Pediatric Donor Glomerulopathy Is a Possible Cause of Abnormal Urinalysis in Adults Receiving Small Pediatric Donor Kidneys

Construction of chrysophanol loaded nanoparticles with N-octyl-O-sulfate chitosan for enhanced nephroprotective effect

Natural occurring anthraquinone like chrysophanol has been studied because of its anti-diabetic, anti-tumor, anti-inflammatory, hepatoprotective and neuroprotective properties. Nonetheless, its poor water solubility and unstable nature are big concerns in achieving efficient delivery and associated pharmacokinetic and pharmacodynamic effects. Herein, this study sought to solve the above-mentioned problem through development of chrysophanol-loaded nanoparticles to enhance the bioavailability of chrysophanol and to evaluate its anti-renal fibrosis effect in rats. After synthesis of a safe N-octyl-O-sulfate chitosan, we used it to prepare chrysophanol-loaded nanoparticles through dialysis technique before we performed and physical characterization. Also, we tested the stability of the nanoparticles for 21 days at 4 °C and room temperature (25 °C) and evaluated their pharmacokinetics and anti-renal fibrosis effect in rat model of chronic kidney disease (CKD). In terms of results, the nano-preparation demonstrated an acceptable narrow size distribution, wherein the encapsulation rate, size, polydispersed index (PDI) and electrokinetic potential at room temperature were respectively 83.41±0.89 %, 364.88±13.62 nm, 0.192±0.015 and 23.78±1.39 mV. During 21 days of storage, we observed that size of particles and electrokinetic potential altered slightly but the difference was statistically insignificant (p > 0.05). Also, in vitro release studies showed that the formulation reached 84.74 % at 24 h. Chrysophanol nanoparticles showed a 2.57-fold increase in bioavailability compared to unformulated chrysophanol. More importantly, chrysophanol nanoparticles demonstrated certain renal internalization properties and anti-renal fibrosis effects, which could ultimately result in reduced blood-urea nitrogen (BUN), kidney-injury molecule-1 (KIM-1) and serum creatinine (SCr) levels in model rats. In conclusion, the prepared chrysophanol-loaded nanoparticles potentially increased bioavailability and enhanced nephroprotective effects of chrysophanol.

Excellent Clinical Long-Term Outcomes of Kidney Transplantation From Small Pediatric Donors (Age ≤ 5 Years) Despite Early Hyperfiltration Injury

Background:

The use of small pediatric donors (age ≤ 5 years and body weight < 20kg) for adult transplant recipients is still regarded controversially in terms of early complications, long-term outcomes, and development of hyperfiltration injury due to body size mismatch.

Objective:

To investigate long-term outcomes of adult renal allograft recipients receiving a kidney from small pediatric donor (SPD) in terms of kidney function and early features of hyperfiltration injury such as histological changes and proteinuria.

Design:

Retrospective, single center study.

Settings:

Transplant center of the University Hospital of Basel, Switzerland.

Patients:

Adult renal allograft recipients receiving a kidney from a small pediatric donor at our center between 2005 and 2017.

Methods:

The outcome of 47 transplants from SPD were compared with 153 kidney transplants from deceased-standard criteria donors (SCD) occurring during the same time period. Incidence of clinical signs of hyperfiltration injury (eg, proteinuria) was investigated. According to our policy, surveillance biopsies were taken at 3 and 6 months post-transplant and were evaluated in terms of signs of hyperfiltration injury.

Results:

At a median follow-up of 2.3 years post-transplant, death-censored graft survival of SPD was comparable to transplants from SCD (94% vs 93%; P = .54). Furthermore, allograft function at last follow-up (estimated glomerular filtration rate–Modification of Diet in Renal Disease) was significantly higher in pediatric transplant (80 vs 55 ml/min/1.73 m2, P = .002). We found histological signs of early hyperfiltration injury in 55% of SPD. There was an equally low proteinuria in both groups during follow-up.

Limitations:

It is a single center and retrospective observational study with small sample size. The outcomes were investigated in a well-selected population of recipients with low body mass index, low immunological risk, and well-controlled hypertension and was not compared with equal selected group of recipients.

Conclusions:

Early histological and clinical signs of hyperfiltration injury in SPD is frequent. Despite the hyperfiltration injury, there is an equal allograft survival and even superior allograft function in SPD compared with SCD during follow-up. This observation supports the concept of high adaptive capacity of pediatric donor kidneys.

Small donors for small recipients - excellent growth and long-term function of single kidney grafts

Small-donor kidneys (≤20 kg donor weight, SDK) are preferably transplanted en bloc in adults. Concerns about thrombotic complications or hyperfiltration hinder their use in children, particularly as single grafts. Low centre experience and donor-to-recipient size are rated critical regarding outcomes. We evaluated SDK transplantation (SDTx) in paediatric recipients at a specialized transplant centre. Between 2008 and 2018, SDTx was performed in 40 children (mean age 5.4 ± 1.4 years, single grafts n = 38, donor weight ≤10 kg: n = 10). Perioperative complications were rare (n = 3), mainly thromboses despite immediate heparinization and resulted in graft loss in one patient. Overall, early and long-term GFR were excellent (76 ± 21 and 100 ± 11 ml/min/1.73 m² , first month and year 5, respectively). Three patients presented with delayed graft function. Graft volume increased significantly (69 ± 38 vs. 111 ± 33 ml within 5 years; P < 0.0001). Patients showed catch-up growth to normal range (SDS for height -2.06 ± 1.6 to -1.60 ± 1.5). Stratification by recipient age and donor weight revealed superior results in young recipients (≤3 years) and ≤10 kg donors, respectively. Outcome of single SDK grafts was excellent. Gain of GFR and graft volume was even higher in patients with very small donor or recipient size, regardless of a reduced donor-to-recipient weight ratio. Therefore, SDTx should be considered favouring small paediatric recipients.

De novo Glomerular Disease and the Significance of Electron Microscopy in Renal Transplantation

Background

De novo glomerular diseases comprising those both common and unique to transplant may develop in the renal allograft leading to posttransplant proteinuria, hematuria, or allograft failure. Electron microscopy (EM) is a useful adjunct to the standard light and immunofluorescence microscopy for accurately diagnosing these diseases and subsequently aiding the clinician in initiating appropriate treatments.

Summary

De novo diseases are those new-onset diseases in renal transplantation that are unrelated to the original kidney disease in the recipient. They include virtually any primary or secondary glomerular, tubulointerstitial, or vascular diseases, ranging from subclinical to clinically overt, having acute, subacute, or chronic clinical presentations. This review focuses on common or significant, mainly glomerular, entities, with particular attention to the EM findings. The time of onset, stage, and severity of these diseases may often be modified by the current immunosuppressive protocols and other donor and recipient predisposing characteristics.

Key Messages

A renal allograft biopsy not only improves our understanding of the pathophysiology but also provides diagnostic accuracy prognostic information, and potential for reversibility. In some cases, the biopsy leads to detection of unsuspected or clinically asymptomatic de novo diseases in the setting of other concomitant rejection processes, infection, or toxicity, which can dictate appropriate therapy. Routine EM in transplant kidney biopsies is a valuable modality in recognizing fully developed or early/subtle features of evolving de novo diseases, often during the subclinical phases, in "for cause" or surveillance/protocol allograft biopsies.