[Interdisciplinary interaction in vascular diseases of the eye, diabetes and diabetic retinopathy]. / Interdisziplinäre Interaktion bei vaskulärer Erkrankung des Auges, Diabetes und diabetischer Retinopathie.

The incidence of diabetes mellitus type 2 is greatly increasing worldwide. An early therapy with intensified control of diabetes and blood pressure is especially important to avoid delayed complications. In addition to diabetic foot syndrome, diabetic retinopathy and diabetic nephropathy still represent commonly occurring problems. Despite improvements in the quality of care, the targets of the St. Vincent Declaration have still not yet been achieved. Diabetic retinopathy and diabetic nephropathy show parallels in the course of the disease and in the pathological anatomical alterations which have led to the inauguration of a diabetic renal-retinal syndrome. The ophthalmological assessment of the retina was previously considered to be a diagnostic aid for assessment of diabetic nephropathy; however, nowadays a simple estimation of the glomerular filtration rate using the modification of diet in renal disease (MDRD) formula and determination of microalbuminuria can in contrast give ophthalmologists an early indication of the possible presence of microangiopathic alterations.

Determination of Vasopressin and Desmopressin in urine by means of liquid chromatography coupled to quadrupole time-of-flight mass spectrometry for doping control purposes.

The anti-diuretic neurohypophysial hormone Vasopressin (Vp) and its synthetic analogue Desmopressin (Dp, 1-desamino-vasopressin) have received considerable attention from doping control authorities due to their impact on physiological blood parameters. Accordingly, the illicit use of Desmopressin in elite sport is sanctioned by the World Anti-Doping Agency (WADA) and the drug is classified as masking agent. Vp and Dp are small (8-9 amino acids) peptides administered orally as well as intranasally. Within the present study a method to determine Dp and Vp in urinary doping control samples by means of liquid chromatography coupled to quadrupole high resolution time-of-flight mass spectrometry was developed. After addition of Lys-Vasopressin as internal standard and efficient sample clean up with a mixed mode solid phase extraction (weak cation exchange), the samples were directly injected into the LC-MS system. The method was validated considering the parameters specificity, linearity, recovery (80-100%), accuracy, robustness, limit of detection/quantification (20/50 pg mL(-1)), precision (inter/intra-day<10%), ion suppression and stability. The analysis of administration study urine samples collected after a single intranasal or oral application of Dp yielded in detection windows for the unchanged target analyte for up to 20 h at concentrations between 50 and 600 pg mL(-1). Endogenous Vp was detected in concentrations of approximately 20-200 pg mL(-1) in spontaneous urine samples obtained from healthy volunteers. The general requirements of the developed method provide the characteristics for an easy transfer to other anti-doping laboratories and support closing another potential gap for cheating athletes.

The Primavera study protocol design: evaluating the effect of continuous erythropoiesis receptor activator (C.E.R.A.) on renal function in non-anemic patients with chronic kidney disease.

Erythropoiesis stimulating agents (ESA) are widely used for hemoglobin correction in patients suffering from renal anemia. However, their beneficial non-hematopoietic effects on renal deterioration have not been adequately assessed. The Primavera study is the first prospective, controlled trial to assess whether ESA treatment could ameliorate progression of chronic kidney disease (CKD) in non-anemic patients. Primavera is a single-blind, 24-month trial in which patients are randomized to placebo or to C.E.R.A., a continuous erythropoietin receptor activator. Patients with type 2 diabetes or who have undergone kidney transplantation are eligible to enter the study if they have CKD stage III (estimated GFR [eGFR] 30-59 mL/min/1.73 m(2)), urinary albumin to creatinine ratio (UACR) ≥ 50 g/g and ≤ 1500 g/g, or total urine protein ≥ 50mg/24h and ≤ 1500mg/24h, and hemoglobin 11-14 g/dL. The primary efficacy endpoint is the change in eGFR from baseline to month 24. Secondary efficacy endpoints are the changes in UACR, serum cystatin C and serum creatinine from baseline. Safety endpoints include adverse events and discontinuation due to pre-specified adverse events. An interim analysis will be performed after all patients have completed the first year. The planned sample size is 400 patients (200 type 2 diabetics, 200 transplant recipients) conferring 90% power to detect a prespecified significant difference of 1.5 mL/min/1.73 m(2) in the annual reduction in eGFR between treatment groups. The results of Primavera are expected in 2013.

