Nephrology Dialysis Transplantation

Certified deaths for the six quinquennia considered (from 1970-74 to 1995- 99), stratified for sex and 5-year age groups, from 13 selected can- cer sites and for total cancer, were derived from the WHO database (15). Data for 1984 were unavailable for all neoplasms. Mortality data for ovar- ian and testicular cancers were unavailable for 1970 and 1975-97, and bladder cancer data were unavailable for 1970 and 1975-78. No extrapol- ations were made for missing data. During the calendar periods considered, three different revisions of the International Classification of Diseases (ICD) were used (16- 18). Classifi- cation of cancer deaths was thus recoded for all calendar periods accord- ing to the IX Revision of the ICD (17, 19). To reduce classification problems and improve comparability of data, we pooled all intestinal can- cers (chiefly colon and rectum), all uterine cancers (cervix and corpus) and all leukaemias. No reliable data were available for several rarer can- cers (i.e. gallbladder, soft tissue sarcomas, lymphomas and thyroid) and a few other sites (i.e. pancreas, kidney and brain), which involve major dif- ficulties in diagnosis and certification (20). Data for liver, bone and skin cancer were excluded from the present analysis due to potential problems with reliability of certification. Estimates of the resident population, based on official censuses, were obtained from the same WHO database for the period 1970-95 (excluding 1984) (15) and from the Pan American Health Organization (PAHO) (21) for 1996- 99. Since the PAHO database provided only data for the total population, the 5-year age groups were estimated by interpolating from the 1995 WHO distribution. From the matrices of certified deaths and resi- dent population, age-specific rates for each 5-year age group and calendar period were computed. Age-standardised rates, at all ages and truncated at age 35-64 years, were computed by the direct method on the basis of

The osmotic effectiveness of an isosmolar glucose polymer (GP) solution during long-dwell (8-12 h) peritoneal dialysis has been demonstrated. The absorption of GP, though only a fraction of currently used glucose, is usually accompanied by the systemic accumulation of its breakdown product, maltose. The long-term consequences of maltose accumulation remain unknown. We studied the accumulation pattern of GP fractions, changes in serum electrolytes, osmolality, and adverse reaction profile over a 3-month period using a daily regime of an overnight exchange of 7.5% GP+0.35% glucose solution with three daytime exchanges of 1.36% glucose in five non-diabetic CAPD patients. The GP solution (299 +/- 0.7 mOsm/kg) produced mean daily overnight UF of 589 ml and maintained stable serum biochemistry. The mean serum maltose level increased from a predialysis value of 0.03 +/- 0.08 g/l to a steady-state level of 1.1 +/- 0.14 g/l within 2 weeks and remained stable throughout the study. This did not influence serum osmolality or sodium and produced no significant adverse effects. Once-daily overnight use of an isosmolar GP solution is safe and effective. The accumulation of maltose reaches steady-state levels quickly and produces no adverse toxic effects in the short term. Further long-term studies are planned.

Apart from their standard applications, haemofiltration (HF) and plasmafiltration (PF) may provide helpful therapy for sepsis, multiple organ- and acute liver-failure. Some colloids cause either decreases or increases in blood cell agglomeration. We hypothesized that solutions which reduce cell aggregability may lead to both improved filter clearance and better haemocompatibility due to decreasing rates of clogged hollow fibres. Heparinized porcine blood (5 IU/ml) was used in an in vitro circuit. The filter types tested were from GAMBRO: HF66D (effective membrane surface: 0.6 m2) and PF1000N (effective membrane surface: 0.15 m2). Albumin (ALB), hydroxyethyl starch (HES) 200/0.5, HES 130/0.4, gelatin (GEL) or normal saline (0.9%) were added to the blood (n = 6/group). Recirculation systems were run for 2 h. Spontaneous haemolysis and filter resistance >420 mmHg were selected as indications of maximal flow rates. Sieving coefficients were determined for 17 parameters at the lowest and highest blood flows and filtration rate. Based on the filter types used, supplementation of ALB and HES130/0.4 led to an improved filter clearance without increasing the number of clogged capillary membranes or causing impaired haemocompatibility. Sieving coefficients for most solutes were independent of volume substitute and flow rate. Haemocompatibility and filter clearance deteriorated after addition of HES200 or GEL to the blood. Under standardized in vitro conditions, we found that colloids which reduce cell aggregability cause improved HF- and PF-performance. This phenomenon may provide new options for higher clearances and may lead to new concepts in low dose anticoagulation.

Drug trials often exclude subjects with relevant comorbidity or comedication. Nevertheless, after approval, these drugs will be prescribed to a much broader collective. Our goal was to quantify the impact of drugs and comorbidity on serum potassium in unselected patients admitted to the hospital. This was a retrospective pharmacoepidemiologic study in 15 000 consecutive patients admitted to the medical department of the Kantonsspital St. Gallen, a 700-bed tertiary hospital in eastern Switzerland. Patients with 'haemolytic' plasma and patients on dialysis or with an estimated glomerular filtration rate (GFR) <10 mL/min/1.73 m(2) were excluded. For the remaining 14 146 patients, drug history on admission, age, sex, body weight, physical findings, comorbidity (ICD-10 diagnoses) and laboratory information (potassium and creatinine) were extracted from electronic sources. Estimated GFR was the strongest predictor of serum potassium (P < 0.0001). Angiotensin-converting enzyme inhibitors, cyclosporine, loop diuretics and potassium-sparing diuretics all showed a significant effect modification with decreasing GFR (P < 0.001). Similarly, in patients with liver cirrhosis a significantly stronger effect on potassium was found for angiotensin receptor blockers, betablockers and loop diuretics (P < 0.01). Several significant drug-drug interactions were identified. Diabetes, male sex, older age, lower blood pressure and higher body weight were all independently associated with higher serum potassium levels (P < 0.001). The model explained 14% of the variation of serum potassium. The effects of various drugs on serum potassium are highly influenced by comorbidity and comedication. Although the presented model cannot be used to predict potassium in individual patients, we demonstrate that clinical databases could evolve as a powerful tool for industry-independent analysis of postmarketing drug safety.

Single-centre and retrospective studies suggest superiority of tacrolimus over cyclosporin as cornerstone immunosuppressive therapy for simultaneous pancreas-kidney (SPK) transplantation. This open-label, multicentre trial compared the efficacy and safety of tacrolimus with cyclosporin microemulsion (ME) in diabetic patients with end-stage renal disease undergoing their first cadaveric SPK transplantation. The 3-year results are reported. Patients were recruited from 10 centres in Europe and one centre in Israel: 103 were randomized to receive tacrolimus (initial dose: 0.2 mg/kg/day p.o.) and 102 to cyclosporin-ME (7 mg/kg/day p.o.). All patients received concomitant rabbit anti-T-cell globulin induction, mycophenolate mofetil (MMF) and short-term corticosteroids. Fewer patients receiving tacrolimus (36.9%) than cyclosporin-ME (57.8%) were discontinued from treatment (P = 0.003). The initial episodes of biopsy-proven rejection were moderate or severe in just one out of 31 (3%) tacrolimus-treated patients compared with 11 out of 39 (28%) patients receiving cyclosporin-ME (P = 0.009). While 3-year patient and kidney survival rates were similar in the two treatment groups, pancreas survival was superior with tacrolimus (89.2 vs 72.4%; P = 0.002). Thrombosis resulted in pancreas graft loss in 10 patients receiving cyclosporin-ME and in only two treated with tacrolimus (P = 0.02). Overall adverse event frequency was similar in both groups, but MMF intolerance was more frequent with tacrolimus and hyperlipidaemia more frequent with cyclosporin-ME. In this 3-year study, tacrolimus was more effective than cyclosporin-ME in preventing moderate or severe kidney or pancreas rejection after SPK transplantation. It also provided superior pancreas survival and reduced the risk of pancreas graft thrombosis.

