Non-invasive biomarkers of acute rejection in pediatric kidney transplantation: New targets and strategies.

Kidney transplantation is the preferred treatment for pediatric end-stage renal disease. However, pediatric recipients face unique challenges due to their prolonged need for kidney function to accommodate growth and development. The continual changes in the immune microenvironment during childhood development and the heightened risk of complications from long-term use of immunosuppressive drugs. The overwhelming majority of children may require more than one kidney transplant in their lifetime. Acute rejection (AR) stands as the primary cause of kidney transplant failure in children. While pathologic biopsy remains the "gold standard" for diagnosing renal rejection, its invasive nature raises concerns regarding potential functional impairment and the psychological impact on children due to repeated procedures. In this review, we outline the current research status of novel biomarkers associated with AR in urine and blood after pediatric kidney transplantation. These biomarkers exhibit superior diagnostic and prognostic performance compared to conventional ones, with the added advantages of being less invasive and highly reproducible for long-term graft monitoring. We also integrate the limitations of these novel biomarkers and propose a refined monitoring model to optimize the management of AR in pediatric kidney transplantation.

The Protective Effect of Ursolic Acid on Unilateral Ureteral Obstruction in Rats by Activating the Nrf2/HO-1 Antioxidant Signaling Pathway.

Renal interstitial fibrosis is a common pathological feature of a variety of kidney diseases that progress to end-stage renal disease. The excessive deposition of extracellular matrix (ECM) is a typical pathological change of renal interstitial fibrosis. The production of reactive oxygen species in renal tubules is an important factor leading to the development of renal interstitial fibrosis. Ursolic acid (UA) is a natural pentacyclic triterpene carboxylic acid compound widely found in plants. It has anti-inflammatory, antioxidant, and antitumor cell proliferation effects. It can reduce the development of fibrosis by inhibiting the oxidative stress response of the liver; there is currently no relevant research on whether UA can protect the renal interstitial fibrosis by resisting oxidative stress in the kidneys. In this study, our purpose is to investigate the effect of ursolic acid on renal interstitial fibrosis after unilateral ureteral obstruction (UUO) in rats and its related mechanisms. We established a UUO model by surgically ligating the right ureter of the rat and instilling UA preparation (40 mg/kg/d) through the stomach after the operation, once a day for 7 days. We found that UUO caused impaired renal function, increased pathological damage, increased renal interstitial fibrosis, increased apoptosis, increased oxidative stress damage, and decreased antioxidants. However, after UA preparations were given, the abovementioned damage was significantly improved. At the same time, we also found that UA preparations can significantly increase the relative expression of Nrf2/HO-1 signaling pathway in kidney tissue after UUO. In order to further verify whether the Nrf2/HO-1 signaling pathway is involved in the development of renal interstitial fibrosis, we injected zinc protoporphyrin (ZnPP, 45 umol/kg), a specific blocker of the Nrf2/HO-1 signaling pathway, into the intraperitoneal cavity after UUO in rats and before the gastric perfusion of ursolic acid preparations. Subsequently, we observed that the protective effect of UA on renal interstitial fibrosis after UUO in rats was reversed. Combining all the research results, we proved that UA has a protective effect on renal interstitial fibrosis after UUO in rats, which may be achieved by activating the Nrf2/HO-1 signaling pathway.

Retrospective Analysis of the Efficacy of Da Vinci Robot-Assisted Pyeloplasty in the Treatment of Ureteropelvic Junction Obstruction in Children.

Ureteropelvic junction obstruction (UPJO) is one of the common causes of hydronephrosis in children, and the purpose of this study was to observe the application effect of da Vinci robot-assisted laparoscopic treatment of UPJO and to investigate the safety, feasibility, and advantages of da Vinci robot-assisted laparoscopic surgery. 13 patients who underwent robot-assisted pyeloplasty (RAP) for UPJO admitted from May 2020 to March 2021 were retrospectively analyzed in our study. The clinical data among them revealed the intraoperative and postoperative indicators and complications as follows. UPJO was found on the left side in 9 patients and on the right side in 4 patients. The average operative time, blood loss, and hospital stay were 227.3 (175-310) min, 9.2 (5-30) mL, and 9.2 (6-14) days, respectively. Two cases of gross hematuria and two cases of minor urinary tract infection occurred after surgery, and the rest had no perioperative complications. The clinical treatment efficiency at postoperative follow-up was 100%. Our initial analysis showed that da Vinci robot-assisted laparoscopic surgery is a highly effective and safe option for the treatment of UPJO in children.

Retardation of Preputial Wound Healing in Rats with Hypospadias Induced by Flutamide.