Dosing strategies for conversion of haemodialysis patients from short-acting erythropoiesis stimulating agents to once-monthly C.E.R.A.: experience from the MIRACEL study.

AIMS: To analyse the impact of dosing decisions for continuous erythropoietin receptor activator (C.E.R.A.), a continuous erythropoietin receptor activator. METHODS: This was a prospective, multicentre, single-arm study in haemodialysis patients receiving epoetin alfa/beta or darbepoetin alfa. After a 2-month screening phase, patients were converted to monthly C.E.R.A. using pre-filled syringes during a 5-month titration phase and a 2-month evaluation phase. RESULTS: Four hundred and twenty-four eligible patients were converted to C.E.R.A. Mean Hb were 11.7 ± 0.7, 11.7 ± 0.8 and 11.5 ± 0.8 g/dl during screening, titration and evaluation, respectively. C.E.R.A. starting dose was 125 µg (n = 311) or 200 µg (n = 106), with corresponding final doses of 129 ± 61 µg and 203 ± 58 µg. The mean number of C.E.R.A. dose decreases and increases were 0.9 ± 1.0 and 1.1 ± 1.0 per patient, respectively. Hb rarely exceeded 12.5 g/dl after a C.E.R.A. dose increase (< 8%) and remained ≥ 11 g/dl after a dose reduction on approximately three-quarters of occasions. Among the 53 occasions where Hb decreased ≥ 2 g/dl between two consecutive visits, the previous dose had been withheld (n = 9), concomitant blood loss, coagulopathy or infection was present (n = 13), or iron parameters were low (n = 17). There were 104 adverse events/month during screening, and 45/month during the titration/evaluation phases. Serious adverse events occurred in 18.0 and 21.0 patients/month during the screening and titration/evaluation phases, respectively. CONCLUSION: Switching haemodialysis patients from shorter-acting ESA to once-monthly C.E.R.A. using pre-filled syringes is straightforward, and Hb levels remain stable. Starting dose recommendations and dose changes correlated well with the clinical setting. Collateral factors such as infection or aggravating concomitant medical conditions should be taken into account.

Evaluation of maintenance of stable haemoglobin levels in haemodialysis patients converting from epoetin or darbepoetin to monthly intravenous C.E.R.A.: the MIRACEL study.

BACKGROUND AND OBJECTIVES: C.E.R.A., a continuous erythropoietin receptor activator, offers once-monthly dosing without compromising haemoglobin control. This study was undertaken to examine whether monthly C.E.R.A. using pre-filled syringes maintains stable haemoglobin levels when administered according to local clinical judgement. RESEARCH, DESIGN AND METHODS: MIRACEL was a prospective, open-label, single-arm, multicentre study performed at 90 nephrology centres in Germany. After a 2-month screening phase, haemodialysis patients receiving epoetin or darbepoetin were converted to monthly intravenous C.E.R.A., with a 5-month titration phase followed by a 2-month evaluation phase. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov: NCT00413894 RESULTS: Of 661 patients screened, 424 (64.1%) started C.E.R.A. therapy (previous treatment: 72.2% epoetin, 27.8% darbepoetin); 416 were eligible for inclusion in the intent-to-treat population. A mean of two C.E.R.A. dose changes were required during the 7-month treatment period. The primary efficacy variable, haemoglobin within 11-12.5 g/dL or 10-13 g/dL during the evaluation phase, was achieved in 109 (30.8%) and 265 (74.9%) of the 354 evaluable patients, respectively, with no differences observed between patients formerly receiving epoetin or darbepoetin or different dosing frequencies. During the screening, titration and evaluation phases, mean haemoglobin was 11.7 +/- 0.7 g/dL, 11.6 +/- 0.9 g/dL and 11.4 +/- 1.0 g/dL, respectively, and 90.6% (377/416), 70.4% (293/416) and 82.9% (345/416) of patients exhibited < or = 1 g/dL change from phase-specific individual means. C.E.R.A. was well-tolerated with a safety profile similar to that reported in phase III studies. CONCLUSIONS: In this single-arm, open-label, multicentre study, conversion of a large population of haemodialysis patients from epoetin or darbepoetin to monthly C.E.R.A. administration using pre-filled syringes was shown to be practical, convenient and offer good control of haemoglobin levels, regardless of the previous type of therapy or dosing frequency.

