Administration of Recombinant Soluble Urokinase Receptor Per Se Is Not Sufficient to Induce Podocyte Alterations and Proteinuria in Mice

Circulating levels of soluble forms of urokinase-type plasminogen activator receptor (suPAR) are generally elevated in sera from children and adults with FSGS compared with levels in healthy persons or those with other types of kidney disease. In mice lacking the gene encoding uPAR, forced increases in suPAR concentration result in FSGS-like glomerular lesions and proteinuria. However, whether overexpression of suPAR, per se, contributes to the pathogenesis of FSGS in humans remains controversial. We conducted an independent set of animal experiments in which two different and well characterized forms of recombinant suPAR produced by eukaryotic cells were administered over the short or long term to wild-type (WT) mice. In accordance with the previous study, the delivered suPARs are deposited in the glomeruli. However, such deposition of either form of suPAR in the kidney did not result in increased glomerular proteinuria or altered podocyte architecture. Our findings suggest that glomerular deposits of suPAR caused by elevated plasma levels are not sufficient to engender albuminuria.     

68Ga-labeling and in vivo evaluation of a uPAR binding DOTA- and NODAGA-conjugated peptide for PET imaging of invasive cancers

IntroductionThe urokinase-type plasminogen activator receptor (uPAR) is a well-established biomarker for tumor aggressiveness and metastatic potential. DOTA-AE105 and DOTA-AE105-NH₂ labeled with ⁶⁴Cu have previously been demonstrated to be able to noninvasively monitor uPAR expression using positron emission tomography (PET) in human cancer xenograft mice models. Here we introduce ⁶⁸Ga-DOTA-AE105-NH₂ and ⁶⁸Ga-NODAGA-AE105-NH₂ and evaluate their imaging properties using small-animal PET.MethodsSynthesis of DOTA-AE105-NH₂ and NODAGA-AE105-NH₂ was based on solid-phase peptide synthesis protocols using the Fmoc strategy. ⁶⁸GaCl₃ was eluted from a ⁶⁸Ge/⁶⁸Ga generator. The eluate was either concentrated on a cation-exchange column or fractionated and used directly for labeling. For in vitro characterization of both tracers, partition coefficient, buffer and plasma stability, uPAR binding affinity and cell uptake were determined. To characterize the in vivo properties, dynamic microPET imaging was carried out in nude mice bearing human glioma U87MG tumor xenograft.ResultsIn vitro experiments revealed uPAR binding affinities in the lower nM range for both conjugated peptides and identical to AE105. Labeling of DOTA-AE105-NH₂ and NODAGA-AE105-NH₂ with ⁶⁸Ga was done at 95°C and room temperature, respectively. The highest radiochemical yield and purity were obtained using fractionated elution, whereas a negative effect of acetone on labeling efficiency for NODAGA-AE105-NH₂ was observed. Good stability in phosphate-buffered saline and mouse plasma was observed. High cell uptake was found for both tracers in U87MG tumor cells. Dynamic microPET imaging demonstrated good tumor-to-background ratio for both tracers. Tumor uptake was 2.1% ID/g and 1.3% ID/g 30 min postinjection and 2.0% ID/g and 1.1% ID/g 60 min postinjection for ⁶⁸Ga-NODAGA-AE105-NH₂ and ⁶⁸Ga-DOTA-AE105-NH₂, respectively. A significantly higher tumor-to-muscle ratio (P<.05) was found for ⁶⁸Ga-NODAGA-AE105-NH₂ 60 min postinjection.ConclusionsThe use of ⁶⁸Ga-DOTA-AE105-NH₂ and ⁶⁸Ga-NODAGA-AE105-NH₂ as the first gallium-68 labeled uPAR radiotracers for noninvasive PET imaging is reported, which combine versatility with good imaging properties. These new tracers thus constitute an interesting alternative to the ⁶⁴Cu-labeled version (⁶⁴Cu-DOTA-AE105 and 64Cu-DOTA-AE105-NH₂) for detecting uPAR expression in tumor tissue. In our hands, the fractionated elution approach was superior for labeling of peptides, and ⁶⁸Ga-NODAGA-AE105-NH₂ is the favored tracer as it provides the highest tumor-to-background ratio.     

Contact sensitivity to chlorhexidine?

In a joint study, 2061 patterns (1346 women and 715 men) were patch tested with chlorhexidine gluconate 1% in Water. included in a standard lest series. 4H patients (2.3%) showed a positive reaction. These were relatively marc common in men (3.2%) than in women (1.9%), Positive reactions were most common in patients with leg eczema (6.8%) or leg ulcer (10.9%). Of the 48 patients who were patch test positive. 14 (2 with leg ulcer) were retested with chlorhexidine gluconate 0.01 and 1%. Only one with a leg ulcer was positive. These findings indicate that false positive reactions, known as "the incited skin syndrome", may arise from testing eczema patients in a standard series The sensitizing potential of chlorhexidine may be very low, but the potential in patients with an eczema or ulcer of the leg has to be further evaluated.     

The right to refuse diagnostics and treatment planning by artificial intelligence

Medicine, Health Care and Philosophy - In an analysis of artificially intelligent systems for medical diagnostics and treatment planning we argue that patients should be able to exercise a right to...