Differential effects of short-term growth hormone therapy on the cardiovascular risk profile in patients with chronic kidney disease: a pilot study.

Chronic kidney disease (CKD) is highly associated with an increased cardiovascular morbidity and mortality and is also a state of growth hormone (GH) resistance. We examined the impact of a short-term treatment with rhGH on circulating markers of cardiovascular risk in nonmalnourished CKD patients in a single-center, nonrandomized pilot study. Patients with stable CKD Stage 3 - 5 and age- and sex-matched healthy controls (n = 15 each) received a 7-day treatment with rhGH (1.33 mg/m2 body surface area per day, approximately 30 microg/kg). Prior to onset of rhGH therapy, at the end of the treatment period and at the end of a 7-day wash-out period blood was drawn to assess changes in circulating markers of cardiovascular risk. At time of enrollment CKD patients showed elevated serum concentrations of phosphate, calcium x phosphate product, PTH, fibroblast growth factor-23 (FGF-23), triglycerides, leptin and homocysteine compared to controls. In patients and controls rhGH treatment induced an increase in circulating insulin-like growth factor I (IGF-I), and the molar ratio of IGF-I/IGF binding protein 3 as well as an elevation of glucose, insulin, and triglycerides, whereas serum urea was decreased. In CKD patients, rhGH treatment raised concentrations of leptin, whereas LDL-cholesterol, homocysteine, phosphate, and 25-hydroxyvitamin D were significantly reduced. In controls, but not in CKD patients, rhGH raised 1,25-dihydroxy-vitamin D3 serum levels, which were even more elevated at the end of the wash-out period. In conclusion, short-term treatment with rhGH in CKD patients affects not only insulin and glucose metabolism but also affects serum lipid profile, i.e., LDL-cholesterol, leptin and homocysteine. Long-term trials are required to evaluate the impact of rhGH on cardiovascular morbidity and mortality.

Release of microparticles in LDL apheresis.

Particle contamination of blood always takes place in extracorporeal systems and few studies have been conducted to evaluate potential risks. Particle concentration was measured in the efferent blood line on original equipment for two established LDL elimination procedures (DALI) (Fresenius) and Liposorber (Kaneka). Acquired data were compared with standards for infusion solutions from European (EP) and American (USP) Pharmacopoeia. All values were well below the given limits. Even in extreme situations (>20 pump stops) particle concentration did not exceed the standards. Considering an average treated blood volume of 7.31 for the DALI-System and 17.01 for Liposorber (long term clinical studies) the absolute amount of particles infused per treatment was 167,000 (DALI) and 465,000 (Liposorber) particles > or = 2 microm.

The outcome in myasthenia gravis patients--an eight-year follow-up after finishing immunoabsorption therapy.

Eight years ago four patients suffering from myasthenia gravis (MG) type C and E according to Compston with failed drug therapy were treated three times (one patient 11 times) by protein A immunoabsorption (Immunosorba, Excorim, Fresenius Hemocare GmbH, StWendel, Germany). No further immunoabsorption treatments have been carried out. In addition, three patients were given a thymectomy. The present status of the patients was checked six and eight years thereafter. We could see a beneficial effect in all MG patients. The patients are fit for work; all have an improved Besinger index. The patients were used as their own controls. A higher anti-AChR-ab level six years after protein A immunoabsorption than at the beginning was seen in all patients combined with a less serious MG. In addition, their immunomodulation could be induced as seen in lymphocyte and inflammatory protein changes during the first 36 days after beginning immunoabsorption treatment. A larger population has to be investigated to verify these results.

Two cases of refractory endocrine ophthalmopathy successfully treated with extracorporeal immunoadsorption.

Endocrine ophthalmopathy (EO) is a severe disease entity that is characterized by retrobulbar swelling due to accumulation of glycosaminoglycans on an autoimmune basis. This disorder can lead to the loss of vision and often is resistant to conventional therapy. There is a relation to Graves' hyperthyroidism, but probably no close association. Two patients with severe EO that was resistant to usual therapeutic approaches including steroids and radiological and surgical measures underwent a 20 session course of intensive immunoadsorption therapy (Plasmaselect/Therasorb Anti-IgG) with a mean 2- to 3-fold plasma volume treated. After the first sessions, both patients voiced an impressive relief of their major symptoms, which was confirmed by ophthalmological investigation. Throughout the time of therapy until present, these patients have remained at their respective levels of improvement. We consider immunoadsorption an effective therapeutic opportunity in severe EO resistant to conventional treatment.

