical, demographic, and biochemical data were collected from charts and included uric acid, parathyroid hormone (PTH), 25(OH)-vitamin D, calcium, phosphate, renal function (estimated glomerular filtration rate-eGFR), and medications such as allopurinol, furosemide, and cholecalciferol. SHPT was defined as PTH 65 pg/ml.Our patients were mostly Caucasian women, with a mean age of 64 ± 16 years. SHPT and hyperuricemia were observed in 70% and 62.4% of patients, respectively. Patients with SHPT presented higher levels of uric acid (7.2 ± 1.8 vs. 6.6 ± 1.7 mg/dL, p = 0.0001) and a higher frequency of hyperuricemia (66% vs. 33%, p = 0.0001). Patients with hyperuricemia were mostly female, with lower eGFR, higher phosphate, and higher PTH. The risk of hypovitaminosis D was higher among patients with SHPT (69.7% vs. 53.1%, p = 0.0001). Hyperuricemia remained independently associated with hyperparathyroidism, (p = 0.033) even after adjustments for eGFR, calcium, phosphate, hypovitaminosis D, and use of allopurinol, calcitriol, furosemide, and cholecalciferol.Hyperuricemia seems to be a contributing factor for SHPT in patients with CKD. The mechanisms behind this finding have yet to be elucidated.

BackgroundHypothyroidism is highly prevalent in patients with chronic kidney disease (CKD) and has been associated with poorer clinical outcomes, including faster decline of kidney function. However, there is no consensus whether low free thyroxin (LFT) affects the rate of estimated glomerular filtration rate (eGFR) decline and how the presence of proteinuria influences the progression of renal dysfunction in hypothyroidism.MethodsWe assessed thyroid status, proteinuria, and progression of eGFR by Modification of Diet in Renal Disease equation and CKD-EPI equation in a cohort of CKD patients followed in general nephrology clinics. We estimated the association of LFT levels, and the degree of proteinuria on progression of eGFR. We adjusted for other covariables: age, gender, body mass index, diabetes, hypertension, HbA1c, uric acid, cholesterol, and triglycerides levels..ResultsOne thousand six hundred ten patients (64 ± 15 years, 46.8% men, 25.3% diabetic) were included. At beggnining of follow up eGFR was between 45 and 60, 30–45 and 15-30 ml/min/1.73m2in 479 (29.8%), 551(34.2%), and 580(36.0%) patients, respectively. LFT levels were available at initial evaluation in 288(17.9%) patients and 735(48.5%) had assessment of proteinuria (19.6% with LFT vs. 15.4% without LFT,p = 0.032). Median follow-up time was of 21 months, and 1223(76%) had at least 1 year of follow up. Overall, eGFR decline per month was − 0.05(− 0.26, 0.23) ml/min/1.73m2, reaching 1.7(1.3, 2.4) ml/min/1.73m2by the end of study period. Similar results were obtained using CKD-EPI. Multivariable mixed linear analysis showed that proteinuria and age were independently associated with eGFR decline, with no effect of LFT, and no interaction between proteinuria and LFT. In patients without proteinuria, there was an improvement of eGFR despite the presence of LFT.ConclusionsWe confirmed a faster rate of eGFR declined in patients with proteinuria. However, despite the pathophysiological rational that hypothyroidism can lead to increased rate of CKD progression, we failed to demonstrate an association between LFT and rate of CKD progression. We conclude that the benefit of hypothyroidism treatment in CKD patients needs to be evaluate in prospective studies.

Background: Patients with chronic kidney disease (CKD) are less likely to be submitted to coronary artery bypass grafting (CABG) then clinical medical treatment based on the potential high risk of mortality. However, whether patients on maintenance dialysis who underwent an elective CABG experience high hospital- and long-term mortality is still debatable. Methods: This is a prospective observational study that evaluated patients who underwent elective CABG. Three groups were compared: reference (n = 167, estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m2), CKD3–4 (n = 84, eGFR 15–59 mL/min/1.73 m2), and maintenance hemodialysis (n = 31). Demographic, clinical, biochemical, fluid balance data, and Sequential Organ Failure Assessment (SOFA) scores were assessed daily for the same observer from day 1 (surgery) to hospital discharge. Results: The main outcomes were in-hospital and 1-year mortality. Patients aged 63 ± 10, 63 ± 8, and 65 ± 6 years old, in reference, CKD3–4, and dialysis groups, respectively (p = 0.605). Patients from the reference group had a lower prevalence of diabetes (p = 0.010) and hypertension (p = 0.021). SOFA scores were higher in CKD3–4 and dialysis groups (p = 0.001), though this difference disappeared without the renal component (p = 0.326). In-hospital mortality (n = 17) was similar across groups (p = 0.955). There was no difference in 1-year mortality among groups even after adjustments for age, diabetes, intraoperative blood loss, and time on ventilation. Conclusions: CABG short-term mortality seems not to be greater among selected patients on maintenance dialysis. A multidisciplinary team has been helping cardiologists and cardiac surgeons in the decision-making process regarding the best approach in coronary artery disease, and CABG should be considered a worthy therapeutic option.

