Serum vitamin D in obese and overweight subjects according to estimated glomerular filtration rate.

OBJECTIVE: Obesity and renal disease are both associated with low serum 25(OH)D. The aims of the present study were to (a) assess vitamin D status and compare serum vitamin D levels in overweight/obese versus normal-weight individuals according to eGFR and (b) assess the role of 25(OH)D in the development of secondary hyperparathyroidism (SHPT). DESIGN: Serum 25(OH)D, 1,25(OH)2D, parathyroid hormone (PTH), calcium, and phosphate were measured in 104 subjects with BMI > 25 kg/m2. Participants were categorized according to eGFR (ml/min/1.73m2): G1 ≥ 60 (n = 53), G2 30-59 (n = 35), and G3 15-29 (n = 16). Fifty normal-weight individuals with comparable eGFR served as controls: G1-nw (n = 23), G2-nw (n = 18), and G3-nw (n = 9). RESULTS: 25(OH)D levels were lower in G1 compared to those in G1-nw (21.7 ± 6.5 vs 26.5 ± 7.0 ng/ml, p = 0.005), G2 versus G2-nw (19.0 ± 6.0 vs 25.0 ± 5.2 ng/ml, p = 0.001), and G3 vs G3-nw (15.8 ± 4.7 vs 20.3 ± 4.5 ng/ml, p = 0.030). 1,25(OH)2D and PTH levels were similar in obese/overweight versus normal-weight individuals in each of the eGFR categories. Factors independently associated with low 25(OH)D levels were BMI > 25 kg/m2, lower eGFR, and female gender. Mean 25(OH)D levels were < 30 ng/ml in both overweight and controls, in all eGFR groups. SHPT was universally observed when eGFR was < 30 ml/min/1.73m2. CONCLUSIONS: Lower serum 25(OH)D but similar 1,25(OH)2D and PTH levels were observed in overweight/obese compared to normal-weight individuals. Even though vitamin D insufficiency was common across all eGFR categories, secondary hyperparathyroidism was more prevalent as eGFR declined.

Inflammation, Endothelial Dysfunction and Increased Left Ventricular Mass in Chronic Kidney Disease (CKD) Patients: A Longitudinal Study.

INTRODUCTION: Within this longitudinal study we investigated the association of inflammation markers C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNFα) and endothelial dysfunction markers intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) with left ventricular mass indexed for height(2.71) (LVMI) in hypertensive predialysis CKD patients. MATERIAL AND METHODS: From 2004 to 2005, 182 incident consecutive adult patients from the outpatient CKD clinics of two hospitals in Greece with CKD and hypertension or using antihypertensive medication, were included. Of these, 107 patients underwent CRP (mg/l) and LVMI (g/height(2.71)) measurements annually for three years. RESULTS: In the longitudinal analyses, using linear mixed modeling, a higher IL-6 (ß = 1.9 (95%ci:0.38;3.5), inflammation score based on CRP, IL-6 and TNF-α (ß = 5.0 (95%ci:0.72; 9.4) and VCAM-1 (ß = 0.01 (95%ci:0.005;0.02) were associated with higher LVMI. These models were adjusted for age, gender and primary renal disease, and for confounders that on top changed the beta with ≥ 10%, i.e. diuretic use (for IL-6 and inflammation score). CONCLUSION: The results suggest that in predialysis CKD patients, inflammation as well as endothelial dysfunction may play an important role towards the increase in LVMI.

Longitudinal association of body mass index and waist circumference with left ventricular mass in hypertensive predialysis chronic kidney disease patients.

