G. Asmus

Bone Fracture History and Prospective Bone Fracture Risk of Hemodialysis Patients are Related to Apolipoprotein E Genotype

Abstract. This investigation of 219 hemodialysis patients relates the history and prospective risk of bone fractures to apolipoprotein E (apoE) genotype. A greater percentage of the 41 patients with the E3/4 and E4/4 genotypes than of the 38 patients with the E2/3 and E2/2 genotypes had a history of bone fractures at the time of recruitment (44% versus 16%, P < 0.005). During the 4 years following recruitment, more of the patients with apoE genotypes E3/4 and E4/4 than with apoE genotypes E2/3 and E2/2 suffered bone fractures, but this difference was not statistically significant (17.1 versus 5.3%, P < 0.1). ApoE genotype appears to be an important genetic risk factor for bone fracture, possibly due to its previously reported influence on vitamin K concentrations in blood.

Significant Reduction of Factor D and Immunosuppressive Complement Fragment Ba by Hemofiltration

Because of their effect on the immune response, especially in patients with chronic or acute renal failure, factor D (FD) and the immunosuppressive complement fragment Ba are substances which may be important for the immunological status. Since they cannot be eliminated by conventional Cuprophan hemodialysis because of their high molecular weight (24,000 and 33,000 D, respectively), the effect of hemofiltration (HF) on the plasma concentration of both components was tested. It was shown that plasma levels of FD can be lowered by 43.5% during an HF treatment and the plasma concentration of Ba by 30.6%. Moreover, the two substances could be detected in the hemofiltrate. Up to 75 mg FD and up to 37 mg Ba could be eliminated per treatment, depending on the plasma concentrations and the filtration volume. A convective method such as chronic HF is therefore clearly superior to diffusive methods of blood purification when substances with such a high molecular weight have to be eliminated. It has still to be established whether the elimination of FD and Ba by chronic intermittent HF results in a sustained improvement in the immunological status of patients treated in this way.

HTLV-III antibodies in hemodialysis patients — A consequence of blood transfusions?

SummaryAn investigation for HTLV-III antibodies in chronic hemodialysis patients revealed in four out of 276 patients a positive result using the ELISA and western blot techniques. All HTLV-III positive patients had received blood transfusions. As it has been shown that a needle stick could transmit the HTLV-III, it is suggested that hemodialysis patients who have received frequent blood transfusions should be screened.

Renal osteodystrophy in asymptomatic hemodialysis patients: evidence of a sex-dependent distribution and predictive value of serum aluminum measurements.

Bone histologies and serum concentrations of calcium, phosphate, alkaline phosphatase, iPTH, 25 OHD, 1,25(OH)2D3, and aluminum were obtained from 113 chronically hemodialyzed patients free of symptoms and signs of renal osteodystrophy. All patients had a pathologic bone histology; in 69.0%, a mixed form with predominant osteitis fibrosa and concomitant osteoidosis. In 30.1%, we found pure hyperosteoidosis, nearly half of these cases showing osseous aluminum deposits. Hyperosteoidosis was much more frequent in women (35.7%) than in men (20.9%), although the prescribed intake of aluminum-containing phosphate binders was the same. It is possible that female hemodialysis patients were more prone to aluminum accumulation or that they had a better compliance in taking the aluminum hydroxide. Serum parameters alone were not very helpful in predicting the underlying bone disease. Mean iPTH concentrations tended to be lower in the patients with hyperosteoidosis than in those with the mixed lesion, but there was wide variation. Serum aluminum was only predictive for aluminum deposits in the bone when concentrations exceeded 100 micrograms/L.

Clinical aspects of hemofiltration.

We report on clinical experiences obtained in 7 uremic patients treated since January 1976 3 times weekly by chronic hemofiltration. The observations which we collected in more than 300 treatments suggest that hemofiltration might be superior to conventional hemodialysis. The main advantages of this treatment are characterized by its better control of hypertension, hyperhydration, and possibly of uremic bone disease. Furthermore, the applied acrylonitrile membrane allows the removal of substances with a molecular weight up to 60,000, similar to the glomerular basement membrane. Additionally, we report on methodological problems, on the compatibility of hemofiltration, and finally on its efficiency for removal of different uremic solutes.

The Hemofiltration System: Variations of the Negative Pressure

The physical conditions of the hemofiltration process are briefly discussed to describe the applied system that is characterized by a negative pressure pump which is directly attached behing the filter. A schema is presented that shows the characteristics of a fully automatic hemofiltration apparatus that is presently in development.