Introduction Restless legs syndrome (RLS) is a highly prevalent sleep movement disorder usually accompanied by periodic limb movements of sleep (PLMS). The incidence of RLS and PLMS in patients with end-stage renal disease (ESRD) on dialysis is much higher. Clinically, RLS and PLMS can co-occur. We hypothesized that patients with ESRD on dialysis would have a distinct presentation of RLS, with a higher prevalence of PLMS. Methods We examined clinical, demographic, biochemical, and polysomnographic characteristics of RLS in patients on dialysis matched to control subjects with normal renal function based on age, sex, body mass index, and frequency of apneas and hypopneas per hour of sleep, defined by the apnea and hypopnea index (AHI), in a proportion of 3:1. Patients with ESRD were on hemodialysis three times per week. Polysomnography was performed overnight in the sleep laboratory. Findings Patients on dialysis compared to control subjects had a lower amount of N3 sleep (77.6 ± 39.9 minutes vs. 94.8 ± 33.7 minutes, p = 0.037) and REM sleep (55.6 ± 27.5 minutes vs. 74.1 ± 28.4 minutes, p = 0.006), regardless of the presence of RLS. Among the patients on dialysis, those with RLS had higher PLMS. In the control group, patients with RLS had a lower ferritin level, which was not observed in the dialysis group. There was a significant interaction between PLMS and ESRD (p = 0.001), with a higher prevalence of PLMS in patients with ESRD on dialysis in a model adjusted for AHI, sex, arousals, and age. Factors that were associated with PLMS were RLS (p = 0.003), ESRD (p = 0.0001), and AHI (p = 0.041), with an adjusted R2 of 0.321. Conclusion RLS in patients with ESRD on dialysis is independently associated with PLMS, regardless of the severity of sleep apnea, arousals, and age.

Background: Current guidelines recommend assessment of 25-vitamin D status in patients with chronic kidney disease (CKD). Although significant differences among assays have been described, the impact of CKD on this variability has never been tested. Methods: We tested the variability between two 25-vitamin D assays in patients with CKD (eGFR < 60 mL/min/1.73m2) who had consecutive 25-vitamin D measurements in 2015 (Assay 1 - Diasorin LIASON 25 TOTAL - D assay®) and 2016 (Assay 2 - Beckman Coulter Unicel Xl 800®). The cohort consisted of 791 adult patients (122 with normal renal function and 669 with CKD - 33, 30, and 37% in stages 3, 4, and 5 on dialysis, respectively). Results: Levels of 25-vitamin D were lower and the prevalence of hypovitaminosis D using assay 1 was higher than using assay 2 in patients with CKD, regardless of similar levels of calcium, phosphate, and parathyroid hormone. As kidney function decreased, the percentage of disagreement between the assays increased. Conclusion: There is a noteworthy variability between assays in patients with CKD such that the diagnosis of hypovitaminosis D is modified. The mechanism behind this result is still unclear and might be due to a possible interference in the analytical process. However, the clinical significance is unquestionable, as the supplementation of vitamin D can be erroneously prescribed to these patients.

