This 2 year study shows that calcium carbonate use is continuously associated with progressive arterial calcification in haemodialysis patients. In addition, it suggests that it is also associated with decreased trabecular bone density. However, this latter finding requires confirmation by a study specifically devoted to this issue.

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Patients with primary and secondary hyperparathyroidism showed lower levels of the putative stimulatory IGFBP-5 but higher levels of IGFBP-1, -2, -3, and -6, whereas total IGF-I and IGF-II levels were not or only moderately increased. The marked increase in serum levels of IGFBP-4 appeared to be characteristic for chronic renal failure. IGFBP-5 correlated with biochemical markers and histologic indices of bone formation in renal osteodystrophy patients and was not influenced by renal function. Therefore, IGFBP-5 may gain significance as a serological marker for osteopenia and low bone turnover in long-term dialysis patients.

Heparin is used as standard anticoagulant in the extracorporeal circuit of hemodialysis. Widespread use of this drug revealed several potentially adverse effects, such as release of lipoprotein lipase and hepatic lipase from the endothelial surface. Recently it was found that anticoagulatory potency and provocation of adverse effects are linked to different subfractions of heparin. A heparin subfraction of 4000 to 6000 Daltons rather specifically inhibits factor Xa and therefore has a very high antithrombotic potency. Its effects on release of lipases are minor. During a four year period five patients on maintenance hemodialysis were treated with this low molecular weight heparin (LMWH) subfraction. Additionally, another five patients successively received standard heparin, LMWH and again standard heparin. At all circumstances during treatment with LMWH there was a significant (0.001 less than P less than 0.05) reduction both of cholesterol and triglyceride blood concentrations. LMWH is efficient in avoiding clotting in extracorporeal circuit during hemodialysis in doses of 17 to 95 U/kg (initial dose) and 7 to 20 U/kg/hr (continuous dose).

BACKGROUND: Insulin-like growth factor (IGF) system components are important regulators of bone formation. Alterations of individual IGF system components have been described in osteoporosis (OP) patients; however, no study has addressed changes in free IGF-I and in all six IGF binding proteins (IGFBPs). METHODS: A cross-sectional study was performed in 45 OP patients and 100 healthy matched controls. Serum levels of free and total insulin-like growth factor I (IGF-I), IGFBP-1 through -6, intact parathyroid hormone (PTH), 25-OH-vitamin D(3) (25OHD(3)), 1,25-(OH)(2)-vitamin D(3) (1,25-(OH)(2)D(3)), osteocalcin (OSC), bone alkaline phosphatase (B-ALP), and carboxyterminal propeptide of type-I procollagen (PICP) were measured with specific assays. Bone mineral density (BMD) of the lumbar spine was determined by dual-energy X-ray absorptiometry (DEXA). RESULTS: Compared with age- and sex-matched control subjects, OP patients showed a 73% decrease in free IGF-I, a 29% decrease in total IGF-I, a 10% decrease in IGFBP-3, and a 52% decrease in IGFBP-5 levels; they had higher levels of IGFBP-1 (4.1-fold), IGFBP-2 (1.8-fold), IGFBP-4 (1.3-fold), and IGFBP-6 (2.1-fold). Alterations in IGF system components were most evident in 13 OP patients with vertebral fractures in the past 4 years compared to patients without fractures. In OP patients with fractures, the ratio between IGFBP-4 and IGFBP-5 was increased whereas levels of OSC were decreased. CONCLUSIONS: Our data provide strong indirect evidence for a functional connection between circulating IGF system components and bone metabolism and the susceptibility to fractures in OP patients.