Plasma concentrations of extracellular matrix protein fibulin-1 are related to cardiovascular risk markers in chronic kidney disease and diabetes

BACKGROUND

Fibulin-1 is one of a few extracellular matrix proteins present in blood in high concentrations. We aimed to define the relationship between plasma fibulin-1 levels and risk markers of cardiovascular disease.

METHODS

Plasma fibulin-1 was determined in subjects with chronic kidney disease (n = 32; median age 62.5, inter-quartile range 51 - 73 years) and 60 age-matched control subjects. Among kidney disease patients serological biomarkers related to cardiovascular disease (fibrinogen, interleukin 6, C-reactive protein) were measured. Arterial applanation tonometry was used to determine central hemodynamic and arterial stiffness indices.

RESULTS

We observed a positive correlation of fibulin-1 levels with age (r = 0.38; p = 0.033), glycated hemoglobin (r = 0.80; p = 0.003), creatinine (r = 0.35; p = 0.045), and fibrinogen (r = 0.39; p = 0.027). Glomerular filtration rate and fibulin-1 were inversely correlated (r = -0.57; p = 0.022). There was a positive correlation between fibulin-1 and central pulse pressure (r = 0.44; p = 0.011) and central augmentation pressure (r = 0.55; p = 0.001). In a multivariable regression model, diabetes, creatinine, fibrinogen and central augmentation pressure were independent predictors of plasma fibulin-1.

CONCLUSION

Increased plasma fibulin-1 levels were associated with diabetes and impaired kidney function. Furthermore, fibulin-1 levels were associated with hemodynamic cardiovascular risk markers. Fibulin-1 is a candidate in the pathogenesis of cardiovascular disease observed in chronic kidney disease and diabetes.

Randomized controlled trial of cholecalciferol supplementation in chronic kidney disease patients with hypovitaminosis D

BACKGROUND

Hypovitaminosis D is common in chronic kidney disease (CKD). Effects of 25-hydroxyvitamin D replenishment in CKD are not well described.

METHODS

An 8-week randomized, placebo-controlled, double-blind parallel intervention study was conducted in haemodialysis (HD) and non-HD CKD patients. Treatment consisted of 40,000 IU of cholecalciferol orally per week. Plasma 25-hydroxyvitamin D (25-OHD), plasma 1,25-dihydroxyvitamin D (1,25-diOHD), plasma parathyroid hormone (PTH), serum phosphate, ionized serum calcium and serum fibroblast growth factor 23 (FGF-23) were analysed. We also investigated biomarkers related to cardiovascular disease (plasma D-dimer, plasma fibrinogen, plasma von Willebrand factor antigen and activity, plasma interleukin 6, plasma C-reactive protein, blood pressure, aortic augmentation index, aortic pulse wave velocity and 24-h urinary protein loss). Objective and subjective health variables were assessed (muscle function tests, visual analogue scores and Health Assessment Questionnaire).

RESULTS

Fifty-two CKD patients with 25-OHD <50 nmol/L at screening were included. Cholecalciferol supplementation led to a significant increase to a median of 155 nmol/L 25-OHD (interquartile range 137-173 nmol/L) in treated patients (n = 25, P < 0.001). In non-HD patients, we saw a significant increase in 1,25-diOHD (n = 13, P < 0.01) and a lowering of PTH (n = 13, P < 0.001). This was not observed in HD patients. Cholecalciferol supplementation caused a significant increase in serum calcium and FGF-23.

CONCLUSIONS

25-OHD replenishment was effectively obtained with the employed cholecalciferol dosing. In non-HD patients, it had favourable effects on 1,25-diOHD and PTH. Vitamin D-supplemented patients must be monitored for hypercalcaemia. The present study could not identify significant pleiotropic effects of 25-OHD replenishment.

Cancer rates after kidney transplantation

INTRODUCTION

Previous studies demonstrated a 3-5-fold increased cancer risk in kidney allograft recipients compared with the general population. Our aim was to estimate cancer frequencies among kidney allograft recipients who were transplanted in 1997-2000 and who were immunosuppressed according to a more modern steroid-free standard protocol based on basixilimab, ciclosporine and mycophenolate mofetil.