BACKGROUND: This study aimed to investigate the association of both body mass index (BMI) and waist circumference (WC) with left ventricular mass (LVM) in hypertensive predialysis chronic kidney disease (CKD) patients. METHODS: From 2004 to 2005, 206 consecutive incident adult patients from the outpatient CKD clinics of two hospitals in Greece were included. Inclusion criteria were the presence of CKD and hypertension. BMI (kg/m(2)), WC (cm) and LVM (g) were assessed annually for 3 years. RESULTS: The mean age was 68.1 years, mean BMI 29.1 kg/m(2) and mean WC was 103.7 cm. The median LVM was 245.7 g (n = 179). In the cross-sectional data, linear regression models showed that WC {ß = 1.2 [95% confidence interval (CI) 0.15; 2.3]}, and not BMI [ß = 2.1 (95% CI: -0.70; 4.8)], was significantly associated with LVM. After adjustment for age, sex, primary renal disease, smoking and history of cardiovascular disease, both BMI [ß = 4.7 (95% CI: 2.0; 7.4] and WC [ß = 1.2 (95% CI: 0.14; 2.3)] were significantly associated with LVM. These associations were pronounced in CKD stage 1-3, but not in CKD stage 4-5. In the longitudinal analysis, linear mixed models adjusting for confounders showed that both an increase in BMI [ß = 2.9 (95% CI: 0.74; 5.1)] and an increase in WC [ß = 1.1 (95% CI: 0.28; 1.8)] were significantly associated with an increase in LVM. CONCLUSIONS: In hypertensive predialysis CKD patients, both BMI and WC were associated with LVM in CKD stage 1-3, but not in CKD stage 4-5. In the longitudinal analysis, both an increase in BMI and WC were associated with an increase in LVM. Future studies should focus on mechanisms responsible for the associations between anthropometric variables and LVM.

Optimal medical management in patients with renovascular hypertension.

Renovascular hypertension refers to the rise of arterial pressure due to reduced perfusion of the kidney caused by the stenotic renal artery/ies. The most common cause of stenotic renal artery is atherosclerosis. Atherosclerotic renal stenosis is usually part of a systemic syndrome that involves hypertension, intrinsic renal damage, and cardiovascular morbidity. So far, large trials have not proven the superiority of interventional therapies to medical management. As a result, renal artery stenosis should be treated mainly as a coronary artery disease equivalent focusing on rigorous management of hypertension, hyperglycemia, and hyperlipidemia. Antihypertensive treatment should include renin-angiotensin system blockade medication in most cases, while HMG-CoA reductase inhibitors (statins) can be used even in chronic kidney disease with safety. Lifestyle modifications, such as cessation of smoking, and antiplatelet therapy have reduced the risk of cardiovascular events in high-risk patients.

Mononuclear leukocyte apoptosis and inflammatory markers in patients with chronic kidney disease.

BACKGROUND/AIM: Increased apoptosis along with enhanced inflammation has been reported in hemodialysis and pre-dialysis patients. However, there is limited information at which stage during the progression of chronic kidney disease (CKD) the balance between pro- and anti-apoptotic mechanisms is disturbed and inflammatory response is activated. The aim of this study was to investigate possible alterations in apoptotic and inflammatory markers during CKD (stages 1-4) progression and the probable interactions between them. METHODS: In a cross-sectional study, 152 steady-state CKD outpatients (83 males, 55%) with mean estimated glomerular filtration rate 46 (29-76) ml/min/1.73 m(2) were studied. Apoptosis was assessed in peripheral blood mononuclear cells by estimating Bcl-2 expression, annexin V-propidium iodine staining and serum soluble Fas (sFas) and Fas-ligand. Serum levels of C-reactive protein, tumor necrosis factor-α (TNF-α), interleukin-6 and plasma levels of fibrinogen were measured as markers of inflammation. RESULTS: Bcl-2 expression was found to decrease significantly in both lymphocytes and monocytes from CKD stage 1 to 4. In contrast, the activity of sFas increased significantly and so did the levels of TNF-α and fibrinogen. The majority of these alterations occurred as soon as patients entered stage 3 of CKD. A multivariate regression analysis demonstrated that CKD remained a significant predictor of the aggregate of the assessed markers. CONCLUSIONS: Apoptosis appeared to increase across CKD stages 1-4, and this was associated with increased proinflammatory activity.