Purpose. We hypothesized that adventitial transplantation of blood outgrowth endothelial cells (BOEC) to the vein-to-graft anastomosis of polytetrafluoroethylene grafts will reduce neointimal hyperplasia by reducing hypoxia inducible factor-1alpha (HIF-1alpha), by increasing angiogenesis in a porcine model of chronic renal insufficiency with haemodialysis polytetrafluoroethylene grafts. Because matrix metalloproteinases (MMPs) have been shown to be involved with angiogenesis, the expression of MMPs and their inhibitors was determined. Chronic renal insufficiency was created by subtotal renal infarction and 28 days later, arteriovenous PTFE grafts were placed bilaterally from the carotid artery to the jugular vein. Autologous blood outgrowth endothelial cells labeled with Lac Z were transplanted to the adventitia of the vein-to-graft anastomosis using polyglycolic acid scaffolding and scaffolding only to other side (control). Animals were killed 14 days later and vessels were explanted from the vein-to-graft anastomosis of both sides and underwent immunohistochemical analysis, western blotting and zymography for HIF-1alpha, MMP-2, MMP-9, TIMP-1 and TIMP-2. BOEC were also made hypoxic and normoxic for 12, 24 and 48 h to determine protein expression for MMPs and TIMPs. Under hypoxia, BOEC significantly increased the expression of pro MMP-2 by 12 h and TIMP-2 by 24 h when compared to normoxic cells (P < 0.05). Transplantation of BOEC resulted in a significant decrease in both HIF-1alpha and intima-to-media ratio with a significant increase in both pro and active MMP-9 when compared to control vessels (P < 0.05). MMP-9 activity was localized to the neointima of the transplanted vessels by immunohistochemistry. There was increased CD31 density with engraftment of BOEC cells into the neointima of both the transplanted vessels compared to controls (P = NS). Transplantation of BOEC resulted in a significant decrease in intimal hyperplasia and HIF-1alpha with a significant increase in both pro and active MMP-9 that was localized to the neointima of transplanted vessels. The increase in MMP-9 offers a possible mechanism for angiogenesis and the reduced intima-to-media ratio. Furthermore, we observed that BOEC had homed to the neointima of the contralateral vessels that had increased levels of HIF-1alpha, suggesting that hypoxia may be an important stimulus for BOEC migration.

A catheter lock with a highly concentrated heparin solution is often used to maintain its patency. The result of the in vitro study shows a significant catheter leakage that occurs after locking the catheter. The goal of this study is to develop a model to measure the catheter leakage in vivo and test it on various kinds of catheters. Twenty-four patients with central venous dialysis catheters were examined. After the 48-h interdialytic period, we aspirated the contents of the catheter lumen for analysis. We simultaneously took a sample of the peripheral blood for analysis. In the second part of the test, instead of taking the sample after 48 h, we took it after 10 min. Based on the difference in haematocrit in those two samples, we were able to determine the amount of heparin that remained in the catheter, and indirectly, the amount of heparin that leaked out of the catheter. Using the lock volumes indicated on the catheter by the manufacturer, the early leakage is significantly higher in nontunnelled catheters compared to tunnelled Hemoflow and Ash Split catheters (P = 0.05). There is no significant statistical difference in the early leakage between Ash Split and Hemoflow catheters. The late leakage is significantly higher in nontunnelled catheters compared to Hemoflow and Ash Split catheters (P = 0.05). There is no significant statistical difference in the total leakage between Ash Split and Hemoflow catheters. We present a model that enables the measurement of the catheter leakage in vivo. We applied the model on three kinds of catheters and concluded that both early and late leakages are significantly higher in nontunnelled catheters compared to Hemoflow and Ash Split tunnelled catheters. Our results show that the so-called early leakage measured in vivo is significantly lower compared to the results from in vitro studies. Further research is necessary to determine the amount of leakage volume for different kinds of catheters and to determine the exact leakage dynamics of lock solutions in vivo.

Despite the rapid introduction of laparoscopic living donor nephrectomy, doubts exist about safety compared with open surgery. Early series have often reported on selective donor groups. We present a consecutive, prospective analysis of morbidity following hand-assisted laparoscopic donor nephrectomy (HALDN) compared with historical controls undergoing open donation (ODN) in a total of 200 living donors at a single UK centre. The results of 144 consecutively performed HALDN donors were compared to 56 preceding ODN patients. Patients with multiple arteries, right-sided nephrectomies and obesity were included. Data on recovery and complications were collected prospectively and consecutively. There were two (1.4%) major complications in the HALDN group and one in the ODN group (1.8%, P = 0.629). Additionally, there were 24 minor complications in 23 HADLN patients (16.7%), compared with 21 in 21 ODN patients (37.5%, P = 0.003). Time taken to return to normal activity and mean post-operative stay was significantly shorter for the HALDN group. There was no mortality in either group. Contrary to concerns, we report a safe experience with HALDN with a low rate of major complications. Furthermore, our patients spend less time in hospital with an earlier return to normal activity compared with open donation.

Anti-r-HuEpo associated PRCA developed in patients received subcutaneous injection of r-HuEpo for treatment of renal anemia in chronic kidney disease. This adverse immunological effect of r-HuEpo causes sudden loss of r-HuEpo efficacy, low circulating reticulocyte count and bone marrow biopsy shows an absence of erythroid precursor cells with normal cell population of non-erythroid lineage. There are postulation cause of anti-r-HuEpo associated PRCA including genetic factor, immunogenicity factor, storage and handlings factor and formulation of r-HuEpo product. Previous observation of our report showed an aggregation of HLA-DRB1*09 in four anti-r-HuEpo associated PRCA cases. This allele is rare in Caucasian (<1%) but more common in Thai population (8.4-12.5%). This study was aimed to investigate the possible association between HLA-DRB1*09 or other specific HLA and anti-r-HuEpo associated PRCA. Twenty two cases of proven anti-r-HuEpo associated PRCA were recruited and studied retrospectively based on the incidence report of serious adverse drug reaction. The EDTA bloods were drawn for HLA typing using sequence specific primer polymerase chain reaction (SSP-PCR). The HLA data of 1,800 potential cadaveric kidney transplantation recipients in the waiting list as chronic kidney disease control and 1,500 potential bone marrow stem cell donors in national stem cell registry as healthy population control were retrieved from the database of Thai Red Cross for comparison. The distribution of gene frequency of HLA-A, -B, -DR and -DQ alleles in anti-r-HuEpo associated PRCA cases showed high gene frequency of HLA-A*02, HLA-A*11 and HLA-A*24 for HLA-A loci, HLA-B*18, HLA-B*46, HLA-B*60 and HLA-B*62 for HLA-B loci, and HLA-DRB1*09, HLA-DRB1*12 and HLA-DRB1*15 for HLA-DR loci. There was a significant difference of HLA-DRB1*09 gene frequency (P < 0.001) which associated with HLA-DQB1*0309 between anti-r-HuEpo associated PRCA cases, and potential cadaveric kidney transplantation in the waiting list or potential national stem cell registry donor. The odd ratio of HLA-DRB1*09 allele for anti-r-HuEpo associated PRCA was 2.89 (95% CI: 1.88-4.46; p-value: <0.001). Our data demonstrated the association of HLA-DRB1*09-DQB1*0309 and anti-r-HuEpo associated PRCA cases. This association may be used in identifying the risk of the patients.

The Netherlands has a low number of deceased organ donors per million population. As long as there is a shortage of suitable organs, the need to evaluate the donor potential is crucial. Only in this way can bottlenecks in the organ donation process be detected and measures subsequently taken to further improve donation procedures. Within a time frame of 4 years, 2005-08, medical charts of all intensive care deaths in 64 hospitals were reviewed by transplant coordinators and donation officers. Data were entered in a web-based application of the Dutch Transplant Foundation, both to identify the number of potential organ donors (including donation after cardiac death), as well as to analyse the reasons for potential donor loss. In total, 23 508 patients died in intensive care units, of which 64% were younger than 76 years. The percentage of all potential organ donors out of the total number of deaths decreased from 8.2% in 2005 to 7.1% in 2008. Donor detection increased from 96% in 2005 to 99% in 2008. Of the potential donors, 17-21% recorded consent and 17-18% recorded objection in the national Donor Register. If the Donor Register was not decisive, the consent rate of families approached for organ donation was 35% in 2005, 29% in 2006, 41% in 2007 and 31% in 2008. The overall conversion rate (the number of actual donors divided by the number of potential donors) was 30%, 26%, 35% and 29% in these years. In the group of potential donor losses, objection by families accounted for about 60% during this study. This study showed that the maximal number of potential organ donors is about three times higher than the number of effective organ donors. The main reason accounting for approximately 60% of the potential donor losses was the high family refusal rate. The year 2007 showed that a higher percentage of deceased organ donors can be procured from the pool of potential donors. All improvements should focus on decreasing the unacceptably high family refusal rates.

