UHPLC-MS/MS method for iohexol determination in human EDTA and lithium-heparin plasma, human urine and in goat- and pig EDTA plasma

Semaglutide in patients with overweight or obesity and chronic kidney disease without diabetes: a randomized double-blind placebo-controlled clinical trial

Semaglutide reduces albuminuria and the risk of kidney disease progression in patients with type 2 diabetes and chronic kidney disease (CKD). We conducted a randomized placebo-controlled double-blind clinical trial in adults with CKD (estimated glomerular filtration rate (eGFR) ≥25 ml min-1 1.73 m-2 and urine albumin-to-creatinine ratio (UACR) ≥30 and <3,500 mg g-1) and body mass index ≥27 kg m-2. Participants were randomized to semaglutide 2.4 mg per week or placebo. The primary endpoint was percentage change from baseline in UACR at week 24. Safety was monitored throughout. Overall, 125 participants were screened, of whom 101 were randomized to semaglutide (n = 51) or placebo (n = 50). Mean age was 55.8 (s.d. 12) years; 40 participants (39.6%) were female; median UACR was 251 mg g-1 (interquartile range 100, 584); mean eGFR was 65.0 (s.d. 25) ml min-1 1.73 m-2; and mean body mass index was 36.2 (s.d. 5.6) kg m-2. Chronic glomerulonephritis (n = 25) and hypertensive CKD (n = 27) were the most common CKD etiologies. Treatment for 24 weeks with semaglutide compared to placebo reduced UACR by -52.1% (95% confidence interval -65.5, -33.4; P < 0.0001). Gastrointestinal adverse events were more often reported with semaglutide (n = 30) than with placebo (n = 15). Semaglutide treatment for 24 weeks resulted in a clinically meaningful reduction in albuminuria in patients with overweight/obesity and non-diabetic CKD. ClinicalTrials.gov registration: NCT04889183 .

A Uremic Pig Model for Peritoneal Dialysis

With increasing interest in home dialysis, there is a need for a translational uremic large animal model to evaluate technical innovations in peritoneal dialysis (PD). To this end, we developed a porcine model with kidney failure. Stable chronic kidney injury was induced by bilateral subtotal renal artery embolization. Before applying PD, temporary aggravation of uremia was induced by administration of gentamicin (10 mg/kg i.v. twice daily for 7 days), to obtain uremic solute levels within the range of those of dialysis patients. Peritoneal transport was assessed using a standard peritoneal permeability assessment (SPA). After embolization, urea and creatinine concentrations transiently increased from 1.6 ± 0.3 to 7.5 ± 1.2 mM and from 103 ± 14 to 338 ± 67 µM, respectively, followed by stabilization within 1–2 weeks to 2.5 ± 1.1 mM and 174 ± 28 µM, respectively. Gentamicin induced temporary acute-on-chronic kidney injury with peak urea and creatinine concentrations of 16.7 ± 5.3 mM and 932 ± 470 µM respectively. PD was successfully applied, although frequently complicated by peritonitis. SPA showed a low transport status (D/P creatinine at 4 h of 0.41 (0.36–0.53)) with a mass transfer area coefficient of 9.6 ± 3.1, 4.6 ± 2.6, 3.4 ± 2.3 mL/min for urea, creatinine, and phosphate respectively. In conclusion, this porcine model with on-demand aggravation of uremia is suitable for PD albeit with peritoneal transport characterized by a low transport status.

A convenient online desalination tube coupled with mass spectrometry for the direct detection of iodinated contrast media in untreated human spent hemodialysates

Background

Mass spectrometry (MS) analysis using direct infusion of biological fluids is often problematic due to high salts/buffers. Iodinated contrast media (ICM) are frequently used for diagnostic imaging purposes, sometimes inducing acute kidney injury (AKI) in patients with reduced kidney function. Therefore, detection of ICM in spent hemodialysates is important for AKI patients who require urgent continuous hemodiafiltration (CHDF) because it allows noninvasive assessment of the patient’s treatment. In this study, we used a novel desalination tube before MS to inject the sample directly and detect ICM.