Three cases of C-ANCA-positive vasculitis treated with immunoadsorption: possible benefit in early treatment.

Wegener's granulomatosis is a vasculitic disease predominantly affecting the upper respiratory tract, lungs, and kidneys. Three patients with Wegener's granulomatosis and rapidly progressive glomerulonephritis were treated with an intensified regimen of immunoadsorption (IA) (Excorim or Therasorb) in addition to cyclophosphamide (CYC) and methylprednisolone (PRE). Patient A had been in remission under oral CYC/PRE. The first exacerbation was treated successfully with 4 IA treatments without changing medication. Patient B experienced 3 flares within 1 year, which were treated with 28 IA (3-7 IAs/course), intravenous CYC after each course, and PRE. A fall of creatinine levels from 120 to 190 micromol/L to 100 micromol/L was noted after IA and before administration of CYC. Patient C presented in uremia. Autoantibodies were eliminated by 11 IA treatments parallel to CYC/PRE therapy. They remained within a normal range for >1 year's follow-up; however, kidney function did not return. In conclusion, the observations in Patients A and B suggest a beneficial therapeutic effect of early IA in WG.

Immunoadsorption of immunoglobulins alters intracytoplasmic type 1 and type 2 T cell cytokine production in patients with refractory autoimmune diseases.

Intracellular cytokine staining and flow cytometry were used to investigate whether immunoadsorption (IA) of immunoglobulins alters intracytoplasmic cytokine production in CD4+ and CD8+ T cells from the blood of patients with refractory rheumatoid arthritis (n = 7), membrane proliferative glomerulonephritis (n = 1), and Goodpasture's syndrome (n = 1). Four patients (Group 1) showed severely depressed production of TNF-alpha, IL-2, IFN-gamma, and IL-4 by CD4+ and CD8+ T cells and responded to 3 IA sessions with significant increases in CD4+TNF-alpha+, CD4+IL-2+, and CD8+IL-2+ T cells. Also, a tendency toward increased percentage levels of CD4+ T cells producing IFN-gamma or IL-4 and of CD8+ T cells producing either TNF-alpha or IFN-gamma was seen, but due to the small number of patients investigated, these differences did not attain statistic significance. Group 2 (n = 5) showed unimpaired intracellular cytokine levels and responded to IA with a heterogeneous pattern of changes in TNF-alpha, IL-2, IFN-gamma, and IL-4 production, but these alterations were smaller than those in Group 1. The present findings indicate that the extracorporeal removal of immunoglobulins by anti-IgG or protein A adsorber columns has an impact on T cell immunity and suggest that modulating effects on cellular immune system function are involved in the mode of action of IA.

Particle release in extracorporeal low-density lipoprotein lowering therapies.

Release of microparticles into the blood during extracorporeal circulation must be kept low because of possibly serious acute and chronic adverse effects. Concentration and size distribution of microparticles were measured during simulated treatments (n = 7) on original equipment for 2 standard low-density lipoprotein (LDL) elimination procedures (DALI 750, Fresenius AG, St. Wendel, Germany and Liposorber, Kaneka Corporation, Osaka, Japan) and compared to hemofiltration solutions. For both systems as well as in hemofiltration solutions, the mean particle concentrations in 500 ml portions gathered from the efferent blood line stayed below 10% of pharmacopoeia standards for infusion solutions (United States Pharmacopoeia, European Pharmacopoeia) in all measured size classes. Although particle concentrations were comparable in all systems, the mean total number of particles > or =2 microm released per session was lowest in the DALI (167,000) compared to the Liposorber (465,000) and hemofiltration solutions (2,240,000). This was mainly due to different total processed blood volumes necessary to achieve the required LDL reduction.

Extracorporeal removal of circulating immune complexes: from non-selective to patient-specific.