This study was conducted to estimate incidences of renal replacement therapy (RRT) in the diabetic and non-diabetic populations in Germany, as well as relative and attributable risks of RRT due to diabetes. Using the data of a regional dialysis centre (region population of 310 000), we assessed all incident RRT patients aged 30 years or older in 2002-08. We estimated sex- and age-specific and -standardized incidences of RRT in the diabetic and non-diabetic populations, which were estimated by applying diabetes prevalences from a population-based study, and relative and attributable risks due to diabetes. Of all subjects with incident RRT (n = 544), 49.6% had diabetes. Fifty-eight percent were male, mean age (SD) was 70.3 years (11.4 years). Incidences per 100 000 person-years (standardized to the 2004 German population) in the diabetic and the non-diabetic populations were 213.7 [95% confidence interval (95% CI), 159.5-267.8] and 26.9 (95% CI, 22.5-31.3) in men and 130.2 (95% CI, 65.6-194.9) and 16.4 (95% CI, 13.5-19.3) in women, respectively. Standardized relative risks were 7.9 (5.9-10.8) in men and 8.0 (4.7-13.5) in women. There was a significant interaction between age and diabetes, with lower relative risks in higher ages. Attributable risks among diabetic individuals were 0.87 in men and women, and population-attributable risks were 0.41 and 0.35 in men and women, respectively. In this population-based study in a German region, we found the relative risk of RRT in the estimated adult diabetic population to be 8-fold increased compared with the non-diabetic population. A high proportion of the RRT risk can be attributed to diabetes in the diabetic as well as in the whole population.

The aim of this study was to evaluate the effect of calcitriol treatment on glucose intolerance in uraemia Thirty one patients on haemodialysis who had never been treated with vitamin D or related drugs, and 12 healthy control subjects with normal renal functions were studied. Uraemic patients were randomly divided into two groups; 16 patients were treated with oral calcitriol (0.5 μg/day) for 8 weeks,and 15 uraemic patients and 12 healthy subjects were given aplacebo In all these cases, before and 8 weeks after treatment,baseline serum glucose, insulin, calcium, parathormone (PTH), and 1,25 (OH)2D3 were measured.After an oral load of 75 g glucose, blood glucose and insulin were determined at 30, 60, 90, and 120 min.The same measurementswere repeated after 8 weeks.HbAlc and fructosamine were also measured at 0 and 8 weeks Baseline serum insulin was significantly elevated after calcitriol treatment (7.81 versus 11.63μIU/ml) there was also a significant increase in insulin following calcitriol treatment at 30, 60, 90, and 120 min On the other hand, glycosylated haemoglobin (HbAlc) and fructosamine decreased after calcitriol treatment (HbAlc 7.09% versus 5.22% P<0.01 and fructosamine 2.92 versus 2.50 mmol/1 P<0.01) Blood glucose significantly decreased after calcitriol treatment at 0, 30, 60, 90, and 120 min In the other two groups there were no significant changes in any parameters These results seem to confirm that vitamin D influences pancreatic beta (β) cell secretion and suggest that calcitriol may improve glucose intolerance in uraemic haemodialysis patients. This effect of calcitriol is probably due to normalization of serum PTH and regulation of intracellular calcium concentration

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3), calcitriol) has been used for the treatment of secondary hyperparathyroidism (2HPT) associated with chronic renal failure (CRF). However, hypercalcaemia frequently precludes the administration of ideal doses of 1,25(OH)(2)D(3). 1,25-Dihydroxy-22-oxavitamin D(3) (22-oxacalcitriol, OCT) is an analogue of 1,25(OH)(2)D(3) with less calcaemic activity. Several investigators have reported the effect of this analogue on suppressing parathyroid hormone (PTH) in vitro and in vivo in rats and dogs. The first experiments were designed to compare the relative potency of an i.v. injection of OCT and 1,25(OH)(2)D(3) (i.v. OCT vs i.v. 1,25(OH)(2)D(3)) on serum PTH and ionized calcium (ICa). A single dose of OCT (5 microg/kg) to uraemic dogs suppressed PTH by 81% without a statistical significant change in serum ICa. On the other hand, any of the effective doses of 1,25(OH)(2)D(3) on PTH suppression were hypercalcaemic. The intermittent administration of OCT (0.1 microg/kg) or 1,25(OH)(2)D(3) (0.025 microg/kg), three times per week i.v. suppressed serum PTH by 89 or 77%, respectively without hypercalcaemia. To evaluate OCT as an oral drug, it was given intermittently (three times per week) to a group of six dogs for a period of 4 weeks. Subsequently, it was changed to a daily administration (0.05 microg/kg) for a period of 2 weeks. Finally the dose was reduced to 0.025 microg/kg. Daily OCT 0.05 microg/kg suppressed serum PTH by 67%. Subsequently, 0.025 microg/kg maintained serum PTH within the normal range without hypercalcaemia for 4 weeks. The time course of serum OCT concentrations following a single i.v. or oral OCT dose to uraemic dogs showed that oral OCT was rapidly absorbed and reached maximum plasma concentration and its disappearance from blood was similar to that of i.v. injection. In conclusion, our results suggest that OCT is a useful vitamin D(3) analogue, with a potentially larger therapeutic window than that of i.v. 1,25(OH)(2)D(3) and which is available for i.v./oral, in the management of 2HPT.

A trial on the long-term administration of 1,25-dihydroxy-22-oxavitamin D(3) (22-oxacalcitoriol, OCT) was conducted among 124 patients with chronic renal failure on maintenance haemodialysis (HD) complicated with secondary hyperparathyroidism (2HPT). In the trial, OCT was administered three times weekly for 26 weeks subsequent to a 26-week pre-trial. As a result, intact-parathyroid hormone (PTH) levels fell significantly after the start of administration and, at the end of the trial, PTH was decreased by over 30% in 51.6% (64/124) of the patients, and the levels of bone metabolism markers such as alkaline phosphatase (ALP), bone ALP, and tartrate-resistant acid phosphatase (TRACP) were significantly decreased compared with those at the start of administration, suggesting a correction of high-turnover bone disease. Serum calcium (Ca) levels rose significantly following OCT administration, but were successfully maintained within a physiological level. Hypercalcaemia, which was diagnosed in 33.1% of patients, was found to resolve or ameliorate immediately after the withdrawal or dose reduction of OCT. OCT can be administered for as long as 1 year without any major problems other than hypercalcaemia. The final doses ranged from 2.5 to 20.0 microg/HD, and the optimal dose varied among patients depending on the intact-PTH and adjusted serum Ca levels. These results suggest that OCT is a highly effective drug for the suppression of PTH levels in 2HPT, and is an overall safe drug if the dosage is adjusted for serum Ca and intact-PTH levels. This study confirmed that the long-term (1-year) administration of OCT is very useful for the treatment of 2HPT.

The vitamin D receptor is expressed in nuclei of parathyroid cells and plays an important role in the regulation of cell growth and parathyroid hormone secretion. A number of studies have shown reduced receptor expression in uraemic parathyroid glands but the relationship between receptor expression and renal function has not been identified. This study used archive parathyroid tissue from patients with primary adenomas, dialysis patients with diffuse hyperplasia secondary to uraemia and normal parathyroid tissue. An immunocytochemical assay with a vitamin D receptor antibody was used to identify parathyroid cells expressing receptor in their nuclei. In patients with a serum creatinine < or = 110 mumol/l, 81.94% +/- 6.5 of parathyroid cells expressed vitamin D receptor. This fell to a mean of 49.3% in two patients with a serum creatinine between 110 and 300 mumol/l and to 40.17% +/- 8.6 in dialysis patients. Vitamin D receptor expression in parathyroid glands is reduced in renal failure.

Background: Klotho(-/-) mice display disturbed Ca(2+) and vitamin D homeostasis. Renal cytochrome p450 27b1 (Cyp27b1), the enzyme that catalyzes the hydrolysis to 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), is increased in klotho(-/-) mice, and a 1,25(OH)(2)D(3)-deficient diet partially normalized Ca(2+) homeostasis in these klotho(-/-) mice. The aim of the present study was to further delineate the interplay between 1,25(OH)(2)D(3) and klotho and their relative contribution to the Ca(2+) homeostasis of klotho(-/-) mice. Methods: Double-klotho(-/-)/Cyp27b1(-/-) mice were generated and mice aged 8-12 weeks were housed in metabolic cages to collect 24-h urine. Blood samples were taken and the animals were sacrificed, and the kidney and duodenum tissues were sampled for RNA extraction. The bone was fixed in 10% v/v formalin and analysed by microcomputed tomography (μCT) scans. Results: Klotho(-/-)/Cyp27b1(-/-) mice, like Cyp27b1(-/-) mice, displayed significantly decreased serum total calcium concentrations compared with wild-type mice (1.44 ± 0.03 and 2.25 ± 0.02 mM) along with normal urinary total calcium excretion. Hyperphosphataemia of klotho(-/-) mice normalized to wild-type levels in klotho(-/-)/Cyp27b1(-/-) mice. The mRNA levels of duodenal transient receptor potential vanilloid subtype 6 (TRPV6) and calcium-binding protein-D(9K), and renal calbindin-D(28K) and NCX1 were significantly reduced in the double knockouts compared with wild-type or klotho(-/-) mice. Elevated TRPV5 protein levels in klotho(-/-) mice normalized to wild type in klotho(-/-)/Cyp27b1(-/-) mice, but were decreased in Cyp27b1(-/-) mice. μCT scans showed that klotho(-/-)/Cyp27b1(-/-) mice, as Cyp27b1(-/-) mice, display significant bone hypomineralization and severely decreased bone mass. Klotho(-/-) mice show a reduced bone mass and increased trabecular numbers. Conclusions: Klotho(-/-)/Cyp27b1(-/-) mice resemble Cyp27b1(-/-) mice. Since 1,25(OH)(2)D(3) is absent in these mice, our results imply that Ca(2+) homeostasis in klotho(-/-) mice is affected by their excessive 1,25(OH)(2)D(3) levels.