Background: Patients undergoing maintenance hemodialysis (HD) exhibit increased levels of uremic toxins, which are associated with poor outcomes. Recently, new dialysis membranes have allowed clearance of solutes with higher molecular weight, without significant albumin losses high-retention-onset-HD (HRO-HD). Methods: Prospective crossover trial, in which 16 prevalent patients switched from high-flux HD (HF-HD) to online hemodiafiltration (olHDF) and HRO-HD for 4 weeks. The following variables were evaluated: pre- and post-dialysis serum concentrations of albumin, urea, phosphate (P), beta-2 microglobulin (β2M), and total mass (TM) extraction and dialyzer clearance of urea, P, and β2M. Results: Comparing HF-HD, olHDF, and HRO-HD, respectively, there were no differences regarding pre-dialysis serum concentrations of albumin (3.94 ± 0.36, 4.06 ± 0.22, and 3.93 ± 0.41 g/dL, p = 0.495), urea (166 ± 29, 167 ± 30, and 164 ± 27 mg/dL, p = 0.971), P (4.9 ± 2.1, 5.2 ± 1.6, and 4.9 ± 2.1 mg/dL, p = 0.879), and β2M (31.3 ± 7.1, 32.6 ± 8.6, and 33.7 ± 5.9 µg/mL, p = 0.646). β2M clearance was significantly lower in HF-HD in comparison to both olHDF and HRO-HD: 43 (37–53) versus 64 (48–85) mL/min, p = 0.013, and 69 (58–86) mL/min, p = 0.015, respectively. Post-dialysis β2M serum concentration was higher in HF-HD in comparison to olHDF and HRO-HD: 11.6 (9.6–12.4) vs. 5.7 (4.5–7.0) µg/mL, p = 0.001, and 5.6 (5.3–7.6) µg/mL, p = 0.001, respectively. TM extraction of urea, P, and β2M were similar across the 3 dialysis modalities. Conclusions: olHDF and HRO-HD were superior to HF-HD regarding β2M clearance, leading to lower post-dialysis β2M levels.

Several factors contribute to renal-function decline in CKD patients, and the role of phosphate content in the diet is still a matter of debate. This study aims to analyze the mechanism by which phosphate, independent of protein, is associated with the progression of CKD. Adult Munich-Wistar rats were submitted to 5/6 nephrectomy (Nx), fed with a low-protein diet, and divided into two groups. Only phosphate content (low phosphate, LoP, 0.2%, high phosphate, HiP, 0.95%) differentiated diets. After sixty days, biochemical parameters and kidney histology were analyzed. The HiP group presented worse renal function, with higher levels of PTH, FGF-23, and fractional excretion of phosphate. In the histological analysis of the kidney tissue, they also showed a higher percentage of interstitial fibrosis, expression of α-actin, PCNA, and renal infiltration by macrophages. The LoP group presented higher expression of beclin-1 in renal tubule cells, a marker of autophagic flux, when compared to the HiP group. Our findings highlight the action of phosphate in the induction of kidney interstitial inflammation and fibrosis, contributing to the progression of renal disease. A possible effect of phosphate on the dysregulation of the renal cell autophagy mechanism needs further investigation with clinical studies.

There is a paucity of data on the prognosis for patients returning to peritoneal dialysis (PD) after a failed transplant. PD has an advantage over hemodialysis in preserving residual renal function, which is associated with better outcomes.We have reviewed the electronic charts of patients on PD in a tertiary academic hospital for the last 8 years. We have compared technique survival, peritonitis-free survival, and residual diuresis in two groups: patients with graft failure which returned to PD (PD-KTx, N = 18) and patients starting PD for other causes (PD-not KTx, N = 163).The median follow-up was similar between groups [42(16,71) in PD-not KTx vs. 48(22,90) months in PD-KTx, p = 0.293]. Kaplan-Meier survival comparing PD-KTx and PD-not KTx showed no difference in technique survival (p = 0.196), and peritonitis-free survival (log-rank 0.238), which were confirmed in a fully adjusted Cox regression. Diuresis at baseline and at the end of the first year was similar between groups (p = 0.799 and p = 0.354, respectively). Six out of 18 patients from the PD-KTx group had the immunosuppression maintained and none of those had peritonitis. The reduction of diuresis across the first year of PD was significant for all patients, except for those on continued immunosuppressive therapy.PD is a worthy dialysis alternative after a failed kidney transplant, providing similar outcomes when compared to patients who started PD for other reasons.

Although diuretics are often prescribed to control fluid overload, they can change Chronic kidney disease-mineral and bone disorder (CKD-MBD) parameters. Previous studies have shown an association between diuretic prescription and changes in both calciuria and parathormone levels. However, the causal relationship could not be confirmed. In addition, the effects of diuretics on bone mineral density and turnover markers are yet to be established. To evaluate the effects of diuretics on CKD-MBD, we have performed a prospective randomized trial comparing hydrochlorothiazide with furosemide in a stage 3CKD population followed for 1 year. Furosemide increased bone remodeling and parathormone levels, whereas hydrochlorothiazide attenuated parathyroid hormone rise and decreased bone turnover markers., Highlights • Diuretics may change parathormone (PTH), although a randomized trial was missing. • Patients with CKD were randomized to either Furosemide or Hydrochlorothiazide. • Furosemide increased PTH levels, CTx and P1NP. • Hydrochlorothiazide attenuated PTH rise and decreased CTx and P1NP.