The classical immune complex-mediated disease, termed serum sickness, developed a short time after the injection of horse anti-tetanus toxin. Antibodies against circulating horse plasma proteins lead to the formation of immune complexes within the blood circulation (CIC). The inflammatory response, including systemic complement activation and vasculitis, seriously affected the function of all organs, including the most susceptible kidney. Meanwhile CIC have been detected in almost every systemic disease, including autoimmune disorders and also cancer and infections. This brief review will focus on the rationale and the equipment for extracorporeal elimination of CIC.

Removal of immunoglobulins by a protein A versus an antihuman immunoglobulin G-based system: evaluation of 602 sessions of extracorporeal immunoadsorption.

Elimination of IgG can be achieved by extracorporeal immunoadsorption (IA) based on specific binding to either staphylococcal protein A (Excorim) or sheep polyclonal antibodies directed against human IgG (Therasorb). In 602 analyzed sessions of IA, elimination of IgG was 60% through 80% depending on the treated plasma volume, with no significant difference between the mentioned systems. However, the decrease of IgM and IgA was approximately 50% in the anti-IgG compared to 20-40% in the protein A system. Plasma albumin concentration decreased by 20% in the anti-IgG system compared to 15% in the protein A system, and hemoglobin values increased by 2% in the anti-IgG system and decreased by 6% in the protein A system. In conclusion, a clinical relevance for these findings cannot be ruled out, and the individual choice might depend on the clinical situation and laboratory findings.

Therapeutic apheresis in myasthenia gravis patients: a six year follow-up.

Six years ago 4 patients suffering from myasthenia gravis (MG) types C and E according to Compston with failed drug therapy were initially treated 3 times (1 patient, a total of 11 times) by protein A immunoadsorption (Immunosorba, Excorim AB, Lund, Sweden). No further immunoadsorption treatments have been carried out. In addition, 3 patients were given a thymectomy. The present status of the patients was checked. We could see a beneficial effect in all MG patients. The patients are fit for work; each has an improved Besinger index. The patients were used as their own controls. A higher anti-AChRAb level 6 years after protein A immunoadsorption than at the beginning was seen in all patients, combined with less serious MG. In addition, their immunomodulation could be induced as seen in lymphocyte and inflammatory protein changes during the first 36 days after beginning immunoadsorption treatment. A larger population has to be investigated to verify these results.

On-line hemodiafiltration with pre- and postdilution: impact on the acid-base status.

With on-line formation of the substitution fluid, high substitution rates in predilution (PRD) and postdilution (POD) can be obtained (Fresenius 4008 On-Line HDF; Gambro AK 100 Ultra). The substitution fluid is branched off from the dialysate produced by the dialysate delivery system of the HDF machine. Under these conditions it is desirable to consider the effect of the different treatment modes on the acid-base status. Using Fresenius 4008 On-Line HDF machines, ESRD-patients were treated alternately with high-flux hemodialysis (HD), postdilution HDF (POD-HDF) and predilution HDF (PRD-HDF), while all other treatment parameters were kept constant, in particular the bicarbonate dialysate concentration. Plasma-HCO3, -pH and -pCO2 were measured and compared with the results of a multicompartment bicarbonate model developed by Thews. Also plasma-pO2 and K+ were measured. The results showed no significant differences between HD, POD- and PRD-HDF. Acidosis was corrected effectively and no excessive compensation of the acid-base disturbance was observed.

Immunoadsorption--a new therapeutic possibility for multiple sclerosis?

A 46 year old woman suffers from chronic progressive multiple sclerosis. She was diagnosed in 1993. Because of many complications seen in conservative treatment, plasma exchange was started. The expanded disability status scale by Kurtzke could be improved but the interval between the treatments became shorter and shorter. It was therefore decided to commence protein A immunoadsorption treatment. With this treatment the patient shows good and stable improvement in neurological and functional status with an acceptable treatment frequency of once every 3 weeks.

On-line hemodiafiltration with pre- and postdilution: a comparison of efficacy.