In spite of the fact that absolute or relative deficiency of 1,25(OH)2D3 has a definite role in the genesis of uraemic secondary hyperparathryoidism in association with phosphate retention, which alone cannot account for it, the therapeutic place of 1,25(OH)2D3 in the prevention of uraemic hyperparathyroidism is currently limited by a lack of non-toxic phosphate binders and the fact that 1,25(OH)2D3, with the exception of very early renal failure, may worsen phosphate retention. Therefore, for the time being, its use without phosphate binders seems warranted only in early renal failure. It is not known, because of lack of controlled trials, whether high doses of CaCO3 alone could not be as effective and safe. In more advanced renal failure and in dialysis patients, phosphate binders are necessary, and since the commonly used aluminium phosphate binders may have long-term deleterious effects on bone, brain and haemopoiesis, other phosphate binders such as CaCO3 at high doses and magnesium hydroxide or carbonate should be used. These latter should be reserved for dialysis patients, since toxic hypermagnesaemia would occur unless the dialysate magnesium concentration was decreased. Only then should 1α hydroxylated vitamin D derivatives be added to decrease the set point of calcium-regulated PTH secretion, to normalise the hypercalcaemic response to PTH, and to better prevent the bone mineralisation defect which may occur in patients not yet on dialysis and especially in children because of 1,25(OH)2D3 deficiency. The doses of 1α hydroxylated vitamin D should always be very small because the likelihood of inducing hypercalcaemia is high in the presence of high doses of oral CaCO3. To increase the dose of 1α hydroxylated vitamin D derivatives, the exclusive use of magnesium hydroxide or carbonate, i.e. without high doses of calcium, may be used in dialysis patients, but a zero magnesium dialysate is then necessary. This carries the hazards of magnesium depletion if the patient does not comply with his magnesium therapy. Treatment of renal osteodystrophy is thus complex, and administration of 1α hydroxylated vitamin D should be always considered with the problem of phosphate retention, in order effectively to prevent hyperparathyroidism without inducing osteomalacia and osteopenia.

Since Slatopolsky et al. (J Clin Invest 1984; 74: 2136-2143) reported the effect of active vitamin D, 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), on secondary hyperparathyroidism (2HPT) which accompanies chronic renal failure, there have been several studies of the therapeutic effects of 1,25(OH)(2)D(3) in this disease. Although parathyroid hormone (PTH) is suppressed by treatment with 1,25(OH)(2)D(3), long-term treatment with 1,25(OH)(2)D(3) tends to induce hypercalcaemia. Therefore, an analogue of 1,25(OH)(2)D(3), 1,25-dihydroxy-22-oxavitamin D(3) (22-oxacalcitriol, OCT) with less calcaemic activity, was developed for the treatment of 2HPT. In order to clarify the differences between the effects of 1,25(OH)(2)D(3) and OCT on 2HPT associated with chronic renal failure, these compounds were administered by intermittent i.v. injection for 2 weeks in rats with mild to moderate uraemia. 1,25(OH)(2)D(3) markedly suppressed PTH levels, but increased serum calcium (Ca). OCT also markedly suppressed PTH levels, but induced only a slight increase in serum Ca. 1,25(OH)(2)D(3) caused a dose-dependent decrease in body weight, whereas OCT had no effect on body weight in uraemic rats. Based on those doses of OCT and 1,25(OH)(2)D(3), which resulted in a 60% suppression of PTH, and induced hypercalcaemia, we consider the relative ratios for efficacy and Ca-elevating activity between OCT and 1,25(OH)(2)D(3) to be 1 : 8 and 1 : 48, respectively. OCT suppressed PTH levels with a slight increase in serum Ca without changing the body weight in uraemic rats. This observation suggests that OCT might be a useful vitamin D analogue for 2HPT management in long-term clinical treatment.

1,25-Dihydroxy-22-oxavitamin D3 (22-oxacalcitriol, OCT), is a new synthetic analogue of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3, calcitriol), to be used in the treatment of secondary hyperparathyroidism. This study used receptor micro-autoradiography in the parathyroid gland to determine and compare the time-course of receptor binding between OCT and 1,25(OH)2D3. Mice were injected with 4 μg/kg of [26-3H]OCT or [26,27-methyl-3H]1,25(OH)2D3, and killed at 5, 15, 30 min, 1, 2, 4, 8, 12, and 24 h afterwards. Thyroid-parathyroid tissue was excised and autoradiograms were prepared. Under identical conditions of dose and adjusted specific radioactivity between [3H]OCT and [3H]1,25(OH)2D3, the plasma concentration of [3H]OCT was much lower than that of [3H]1,25(OH)2D3. In the parathyroid at all time points, chief cell nuclei were labelled with varying degrees while connective tissue cells remained unlabelled. Nuclear receptor binding of [3H]OCT appeared equal to or higher than that of [3H]1,25(OH)2D3. Nuclear uptake of [3H]OCT was maximal at 15 min and higher than that of [3H]1,25(OH)2D3, which was maximal at 1 h after injection. Low levels of nuclear retention of the two compounds were still similarly detectable at 12 h. The results indicate the high affinity of OCT to parathyroid cells, and suggest that OCT has a higher therapeutic potential than 1,25(OH)2D3, especially under clinical conditions, at which OCT with its lower calcaemic effect would allow treatment with a dose several times higher than 1,25(OH)2D3.

1,25-Dihydroxy-22-oxavitamin D(3) (22-oxacalcitriol, OCT) is an analogue of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3), calcitriol) with less calcaemic activity, thus more suitable than 1,25(OH)(2)D(3) for the control of parathyroid hormone (PTH) secretion in chronic dialysis patients. As the low-calcaemic action of OCT has been mainly attributed to its short half-life in the blood stream, the number of doses per week is the key factor to effective OCT therapy toward suppression of PTH secretion and hypercalcaemia. Thus, we investigated a comparison between daily and thrice-weekly i.v. administration of OCT regarding suppression of PTH secretion and calcaemic action in 5/6 nephrectomized rats as a model for chronic renal failure. Model rats of chronic renal failure were made by 5/6 nephrectomy. At 3 months after surgery, they were administered either vehicle or OCT intravenously, daily (0.125 or 0.625 microg/kg) or thrice-weekly (0.6 or 3.0 microg/kg) for 2 weeks. The data show that 0.625 microg/kg/day (=4.375 microg/kg/week) suppresses PTH secretion with significant increase in calcium levels at 24 h after the final administration, on the other hand, 3.0 microg/kg/ thrice-weekly (=9.0 microg/kg/week) suppresses PTH secretion, although moderate compared with 0.625 microg/kg/day, with a slight (not significant) increase in calcium. The current clinical mode of OCT therapy, i.v. thrice-weekly administration, is a practically recommendable protocol.

The formation of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) after single intravenous injections of 1 alpha-hydroxycholecalciferol (1 alpha-OHD3) was examined in four patients with chronic renal failure on regular haemodialysis. Following 1-3 micrograms 1 alpha-OHD3, administered at weekly intervals, 1,25-(OH)2D3 appeared in the circulation within 1 h, and peak concentrations were reached between 2 h and 5 h. By 8 h serum 1,25-(OH)2D3 concentrations had started declining and by 44 h they had returned to baseline after 1 microgram 1 alpha-OHD3, but they were still above basal after 2 and 3 micrograms by an average of 30 pmol/l. One week after injections, concentrations were back to basal in all patients studied. The serum 1,25-(OH)2D3 dose response to injected 1 alpha-OHD3 was linear, indicating ample capacity of the liver 25-hydroxylase to further hydroxylate 1 alpha-OHD3. However, examination of the individual responses revealed lower increments in serum 1,25-(OH)2D3 concentrations in the patients with the highest basal serum 25-hydroxyvitamin D concentrations. Intravenous 1 alpha-OHD3 may be useful in the further study of the interactions between 1,25-(OH)2D3, calcium and PTH in chronic renal failure, as well as of the hepatic metabolism of vitamin D.

