Background. Urolithiasis is common worldwide and can predispose to urinary tract infections and renal failure. We aimed to explore the global, regional, and national burden of urolithiasis between 1990 and 2019, stratified by sex, age, and sociodemographic index (SDI). Methods. From 1990 to 2019, data on the number of incident cases of urolithiasis, associated deaths, and disability‐adjusted life years (DALYs) were extracted from the 2019 Global Burden of Disease (GBD) study. The trends for the incidence rate, mortality, and DALYs were evaluated using estimated annual percentage changes (EAPCs). Results. The incidence of urolithiasis increased by 48.57%, from 77.78 million incident cases in 1990 to 115.55 million in 2019, while its age‐standardized incidence rate (ASIR) decreased. The ASIR increased slightly in the low SDI regions (EAPC = 0.33; 95% confidence interval [CI]: 0.24–0.43), while ASIRs in other SDI regions decreased. The incidence of urolithiasis by age presented a unimodal distribution, with the peak observed in patients aged between 50 years and 70 years. Urolithiasis‐related mortality and DALYs also increased over time. Yet, the age‐standardized death rate (ASDR) decreased by 2.05% (95% CI, −2.25% to −1.85%) per year, and the annual age‐standardized DALY rate decreased by 1.77% (95% CI, −1.92% to −1.63%). The mortality and DALYs increased with age. The incidence, mortality, and DALYs were greater in males than those in females. The burden of urolithiasis showed obvious differences in its regional distribution over the past three decades. Conclusion. From 1990 to 2019, ASIR, ASDR, and age‐standardized DALY rate of urolithiasis have decreased. Yet, particularly significant differences exist in the geographic, age, and sex distribution. Thus, medical resources should be rationally allocated and adjusted according to the geographic and demographic distribution of urolithiasis.

To update a previously published systematic review and meta-analysis on the efficacy and safety of tubeless percutaneous nephrolithotomy (PCNL). A systematic literature search of EMBASE, PubMed, Web of Science, and the Cochrane Library was performed to confirm relevant studies. The scientific literature was screened in accordance with the predetermined inclusion and exclusion criteria. After quality assessment and data extraction from the eligible studies, a meta-analysis was conducted using Stata SE 12.0. Fourteen randomized controlled trials (RCTs) involving 1148 patients were included. Combined results demonstrated that tubeless PCNL was significantly associated with shorter operative time (weighted mean difference [WMD], −3.79 min; 95% confidence interval [CI], −6.73 to −0.85; P = 0.012; I2 = 53.8%), shorter hospital stay (WMD, −1.27 days; 95% CI, −1.65 to −0.90; P < 0.001; I2 = 98.7%), faster time to return to normal activity (WMD, −4.24 days; 95% CI, −5.76 to −2.71; P < 0.001; I2 = 97.5%), lower postoperative pain scores (WMD, −16.55 mm; 95% CI, −21.60 to −11.50; P < 0.001; I2 = 95.7%), less postoperative analgesia requirements (standard mean difference, −1.09 mg; 95% CI, −1.35 to −0.84; P < 0.001; I2 = 46.8%), and lower urine leakage (Relative risk [RR], 0.30; 95% CI 0.15 to 0.59; P = 0.001; I2 = 41.2%). There were no significant differences in postoperative hemoglobin reduction (WMD, −0.02 g/dL; 95% CI, −0.04 to 0.01; P = 0.172; I2 = 41.5%), stone-free rate (RR, 1.01; 95% CI, 0.97 to 1.05; P = 0.776; I2 = 0.0%), postoperative fever rate (RR, 1.05; 95% CI, 0.57 to 1.93; P = 0.867; I2 = 0.0%), or blood transfusion rate (RR, 0.79; 95% CI, 0.36 to 1.70; P = 0.538; I2 = 0.0%). The results of subgroup analysis were consistent with the overall findings. The sensitivity analysis indicated that most results remained constant when total tubeless or partial tubeless or mini-PCNL studies were excluded respectively. Tubeless PCNL is an available and safe option in carefully evaluated and selected patients. It is significantly associated with the advantages of shorter hospital stay, shorter time to return to normal activity, lower postoperative pain scores, less analgesia requirement, and reduced urine leakage.

Purpose. To clarify the efficiency and outcomes of suctioning ureteral access sheath (UAS) during flexible ureteroscopic lithotripsy (fURL) for the management of renal stones. Methods. Between January 2017 and January 2019, a total of 444 patients with renal stones undergoing fURL were divided into suctioning UAS and nonsuctioning UAS groups. The outcomes of patients in both groups were compared using a matched‐pair analysis (1 : 1 scenario). Furthermore, a directed acyclic graph (DAG) was drawn to guide the multivariate logistic regression model and analyze the protective effect of suctioning UAS on the incidence of postoperative systemic inflammatory response syndrome (SIRS). Results. Before propensity score matching, significant differences were observed between the two groups in blood white cell counts, urine white cell counts, preoperative fever, preoperative indwelling stents, and laterality (P < 0.05). Eighty‐one patients in the suctioning UAS group were successfully matched with 81 patients in the nonsuctioning group. The stone‐free rate (SFR) on postoperative day 1 after fURL in the suctioning group was higher than that in the nonsuctioning group (86.4% vs. 71.6%; P = 0.034), whereas it was comparable between the two groups 1 month after the surgery (88.9% vs. 82.7%; P = 0.368). The incidence of postoperative fever or SIRS was lower in the suctioning group (fever: 3.70% vs. 14.8%; P = 0.030; SIRS: 1.23% vs. 12.3%; P = 0.012). However, the operative duration was similar in both groups (mean (SD)) (72.9 (28.1) min vs. 80.0 (29.5) min; P = 0.121). The result of the multivariate logistic regression model guided by DAG revealed that the application of nonsuctioning UAS (odds ratio: 5.28 [1.38–35.07], P = 0.034) during fURL was associated with postoperative SIRS. Conclusions. The application of suctioning UAS during fURL was associated with higher SFR on day 1 after surgery and a lower incidence of postoperative fever or SIRS.