Efficacy of cinacalcet administered with the first meal after dialysis: the SENSOR Study.

BACKGROUND: Cinacalcet, a novel calcimimetic, simultaneously lowers parathyroid hormone (PTH), phosphorus (P), calcium (Ca) and Ca x P in patients who are on dialysis with secondary hyperparathyroidism (sHPT) associated with CKD. Previous studies have required cinacalcet to be administered during the dialysis session and at the same time on non-dialysis days. The aim of the SENSOR study was to demonstrate that cinacalcet given in a more clinically practical manner with the first major meal after dialysis is noninferior to cinacalcet given with food during the dialysis session. METHODS: In this open-label study dialysis patients with poorly controlled sHPT (intact PTH (iPTH) (3) 300 pg/ml) were randomized to receive cinacalcet either daily with their post-dialysis meal (n = 337) or with food during the dialysis session (n = 336). The primary endpoint was the proportions of patients with mean iPTH pound 300 pg/ml ( pound 31.8 pmol/l) at Weeks 11 and 13 of a 21-week treatment period. Secondary endpoints included the proportion of patients with Ca x P < 55 mg2/dl2 (< 4.44 mmol2/l2) at Weeks 11 and 13 and patients who discontinued the study due to nausea or vomiting. RESULTS: Comparable proportions of patients in the cinacalcet "during dialysis" and "post-dialysis meal" groups had a mean iPTH pound 300 pg/ml (54 vs. 57%, respectively, 95% confidence interval (CI) difference -4, +10%) and Ca x P < 55 mg2/dl2 (78 vs. 73%, respectively, 95% CI difference -11, +2%) at Weeks 11 and 13. The groups were also comparable at Week 21. Cinacalcet was well tolerated, with < 3% of patients in both groups discontinuing due to nausea or vomiting. A combined post-hoc analysis of both groups showed the incidence of nausea and vomiting was lower if cinacalcet was administered during the evening. CONCLUSIONS: Administering cinacalcet with the first main meal after dialysis was as effective as administration with food during the dialysis session. Cinacalcet was well tolerated. The incidence of gastrointestinal adverse events appeared to be lower when cinacalcet was administered in the evening.

Internal filtration--advantage in haemodialysis?

Internal filtration is defined as the total water flux across the membrane within the closed blood and dialysate compartment of a dialyser. The aim of our study was to increase convection by increasing the amount of internal filtration and to study the effect on elimination of high and low molecular weight uraemic toxins during regular haemodialysis. Three high-flux polysulfone dialysers with identical type of membrane (Fresenius Sps600) and same number of fibres but with different inner diameters () and therefore different surface areas [] (175 microns [0.55 m2], 200 microns [0.65 m2] and 250 microns [0.79 m2]) were tested in routine haemodialysis sessions (10 patients). At a blood flow of 250 ml/min and a dialysate flow of 500 ml/min hydrostatic pressures at dialysate-in/outlet (PD(in), PD(out) and blood-in/outlet (PBin, PBout), mTMP, clearances (Cl) and mass balances of creatinine, urea, phosphate and beta-2-microglobulin (beta 2-M) at 30 and 180 min were measured at net ultrafiltration rate of 0 ml/min. Clearances of all three dialysers were matched for small toxins (urea: 180 +/- 4.83 ml/min). The 175 microns diameter dialyser achieved a significantly better removal of beta 2M (Cl beta 2-M 57.4 +/- 9.43 ml/min) than the two other filters (200 microns: 29.9 +/- 8.4 ml/min; 250 microns: 11.1 +/- 6.79 ml/min) although the surface area of the 175 microns filter was smallest. Hydrostatic pressure analysis revealed that at the same median transmembrane pressures (mTMP) internal filtration increased with decreasing inner fibre diameter. Longitudinal flow resistance and thereby local transmembrane pressure difference increased with narrowing the inner fibre diameter.