MATERIAL AND METHODS

This was a retrospective cohort study of patients receiving their first kidney allograft in 1997-2000 at Odense University Hospital, Denmark (n = 90). Histologically verified cancers were identified from a detailed search of the individual patient's medical records.

RESULTS

During an average follow-up time of 8.4 years, a total of 14 cancers were observed. The cancer incidence rate was 18.5 (95% confidence interval (CI): 11.0-31.3) per 1,000 years, and the cancer prevalence was 13.4% (95% CI: 5.6-21.2%) among survivors in 2007. The relative risk of prevalent cancer was 3.6 (95% CI: 2.0-6.5) compared with the general population. Patients with cancer had a poorer survival than patients without cancer.

CONCLUSION

The observed cancer incidence rate and prevalence were similar to figures derived from studies performed in the earlier eras of kidney transplantation. Reducing cancer rates after kidney transplantation remains an important challenge for nephrologists.

FUNDING

not relevant.

TRIAL REGISTRATION

not relevant.

Vitamin d and stage 5 chronic kidney disease: a new paradigm?

Vitamin D receptor agonists (VDRA) are currently recommended for the treatment of secondary hyperparathyroidism in stage 5 CKD. They are considered to be contraindicated in the presence of low or normal (for a dialysis patient) levels of PTH due to the risk of developing adynamic bone disease, with consequent vascular calcification. However, these recommendations are increasingly at odds with the epidemiological evidence, which consistently shows a large survival advantage for patients treated with low-dose VDRAs, regardless of plasma calcium, phosphate, or PTH. A large number of pleiotropic effects of vitamin D have been described, including inhibition of renin activity, anti-inflammation, and suppression of vascular calcification stimulators and stimulation of vascular calcification inhibitors present in the uremic milieu. Laboratory studies suggest that a normal cellular vitamin D level is necessary for normal cardiomyocyte and vascular smooth muscle function. While pharmacological doses of VDRA can be harmful, the present evidence suggests that the level of 1,25-dihydroxycholecalciferol should also be more physiological in stage 5 CKD, and that widespread use of low-dose VDRA would be beneficial. A randomized controlled trial to test this hypothesis is warranted.

Replacing dairy fat with rapeseed oil causes rapid improvement of hyperlipidaemia: a randomized controlled study

BACKGROUND

Rapeseed oil (RO), also known as canola oil, principally contains the unsaturated fatty acids 18:1n-9, 18:2n-6 and 18:3n-3 and may promote cardiometabolic health.

OBJECTIVE

To investigate the effects on lipoprotein profile, factors of coagulation and insulin sensitivity of replacing a diet rich in saturated fat from dairy foods (DF diet) with a diet including RO-based fat (RO diet).

DESIGN

During a 2×3-week randomized, controlled, cross-over trial, 20 free-living hyperlipidaemic subjects were provided with isocaloric test diets that differed in fat composition alone. Blood lipoprotein profile, coagulation and fibrinolytic factors and insulin sensitivity (euglycaemic clamp) were determined before and after the dietary intervention.

RESULTS

All subjects completed the study, and compliance was high according to changes in serum fatty acids. The RO diet, but not the DF diet, reduced the levels of serum cholesterol (-17%), triglycerides (-20%) and low-density lipoprotein cholesterol (-17%), cholesterol/high-density lipoprotein (HDL) cholesterol ratio (-21%), apolipoprotein (apo) B/apo A-I ratio (-4%) and factor VII coagulant activity (FVIIc) (-5%) from baseline. These changes were significantly different between the diets (P=0.05 to P<0.0001), except for FVIIc (P=0.1). The RO diet, but not the DF diet, modestly increased serum lipoprotein(a) (+6%) and tended to increase the glucose disappearance rate (K-value, +33%). HDL cholesterol, insulin sensitivity, fibrinogen and tissue plasminogen activator inhibitor-1 levels did not change from baseline or differ between the two diets.

CONCLUSIONS

In a diet moderately high in total fat, replacing dairy fat with RO causes a rapid and clinically relevant improvement in serum lipoprotein profile including lowering of triglycerides in hyperlipidaemic individuals.