Methods

Firstly, spent hemodialysates of one patient were injected directly into the electrospray ionization (ESI) source equipped with a quadrupole time-of-flight mass spectrometer (Q-TOF MS) coupled to an online desalination tube for the detection of ICM and other metabolites. Thereafter, spent hemodialysates of two patients were injected directly into the ESI source equipped with a triple quadrupole mass spectrometer (TQ-MS) connected to that online desalination tube to confirm the detection of ICM.

Results

We detected iohexol (an ICM) from untreated spent hemodialysates of the patient-administered iohexol for computed tomography using Q-TOF MS. Using MRM profile analysis, we have confirmed the detection of ICM in the untreated spent hemodialysates of the patients administered for coronary angiography before starting CHDF. Using the desalination tube, we observed approximately 178 times higher signal intensity and 8 times improved signal-to-noise ratio for ioversol (an ICM) compared to data obtained without the desalination tube. This system was capable of tracking the changes of ioversol in spent hemodialysates of AKI patients by measuring spent hemodialysates.

Conclusion

The online desalination tube coupled with MS showed the capability of detecting iohexol and ioversol in spent hemodialysates without additional sample preparation or chromatographic separation. This approach also demonstrated the capacity to monitor the ioversol changes in patients’ spent hemodialysates.

Simplified Iohexol-Based Method for Measurement of Glomerular Filtration Rate in Goats and Pigs

Simple Summary

To improve the treatment of patients with kidney disease, new therapies are being developed. Before being used on humans, such therapies need to be tested on animals with kidney disease because reduced kidney function may influence the safety and efficacy of the treatment. Using large animals for this purpose is important because they tolerate frequent blood sampling, which allows for repeated monitoring. Goats seem particularly suitable for the evaluation of novel hemodialysis therapies since they are docile, have easily accessible neck veins to obtain blood access and body weights comparable with humans. Currently, no simple method is available to measure kidney function in goats (with or without impaired kidney function). Therefore, we developed a simple method to measure the kidney function in goats and pigs, which is based on a single injection of iohexol and requires three blood samples. Subsequently, kidney function can be calculated using a formula derived from pharmacokinetic modelling. The measurement of kidney function using our simplified method is relatively easy to perform, reduces total blood sampling and eliminates the need for an indwelling bladder catheter as compared to existing methods that require continuous infusion of a substance and timed urine collection.

Abstract

The preclinical evaluation of novel therapies for chronic kidney disease requires a simple method for the assessment of kidney function in a uremic large animal model. An intravenous bolus of iohexol was administered to goats (13 measurements in n = 3 goats) and pigs (23 measurements in n = 5 pigs) before and after induction of kidney failure, followed by frequent blood sampling up to 1440 min. Plasma clearance (CL) was estimated by a nonlinear mixed-effects model (CL_NLME) and by a one-compartmental pharmacokinetic disposition model using iohexol plasma concentrations during the terminal elimination phase (CL_1CMT). A simple method (CL_SM) for the calculation of plasma clearance was developed based on the most appropriate relationship between CL_NLME and CL_1CMT. CL_SM and CL_NLME showed good agreement (CL_NLME/CL_SM ratio: 1.00 ± 0.07; bias: 0.03 ± 1.64 mL/min; precision CL_SM and CL_NLME: 80.9% and 80.7%, respectively; the percentage of CL_SM estimates falling within ±30% (P30) or ±10% (P10) of CL_NLME: 53% and 12%, respectively). For mGFR_NLME vs. mGFR_SM, bias was −0.25 ± 2.24 and precision was 49.2% and 53.6%, respectively, P30 and P10 for mGFR based on CL_SM were 71% and 24%, respectively. A simple method for measurement of GFR in healthy and uremic goats and pigs was successfully developed, which eliminates the need for continuous infusion of an exogenous marker, urine collection and frequent blood sampling.