C.E.R.A. once every 4 weeks in patients with chronic kidney disease not on dialysis: The ARCTOS extension study.

C.E.R.A., a continuous erythropoietin receptor activator is approved for the treatment of anemia in patients with chronic kidney disease (CKD). The ARCTOS (administration of C.E.R.A. in CKD patients to treat anemia with a twice-monthly schedule) phase 3 study demonstrated the efficacy and safety of C.E.R.A. in correcting anemia when administered once every 2 weeks (Q2W) subcutaneously in patients with CKD not on dialysis. We assessed the feasibility and long-term safety of converting patients who responded to treatment with C.E.R.A. Q2W to C.E.R.A. once every 4 weeks (Q4W) during a 24-week extension period. After the core ARCTOS study period (28 weeks), 296 patients entered the 24-week extension period. At week 29, patients who responded to C.E.R.A. Q2W during the core period were rerandomized to receive subcutaneous C.E.R.A. Q2W or Q4W. Patients in the comparator arm could receive darbepoetin alfa once weekly or Q2W. Dosage was adjusted to maintain hemoglobin (Hb) between 11 and 13 g/dL. Mean Hb levels remained stable in all groups, and were comparable at the end of the extension period (mean [standard deviation], C.E.R.A. Q2W, 11.92 [0.90] g/dL; C.E.R.A. Q4W, 11.70 [0.86] g/dL; darbepoetin alfa, 11.89 [0.98] g/dL). Mean within-patient standard deviation values for Hb were also comparable in all groups (0.66, 0.62, and 0.65 g/dL for C.E.R.A. Q2W, C.E.R.A. Q4W and darbepoetin alfa, respectively). All treatments were well tolerated. Subcutaneous C.E.R.A. Q4W is safe and effective in maintaining stable Hb levels in patients with CKD not on dialysis following correction with subcutaneous C.E.R.A. Q2W.

Flow cytometric estimation of 'labile iron pool' in human white blood cells reveals a positive association with ageing.

A small part of cellular iron, usually called 'labile iron pool' (LIP), is not securely stored and has the potential to catalyse the formation of highly reactive oxygen species. The present work estimated LIP levels in human white cells by using the analytical power of flow cytometry. The method relies essentially on already established principles but has the added value of monitoring LIP in different subpopulations of human blood cells concurrently in a single sample. Examination of 41 apparently healthy individuals revealed a positive correlation between LIP levels and the age of the donors (r=0.656, 0.572 and 0.702 for granulocytes, lymphocytes and monocytes, respectively, p<0.0001), indicating that cells of older individuals are prone to oxidations in conditions of oxidative stress. It is suggested that LIP estimation may represent a valuable tool in examinations searching for links between iron and a variety of oxidative stress-related pathological conditions.

Correction of anemia with erythropoietin in chronic kidney disease (stage 3 or 4): effects on cardiac performance.