Background Bone and mineral disorders commonly affect kidney transplant (KTx) recipients and have been associated with a high risk of fracture. Bisphosphonates may prevent or treat bone loss in such patients, but there is concern that these drugs might induce adynamic bone disease (ABD). Methods In an open label, randomized trial to assess the safety and efficacy of zoledronate for preventing bone loss in the first year after kidney transplant, we randomized 34 patients before transplant to receive zoledronate or no treatment. We used dual-energy x-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and bone biopsies to evaluate changes in bone in the 32 evaluable participants between the time of KTx and 12 months post-transplant. Results Both groups of patients experienced decreased bone turnover after KTx, but zoledronate itself did not affect this outcome. Unlike previous studies, DXA showed no post-transplant bone loss in either group; we instead observed an increase of bone mineral density in both lumbar spine and total hip sites, with a significant positive effect of zoledronate. However, bone biopsies showed post-transplant impairment of trabecular connectivity (and no benefit from zoledronate); HR-pQCT detected trabecular bone loss at the peripheral skeleton, which zoledronate partially attenuated. Conclusions Current immunosuppressive regimens do not contribute to post-transplant central skeleton trabecular bone loss, and zoledronate does not induce ABD. Because fractures in transplant recipients are most commonly peripheral fractures, clinicians should consider bisphosphonate use in patients at high fracture risk who have evidence of significantly low bone mass at these sites at the time of KTx.

Mineral and bone metabolism disorders are relatively common among patients with end-stage renal disease on maintenance hemodialysis. Corneal and conjunctival calcification is the main extravascular site for calcification. Recently, this form of calcification has been linked to vascular calcification. Secondary hyperparathyroidism can lead to high levels of calcium and phosphorus and increase the risk of calcification. Here, we report a case of a 38-year-old female with severe hyperparathyroidism who underwent eye examination before and after parathyroidectomy. Anterior segment optical coherence tomography showed an improvement in the number and size of ocular calcifications 6 months after surgery. This case calls attention to the importance of eye examination in patients on dialysis and brings the possibility of recovery of calcification in a short-term follow-up.

Introduction: Body composition is critical for the evaluation of patients with Chronic Kidney Disease (CKD) and can be obtained from either multifrequency bioelectrical impedance analysis (BIA) or dual-energy absorptiometry (DXA). Although the discrepancy between the results obtained from both methods has already been described, reasons are unknown, and might be related to secondary hyperparathyroidism, which is associated with bone loss. Methods: We have evaluated 49 patients (25 males and 24 females): 20 with CKD not on dialysis and 29 on maintenance hemodialysis [18 with severe hyperparathyroidism (HD-SHPT) and 11 submitted to parathyroidectomy (HD-PTX)]. All patients underwent DXA and BIA. Results: The median age and body mass index (BMI) were 49 years and 25.6 kg/m2, respectively. Patients exhibited low bone mineral content (BMC) measured by DXA, particularly those from the HD-SHPT group. The largest BMC measurement disagreement between DXA and BIA was found in the HD-SHPT group (p=0.004). Factors independently associated with this discrepancy in BMC measurement were serum phosphate (p=0.003) and patient group (p=0.027), even after adjustments for age, BMI, and gender (adjusted r2=0.186). PTX attenuated this difference. Discussion: BIA should be interpreted with caution in patients with SHPT due to a loss of accuracy, which can compromise the interpretation of body composition. Resumo Introdução: A composição corporal é fundamental para a avaliação de pacientes com Doença Renal Crônica (DRC), e pode ser obtida por análise de impedância bioelétrica por multifrequência (BIA) ou absorciometria de dupla energia (DXA). Embora a discrepância entre os resultados obtidos pelos dois métodos já tenha sido descrita, os motivos são desconhecidos e podem estar relacionados ao hiperparatireoidismo secundário, devido à perda óssea. Métodos: Avaliamos 49 pacientes (25 homens e 24 mulheres): 20 com DRC não em diálise e 29 em hemodiálise de manutenção [18 com hiperparatireoidismo grave (HD-SHPT) e 11 submetidos à paratireoidectomia (HD-PTX)]. Todos os pacientes foram submetidos à DXA e BIA. Resultados: A mediana da idade e do índice de massa corporal (IMC) foram de 49 anos e 25,6 kg/m2, respectivamente. Os pacientes exibiram baixo conteúdo mineral ósseo (CMO) medido pelo DXA, particularmente aqueles do grupo HD-SHPT. A maior discordância da medida do CMO entre DXA e BIA foi encontrada no grupo HD-SHPT (p = 0,004). Os fatores independentemente associados a essa discrepância na medida do CMO foram fosfato sérico (p = 0,003) e grupo de pacientes (p = 0,027), mesmo após ajustes para idade, IMC e sexo (r2 ajustado = 0,186). PTX atenuou essa diferença. Discussão: A BIA deve ser interpretada com cautela em pacientes com HPTS devido a uma perda de precisão, o que pode comprometer a interpretação da composição corporal.