Vitamin D status in children and adolescents with kidney transplants

Hypovitaminosis D is highly prevalent in adult kidney-transplanted patients. The knowledge of vitamin D status in kidney-transplanted children and adolescents is sparse. The present study investigated the vitamin D status of a cohort of kidney-transplanted children and adolescents, and the association between vitamin D status and plasma concentrations of PTH, ionized calcium, and phosphate. The study included 35 patients with a functioning graft. Their mean age was 12.0 yr, and the mean graft age was 2.8 yr. Forty percent of the patients were vitamin D insufficient (P-25-hydroxyvitamin D 40-75 nm), and 14% were deficient (P-25-hydroxyvitamin D < 40 nm). S-25-hydroxyvitamin D was inversely associated with PTH (p = 0.02) and positively associated with S-1,25-dihydroxyvitamin D (p = 0.02). There was no significant association between S-1,25-dihydroxyvitamin D and PTH. In conclusion, we found hypovitaminosis D in 54% of the study population despite the fact that samples were collected in spring and summer months. Hypovitaminosis D was associated with adverse effects on PTH and 1,25-dihydroxyvitamin D. Our data suggest that it is warranted to monitor vitamin D status of kidney-transplanted children and adolescents and indicate that correction of hypovitaminosis D might have favorable effects on calcium-phosphate metabolism.

Effects of unsaturated fat dietary supplements on blood lipids, and on markers of malnutrition and inflammation in hemodialysis patients

OBJECTIVE

We examined the effects of commercially available unsaturated fat dietary supplements on blood lipids, and on markers of malnutrition and inflammation, in an adult population of hemodialysis (HD) patients.

DESIGN

This was a restricted, randomized (equal blocks), investigator-blinded 2x6 week crossover trial, without a washout interval.

SETTING

This study was conducted at the Department of Nephrology, Copenhagen University Hospital Herlev, Herlev, Denmark, in spring 2007.

PATIENTS

Participants included 40 (30 males and 10 females) stable, adult patients undergoing regular HD, with a mean age of 64.6 years and a mean body mass index of 23.3kg/m(2).

INTERVENTION

In addition to patients' habitual diets, oral unsaturated fat supplements (90mL of Calogen [SHS International, Ltd., Liverpool, UK] and 4 capsules of Pikasol [Dansk Droge, Ishoej, Denmark]) were given in one period, whereas no supplements were given in the other. Dietary supplements contributed 1.8 MJ (430kcal), 47g fat, 26.5g monounsaturated fatty acids, and 3g marine n-3 polyunsaturated fatty acids per day. Blood sampling and nutritional assessments were performed at baseline, after 6 weeks, and after 12 weeks.

MAIN OUTCOME MEASURES

Dietary intakes, blood lipids, dry body weight, serum albumin, and serum C-reactive protein comprised our main outcome measures.

RESULTS

According to a per-protocol analysis of 14 study completers, fat supplementation resulted in significantly increased total energy intake (+1.6 MJ/day, or 380kcal/day) and an increased dietary fat energy percentage (+9%). We observed no significant changes in blood lipids. Dry body weight (+0.49kg, P=.04) increased, and serum C-reactive protein concentration fell (-1.69mg/L, P=.01), with fat supplementation. Intention-to-treat analysis of 39 participants confirmed the absence of adverse blood-lipid changes.

CONCLUSIONS

Unsaturated fat supplementation increased total dietary energy intake to recommended levels, had no adverse impact on blood lipids, improved nutritional status as assessed according to dry body weight, and reduced systemic inflammation as assessed according to C-reactive protein serum concentrations. Adding unsaturated fat to the diet seems to be a safe and effective way to prevent and treat malnutrition in hemodialysis patients.

[Calciphylaxis]

Calciphylaxis is a serious condition including ischaemic, nodular necrosis of the subcutaneous tissue and occlusion of small and medium-sized arteries. The prevalence of calciphylaxis among patients on chronic haemodialysis constitutes 1-4 percent. The condition is associated with high mortality due to co-morbidity. Calciphylaxis seems to be preventable by optimized control of calcium-phosphorous metabolism in susceptible individuals. New and promising therapies are evolving. It is important to focus on this condition in order to provide the relevant therapy to the affected cases.

Nephrogenic systemic fibrosis: late skin manifestations

BACKGROUND

Nephrogenic systemic fibrosis (NSF) is a serious disease that occurs in patients with severe renal disease and is believed to be caused by gadolinium-containing contrast agents. A detailed description of the late skin manifestations of NSF is important to help dermatologists and nephrologists recognize the disease.