BACKGROUND: It is not clear whether the correction of anemia with erythropoietin (rhuEpo) in patients with chronic kidney disease (CKD) has any benefit on cardiac function and geometry. Most studies are based on indices of systolic function and left ventricular mass (LVM) and the results are conflicting. PATIENTS AND METHODS: We sought to investigate the effect of rhuEpo on LV systolic and diastolic performance using conventional and novel echocardiographic indices. Thirty one patients with CKD (stage 3 or 4) were included. Fifteen patients (group I) treated with rhuEpo targeting at Hb >or=13.0 g/dL, while the remaining (group II) were not treated. Clinical and laboratory parameters were recorded at baseline and 1 year later. Ejection fraction (EF) and LVM were carefully determined. Diastolic function was assessed by mitral inflow indices (E and A wave velocities, Edt deceleration time and E/A) and novel indices of mitral annulus motion using Tissue Doppler Imaging (Em, Am, and E/Em). An index of global cardiac function (Tei) was also calculated. RESULTS: At baseline, the 2 groups had comparable clinical and laboratory characteristics. After 1 year, a significant improvement in Hb levels (13.6 +/- 1.2 vs 10.3 +/- 1.2 g/dL, p < 0.05) as well as in systolic and diastolic function indexes was observed in group I compared to group II patients: EF (70.5 +/- 7.6 vs 63.4 +/- 9.3%, p < 0.05), LVM (116.5 +/- 34.9 vs 155.6 +/- 51.6 g/m(2), p < 0.05), Edt (233.9 +/- 98.6 vs 166.9 +/- 45.1 ms, p < 0.05), Tei index (0.35 +/- 0.12 vs 0.51 +/- 0.17, p < 0.01) and E/Em (9.7 +/- 2.4 vs 14.8 +/- 5.2, p < 0.05), respectively. Blood pressure and heart rate did not show significant changes. CONCLUSIONS: Correction of anemia with rhuEpo in patients with CKD seems to improve cardiac performance and geometry.

Evaluation of tubulointerstitial lesions' severity in patients with glomerulonephritides: an NMR-based metabonomic study.

An 1H NMR-based metabonomic approach was used to investigate the correlation of histopathologically assessed tubulointerstitial lesions with the urinary metabolite profile in 77 patients with glomerulonephritides submitted to renal biopsy. The presence of renal damage was predicted with a sensitivity of 96% and a specificity of 99%. Patients with mild, moderate, and severe tubulointerstitial lesions were progressively differentiated from the healthy individuals in the Orthogonal Signal Correction Partial Least-Squares-Discriminant Analysis (OSC/PLS-DA) models with a statistically significant separation between those with mild and with severe lesions. The onset of the tubulointerstitial lesions is characterized by decreased excretion of citrate, hippurate, glycine, and creatinine, whereas further deterioration is followed by glycosuria, selective aminoaciduria, total depletion of citrate and hippurate, and gradual increase in the excretion of lactate, acetate, and trimethylamine-N-oxide. NMR-based metabonomic urinalysis could contribute to the early evaluation of the severity of the renal damage and possibly to the monitoring of kidney function.

Outcomes in subgroups of hypertensive patients treated with regimens based on valsartan and amlodipine: An analysis of findings from the VALUE trial.

BACKGROUND: In the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial the primary outcome (cardiac morbidity and mortality) did not differ between valsartan and amlodipine-based treatment groups, although systolic blood pressure (SBP) and diastolic blood pressure reductions were significantly more pronounced with amlodipine. Stroke incidence was non-significantly, and myocardial infarction was significantly lower in the amlodipine-based regimen, whereas cardiac failure was non-significantly lower on valsartan. OBJECTIVES: The study protocol specified additional analyses of the primary endpoint according to: sex; age; race; geographical region; smoking status; type 2 diabetes; total cholesterol; left ventricular hypertrophy; proteinuria; serum creatinine; a history of coronary heart disease; a history of stroke or transient ischemic attack; and a history of peripheral artery disease. Additional subgroups were isolated systolic hypertension and classes of antihypertensive agents used immediately before randomization. METHODS: The 15,245 hypertensive patients participating in VALUE were divided into subgroups according to baseline characteristics. Treatment by subgroup interaction analyses were carried out by a Cox proportional hazard model. Within each subgroup, treatment effects were assessed by hazard ratios and 95% confidence intervals. RESULTS: For cardiac mortality and morbidity, the only significant subgroup by treatment interaction was of sex (P = 0.016), with the hazard ratio indicating a relative excess of cardiac events with valsartan treatment in women but not in men, but SBP differences in favour of amlodipine were distinctly greater in women. No other subgroup showed a significant difference in the composite cardiac outcome between valsartan and amlodipine-based treatments. For secondary endpoints, a sex-related significant interaction was found for heart failure (P < 0.0001), with men but not women having a lower incidence of heart failure with valsartan. CONCLUSION: As in the whole VALUE cohort, in no subgroup of patients were there differences in the incidence of the composite cardiac endpoint with valsartan and amlodipine-based treatments, despite a greater blood pressure decrease in the amlodipine group. The only exception was sex, in which the amlodipine-based regimen was more effective than valsartan in women, but not in men, whereas the valsartan regimen was more effective in preventing cardiac failure in men than in women.