Parathyroid hormone (PTH) has an important role in the maintenance of serum calcium levels. It activates renal 1α-hydroxylase and increases the synthesis of the active form of vitamin D (1,25[OH]2D3). PTH promotes calcium release from the bone and enhances tubular calcium resorption through direct action on these sites. Hallmarks of secondary hyperparathyroidism associated with chronic kidney disease (CKD) include increase in serum fibroblast growth factor 23 (FGF-23), reduction in renal 1,25[OH]2D3 production with a decline in its serum levels, decrease in intestinal calcium absorption, and, at later stages, hyperphosphatemia and high levels of PTH. In this paper, we aim to critically discuss severe CKD-related hyperparathyroidism, in which PTH, through calcium-dependent and -independent mechanisms, leads to harmful effects and manifestations of the uremic syndrome, such as bone loss, skin and soft tissue calcification, cardiomyopathy, immunodeficiency, impairment of erythropoiesis, increase of energy expenditure, and muscle weakness.

Background Fluid overload is a risk factor for morbidity, mortality, and prolonged ventilation time after surgery. Patients on maintenance hemodialysis might be at higher risk. We hypothesized that fluid accumulation would be directly associated with extended ventilation time in patients on hemodialysis, as compared to patients with chronic kidney disease not on dialysis (CKD3–4) and patients with normal renal function (reference group). Methods This is a prospective observational study that included patients submitted to isolated and elective coronary artery bypass surgery, divided in 3 groups according to time on mechanical ventilation: 48 h. The same observer followed patients daily from the surgery to the hospital discharge. Cumulative fluid balance was defined as the sum of daily fluid balance over the first 5 days following surgery. Results Patients requiring more than 48 h of ventilation (5.3%) had a lower estimated glomerular filtration rate, were more likely to be on maintenance dialysis, had longer anesthesia time, needed higher dobutamine and noradrenaline infusion following surgery, and had longer hospitalization stay. Multivariate analysis revealed that the fluid accumulation, scores of sequential organ failure assessment in the day following surgery, and the renal function (normal, chronic kidney disease not on dialysis and maintenance hemodialysis) were independently associated with time in mechanical ventilation. Among patients on hemodialysis, the time from the surgery to the first hemodialysis session also accounted for the time on mechanical ventilation. Conclusions Fluid accumulation is an important risk factor for lengthening mechanical ventilation, particularly in patients on hemodialysis. Future studies are warranted to address the ideal timing for initiating dialysis in this scenario in an attempt to reduce fluid accumulation and avoid prolonged ventilation time and hospital stay.

High glucose concentration can activate TLR4 and NF-κB, triggering the production of proinflammatory mediators. We investigated whether the NF-κB pathway is involved in the pathogenesis and progression of experimental diabetic kidney disease (DKD) in a model of long-term type 1 diabetes mellitus (DM). Adult male Munich-Wistar rats underwent DM by a single streptozotocin injection, and were kept moderately hyperglycemic by daily insulin injections. After 12 months, two subgroups – progressors and non-progressors – could be formed based on the degree of glomerulosclerosis. Only progressors exhibited renal TLR4, NF-κB and IL-6 activation. This scenario was already present in rats with short-term DM (2 months), at a time when no overt glomerulosclerosis can be detected. Chronic treatment with the NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), prevented activation of renal TLR4, NF-κB or IL-6, without interfering with blood glucose. PDTC prevented the development of glomerular injury/inflammation and oxidative stress in DM rats. In addition, the NF-κB p65 component was detected in sclerotic glomeruli and inflamed interstitial areas in biopsy material from patients with type 1 DM. These observations indicate that the renal NF-κB pathway plays a key role in the development and progression of experimental DKD, and can become an important therapeutic target in the quest to prevent the progression of human DKD.