Objective: The aim of this study was to identify a theoretical support for the prevention of urethral fistula following hypospadias repair, by comparing the preputial wound healing process in Sprague-Dawley (SD) rats with and without hypospadias induced by flutamide. Methods: Fifteen pregnant SD rats were randomly divided into three groups. These rats in one group received the androgen receptor antagonist flutamide (25 mg/kg/day) from gestation days 11-17, to establish a rat model of hypospadias for further study of the molecular mechanisms of the hypospadias etiology. The pregnant rats in the control groups were not administered flutamide. The pups from the control and experiment groups underwent an incision on the dorsal prepuce on postnatal day 25 and were sacrificed on postoperative days 3, 7, and 14 to collect penis samples. The penis morphology was examined in all groups. Subsequently, transforming growth factor ß1 (TGF-ß1), α-smooth muscle actin (α-SMactin), and signal transducers and activators of the transcription 3 (STAT3) expression levels in the different groups were measured at the indicated time points postoperatively using qRT-PCR and Western blot. Results: There was less regeneration of the subcutaneous tissue in hypospadias rats than in the sham-operated group (P < 0.05) on postoperative day 3. No differences were found in the regeneration of the subcutaneous tissue between these groups on postoperative days 7 or 14. Additionally, there were no differences in the epithelial cell regeneration between the control and the hypospadias groups at any postoperative timepoint. Moreover, the expression levels of TGF-ß1, α-SMactin, and STAT3 were all significantly lower in hypospadias group than that in the sham-operated group (P < 0.05). Conclusion: The results from the present work suggest that preputial wound healing is retarded in rats with hypospadias induced by flutamide and that this retardation might result from multi-gene regulation.

Fine particulate matter leads to reproductive impairment in male rats by overexpressing phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway.

Maintenance of male reproductive function depends on normal sperm generation during which process Sertoli cells play a vital role. Studies found that fine particulate matter (PM) causes decreased male sperm quality, mechanism of which unestablished. We aim to investigate the definite mechanism of PM impairment on male reproduction. Male Sprague-Dawley rats were daily exposed to normal saline (NS) or PM2.5 with the doses of 9 mg/kg.b.w and 24 mg/kg.b.w. via intratracheal instillation for seven weeks. Reproductive function was tested by mating test and semen analysis after last exposure. Testes were collected to assess changes in histomorphology, and biomarkers including connexin 43 (Cx43), superoxide dismutase (SOD), phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (p-Akt). Male rats exposed to PM2.5 showed noticeable decreased fertility, significantly reduced sperm count, increased sperm abnormality rate and severe testicular damage in histomorphology. After PM2.5 exposure, the levels of Cx43 was significantly downregulated, and SOD was upregulated and downregulated significantly with different dose, respectively. Protein expression of PI3K and p-Akt dramatically enhanced, and the later one being located in Sertoli cells, the upward or declining trend was in dose dependent. PM2.5 exposure leads to oxidative stress impairment via PI3K/Akt signaling pathway on male reproduction in rats.

Potential spermatogenesis recovery with bone marrow mesenchymal stem cells in an azoospermic rat model.

Non-obstructive azoospermia is the most challenging type of male infertility. Stem cell based therapy provides the potential to enhance the recovery of spermatogenesis following cancer therapy. Bone marrow-derived mesenchymal stem cells (BMSCs) possess the potential to differentiate or trans-differentiate into multi-lineage cells, secrete paracrine factors to recruit the resident stem cells to participate in tissue regeneration, or fuse with the local cells in the affected region. In this study, we tested whether spermatogenically-induced BMSCs can restore spermatogenesis after administration of an anticancer drug. Allogeneic BMSCs were co-cultured in conditioned media derived from cultured testicular Sertoli cells in vitro, and then induced stem cells were transplanted into the seminiferous tubules of a busulfan-induced azoospermatic rat model for 8 weeks. The in vitro induced BMSCs exhibited specific spermatogonic gene and protein markers, and after implantation the donor cells survived and located at the basement membranes of the recipient seminiferous tubules, in accordance with what are considered the unique biological characteristics of spermatogenic stem cells. Molecular markers of spermatogonial stem cells and spermatogonia (Vasa, Stella, SMAD1, Dazl, GCNF, HSP90α, integrinß1, and c-kit) were expressed in the recipient testis tissue. No tumor mass, immune response, or inflammatory reaction developed. In conclusion, BMSCs might provide the potential to trans-differentiate into spermatogenic-like-cells, enhancing endogenous fertility recovery. The present study indicates that BMSCs might offer alternative treatment for the patients with azoospermatic infertility after cancer chemotherapy.