Biomedical subjects

Markus Ketteler

Publications and source records attributed to Markus Ketteler.

39 records · Page 3Linked to original sources

PubMed2002

Novel insights into uremic vascular calcification: role of matrix Gla protein and alpha-2-Heremans Schmid glycoprotein/fetuin.

Cardiovascular mortality is markedly increased in the dialysis population when compared to non-uremic subjects. Vascular and valvular calcifications are most frequently found in dialysis patients at risk and are independent predictors of cardiovascular death in this population. Traditionally, the presence of hyperphosphatemia and an increased calcium x phosphate product was considered a major pathomechanistic condition leading to excessive vascular and soft-tissue calcifications in uremic subjects. Recent studies in knockout mice, however, revealed that deficiencies in calcium-regulatory proteins may also directly contribute to the development of extraosseus calcifications. alpha(2)-Heremans Schmid glycoprotein and matrix Gla protein are important inhibitors of calcification in vivo and there is novel evidence available that a deficiency in such proteins is involved in the pathogenesis of cardiovascular calcifications in dialysis patients.

Animals↗

PubMedDate not supplied

Biocompatibility of peritoneal dialysis fluids: long-term exposure of nonuremic rats.

OBJECTIVES: Long-term peritoneal dialysis (PD) leads to structural and functional changes in the peritoneum. The aim of the present study was to investigate the long-term effects of PD fluid components, glucose and glucose degradation products (GDP), and lactate-buffered solution on morphology and transport characteristics in a nonuremic rat model. METHODS: Rats were subjected to two daily intraperitoneal injections (20 mL/day) during 12 weeks of one of the following: commercial PD fluid (Gambrosol, 4%; Gambro AB, Lund, Sweden), commercial PD fluid with low GDP levels (Gambrosol trio, 4%; Gambro AB), sterile-filtered PD fluid (4%) without GDP, or a glucose-free lactate-buffered PD fluid. Punctured and untreated controls were used. Following exposure, the rats underwent a single 4-hour PD dwell (30 mL, 4% glucose) to determine peritoneal function. Additionally, submesothelial tissue thickness, percentage of high mesothelial cells (perpendicular diameter > 2 microm), vascular density, vascular endothelial growth factor (VEGF), and transforming growth factor (TGF) beta1 mRNA expression were determined. Submesothelial collagen concentration was estimated by van Gieson staining. RESULTS: Submesothelial tissue thickness and vascular density, mediated by VEGF and TGFbeta production, in the diaphragmatic peritoneum increased significantly in rats exposed to any PD fluid. Gambrosol induced a marked increased fibrosis of the hepatic peritoneum. A significant increase in high mesothelial cells was observed in the Gambrosol group only. Net ultrafiltration was reduced in the Gambrosol and in the glucose-free groups compared to untreated controls. Small solute transport was unchanged, but all groups exposed to fluids showed significantly increased lymph flow. CONCLUSIONS: Our results show that long-term exposure to different components of PD fluids leads to mesothelial cell damage, submesothelial fibrosis, and neoangiogenesis. Mesothelial cell damage could be connected to the presence of GDP; the other changes were similar for all fluids. Peritoneal transport characteristics did not change in any consistent way and the neoangiogenesis observed was not paralleled by increased solute transport.

Animals↗

PubMedDate not supplied

The fate of bone after renal transplantation.

Post-transplantation bone disease is a multifactorial, complex condition. It derives in a significant part from pre-existing renal osteodystrophy, but it is aggravated by factors emerging after renal transplantation. Among the latter factors, the key pathophysiological contributor to bone disease is immunosuppressive agent application (especially glucocorticoids (GC)). Post-transplantation bone disease is detectable even years after renal transplantation in the vast majority of patients, and potentially it never resolves completely. Due to post-transplantation bone disease, a rapid reduction of bone mineral density (BMD) develops that can exceed 10% in the first 12 months. Subsequently, the bone loss slows down or even a secondary increase occurs. Post-transplantation bone disease results in a significantly elevated fracture risk, which largely contributes to the increased morbidity in transplant patients. Currently, vitamin D metabolites and bisphosphonates are the most extensively tested therapeutic agents against this accelerated bone loss. Both substances have proven effective. However, it is yet unproven that they reduce the fracture risk. In patients with adynamic bone disease, bisphosphonate usage cannot be recommended, since this group of drugs could oversuppress bone metabolism.

Bone Density↗