Although we have seen tremendous advances in the comprehension of CKD-MBD pathophysiology during the last few years, this was not accompanied by a significant change in mortality rate and quality of life. This review will address the traditional and updated pathophysiology of CKD-MBD along with the therapeutic limitations that affect CKD-MBD and proposed alternative treatment targets. An innovative concept brings the osteocyte to the center of CKD-MBD pathophysiology, in contrast to the traditional view of the skeleton as a target organ for disturbances in calcium, phosphate, parathyroid hormone, and vitamin D. Osteocytes, through the synthesis of FGF-23, sclerostin, among others, are able to interact with other organs, making bone an endocrine organ. Thus, osteocyte dysregulation might be an early event during the course of CKD. This review will revisit general concepts on the pathophysiology of CKD-MBD and discuss new perspectives for its treatment.

Background Although a successful kidney transplant (KTx) improves most of the mineral and bone disorders (MBD) produced by chronic kidney disease (CKD), hyperparathyroidism may persist (pHPT). Current guidelines recommend parathyroidectomy if serum parathormone is persistently elevated 1 year after KTx, because pHPT has been recently associated with poor graft outcomes. However, whether patients with pHPT and adequate renal function are at risk for long-term graft failure is unknown. Methods Longitudinal follow-up of 911 adults submitted to KTx between January 2005 and December 2014, with estimated glomerular filtration rate (eGFR) ≥ 30 mL/min 1 year after surgery. Clinical and laboratory data were collected from electronic database. Graft failure was defined as return to dialysis. Results Overall, 62% of the patients were classified as having pHPT 1 year after KTx. After a mean follow-up time of 47 months, there were 59 graft failures (49 in pHPT and 10 in non-pHPT group, P = .003). At last follow-up, death-censored graft survival was lower in the pHPT group (P = .009), even after adjustment for age at KTx, donor age, donor type, acute rejection, parathyroidectomy, and eGFR at 1 year after transplantation (odds ratio [OR] 1.99; 1.004–3.971; P = .049). A PTH of 150 pg/mL at 6 months was the best cutoff to predict pHPT at 1 year (specificity = 92.1%). Conclusion Having pHPT after a successful KTx increases the long-term risk of death-censored graft failure. This result highlights the need for better recognition and management of CKD-MBD before and during the first year after KTx, and opens a discussion on the more appropriate timing to perform parathyroidectomy.

Background/Aims: Peritoneal dialysis (PD) has gained interest over the last decade as a viable option for early start dialysis. It is still unknown if shorter break-in periods and less time for proper patient evaluation and training could influence technique survival in comparison to planned-start PD. Methods: A prospective and observational study that compared technique survival in a cohort of patients who started either early or planned PD. Early start PD was defined as break-in period from 3 to 14 days with no previous nephrologist follow-up or patient training. Results: A total of 154 patients were included (40 as early start PD), followed by a median time of 381 days. Comparing early vs. planned-start PD, groups were similar concerning age 56 (40; 70) vs. 48 (32; 63) years, p=0.071, body mass index (BMI) 23.3 ± 4.2 vs. 23.8 ± 4.0 kg/m2, p=0.567 and male gender (60 vs. 48%, p=0.201), respectively. Comparing early vs. planned-start groups, there were no differences regarding PD dropout for peritonitis (7.5 vs. 11.4%, p=0.764), catheter dysfunction (12.5 vs. 17.5%, p=0.619) and patient burnout (0 vs. 4.4%, p=0.328), respectively. Less patients in early start group quit PD for peritoneal membrane failure in comparison to planned-start group (2.5 vs. 16.7%, p=0.026). In multivariate cox-regression analysis, the only factors independently associated with technique failure were BMI> 25 kg/m² (p=0.033) and Diabetes Mellitus (p=0.013), whereas no differences regarding early vs. planned-PD start were observed (p=0.184). Conclusion: Despite the adverse scenario for initiating dialysis, early start PD had similar outcomes in comparison to planned-start PD in long-term follow-up.