Eleven patients on chronic haemodialysis treatment thrice weekly received 1 microgram 1,25(OH)2D3 i.v. after each dialysis for 3 weeks. Phosphate binders were mainly CaCO3, supplemented in a few patients by moderate amounts of Al(OH)3. Ionised calcium was measured by ion-selective electrode, normal values being 1.28-1.42 mmol/l. PTH was estimated by an N-terminal-sensitive assay; normal values are less than 0.25 ng/ml. Results before and after 1,25(OH)2D3 were: ionised calcium before haemodialysis, 1.19 +/- 0.12 and 1.17 +/- 0.14; ionised calcium after haemodialysis, 1.33 +/- 0.07 and 1.30 +/- 0.09; PTH before haemodialysis, 1.39 +/- 0.71 and 1.38 +/- 0.69; PTH after haemodialysis, 0.64 +/- 0.22 and 0.60 +/- 0.17; Phosphate before haemodialysis, 1.85 +/- 0.48 and 2.18 +/- 0.43 (P less than 0.05). No change of PTH concentration and ionised calcium before and after haemodialysis treatment could be documented after i.v. 1,25(OH)2D3 treatment. Mild and severe hyperparathyroidism were indistinguishable. Increased serum calcium concentrations therefore appear to be required for the suppression of PTH secretion by i.v. 1,25(OH)2D3 therapy.

Calcitriol treatment of secondary hyperparathyroidism (HPT) in chronic kidney disease (CKD) patients can lead to increased serum calcium and phosphorus, which have been associated as risk factors for vascular calcification. Cinacalcet HCl (Sensipar/Mimpara) {(alphaR)-(-)-alpha-methyl-N-[3-[3-(trifluoromethylphenyl)propyl]-1-napthalenemethanamine hydrochloride} lowers serum parathyroid hormone (PTH), calcium, phosphorus and calcium-phosphorous (CaxP) product in stage 5 CKD dialysis patients; however, its effects on vascular calcification are unknown. Cinacalcet HCl (10 or 1 mg/kg, p.o. gavage), 1,25-dihydroxyvitamin D(3) (0.1 microg, s.c, calcitriol) or the combination was administered daily for 26 days in a rat model of secondary HPT [5/6 nephrectomy]. After dosing, aortic calcification was determined using the von Kossa staining method. Serum PTH and blood chemistries were determined on days 0, 26 and 0, 14, 26, respectively, prior to and after dosing. Calcitriol-treated rats had moderate to marked aortic calcification, whereas no significant calcification was observed in vehicle- or cinacalcet HCl-only treated groups. Co-administration of cinacalcet HCl with calcitriol did not attenuate the calcitriol-mediated increase in CaxP product or calcitriol-mediated aortic calcification. Both calcitriol and cinacalcet HCl therapy significantly reduced serum PTH levels. Calcitriol significantly elevated serum calcium, serum phosphorous and CaxP product above pretreatment levels, or those seen with vehicle or cinacalcet HCl. Cinacalcet HCl (10 or 1 mg/kg) decreased serum ionized calcium and decreased calcitriol-induced hypercalcaemia. Cinacalcet HCl and calcitriol both effectively reduce PTH, albeit via different mechanisms, but unlike calcitriol, cinacalcet HCl did not produce hypercalcaemia, an increased CaxP product or vascular calcification.

Secondary hyperparathyroidism (2HPT) is characterized by an abnormal threshold for suppression of parathyroid hormone (PTH) secretion by serum ionized Ca (ICa). It is therefore critical to examine the threshold of PTH secretion in chronic renal failure patients in relation to the physiopathological conditions and the severity of 2HPT. The effect of 1,25-dihidroxy-22-oxavitamin D(3) (22-oxacalcitriol, OCT) on parathyroid gland function was investigated in six haemodialysis patients with 2HPT. OCT was administered three times a week for 26 consecutive weeks. The maximum serum PTH (PTHmax), the minimum serum PTH (PTHmin), and ICa concentration required to inhibit 50% of PTHmax were estimated based on the model formula of the sigmoid curve describing the relationship between ICa and intact-PTH levels. The sigmoid ICa-PTH curves displayed a downward shift at 12 and 26 weeks of OCT treatment. Parathyroid gland function, as reflected by both PTHmax and PTHmin, decreased over time. A steep slope was found at 12 and 26 weeks, compared with that at the start of OCT treatment. There were no marked changes in the set point of calcium. Hypercalcaemia and elevated creatine phosphokinase, probably due to OCT therapy, were observed during the study period. In view of the findings that the sigmoid ICa-PTH curve displayed a downward shift, that both PTHmax and PTHmin decreased, and that functional mass of the parathyroid gland was reduced, OCT appears to be useful in ameliorating parathyroid gland function, contributing to the management of 2HPT.

Plasma immunoreactive parathyroid hormone (iPTH), 1,25(OH)2D3, calcium and phosphate and urinary creatinine, calcium and phosphate were measured before and following unilateral nephrectomy in six kidney donors. Unexpectedly, plasma calcium rose, from 2.27 +/- 0.02 mmol/l (mean +/- SEM) to 2.41 +/- 0.03 mmol/l on day 7 and to 2.37 +/- 0.02 mmol/l on day 30 (P less than 0.02). A parallel rise in iPTH occurred, from 0.61 +/- 0.16 ng/ml initially, to 1.83 +/- 0.54 ng/ml on day 7 (P less than 0.05) and to 1.18 +/- 0.18 on day 30 (P less than 0.01). The ratio of maximal tubular reabsorption of phosphate to GFR (TmP/GFR) fell by day 2 (P less than 0.01), remaining reduced on day 30 (P less than 0.05). The significance of elevated iPTH in renal insufficiency was further assessed by determining the time course of the disappearance of iPTH after parathyroidectomy in three haemodialysis subjects. Fifty per cent baseline iPTH level occurred after an average of 104.7 min, suggesting that the assay did not predominantly recognize C-terminal PTH fragments. By day 2, plasma 1,25(OH)2D3 had fallen from 34.3 +/- 4.5 pg/ml to 22.8 +/- 3.8 pg/ml (P less than 0.001), but by day 4 had regained its pre-nephrectomy value. Our results suggest that hypocalcaemia may not be the sole stimulus to parathyroid hormone secretion. It is speculated that reduction in circulating 1,25(OH)2D3 may be involved.

The therapeutic equivalence of 1,25(OH)(2)D(3) and 1alpha(OH)D(3) on the suppression of PTH synthesis and secretion has not clearly been established. The aim of the present study was to evaluate the pharmacokinetics of 1,25(OH)(2)D(3) and 1alpha(OH)D(3) after oral and i.v. administration in healthy volunteers and uraemic patients. Six healthy volunteers and 12 uraemic patients were included in the study. With an interval of 2 weeks, 4 microg of 1,25(OH)(2)D(3) i.v., 4 microg of 1,25(OH)(2)D(3) orally, 4 microg of 1alpha(OH)D(3) i.v. and 4 microg of 1alpha(OH)D(3) orally were administered. Blood samples for analysis of plasma-Ca(2+), plasma-1,25(OH)(2)D(3), and plasma-PTH were drawn at time 0, 0.25, 0.5, 1, 2, 4, 6, 9, 12, 24, 48, and 72 h. The healthy volunteers were studied in all four protocols and the uraemic patients in either the 1alpha(OH)D(3) (n=6) or the 1,25(OH)(2)D(3) (n=6) protocol. After oral administration of 1,25(OH)(2)D(3) the bioavailability of 1,25(OH)(2)D(3) was 70.6+/-5.8/72.2+/-4.8% in healthy volunteers/uraemic patients (n.s.). After i.v. administration the volume of distribution of 1,25(OH)(2)D(3) was similar, 0.49+/-0.14 vs 0.27+/-0.06 l/kg in healthy volunteers vs uraemic patients (n.s.), while the metabolic clearance rate of 1,25(OH)(2)D(3) was 57% lower in the uraemic patients, 23.5+/-4.34 vs 10.1+/-1.35 ml/min in healthy volunteers vs uraemic patients, respectively (P<0.03). The bioavailability of 1,25(OH)(2)D(3) after i.v. administration of 1alpha(OH)D(3) was 42.4+/-11.0/42.0+/-2.0% in healthy volunteers/uraemic patients (n.s.); and after oral administration of 1alpha(OH)D(3) 42.0+/-2.0/29.8+/-3.1% in healthy volunteers/uraemic patients (n.s.). A small, but significant increase in plasma-Ca(2+) was seen after administration of 1,25(OH)(2)D(3) to the uraemic patients, while no increase was seen after administration of 1alpha(OH)D(3). PTH levels were significantly suppressed in the healthy volunteers 24 h after administration of 4 microg of 1,25(OH)(2)D(3) i.v., 4 microg of 1,25(OH)(2)D(3) orally, and 4 microg of 1alpha(OH)D(3) orally by 35+/-7, 30+/-8, and 35+/-4%, respectively (all P<0.03). In the uraemic patients, PTH levels were significantly suppressed after administration of 4 microg of 1,25(OH)(2)D(3) i.v., 4 microg of 1,25(OH)(2)D(3) orally, and 4 microg of 1alpha(OH)D(3) i.v. by 30+/-10, 45+/-7, and 40+/-7%, respectively (all P<0.04). The effect was transitory in the healthy volunteers and lasted for at least 72 h in the uraemic patients. The present study found a 57% lower metabolic clearance rate of 1,25(OH)(2)D(3) in uraemic patients, as compared with that of healthy volunteers (P<0.03). The bioavailability of 1,25(OH)(2)D(3) following administration of 1alpha(OH)D(3) i.v. and orally in both healthy volunteers and uraemic patients was markedly lower than after administration of oral 1,25(OH)(2)D(3) (P<0.03). In spite of lower plasma-1,25(OH)(2)D(3) levels after administration of 1alpha(OH)D(3), no significant difference was observed on the suppressive effect of 4 microg i.v. of either 1,25(OH)(2)D(3) or 1alpha(OH)D(3) on the plasma-PTH levels in the uraemic patients. This might suggest the existence of an effect of 1alpha(OH)D(3) on the parathyroid glands which is independent of the plasma-1,25(OH)(2)D(3) levels, that are achieved after oral or i.v. administration of 1alpha(OH)D(3).

