Articles by Bernhard N. Bohnert in JoVE
Induction of Nephrotic Syndrome in Mice by Retrobulbar Injection of Doxorubicin and Prevention of Volume Retention by Sustained Release Aprotinin Bernhard N. Bohnert1,2,3, Ferruh Artunc1,2,3 1Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University Hospital Tübingen, 2Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich, University Tübingen, 3German Center for Diabetes Research (DZD), University Tübingen Here, we describe the induction of experimental nephrotic syndrome in 129S1/SvImJ mice by rapid retrobulbar injection of doxorubicin. We also treat nephrotic mice with sustained release pellets containing aprotinin to inhibit urinary serine protease activity and prevent sodium retention.
Other articles by Bernhard N. Bohnert on PubMed
Aprotinin Prevents Proteolytic Epithelial Sodium Channel (ENaC) Activation and Volume Retention in Nephrotic Syndrome Kidney International. | Pubmed ID: 29042083 Volume retention in nephrotic syndrome has been linked to activation of the epithelial sodium channel (ENaC) by proteolysis of its γ-subunit following urinary excretion of serine proteases such as plasmin. Here we tested whether pharmacological inhibition of urinary serine protease activity might protect from ENaC activation and volume retention in nephrotic syndrome. Urine from both nephrotic mice (induced by doxorubicin injection) and nephrotic patients exhibited high aprotinin-sensitive serine protease activity. Treatment of nephrotic mice with the serine protease inhibitor aprotinin by means of subcutaneous sustained-release pellets normalized urinary serine protease activity and prevented sodium retention, as did treatment with the ENaC inhibitor amiloride. In the kidney cortex from nephrotic mice, immunofluorescence revealed increased apical γ-ENaC staining, normalized by aprotinin treatment. In Xenopus laevis oocytes heterologously expressing murine ENaC, aprotinin had no direct inhibitory effect on channel activity but prevented proteolytic channel activation. Thus, our study shows that volume retention in experimental nephrotic syndrome is related to proteolytic ENaC activation by proteasuria and can be prevented by treatment with aprotinin. Hence, inhibition of urinary serine protease activity might become a therapeutic approach to treat patients with nephrotic-range proteinuria.
Impact of Phosphorus Restriction and Vitamin D-substitution on Secondary Hyperparathyroidism in a Proteinuric Mouse Model Kidney & Blood Pressure Research. 2015 | Pubmed ID: 25871296 Since the discovery of FGF23, secondary hyperparathyroidism (SHPT) in renal disease has been considered to result primarily from phosphorus retention rather than vitamin D deficiency. However, the impact of phosphorus restriction and vitamin D supplementation on SHPT is still ill defined.