Chronic Kidney Disease (CKD)-Mineral and Bone Disorder (CKD-MBD) is a complex disease that is not completely understood. However, some factors secreted by the osteocytes might play an important role in its pathophysiology. Therefore, we evaluated the bone expression of proteins in a group of patients with CKD 2-3, CKD 4, and CKD 5 on dialysis and healthy individuals. We also tested several bone remodeling markers, and correlated these levels with bone biopsy findings. As expected, as serum calcium decreased, serum phosphate, alkaline phosphatase, fibroblast growth factor-23 (FGF-23), parathyroid hormone, and osteoprotegerin increased, as CKD progressed. Additionally, there was a gradual increase in bone resorption associated with a decrease in bone formation and impairment in bone mineralization. Bone expression of sclerostin and parathyroid hormone receptor-1 seemed to be increased in earlier stages of CKD, whereas FGF-23 and phosphorylated β-catenin had increased expression in the late stages of CKD, although all these proteins were elevated relative to healthy individuals. Immunohistochemical studies showed that FGF-23 and sclerostin did not co-localize, suggesting that distinct osteocytes produce these proteins. Moreover, there was a good correlation between serum levels and bone expression of FGF-23. Thus, our studies help define the complex mechanism of bone and mineral metabolism in patients with CKD. Linkage of serum markers to bone expression of specific proteins may facilitate our understanding and management of this disease.

Results from bone biopsy and high-resolution peripheral quantitative computed tomography (HR-pQCT) were compared in 31 CKD patients. There was an agreement mainly for cortical compartment that may represent a perspective on the fracture risk assessment. HR-pQCT also provided some clues on the turnover status, which warrants further studies. Chronic kidney disease (CKD) patients are at high risk of bone disease. Although bone biopsy is considered the best method to evaluate bone disease, it is expensive and not always available. Here we have compared, for the first time, data obtained from bone biopsy and HR-pQCT in a sample of CKD patients on dialysis. HR-pQCT and dual-energy X-ray absorptiometry (DXA) were performed in 31 CKD patients (30 on dialysis). Biopsies were analyzed by quantitative histomorphometry, and classified according to TMV. We have found an inverse correlation between radius cortical density measured by HR-pQCT, with serum, as well as histomorphometric bone remodeling markers. Trabecular density and BV/TV measured through HR-pQCT in the distal radius correlated with trabecular and mineralized trabecular bone volume. Trabecular number, separation, and thickness obtained from HR-pQCT and from bone biopsy correlated with each other. Patients with cortical porosity on bone histomorphometry presented lower cortical density at the distal radius. Cortical density at radius was higher while bone alkaline phosphatase was lower in patients with low turnover. Combined, these parameters could identify the turnover status better than individually. There was an agreement between HR-pQCT and bone biopsy parameters, particularly in cortical compartment, which may point to a new perspective on the fracture risk assessment for CKD patients. Besides classical bone resorption markers, HR-pQCT provided some clues on the turnover status by measurements of cortical density at radius, although the significance of this finding warrants further studies.

Chronic Kidney Disease (CKD) patients present a micro inflammation state due to failure renal function. The calcitriol has been described as an anti-inflammatory factor that might modulates the inflammatory response in CKD patients. However, these patients have deficiency of Calcitriol due to failure renal function. But, synthesis of this vitamin has been reported in extra renal production, as in monocytes. In this context, it has been reported that the supplementation with 25 vitamin D (calcidiol or inactive form of vitamin D) induces monocytes to downregulate inflammation, due to the intracellular 1α-hidroxilase that converts calcidiol to calcitriol in these cells. Besides some reports used RT-qPCR, Western Blot or immunofluorescence techniques to investigate the expression of inflammatory and vitamin D machinery biomarkers in several disease, in the present study we used flow cytometry technique to evaluate the effect of 25 vitamin D on CD14, Toll-like receptor 4 (TLR4), vitamin D receptor (VDR), 1-α hydroxylase (CYP27), 24 hydroxylase (CYP24) in monocytes lineage (U937). The U937 culture was incubated with healthy or CKD serum and treatment with/without 25-vitamin D (50 ng/ml for 24 h) to evaluate CD14, TRL4, VDR, CYP27 and CYP24 expression. This protocol showed the advantage to investigate the effect of treatment with 25 vitamin D on the intracellular and cell membrane biomarkers expression quickly and simultaneously. In addition, this technique is not laborious, but easy to perform and to interpret compared to RT-qPCR, western blot or immunofluorescence.