We studied 28 patients with parathyroid hormone (PTH) concentrations >65 pg/ml immediately prior to kidney transplant and who had stable allograft function with serum creatinine <2 mg/dl. After 12-18 months of transplantation, biochemical parameters (including 25-hydroxy- and 1,25-dihydroxy-vitamin D3) were studied. Patients were divided into three groups according to their PTH concentrations. Patients with renal transplant were compared with 50 healthy subjects and 20 patients with primary hyperparathyroidism. The mean 1,25-dihydroxy-vitamin D3 concentration of the transplant patients did not differ from the controls, but was lower than in patients with primary hyperparathyroidism. Using univariate linear regression analysis, 1,25-dihydroxy vitamin D3 correlated positively with PTH (P=0.008) and serum calcium (P=0.0015), and inversely with creatinine clearance (P=0.01). However, it did not correlate significantly with serum phosphorus. Our data suggest that renal transplant recipients may have an inappropriate production of 1,25-dihydroxy vitamin D3; suboptimal allograft function may be a major limiting factor.

Although it effectively suppresses parathyroid hormone (PTH) secretion, vitamin D [1,25(OH)(2)D(3)] therapy often causes tissue calcification over the long term. In patients on chronic dialysis, cardiovascular calcification is clearly linked to an unfavourable prognosis. In pre-dialysis patients, renal calcification of the kidney leads to the deterioration of renal function. We compared the propensities of 22-oxacalcitriol (OCT), with lesser calcaemic action, and 1,25(OH)(2)D(3) for producing their potential side effects in rats: (i) metastatic calcification of heart and aorta, and (ii) renal dysfunction with nephrocalcinosis, using the same effective doses for hyperparathyroidism. OCT (1.25 and 6.25 micro g/kg) or 1,25(OH)(2)D(3) (0.125 and 0.625 micro g/kg) solutions were administered intravenously to subtotally nephrectomized (SNX) rats three times weekly for 2 weeks. Despite the suppression of PTH to comparable levels, the calcification of the hearts, aortas and kidneys in the 1,25(OH)(2)D(3)-treated group was significantly greater than in the OCT-treated group. Of interest was that, in the OCT (6.25 micro g/kg) group, the degree of calcification in hearts, aortas and kidneys were distinctly lower than those in the 1,25(OH)(2)D(3) (0.125 micro g/kg) group despite the comparable serum Ca x Pi products. Therefore, there may be different mechanisms behind the calcifications resulting from OCT and 1,25(OH)(2)D(3). Deterioration of renal function, tubular changes, and atypical hyperplasia of proximal tubules associated with calcification were more severe in the 1,25(OH)(2)D(3)-treated group than in the OCT-treated group. These results indicate that OCT may be an effective agent for the suppression of PTH with a lesser risk of cardiovascular calcification or deterioration of residual renal function.

Reduced galactosylation of the O-linked glycans of the IgA1 hinge region in IgAN has recently been described. To investigate the underlying defect resulting in this abnormality, we have measured the activity of beta 1,3 galactosyltransferase, the enzyme responsible for galactosylation of O-linked sugars. A galactose-acceptor substrate was prepared from degalactosylated hinge region fragments of normal IgA1, and incubated with the T cell, B cell, and monocyte lysates from patients with IgAN and controls for acceptor regalactosylation. The extent of acceptor galactosylation was then measured with biotinylated Vicia villosa lectin (VV), which is specific for ungalactosylated moieties. Lectin binding of serum IgA from the same subjects was also measured. T cell and monocyte beta 1,3 galactosyltransferase activities did not differ between IgAN and control, but B cell lysates in IgAN showed significantly lower beta 1,3 galactosyltransferase activity than control (6.2 +/- 0.71 vs. 9.5 +/- 1.03 AU/microgram, P = 0.018). Furthermore, B cell beta 1,3 galactosyltransferase activity showed a negative correlation (r = -0.87, P = 0.002) with VV lectin binding of serum IgA in IgAN, but not controls. These data indicate that altered IgA1 O-galactosylation in IgAN results from a B cell-restricted reduction of beta 1,3 galactosyltransferase activity. This enzyme defect may be a fundamental pathogenic abnormality in IgAN.

Patients with IgA nephropathy (IgAN) have an increased amount of abnormally O-glycosylated IgA1 in circulation, in glomerular deposits and produced by tissue cells in vitro. Although increased production of Th2 cytokines by peripheral blood lymphocytes and a functional abnormality of core 1 β1,3-galactosyltransferase (C1β3Gal-T) have been proposed as mechanisms underlying pathogenesis of IgAN, they are still obscure and are not connected. To clarify the effect of T-cell cytokines, we analysed the mRNA levels of C1β3Gal-T and its molecular chaperone Cosmc, C1β3Gal-T activity and subsequent O-glycosylation of IgA1 in a human B-cell line stimulated with these cytokines. The surface IgA1-positive human B-cell line was cultured with recombinant human IFN-γ, IL-2, IL-4 or IL-5. The production and glycosylation of IgA1 were determined by sandwich ELISA and enzyme-linked lectin binding assay, respectively. The mRNA levels of C1β3Gal-T and Cosmc were quantitatively measured by real-time PCR. C1β3Gal-T activity was analysed using high-performance liquid chromatography. IgA1 production by IL-4-stimulated cells was significantly higher than controls or after IFN-γ or IL-5. The terminal glycosylation of secreted IgA1 was altered in response to IL-4. IL-4 stimulation significantly decreased the mRNA levels of both C1β3Gal-T and Cosmc and of C1β3Gal-T activity. IL-4 stimulation was clearly blocked by recombinant human IL-4 soluble receptor. It appears that Th2 cytokine IL-4 may play a key role in controlling glycosylation of the IgA1 hinge region.

The renal preservation ability of a flushing solution (F-M) with fructose-1,6-diphosphate (1 g/dl) and mannitol (2 g/dl) during cold ischaemia was studied with the isolated perfused rat kidney model and compared with the Euro-Collins (EC) and University of Wisconsin (UW) solutions. Kidneys were stored in hypothermia for 4 and 18 h after initial flushing with the solution being tested, and then reperfused at 37°C in an isolated perfusion circuit for 90 min with a Krebs-Henseleit solution containing 4.5% albumin. Forty-four kidneys were studied and divided in a control group and six study groups according to the cold ischaemia time and flushing solution used. Renal functional parameters of plasma flow rate (PFR), renal vascular resistance (RVR), urine flow rate (UFR) glomerular filtration rate (GFR), fractional (FRNa) and net (TNa) sodium reabsortion were assessed during reperfusion. Conventional histology and malon-dialdehyde tissue levels (MDA) were also evaluated. Our results show that PFR, RVR, and UFR were similar in all study groups. After 4 and 18 h of cold ischaemia, GFR, FRNa and TNa were better, and conventional histology worse in F-M than in EC flushed kidneys. After 4 and 18 h of cold ischaemia, GFR, FRNa and TNa, in fact, were not different between F-M and UW flushed kidneys. After 4 h of cold ischaemia, conventional histology was similar in F-M and UW flushed kidneys. Nevertheless, after 18 h of cold ischaemia, UW flushed kidneys showed worse histological parameters than F-M flushed kidneys. After 4 h of cold ischaemia, MDA was similar in kidneys flushed with the three solutions. After 18 h of cold ischaemia MDA was higher in EC than in F-M or UW flushed kidneys. In summary, our newly developed cold storage solution shows promising results in renal preservation and its ability to preserve is at least as good as UW solution assessed in the isolated perfused rat kidney.