Hyperoxaluria induces oxidative stress, and inflammation causes renal epithelial cell injury in nephrolithiasis, suggesting that reduced oxalate toxicity may be beneficial. This study aimed to investigate whether nuclear factor (erythroid-derived 2)-like 2 (Nrf2, also called Nfe2l2) induced by dimethyl fumarate (DMF) could protect renal epithelial cells against oxalate-mediated injury both in vivo and in vitro. Glyoxylic acid monohydrate was intraperitoneally injected into Sprague-Dawley rats with or without intragastric administration of DMF. We showed that calcium oxalate crystallisation, accompanied by overexpression of oxidant species and inflammatory cytokines and apoptosis in the rat kidney, was partially reversed by treatment with DMF. Furthermore, oxalate induced a reduction in cell viability, cell damage, oxidant species overexpression, mitochondrial dysfunction, and apoptosis in normal rat kidney epithelial-like (NRK-52E) cells, which were reversed by DMF. Pretreatment of NRK-52E cells with DMF significantly increased Nrf2 levels in the nucleus, with subsequent inhibition of the expression of the nicotinamide adenine dinucleotide phosphate subunits Nox4 and P22, canonical inflammation, and osteogenesis-associated differentiation of target genes in the cytoplasm. This effect was partially inhibited by transfection with Nrf2 siRNA and strengthened by transfection with Kelch-like ECH-associated protein 1 siRNA. These results suggest that DMF exerts beneficial effects in nephrolithiasis by inhibiting inflammation and modulating oxidative stress via regulation of Nrf2.

Many studies compared the serum/plasma 1,25 dihydroxyvitamin D₃ (1,25(OH)₂D) and 25 hydroxyvitamin D₃ (25(OH)D) between people with and without nephrolithiasis, and their results were conflicting. After systematically searching PubMed, Web of Science, The Cochrane Library, CNKI, and the Wanfang Database, we conducted a meta-analysis. Thirty-two observational studies involving 23,228 participants were included. Meta-analysis of these studies showed that of stone formers (SFs), calcium SFs had significantly higher concentrations of 1,25(OH)₂D (weighted mean difference (WMD), 10.19 pg/mL; 95% confidence interval (CI), 4.31–16.07; p = 0.0007 and WMD, 11.28 pg/mL; 95% CI, 4.07–18.50; p = 0.002, respectively) than non-stone formers, while the levels of 25(OH)D (WMD, 0.88 ng/mL; 95% CI, −1.04–2.80; p = 0.37 and WMD, −0.63 ng/mL; 95% CI, −2.72–1.47; p = 0.56, respectively) are similar. Compared with controls and normocalciuria SFs, hypercalciuria SFs had increased circulating 1,25(OH)₂D (WMD, 9.41 pg/mL; 95% CI, 0.15–18.67; p = 0.05 and WMD, 2.75 pg/mL; 95% CI, −0.20–5.69; p = 0.07, respectively) and markedly higher 25(OH)D (WMD, 5.02 ng/mL; 95% CI, 0.99–9.06; p = 0.01 and WMD, 5.02 ng/mL; 95% CI, 2.14–7.90; p = 0.0006, respectively). Normocalciuria SFs had elevated 1,25(OH)₂D level (WMD, 6.85 pg/mL; 95% CI, −5.00–18.71; p = 0.26) and comparable 25(OH)D (WMD, 0.94 ng/mL; 95% CI, −3.55–5.43; p = 0.68). Sensitivity analysis generated similar results. Current evidence suggests that increased circulating 1,25(OH)₂D is associated with urinary stones and a higher level of circulating 25(OH)D is significantly associated with hypercalciuria urolithiasis. Further studies are still needed to reconfirm and clarify the role of vitamin D in the pathogenesis of stones.

As one of the major risks for urolithiasis, hyperoxaluria can be caused by genetic defect or dietary intake. And high oxalate induced renal epithelial cells injury is related to oxidative stress and mitochondrial dysfunction. Here, we investigated whether MitoTEMPO, a mitochondria‐targeted antioxidant, could protect against oxalate mediated injury in NRK‐52E cells via inhibiting mitochondrial dysfunction and modulating oxidative stress. MitoSOX Red was used to determine mitochondrial ROS (mtROS) production. Mitochondrial membrane potential (Δψm) and quantification of ATP synthesis were measured to evaluate mitochondrial function. The protein expression of Nox4, Nox2, and p22 was also detected to explore the effect of oxalate and MitoTEMPO on NADPH oxidase. Our results revealed that pretreatment with MitoTEMPO significantly inhibited oxalate induced lactate dehydrogenase (LDH) and malondialdehyde (MDA) release and decreased oxalate induced mtROS generation. Further, MitoTEMPO pretreatment restored disruption of Δψm and decreased ATP synthesis mediated by oxalate. In addition, MitoTEMPO altered the protein expression of Nox4 and p22 and decreased the protein expression of IL‐6 and osteopontin (OPN) induced by oxalate. We concluded that MitoTEMPO may be a new candidate to protect against oxalate induced kidney injury as well as urolithiasis.