Since the introduction of on-line substituate preparation, high substituate rates (Qs) in pre- and postdilution for hemodiafiltration (HDF) procedures can be realized. During postdilution HDF (POD-HDF) and additional convective removal is possible, but in vivo Qs is limited to approx. 1/3Qb (bloodflow). With predilution HDF (PRD-HDF) higher Qs and therefore high convective transport rates by ultrafiltration can be reached. On the other hand the blood concentration is diminished by predilution. Further decrease of the diffusive transport is caused by reduced dialysate flow Qd due to separation of the substituate from the dialysate (Fresenius 4008 On-Line HDF, Gambro AK100 Ultra). The theoretical description of the combined diffusive-convective transport is limited to 1-dimensional models and small UF-rates. Therefore for practical and theoretical purposes the assessment of the efficacy of on-line PRD-HDF and POD-HDF in different molecular weight ranges is desirable. By means of in vitro experiments the effective clearances Keff of hemodialysis (HD, dialyzer: Fresenius F60) for urea, creatinine, vitamin B12 and inulin were compared with measured and theoretical Keff of POD- and PRD-HDF. The theoretical expectation is confirmed that Keff for small molecular weight substances decreases slightly with PRD-HDF and increases for larger molecules. In the case of POD-HDF Keff for small molecular weight substances increases slightly and strongly for larger molecules. In vivo experiments were performed to measure the real substance removal from patient's blood and to figure out the impact of dialysate flow (collection of the used dialysate during the 1. treatment hour and concentration measurements for urea, creatinine, phosphate, beta 2-MG). The results show that the subtraction of Qs from Qd reduces Keff for urea, creatinine and phosphate but not for beta 2-MG. PRD-HDF with Qd = 500 ml/min is significantly less effective for small molecules than HD. There is no significant difference of Keff for urea, creatinine, phosphate during HD and PRD-HDF with Qd = 800 ml/min, but a significant increase of 10-15% for POD-HDF. Keff for beta 2-MG increases by 75% for PRD-HDF and 95% for POD-HDF compared with HD (Qd = 500 ml/min).

[15N-tracer kinetic studies on the utilization of urea in protein metabolism of infants]. / 15N-tracerkinetische Studien zur Utilisation des Harnstoffs im Eiweissstoffwechsel des Säuglings.

The virtual importance of the urea circuit is not clear. After a 3 to 21 day application of 100 mg [15N]-urea/l in 15 infants a [15N]-excess value of 0.06 in serum protein could be proven. Taking as a basis a protein content of 11.4% of the body mass and a regular distribution of the [15N] within the body one can calculate a retention of the urea nitrogen in the protein pool of 40.4% of the intake. Taking in account an amount of 11.4% urea nitrogen from the total nitrogen in mother's milk then the amount of urea nitrogen from the net protein accumulation comes to 6.5 (3.1-11.8)%.

15N tracer investigations of the physiological availability of urea nitrogen in mother's milk.

The physiological availability of urea in mother's milk was investigated in tracer studies using [15N]2 urea and involving 22 infants. The incorporation of 15N into the body protein was established in 16 subjects by emission spectrophotometrical determination of the 15N excess in the serum protein. Between 2% and 3.6% of the serum protein is synthesized from the urea nitrogen in mother's milk. In further studies on the 15N balance in 6 infants, renal excretion of 15N after oral multiple and single impulse labelling with [15N]2 urea constituted 60% of the dose administered. Three-tenths-2.5% was excreted in the feces. The retention of 15N in the protein pool varied between 16.7 and 61.4%.

Urea utilization by the intestinal flora, of infants fed mother's milk and a formula diet, as measured with the 15N-tracer technique.

15N-Incorporation by intestinal bacteria was measured under different feeding conditions in 16 infants after a single oral loading of 165 mg [15N2]urea X kg-1 body weight as a tracer. In five subjects on a mother's milk diet, the 15N-excess in the isolated intestinal bacteria was 1.08 (0.17-1.85) atom-%. The mean 15N-excess in the intestinal flora of five formula-fed subjects did not differ significantly from these values [0.63 (0.17-1.05) atom-%]. A trend to a higher incorporation of 15N from labeled urea by the intestinal flora was seen in four infants, who were adapted to an increased nutritional urea supply on a special formula, containing 14 g of milk protein, 80 g lactose, 36 g fat, and 0.35 g urea X L-1. The same observation was made in two infants with chronic renal failure. The incorporation of urea nitrogen by the putrefactive intestinal flora of infants on a formula diet as well as by the bifidobacterial flora of those on mother's milk feeding indicates the utilization of ureas as a source of bacterial protein and nucleic acid synthesis. The adaptive usage of urea for the bacterial metabolism can be considered as a sign of supportive detoxification by the intestinal flora.