Research Viviane O M Van Hoof

Abstract

Passage of the blood-brain barrier by free bilirubin (FB) causes neurotoxicity in neonates (deafness and kernicterus). Current methods to measure FB are complex and difficult to apply. A simple and direct method for FB measurement was developed in our Clinical Chemistry lab. Goal is the broad application of the measurement of FB as a point-of-care test for screening and follow-up of neonatal icterus.

Researcher(s)

• Promoter: Van Hoof Viviane O M

Research team(s)

Project type(s)

• Research Project

Abstract

Patiënts with chronic renal insufficiency accumulate many, more or less toxic, substances in their blood, the direct influence of which on bone metabolism is not always clear. In this project, a primary human cell culture model is used to study the influence of uremic toxins, strontium en lanthanum on osteoblast function and mineralization. Urea was long regarded as a relatively harmless substance, but this has been doubted recently. It has been shown that urea, in concentrations similar to those encountered in uremic patients, acts directly on human osteoblasts, thereby enhancing osteoblast proliferation and changing the amount of matrix proteins released into the culture medium. The present proejct aims to study the possible mechanism(s) whereby urea and other uremic toxins (monomethylarginine, assymetric dimethylarginine and methylguanidine) influence osteoblast function. As Moeslinger found that urea enhances macophage proliferation in mice by inhibition of NO synthesis, the present project will study whether the urea induced enhanced osteoblast proliferation is NO related. Whether uremic toxins have an influence on programmed cell death will aslo be studied. Trace elements too can accumulate in renal insufficiency. Recent studies have shown that strontium influences bone metabolism : dialysis patients with osteomalacia had elevated concentrations of strontium in their bones and osteomalcia could be induced through the daily administration of strontium during 12 weeks to renal insufficient rats. Using the aforementioned human cell culture model, the uptake of strontium by the osteoblast and the possible influence of strontium on osteoblast function will be studied. To control serum phosphate, patients with renal insufficiency have to take daily doses of calcium carbonate and/or aluminumhydroxide. The use of these phosphate binders is complicated by serious side effects, and less toxic alternatives are searched for. A potential candidate is lanthanum carbonate. Preliminary results show a possible deleterious effect of this trace element on bone in a renal insufficient rat model. Like strontium, the uptake of lanthanum and its possible effect on osteoblast function and mineralization will be studied by means of the aforementioned model.

Researcher(s)

• Promoter: Van Hoof Viviane O M
• Fellow: Oste Line

Research team(s)

Project type(s)

• Research Project

Abstract

Patiënts with chronic renal insufficiency accumulate many, more or less toxic, substances in their blood, the direct influence of which on bone metabolism is not always clear. In this project, a primary human cell culture model is used to study the influence of uremic toxins, strontium en lanthanum on osteoblast function and mineralization. Urea was long regarded as a relatively harmless substance, but this has been doubted recently. It has been shown that urea, in concentrations similar to those encountered in uremic patients, acts directly on human osteoblasts, thereby enhancing osteoblast proliferation and changing the amount of matrix proteins released into the culture medium. The present proejct aims to study the possible mechanism(s) whereby urea and other uremic toxins (monomethylarginine, assymetric dimethylarginine and methylguanidine) influence osteoblast function. As Moeslinger found that urea enhances macophage proliferation in mice by inhibition of NO synthesis, the present project will study whether the urea induced enhanced osteoblast proliferation is NO related. Whether uremic toxins have an influence on programmed cell death will aslo be studied. Trace elements too can accumulate in renal insufficiency. Recent studies have shown that strontium influences bone metabolism : dialysis patients with osteomalacia had elevated concentrations of strontium in their bones and osteomalcia could be induced through the daily administration of strontium during 12 weeks to renal insufficient rats. Using the aforementioned human cell culture model, the uptake of strontium by the osteoblast and the possible influence of strontium on osteoblast function will be studied. To control serum phosphate, patients with renal insufficiency have to take daily doses of calcium carbonate and/or aluminumhydroxide. The use of these phosphate binders is complicated by serious side effects, and less toxic alternatives are searched for. A potential candidate is lanthanum carbonate. Preliminary results show a possible deleterious effect of this trace element on bone in a renal insufficient rat model. Like strontium, the uptake of lanthanum and its possible effect on osteoblast function and mineralization will be studied by means of the aforementioned model.

Researcher(s)

• Promoter: Van Hoof Viviane O M
• Fellow: Oste Line

Research team(s)

Project type(s)

• Research Project

Abstract

In the clinical part of this study the following markers of bone metabolismare studied : 1) bone specific alkaline phosphatase to evaluate bone formation and 2) pyridinolin cross-links to evaluate bone breakdown. Three populations in whom the evaluation of bone metabolism is of clinical importance are included : malignant tumors (bone metastasis), chronic renal failure (secondary hyperparathyroidism, adynamic bone disease) and multipel myeloma (enhanced bone breakdown, inhibited bone formation). The methodology to determine pyridinolin cross-links in serum will be further evaluated and specific reference values will be calculated for a healthy population and for the chronic renal disease group (decreased renal clearance of the cross-links). The experimental part of this study will examine the production of pyridinolin cross-links by human bone cells in culture.

Researcher(s)

• Promoter: Van Hoof Viviane O M
• Fellow: Van Hoof Viviane O M

Research team(s)

Project type(s)

• Research Project

Abstract

Blood lipid disturbances and cytomegalovirus infections will be prospectively monitored in renal transplant recipients. The renal lesions induced by cyclosporine will be evaluated in a renal biopsy and related to the metabolic and clinical events.

Researcher(s)

• Promoter: Verpooten Gert
• Co-promoter: Nouwen Etienne
• Co-promoter: Van Hoof Viviane O M

Research team(s)

Project type(s)

• Research Project

Abstract

In the clinical part of this study the following markers of bone metabolismare studied : 1) bone specific alkaline phosphatase to evaluate bone formation and 2) pyridinolin cross-links to evaluate bone breakdown. Three populations in whom the evaluation of bone metabolism is of clinical importance are included : malignant tumors (bone metastasis), chronic renal failure (secondary hyperparathyroidism, adynamic bone disease) and multipel myeloma (enhanced bone breakdown, inhibited bone formation). The methodology to determine pyridinolin cross-links in serum will be further evaluated and specific reference values will be calculated for a healthy population and for the chronic renal disease group (decreased renal clearance of the cross-links). The experimental part of this study will examine the production of pyridinolin cross-links by human bone cells in culture.

Researcher(s)

• Promoter: Van Hoof Viviane O M
• Fellow: Van Hoof Viviane O M

Research team(s)

Project type(s)

• Research Project

Abstract

The predictive value of bone alkaline and acid phosphatase, osteocalcin and hydroxyprolin for the detection of bone disease will be studied in patients with multiple myeloma, osteoporosis and chronic renal failure and in the appropriate control populations. Histomorphometry of bone biopsies will be use as gold standard.

Researcher(s)

• Promoter: Van Hoof Viviane O M
• Co-promoter: Van Marck Eric

Research team(s)

Project type(s)

• Research Project

Abstract

The predictive value of bone alkaline and acid phosphatase, osteocalcin and hydroxyprolin for the detection of bone disease will be studied in patients with multiple myeloma, osteoporosis and chronic renal failure and in the appropriate control populations. Histomorphometry of bone biopsies will be use as gold standard.

Researcher(s)

• Promoter: Van Hoof Viviane O M

Research team(s)

Project type(s)

• Research Project