Introduction: Chronic kidney disease (CKD) has a high prevalence and is a worldwide public health problem. Reuse of dialyzers is a cost reduction strategy used in many countries. There is controversy over its effects on clinical parameters and microbiological safety. Methods: In this clinical crossover study, 10 patients performed consecutive hemodialysis (HD) sessions divided in two phases: "single use" sessions (N = 10 HD sessions) followed by "dialyzer reuse" sessions (N = 30 HD sessions). Clinical, laboratory, and microbiological parameters were collected in the following time points: "single use", 1st, 6th, and 12th sessions with reuse of dialyzers, including bacterial cultures, endotoxins quantification in serum and dialyzer blood chamber, and detection of hemoglobin and protein residues in dialyzers. Results: Mean age of the sample was 37 ± 16 years, 6 (60%) were men, and 5 (50%) were white. CKD and HD vintage were 169 ± 108 and 47 (23-111) months, respectively. Serum C-reactive protein (CRP) [4.9 (2.1) mg/mL], ferritin (454 ± 223 ng/mL), and endotoxin levels [0.76 (0.61-0.91) EU/mL] were high at baseline. Comparison of pre- and post-HD variations of serum levels of CRP and endotoxins in the "single use" versus "reuse" phases did not result in differences (p = 0.8 and 0.4, respectively). Samples of liquid in the dialyzer inner chamber were negative for the growth of bacteria or endotoxins. There was no significant clinical manifestation within and between the phases. Conclusion: Dialyzers reuse was safe from a clinical, microbiological, and inflammatory point of view. The dialyzer performance remained adequate until the 12th reuse. Resumo Introdução: A doença renal crônica (DRC) é um problema de saúde pública mundial de alta prevalência. O reúso de dialisadores é uma estratégia de redução de custos empregada em muitos países. Seus efeitos sobre parâmetros clínicos e de segurança microbiológica são alvo de controvérsia. Métodos: No presente estudo clínico cruzado, 10 pacientes realizaram sessões consecutivas de hemodiálise (HD) divididas em duas fases: a primeira com sessões de "uso único" (N = 10 sessões de HD) e a segunda com sessões com "reúso de dialisadores" (N = 30 sessões de HD). Parâmetros clínicos, laboratoriais e microbiológicos foram registrados nos seguintes momentos: "uso único", 1a, 6a e 12a sessões com reúso de dialisadores, incluindo culturas bacterianas, quantificação de endotoxinas no soro e na câmara interna do dialisador e detecção de hemoglobina e resíduos de proteína nos dialisadores. Resultados: A idade média da amostra foi de 37 ± 16 anos seis (60%) eram homens e cinco (50%) eram brancos. Os tempos com DRC e em HD foram de 169 ± 108 e 47 (23-111) meses, respectivamente. Os níveis séricos de proteína C-reativa (PCR) [4,9 (2,1) mg/mL], ferritina (454 ± 223 ng/mL) e endotoxinas [0,76 (0,61-0,91) UE/mL] estavam elevados no início do estudo. A diferença dos níveis séricos de PCR e endotoxinas pré e pós-HD nas fases de "uso único" e "reúso" não foi significativa (p = 0,8 e 0,4, respectivamente). As amostras de líquido retiradas da câmara interna do dialisador foram negativas para crescimento de bactérias e endotoxinas. Não houve registro de manifestações clínicas significativas nas fases do estudo. Conclusão: O reúso de dialisadores foi seguro dos pontos de vista clínico, microbiológico e inflamatório. O desempenho do dialisador permaneceu adequado até o 12º reuso.

Dialysate calcium concentration (d[Ca]) might have a cardiovascular impact in patients on haemodialysis (HD) since a higher d[Ca] determines better hemodynamic tolerability. We have assessed the influence of d[Ca] on global longitudinal strain (GLS) by two-dimensional echocardiography using speckle-tracking imaging before and in the last hour of HD. This is an observational crossover study using d[Ca] 1.75 mmol/L and 1.25 mmol/L. Ultrafiltration was the same between interventions; patients aged 44 ± 13 years (N = 19). The 1.75 mmol/L d[Ca] was associated with lighter drop of blood pressure. Post HD serum total calcium was higher with d[Ca] 1.75 than with 1.25 mmol/L (11.5 ± 0.8 vs. 9.1 ± 0.5 mg/dL, respectively, p