OBSERVATIONS

We studied 17 patients with NSF late in the disease. All patients showed epidermal atrophy and hairlessness of the affected regions, primarily the lower legs. Affected areas were symmetrically distributed and hyperpigmented in most cases. Eleven patients showed confluent dermal plaques with thickening and hardening. In contrast, 3 patients presented with wrinkled, redundant skin as seen in cutis laxa. Patients with NSF had significantly poorer scores than control patients on the Daily Life Quality Index (mean [SD], 11. 4 [7.4] vs 1.5 [2. 3]; P < .001).

CONCLUSIONS

This descriptive case series of patients with NSF gives a detailed clinical picture of the skin manifestations late in the disease. It demonstrates that the clinical picture in the late stage has a varied presentation and that NSF has a significant effect on the quality of life.

Update on nephrogenic systemic fibrosis

Gadolinium-based contrast agents were for many years considered safe, but this is no longer the case. The least stable agents may trigger the development of nephrogenic systemic fibrosis (NSF), a generalized fibrotic disorder, in renal failure patients. The use of gadodiamide and gadopentetate dimeglumine is now contraindicated in Europe and Japan in patients who have a glomerular filtration rate less than 30 mL/min/1.73 m(2), including those on dialysis. The fear of NSF, however, should not lead to an enhanced MR imaging examination being denied when there is a good clinical indication to give a gadolinium-based contrast agent.

[Kidney function and immunosuppression of kidney-transplanted patients]

INTRODUCTION

The number of kidney-transplanted patients is growing. This report describes the age, sex distribution, kidney function, graft age, and immunosuppressive drugs of kidney-transplanted patients followed at the outpatient clinic of the nephrology department at Copenhagen University Hospital, Herlev, Denmark.

MATERIALS AND METHODS

Cross-sectional study of all living kidney-transplanted patients with a functioning graft followed at Copenhagen University Hospital, Herlev (n=241). Data were extracted from patient records during November 2005-March 2006.

RESULTS

The sex distribution (131 males, 110 females) was equal. The average patient age was 52 years (SD 12), the average glomerular filtration rate 43 ml/min/1.73 m2 (range 6-114 ml/min/1.73 m2), and the average graft age was 8.3 years (range 0-28 years). Hyperparathyroidism was highly prevalent (64%). The majority of patients (74%) were treated with triple-drug immunosuppression, in most cases (46%) with the combination prednisolone-ciclosporine-azathioprine. During recent years, azathioprine has been increasingly replaced by mycophenolate mofetil.

CONCLUSIONS

The majority of kidney-transplanted patients with a functioning graft have sufficient kidney function to keep the patients free of uremic symptoms. Hyperparathyroidism is frequent. The immunosuppressive regimens used for kidney-transplanted patients are currently changing.

Possibly enhanced Gd excretion in dialysate, but no major clinical benefit of 3-5 months of treatment with sodium thiosulfate in late stages of nephrogenic systemic fibrosis

BACKGROUND

Gd-related nephrogenic systemic fibrosis was successfully treated with intravenous sodium thiosulfate according to a recent case report.

METHODS

Four haemodialysis patients with severe Gd-related nephrogenic systemic fibrosis were treated with intravenous sodium thiosulfate for 3-5 months. Symptoms and patients' experiences were investigated. The dialysate Gd content was monitored.

RESULTS

We observed no major clinical improvements in any patient. In one patient, we found slightly improved joint motion. Two patients had a subjective impression of slight improvements of joint motion and skin abnormalities. The dialysate Gd content was raised by the treatment, up to fivefold.

CONCLUSIONS

We could not confirm that sodium thiosulfate treatment results in marked and rapid improvement in late stages of Gd-related nephrogenic systemic fibrosis. However, dialysate contents of Gd seemed to increase. It is unknown whether increased Gd excretion will lead to long-term clinical improvements in late stages of nephrogenic systemic fibrosis.

Extracellular Gd-CA: differences in prevalence of NSF

Until recently it was believed that extracellular gadolinium-based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium-based contrast agents may trig the development of nephrogenic systemic fibrosis, a generalized fibrotic disorder, in renal failure patients. As no prospective studies can be performed we must rely on retrospective data. From those data it is obvious that the prevalence of NSF is significantly higher after the unstable agent gadodiamide than after any other gadolinium-based agent (3-7% versus 0-1% per injection) in patients with reduced renal function. Prevalence after exposure to two gadodiamide injections is as high as 36% in patients with chronic kidney disease (CKD) stage 5. No report of NSF after the most stable agents has been reported in the peer-reviewed literature documenting that there is a difference between the various agents regarding triggering NSF.

Vitamin D status in kidney transplant patients: need for intensified routine supplementation

BACKGROUND

A high prevalence of vitamin D insufficiency has been found in the general population and in patients with chronic kidney disease.

OBJECTIVE

The aim was to examine vitamin D status and determinants and metabolic correlates of serum 25-hydroxyvitamin D in a population of adult Danish kidney transplant patients.

DESIGN

This was a cross-sectional study of 173 adult kidney transplant patients with a mean (+/-SD) age of 53.4 +/- 11.7 y and a median graft age of 7.4 y (interquartile range: 3.3-12.7 y). Serum concentrations of intact parathyroid hormone (S-PTH), 25-hydroxyvitamin D [S-25(OH)D], and 1,25-dihydroxyvitamin D [S-1,25(OH)(2)D] were measured. Dietary and supplementary intake of vitamin D, avoidance of solar ultraviolet B exposure, and selected lifestyle factors were assessed in a subgroup (n = 97).

RESULTS

Fifty-one percent of the patients had vitamin D insufficiency [S-25(OH)D 40-75 nmol/L], and an additional 29% had moderate-to-severe vitamin D deficiency [S-25(OH)D < or = 39 nmol/L]. In multiple regression analysis, sun avoidance (negative association) and vitamin D supplementation (positive association) were independent determinants of S-25(OH)D concentrations. Low S-25(OH)D concentrations were associated with 1) increased S-PTH concentrations (P = 0.0002), independently of S-1,25(OH)(2)D concentrations, and 2) decreased S-1,25(OH)(2)D concentrations (P = 0.002), independently of graft function.

CONCLUSIONS

Hypovitaminosis D is common among Danish kidney transplant patients and is associated with reduced concentrations of S-1,25(OH)(2)D and increased S-PTH concentrations. Sun avoidance and vitamin D supplementation are important determinants of vitamin D status. The observed hypovitaminosis D might be corrected by intensified routine vitamin D supplementation as opposed to the current supplementation practice.

Dermal inorganic gadolinium concentrations: evidence for in vivo transmetallation and long-term persistence in nephrogenic systemic fibrosis

BACKGROUND

Gadolinium (Gd)-based magnetic resonance contrast agents (GBMCA), including gadodiamide, have been identified as the probable causative agents of the serious disease, nephrogenic systemic fibrosis (NSF).

OBJECTIVES

To investigate retained Gd-containing deposits in skin biopsies from patients with NSF and to determine their relative concentrations over time from administration of GBMCA.

METHODS

An investigator-blinded retrospective study, analysing 43 skin biopsies from 20 patients with gadodiamide-related NSF and one NSF-negative gadodiamide-exposed dialysis patient, ranging from 16 days to 1991 days after Gd contrast dose. Utilizing automated quantitative scanning electron microscopy/energy-dispersive X-ray spectroscopy we determined the concentration of Gd and associated elements present as insoluble deposits in situ in the tissues.

RESULTS

We detected Gd in skin lesions of all 20 patients with NSF, whereas Gd was undetectable in the NSF-negative patient. Gd concentration increased over time in 60% of patients with multiple sequential biopsies (n=10), decreasing only when the initial sampling time was >23 months after first gadodiamide dose. All Gd-containing deposits contained phosphorus, calcium and sodium. The ratio of Gd to calcium in tissue deposits correlated positively with the gadodiamide dose and with serum ionized calcium at the time of Gd exposure.

CONCLUSIONS

These findings demonstrate the in vivo release (through transmetallation) of the toxic free Gd3+ from gadodiamide, and its retention in apatite-like deposits. We suggest that Gd may be mobilized over time from bone stores, explaining variably delayed onset of NSF and increasing skin concentration over time in patients with NSF.

Nephrogenic systemic fibrosis (NSF): a late adverse reaction to some of the gadolinium based contrast agents

Until recently it was believed that extracellular gadolinium based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium based contrast agents may trigger the development of nephrogenic systemic fibrosis, a generalised fibrotic disorder, in renal failure patients. Accordingly, the use of gadodiamide and gadopentate dimeglumine for renal failure patients was banned in Europe in spring 2007. The same two compounds should only be used cautiously in patients with moderate renal dysfunction. The current paper reviews the situation (July 2007) regarding gadolinium based contrast agent and the severe delayed reaction to some of these agents. The fear of nephrogenic systemic fibrosis should not lead to a denial of a well indicated enhanced magnetic resonance imaging examination.

Case-control study of gadodiamide-related nephrogenic systemic fibrosis

BACKGROUND

Nephrogenic systemic fibrosis may be caused by gadolinium (Gd)-containing magnetic resonance imaging contrast agents. Most reported cases were associated with one particular agent, gadodiamide. Yet, unidentified cofactors might explain why only a minority of renal failure patients exposed to gadodiamide develop nephrogenic systemic fibrosis.

METHODS

We conducted a case-control study of 19 histologically verified cases and 19 sex- and age-matched controls. All subjects had chronic renal failure when exposed to gadodiamide. Clinical, biochemical and pharmacological data were retrieved from medical records.

RESULTS

Cases had been exposed to a mean gadodiamide dose of 0.29 mmol/kg (range 0.18-0.50) shortly before first signs of nephrogenic systemic fibrosis. Controls had been exposed to 0.28 mmol/kg (0.13-0.49). Cumulative gadodiamide exposure while in chronic kidney disease stage 5 was significantly higher among cases compared with controls (0.41 vs 0.31 mmol/kg, P = 0.05) and among severe cases (n = 9) compared with non-severe cases (0.49 vs 0.33 mmol/kg, P = 0.02). Severe cases developed primarily among patients in regular haemodialysis therapy at exposure. Cases had higher serum concentrations of ionized calcium and phosphate than controls and tended to receive higher doses of epoietin-beta than controls at time of exposure. Severe cases were treated with higher doses of epoietin-beta than non-severe cases at exposure (10.8 vs 4.4 10(3) IU/week, P = 0.02).

CONCLUSIONS

Increasing cumulative gadodiamide exposure, high-dose epoietin-beta treatment, and higher serum concentrations of ionized calcium and phosphate increase the risk of gadodiamide-related nephrogenic systemic fibrosis in renal failure patients. Severe cases seem to develop primarily among patients in regular haemodialysis therapy at exposure.

Different effects of diets rich in olive oil, rapeseed oil and sunflower-seed oil on postprandial lipid and lipoprotein concentrations and on lipoprotein oxidation susceptibility

Elevated concentrations of fasting and non-fasting triacylglycerol-rich lipoproteins (TRL) as well as oxidative changes of lipoproteins may increase the risk of ischaemic heart disease. To compare the effects of different diets rich in unsaturated fatty acids on the concentrations andin vitrooxidation of fasting and postprandial lipoproteins eighteen males consumed diets enriched with rapeseed oil (RO), olive oil (OO), or sunflower-seed oil (SO) in randomised order for periods of 3 weeks followed by a RO test meal. In the postprandial state the concentrations of cholesterol and triacylglycerol (TAG) in TRL were higher after consumption of OO compared with RO and SO (P<0·04), possibly related to differences in the fasting state. The propagation rates for VLDL and LDL oxidation were higher in the postprandial compared with the fasting state irrespective of diet. In the fasting state, the propagation rates were highest after SO (P<0·001), and in the postprandial state, SO gave rise to a shorter VLDL lag time (P=0·03) and a higher propagation rate than OO consumption (P=0·04). Overall, the SO diet resulted in a higher postprandial propagation rate of LDL (P<0·001) compared with RO and OO, while there was no effect of diet on LDL oxidation lag time. Our results suggest that RO and SO diets lower the postprandial cholesterol and TAG concentrations compared with OO, while RO and OO diets result in similar and lowerin vitrosusceptibility to oxidation of lipoproteins than SO.