Sevelamer hydrochloride versus aluminum hydroxide: effect on serum phosphorus and lipids in CAPD patients.

BACKGROUND: Dietary phosphorus restriction, oral administration of phosphorus binders, and dialysis are the main strategies to control hyperphosphatemia in patients with stage 5 chronic kidney disease. Aluminum hydroxide (AH) and calcium carbonate, the most commonly used phosphorus binders, have serious disadvantages, such as aluminum toxicity and hypercalcemia. Sevelamer hydrochloride (SH) is a relatively new nonabsorbed calcium- and aluminum-free phosphorus binder. The present study was designed to evaluate the efficacy of SH in the control of hyperphosphatemia and its effect, compared to AH, on serum lipid parameters in patients on continuous ambulatory peritoneal dialysis (CAPD). METHODS: 30 stable patients on CAPD were included in an open-label, randomized crossover study. After a 2-week phosphorus binder washout period, 15 patients (group I) were administered SH for 8 weeks and in the remaining patients (group II), AH was introduced (phase A). After a new 2-week washout period, patients crossed over to the alternate agent for another 8 weeks (phase B). RESULTS: There were similar reductions in serum phosphorus levels over the course of the study with both agents: by 1.18 +/- 0.07 mg/dL (0.38 +/- 0.03 mmol/L) with SH and by 1.25 +/- 0.15 mg/dL (0.40 +/- 0.05 mmol/L) with AH in phase A (p = NS), and by 1.35 +/- 0.25 mg/dL (0.43 +/- 0.08 mmol/L) with AH and by 1.23 +/- 0.80 mg/dL (0.39 +/- 0.25 mmol/L) with SH in phase B (p = NS). Moreover, SH administration was associated with a 10.5% +/- 9.4% and a 20.1% +/- 6.8% fall in total cholesterol (p < 0.05) and low-density Lipoprotein cholesterol (p < 0.001) in phase A, and 11.9% +/- 7.2% (p < 0.05) and 21.5% +/- 2.4% (p < 0.001), respectively, in phase B. In both phases of the study, AH administration was not followed by a significant change in serum lipid parameters. CONCLUSION: Sevelamer hydrochloride is a well-tolerated alternative to calcium- or aluminum-containing phosphorus binder in the control of serum phosphorus in CAPD patients. Furthermore, SH improves the lipid profile in these patients.

Acid-base and electrolyte disturbances in patients with hypercalcemia.

BACKGROUND: In the present study, we analyzed acid-base and electrolyte disturbances in hypercalcemic patients to determine the principal causes of hypercalcemia. METHODS: We studied a total of 76 hypercalcemic patients and 91 healthy individuals. Acid-base and electrolyte parameters were determined before any therapeutic intervention. RESULTS: Hyperparathyroidism and neoplasias were the most common causes of hypercalcemia. Hypercalcemic patients had increased serum urea and creatinine levels, a higher urea/creatinine ratio, and a higher rate of acid-base disorders, but lower serum albumin, potassium, chloride, phosphorus, and magnesium concentrations than those found in the control subjects. Notably, significant differences in acid-base balance and electrolyte concentrations were evident between patients with hyperparathyroidism and patients with cancer. CONCLUSIONS: Primary hyperparathyroidism and neoplasia are the most common causes of hypercalcemia. A wide array of concurrent acid-base and electrolyte disorders may be evident in hypercalcemic patients. Differences in these laboratory parameters are helpful in diagnostic workup.