Higher doses of calcitriol are effective in lowering markedly elevated 1,84 PTH levels of patients with renal secondary hyperparathyroidism. It has not been established, however, whether prophylactic administration of low doses of calcitriol prevents an increase of 1,84 PTH without causing side-effects, i.e. hypercalcaemia, hypercalciuria, or hyperphosphataemia. We carried out a placebo-controlled, double-blind prospective multicentre trial over 12 months in 45 patients with mild to moderate renal failure. Criteria for inclusion were S-creatinine 1.4 mg/dl and 1,84 PTH > 6 pmol/l (normal 6). Calcitriol 0.125 microgram/day per os was compared with placebo. The patients received calcium carbonate per os if serum P exceeded 1.7 mmol/l. Baseline 1,84 iPTH concentrations were not significantly different, i.e. 14.0 pmol/l (6.7-63.3) on placebo vs 16.2 (6.85-82.0) on calcitriol. Intention to treat analysis revealed a significant difference of final 1,84 iPTH, i.e. 27.8 (4.2-68.5) on placebo vs 18.2 (4.45-75.5) on calcitriol. On post-hoc analysis the difference was even more pronounced at S-creatinine concentrations above 3 mg/dl. S-calcium, S-phosphate, and urinary excretion of calcium did not change significantly on either placebo or on calcitriol. There were no episodes of hypercalcaemia or hyperphosphataemia. There was no significant difference of final S-creatinine or change in S-creatinine between placebo and calcitriol. One patient on calcitriol and two on placebo progressed to terminal renal failure. Bone alkaline phosphatase as a non-invasive index of bone metabolism was not decreased to subnormal levels. The results document that a therapeutic window exists in patients with moderate renal failure and elevated of 1,84 iPTH, where low-dose calcitriol (0.125 microgram/day) prevents the increase in 1,84 iPTH without causing side-effects. This observation suggests that the parathyroid is more sensitive to calcitriol than intestine and bone.

A significant percentage of dialysed patients have inadequate protein intake. One strategy for treating the protein malnutrition in peritoneal dialysis patients is to replace glucose in the dialysis solution by amino acids. A new peritoneal dialysis solution containing 1.1% amino acids in a formulation optimized for renal patients and with a lactate concentration of 40 mmol/l has been evaluated. Fifteen CAPD patients completed a non-randomized prospective 3-month study. Each patient received 2 litres of the optimised 1.1% amino acid solution for the second exchange of the day with a dwell time of 5-6 h. Indicators of efficacy were serum albumin and transferrin. After 3 months of intraperitoneal amino acids, serum albumin levels significantly increased from 32.7 +/- 2.3 to 35.1 +/- 2.2 g/l (mean +/- SD; P < 0.01). This occurred in parallel with a significant increase in transferrin levels from 2.21 +/- 0.26 to 2.39 +/- 0.27 g/l (P < 0.05). As expected, urea rose from 23.7 +/- 6.8 to 29.9 +/- 9.4 mmol/l. Interestingly bicarbonate did not change (25.5 +/- 4.2 versus 25.2 +/- 3.3 mmol/l). These results suggest that the optimized formulation is effective in improving nutritional parameters in CAPD patients while avoiding unwanted side-effects such as acidosis.

Effective control of hyperparathyroidism and renal osteodystrophy in CAPD patients requires a combination of calcitriol and calcium carbonate (CaCO3), but is frequently limited by hypercalcaemia. Reducing dialysate calcium (Ca) concentration may overcome this problem, but had not been examined in a controlled trial. 45 stable CAPD patients were randomly assigned in a prospective double-blind trial to either a study group (1.25 mmol/l Ca dialysate) or a control group (1.75 mmol/l Ca dialysate) for 12 months. Clinical, biochemical and radiological parameters of secondary hyperparathyroidism were followed. Twenty-three patients did not complete the study due to death (9), transplantation (7) or conversion to haemodialysis (7). Eleven patients in each group completed the study. Mean serum Ca, phosphate, ionized Ca, aluminium, alkaline phosphatase (AP), and bone mineral density (BMD) Z-scores did not differ significantly at any time within or between the two groups. Severe hypercalcaemia was more common in the control group (11 vs. 2, P = 0.027). Mean serum intact parathyroid hormone (PTH) and osteocalcin (OCN) initially rose in the study group relative to controls at 3 months (40 +/- 7 vs 12 +/- 3 pmol/l, P = 0.004, and 33 +/- 5 vs 15 +/- 2 micrograms/l, P = 0.002 respectively), but were not sustained. Median weekly dosages of calcitriol and daily dosages of CaCO3 increased significantly in the study group (O microgram to 1 microgram P = 0.014 and 1260 mg to 2520 mg P = 0.002 respectively), but not in the control group. Supplementary aluminium hydroxide (A1, (OH)3) was required for phosphate control in both study (n = 5) and control patients (n = 4). Lowering dialysate calcium concentration reduced the frequency of severe hypercalcaemia and allowed prescription of larger quantities of calcitriol and CaCO3. However, in this study it offered no advantage in terms of A1(OH)3 requirement, while bone mass density did and may have initially exacerbated secondary hyperparathyroidism not change.

The effect of two different dialysate solutions with a calcium concentration of 1.25 and 1.75 mmol/l was evaluated in 14 patients, using a cross-over design. Patients were treated with each solution during a period of 6 months. Treatment with calcium supplements, vitamin D and aluminium hydroxide was adapted weekly, according to the results of blood chemistry. PTH, SAP, and ionized calcium were determined monthly, bone density with DXA and QCT before and after 6 months of treatment. During treatment with both 1.25 and 1.75 calcium dialysate (cad), the control of serum calcium and phosphate was similar. PTH did not change during either treatment. SAP decreased during treatment with 1.75, but remained stable with 1.25 mmol/l cad. Bone density evaluated with DXA remained unchanged during both treatments. QCT measured bone density increased from 101.29 +/- 13.50 to 106.79 +/- 13.14 mg/ml in the 1.75 cad group, while it did not vary in the 1.25 cad group, (107.75 +/- 13.48 versus 108.97 +/- 13.40 mg/ml). It is concluded that lowering the calcium content of the dialysate does not negatively influence the control of serum calcium and phosphate, nor does it aggravate hyperparathyroidism when vitamin D is administered simultaneously. Under the present conditions, osteopenia and possibly bone mineralization improve only in the group dialysed with 1.75 Ca.

Renal calcium stones and hypercalciuria are associated with a reduced bone mineral density (BMD). Therefore, the effect of changes in calcium homeostasis is of interest for both stones and bones. We hypothesized that the response of calciuria, parathyroid hormone (PTH) and 1.25 vitamin D to changes in dietary calcium might be related to BMD. A single-centre prospective interventional study of 94 hyper- and non-hypercalciuric calcium stone formers consecutively retrieved from our stone clinic. The patients were investigated on a free-choice diet, a low-calcium diet, while fasting and after an oral calcium load. Patient groups were defined according to lumbar BMD (z-score) obtained by dual X-ray absorptiometry (group 1: z-score <-0.5, n = 30; group 2: z-score -0.5-0.5, n = 36; group 3: z-score >0.5, n = 28). The effect of the dietary interventions on calciuria, 1.25 vitamin D and PTH in relation to BMD was measured. An inverse relationship between BMD and calciuria was observed on all four calcium intakes (P = 0.009). On a free-choice diet, 1.25 vitamin D and PTH levels were identical in the three patient groups. However, the relative responses of 1.25 vitamin D and PTH to the low-calcium diet were opposite in the three groups with the highest increase of 1.25 vitamin D in group 1 and the lowest in group 3, whereas PTH increase was most pronounced in group 3 and least in group 1. Calcium stone formers with a low lumbar BMD exhibit a blunted response of PTH release and an apparently overshooting production of 1.25 vitamin D following a low-calcium diet.

The aim of the present study was to examine the long-term efficacy and safety of treatment with a high-normal calcium dialysate with a calcium concentration of 1.35 mmol/l in patients on CAPD. This dialysate calcium concentration is close to the high-normal plasma ionized calcium level aimed at in dialysis patients in order to suppress the parathyroid hormone secretion. The end-points of the study were (1) plasma ionized calcium (iCa) and phosphate (P) levels, (2) plasma intact parathyroid hormone (PTH) levels, (3) doses of calcium carbonate and alfacalcidol, (4) requirements of Al-containing phosphate binders, and (5) bone mineral density (BMD). Thirty-seven non-selected patients on CAPD treatment were followed for an average of 10 months after switching from a dialysate Ca of 1.75 to 1.35 mmol/l. After 1 week, a significant decrease of mean iCa from 1.26 +/- 0.01 to 1.23 +/- 0.01 mmol/l (P < 0.05) and an increase of median PTH from 80 to 135 pg/ml (P < 0.01) were seen. From the 2nd week and onwards, however, basal levels of iCa and PTH were restored and remained stable. mean plasma iCa was kept within 1.23-1.31 mmol/l; mean plasma P below 1.65 mmol/l and median PTH within 52-135 pg/ml. Episodes of hypercalcaemia were few (1.2 cases of plasma iCa > 1.45 mmol/l per 100 treatment weeks), and the need for Al-containing P binders low with only five patients requring this treatment for isolated and four patients for repeated episodes of hyperphosphataemia or hypercalcaemia. After switching from a dialysate Ca of 1.75 to 1.35 mmol/l, the doses of calcium carbonate and alfacalcidol could be significantly increased. Furthermore, using the dialysate Ca of 1.35 mmol/l made it possible to induce a controlled increase of PTH levels to 80-100 pg/ml by a temporarily discontinuation of alfacalcidol and/or a reduction of calcium carbonate dosage in the patients where PTH had become suppressed to levels below the upper normal limit. The intention of the treatment was to maintain PTH levels within 1.5-2.5 times the upper normal limit for non-uraemic patients. Pre-study BMD of the vertebral bodies L2-L4 and of the femoral neck were normal and not significantly different from post-study measurements. The present study demonstrated that when using a high-normal dialysate Ca concentration of 1.35 mmol/l in non-selected patients on CAPD treatment, high-normal plasma iCa and near-normal plasma P levels could be readily achieved with a minimal risk of incidental hypercalcaemia despite use of calcium carbonate as the main P binder. As a consequence of the tight Ca and P regulation, minimal doses of alfacalcidol were required to keep PTH within acceptable limits. We recommend this dialysate Ca concentration as a first-choice therapy for the majority of patients starting on CAPD treatment.

The feasibility and reliability of a short dialysis technique performed with standard dialysis equipment and a modified cuprammonium rayon hollow-fibre filter has been studied. The hydraulic response of the filter and membrane to high blood flows and transmembrane pressures were tested in vitro and the maximal clearances of different solutes achievable during high-flux bicarbonate dialysis were studied in vivo. Clinical studies were undertaken to evaluate the long-term effects of the short, highly efficient dialysis therapy. Six patients were treated for more than a year with single-pass bicarbonate dialysis with a blood flow of 500 ml/min, dialysate flow of 700 ml/min, and average duration of 150 min/session three times weekly. The treatment showed an adequate efficiency with an average KT/V greater than 1. All patients obtained an average blood urea nitrogen during the study of less than 80 mg/dl and an average protein catabolic rate of 0.9 g/kg per 24 h. The treatment was well tolerated by all patients and, on echocardiography, no significant changes in myocardial function were detected after one year of therapy. The treatment is efficient, well tolerated, simple to monitor and does not require the use of synthetic membranes or machines with advanced technology. Thus the reduction of dialysis treatment time is feasible in all centres at a relatively low cost.

Autogenous radial-cephalic direct wrist arteriovenous fistula (RCF), the gold standard for chronic dialysis, suffers from an elevated early failure rate (up to 20-50% with a pooled rate of 15.3%). Guidelines indicate that a small radial artery internal diameter (<1.6-2 mm) is strongly predictive of this early failure. Microsurgery and preventive haemostasis have been reported to give excellent results in a paediatric population (children <10 kg bw) and have shown a much lower early failure rate of 5-10%. Given these excellent results, we have used microsurgery along with preventive haemostasis in adult patients. We herein describe the results of RCF created in patients with a radial artery internal diameter <1.6 mm. From November 2004 to December 2007, 28 RCFs were created in 28 patients with a distal radial artery internal diameter <1.6 mm using microsurgery and preventive haemostasis. The median age was 68 and the male/female ratio was 6/22. The incidence of age >65 years was 64%, hypertension 96%, diabetes 32.1%, obesity (BMI>30) 35%, vascular disease 46%. The mean distal radial artery and cephalic vein internal diameters, measured with ultrasound examination, were 1.3 mm and 1.9 mm, respectively. Seventy-five percent of the patients were not yet on dialysis treatment; 19% of whom had a previous failed vascular access created elsewhere without microsurgery. The remaining 25% patients were on dialysis treatment with a temporary femoral catheter. All interventions ended with a patent anastomosis; no thrombosis occurred within the initial 24 h. The early failure rate was 14% (4 out of 28 patients). The causes of early failure were thrombosis >1 week after surgery in one patient, lack of maturation (patent but unfunctional fistula) due to juxta-anastomotic vein stenosis in two patients and mid-vein stenosis in one patient. Treatment for all patients was proximalization of the anastomosis at the distal/mid forearm. Primary patency and secondary patency at 1 year were 68 +/- 10% and 96 +/- 5%, respectively. From our findings, we have shown that it is possible to create RCF in adult patients with a radial artery internal diameter of <1.6 mm with an acceptable risk of early failure rate using microsurgery along with preventive haemostasis.

End-stage renal disease care requires enormous economic resources. A timely dialysis start could reduce the costs of the renal replacement therapy (RRT). Our aim was to measure the time to dialysis in CKD patients, with an estimated glomerular filtration rate (eGFR) <or=11.0 ml/min/1.73 m(2) (MDRD derived), and to evaluate the safety, economic impact and the quality of life (QoL). In a prospective, observational study, 70 consecutive CKD patients, stage 5, were screened and 30 patients were selected and followed up monthly, for 24 months or until the start of RRT, set at an eGFR = 6.0 ml/min/ 1.73 m(2) or at the occurrence of pre-defined urgent criteria. The SF-36 questionnaire to evaluate the QoL was performed at the first and the last visit. The median time to the start of dialysis was 11.8 (25th and 75th: 5.5-17.3) months. Only seven patients urgently started dialysis, after 8 months (25th and 75th: 4.8-20). The mean monthly cost of care was euro 1146 +/- 917 per patient. The QoL was similar to that of the general population and did not change at the last assessment. Discussion. This is the first study evaluating the economic impact of intensive conservative management of CKD stage 5 to postpone start of dialysis in tertiary care. This strategy allows us to safely gain a significant amount of time free from dialysis, with good QoL and major savings in the costs of nation's dialysis budget. The present results, however, are applicable only to low comorbidity patients referred to nephrology care and may not be generalized to all patients starting RRT.

Iron deficiency anaemia is common in patients with chronic kidney disease, and intravenous iron is the preferred treatment for those on haemodialysis. The aim of this trial was to compare the efficacy and safety of iron isomaltoside 1000 (Monofer®) with iron sucrose (Venofer®) in haemodialysis patients. This was an open-label, randomized, multicentre, non-inferiority trial conducted in 351 haemodialysis subjects randomized 2 : 1 to either iron isomaltoside 1000 (Group A) or iron sucrose (Group B). Subjects in Group A were equally divided into A1 (500 mg single bolus injection) and A2 (500 mg split dose). Group B were also treated with 500 mg split dose. The primary end point was the proportion of subjects with haemoglobin (Hb) in the target range 9.5-12.5 g/dL at 6 weeks. Secondary outcome measures included haematology parameters and safety parameters. A total of 351 subjects were enrolled. Both treatments showed similar efficacy with >82% of subjects with Hb in the target range (non-inferiority, P = 0.01). Similar results were found when comparing subgroups A1 and A2 with Group B. No statistical significant change in Hb concentration was found between any of the groups. There was a significant increase in ferritin from baseline to Weeks 1, 2 and 4 in Group A compared with Group B (Weeks 1 and 2: P < 0.001; Week 4: P = 0.002). There was a significant higher increase in reticulocyte count in Group A compared with Group B at Week 1 (P < 0.001). The frequency, type and severity of adverse events were similar. Iron isomaltoside 1000 and iron sucrose have comparative efficacy in maintaining Hb concentrations in haemodialysis subjects and both preparations were well tolerated with a similar short-term safety profile. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA.