Emerging urinary markers of renal injury in obstructive nephropathy

Advances in the diagnosis of early biomarkers for acute kidney injury: a literature review

Acute kidney injury (AKI) is a critical condition with diverse manifestations and variable outcomes. Its diagnosis traditionally relies on delayed indicators such as serum creatinine and urine output, making early detection challenging. Early identification is essential to improving patient outcomes, driving the need for novel biomarkers. Recent advancements have identified promising biomarkers across various biological processes. Tubular injury markers, including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), N-acetyl-β-D-glucosaminidase (NAG), and liver-type fatty acid-binding protein (L-FABP), offer insights into early tubular damage. Inflammatory and repair-associated biomarkers, such as interleukin-18 (IL-18), monocyte chemotactic protein-1 (MCP-1), osteopontin (OPN), and C-C motif chemokine ligand 14 (CCL14), reflect ongoing injury and recovery processes. Additionally, stress and repair markers like tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein-7 (IGFBP-7), alongside filtration markers such as cystatin C (CysC) and proenkephalin (PenKid®) e.tal, further enhance diagnostic precision. Oxidative stress-related markers, including Superoxide Dismutase 1 (SOD1), also contribute valuable information. Emerging candidates, such as microRNAs, soluble urokinase plasminogen activator receptor (SuPAR), and chitinase-3-like protein 1 (CHI3L1), hold substantial promise for AKI detection and prognosis. This review summarizes the progress in AKI biomarker research, highlighting their clinical utility and exploring their potential to refine early diagnosis and management strategies. These findings offer a new perspective for integrating novel biomarkers into routine clinical practice, ultimately improving AKI care.

Biomarkers in Contrast-Induced Acute Kidney Injury: Towards A New Perspective

Contrast-Induced Acute Kidney Injury (CI-AKI) remains a frequent iatrogenic condition since radiological procedures using intra-vascular iodinated contrast media (CM) are being widely administered for diagnostic and therapeutic purposes. Despite the improvement of the medical healthcare system worldwide, CI-AKI is still associated with direct short-term and indirect long-term outcomes including increased morbidity and mortality, especially in patients with underlying pre-existing renal function impairment, cardiovascular disease, or diabetes that could rapidly progress into Chronic Kidney Disease. Although the RIFLE (Risk, Injury, Failure, Loss, End-Stage Kidney Disease), AKIN (Acute Kidney Injury Network), and KDIGO (Kidney Disease Improving Global Outcomes) clinical criteria and recommendation guidelines are based on traditional "gold standard" biomarkers known as serum creatinine, glomerular filtration rate, and urinary output, new reliable serum and urinary biomarkers are still needed for an effective unified diagnostic strategy for AKI. Starting from previous and recent publications on the benefits and limitations of validated biomarkers responding to kidney injury, glomerular filtration, and inflammation among others, this review unravels the role of new emerging biomarkers used alone or in combination as reliable tools for early diagnosis and prognosis of CI-AKI, taking into account patients and procedures-risk factors towards a new clinical perspective.

Comparison of Urinary Biomarkers in Diagnosis of Ureteropelvic Junction Obstruction and Differentiation from Nonobstructive Dilatation

Background and Aims

Differentiation of nonobstructive dilatation (NOD) from ureteropelvic junction obstruction (UPJO) is a challenge in children with antenatally detected hydronephrosis. The aim of this study is to compare the utility of urinary biomarkers: carbohydrate antigen (CA 19-9), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule (KIM) in diagnosing UPJO.

Methods

A prospective study was conducted after obtaining ethical clearance between 2021 and 2022. Group 1 - control group (n = 30): children with normal antenatal ultrasound with no urinary symptoms. Group 2 - study group (n = 48): children with unilateral hydronephrosis: Group 2a - NOD (n = 24): children stable on ultrasound and diuretic renogram and Group 2b - UPJO (n = 24): children who worsened to Grade 4 hydronephrosis on ultrasound/worsening of differential renal function (10% drop) on renogram who underwent pyeloplasty. Urinary biomarkers NGAL, KIM-1, and CA 19-9 were measured using the enzyme-linked immune absorbent assay method.

Results

The urine CA 19-9 level was 128.05 ± 4.08 U/mL in the UPJO group, and this was significantly higher (P = 0.001) than NOD, 70.29 ± 4.41, and controls, 1.91 ± 1.57. The urine NGAL level was 21.41 ± 4.44 pg/mL in UPJO, and this was significantly higher than controls, 2.669 ± 0.513, but not NOD, 24.55 ± 2.67. The urine KIM level was 817 ± 15.84 pg/mL in the UPJO group, and this was significantly higher than controls, 285 ± 8.10, but not NOD, 768.23 ± 15.12. Receiver operating characteristic analysis of CA 19-9 revealed a urine biomarker cutoff of 95 U/mL for diagnosing UPJO (sensitivity 95%; specificity 96%; and area under the curve 0.99).

Conclusions

CA 19-9 is a superior marker compared to NGAL and KIM in differentiating UPJO from NOD. Further studies with larger numbers are warranted.

Management of Pediatric Urolithiasis in an Italian Tertiary Referral Center: A Retrospective Analysis

Background and Objectives: In recent years, the prevalence of pediatric urolithiasis has increased in North America and Western countries, though it is endemic in developing countries. The aim of this study is to describe the experience of a tertiary pediatric referral center in the surgical management of pediatric urolithiasis. Materials and Methods: We retrospectively reviewed the experience of patients ≤ 16 years old affected by urinary stones who underwent surgery. Results: From April 2021 to September 2023, 31 pediatric patients underwent surgical procedures for stone diseases at our department: 13 preschool-aged (1-5 years) and 18 school-aged (6-16 years) children. During this period, 12 URSs, 17 RIRSs, and 2 PCNLs were recorded. Five patients had residual fragments at first, so three of them underwent a second endourological lithotripsy (2 RIRSs and 1 URS). Complete clearance was finally achieved in 27 patients. The stone composition was evaluated in 25 cases. Conclusions: Numerous innovations in the surgical treatment of pediatric urolithiasis have resulted from the development of smaller devices and new technology. Our results show how, in experienced centers, retrograde and percutaneous lithotripsy are safe and effective procedures for use in pediatric populations.

The Impact of Chronic Kidney Disease on the Mortality Rates of Patients with Urological Cancers-An Analysis of a Uro-Oncology Database from Eastern Europe

(1) Background: The relationship between chronic kidney disease (CKD) and urological cancers is complex, as most of these cancers are diagnosed in patients with advanced ages, when the kidney function may be already impaired. On the other hand, urological cancers could represent a risk factor for CKD, significantly reducing the life expectancy of the patients. The main objective of our study was to analyze the impact of CKD on the overall mortality of patients diagnosed with the most frequent types of urological cancers. (2) Material and Methods: We conducted an observational retrospective cohort study on a group of 5831 consecutive newly diagnosed cancer patients, followed over a 2-year period (2019-2020), from a large Oncology Hospital in Romania. From this group, we selected only the patients diagnosed with urological malignancies, focusing on prostate cancer, bladder cancer and renal cancer; finally, 249 patients were included in our analysis. (3) Results: In the group of patients with prostate cancer (n = 146), the 2-year overall mortality was 62.5% for patients with CKD, compared with 39.3% for those with no initial CKD (p < 0.05). In the group of patients with bladder cancer (n = 62), the 2-year overall mortality was 80% for patients with initial CKD, compared with 45.2% for the patients with no initial CKD (p < 0.05). Finally, in the group of patients with renal cell carcinoma (n = 41), the 2-year overall mortality was 60% for patients with initial CKD, compared with 50% for the patient group with no initial CKD (p < 0.05). Various correlations between specific oncologic and nephrological parameters were also analyzed. (4) Conclusions: The presence of CKD at the moment of the urological cancer diagnosis is associated with significantly higher 2-year mortality rates.

Cancer Stem Cells in Renal Cell Carcinoma: Origins and Biomarkers

The term "cancer stem cell" (CSC) refers to a cancer cell with the following features: clonogenic ability, the expression of stem cell markers, differentiation into cells of different lineages, growth in nonadhesive spheroids, and the in vivo ability to generate serially transplantable tumors that reflect the heterogeneity of primary cancers (tumorigenicity). According to this model, CSCs may arise from normal stem cells, progenitor cells, and/or differentiated cells because of striking genetic/epigenetic mutations or from the fusion of tissue-specific stem cells with circulating bone marrow stem cells (BMSCs). CSCs use signaling pathways similar to those controlling cell fate during early embryogenesis (Notch, Wnt, Hedgehog, bone morphogenetic proteins (BMPs), fibroblast growth factors, leukemia inhibitory factor, and transforming growth factor-β). Recent studies identified a subpopulation of CD133+/CD24+ cells from ccRCC specimens that displayed self-renewal ability and clonogenic multipotency. The development of agents targeting CSC signaling-specific pathways and not only surface proteins may ultimately become of utmost importance for patients with RCC.

A Cost-effectiveness Model Comparing Urinary Biomarkers with Diuretic Renogram in Diagnosing Ureteropelvic Junction Obstruction in Children

Background and Aims

In this cost-effectiveness model, we compared the cost-effectiveness of commonly used urinary biomarkers with conventional diuretic renogram (DR) in diagnosing ureteropelvic junction obstruction (UPJO). We hypothesized that urinary biomarkers are as effective as DR.

Methods

We used incremental cost-effectiveness ratio (ICER) as a tool for our cost-effectiveness analysis model. The cost of biomarker assay and renogram were sourced from the same center while the accuracy data of DR and urinary biomarkers from the relevant pubications.

Results

As the accuracy of individual biomarker increased, the ICER also got better. As a panel of biomarker was introduced, the ICER went to the negative range suggesting cost saving as well. ICER of most urine biomarkers is currently less expensive and less effective. When a biomarker panel was applied ICER became more expensive and effective. With higher samples, test running cost is likely to go down in future and thus biomarkers are likely become less expensive and more effective.

Conclusions

Individual urine biomarkers are currently less expensive and less effective compared to DR in predicting UPJO. In future, biomarker panel is likely to be more cost-effective and reduce the need for invasive renogram thus reducing the radiation exposure.

Urinary epidermal growth factor and monocyte chemotactic protein-1 as biomarkers of renal injury in patients with obstructed nephropathy

OBJECTIVE

To evaluate the role of urinary Monocyte Chemotactic Protein-1 (MCP1) and urinary epidermal growth factor (EGF) in diagnosing of upper urinary tract obstruction (UUTO).

PATIENT AND METHODS

Over a period of 6 months (January 2022 to June 2022) this prospective case control comparative study was conducted on 120 participants, 60 of them with UUTO and 60 healthy controls. A morning urine sample of all participants was tested for EGF and MCP-1. after taking a detailed history taking and laboratory and radiological evaluation.

RESULTS

Urinary MCP-1(uMCP-1) was significantly (p-value = 0.000) increased in UUTO group showing a mean ± SD of 518.10 ± 51.19 ng/L compared to a mean ± SD of 143.32 ± 58.03 ng/L in the controls, whereas a significantly (p-value = 0.000) decrease of urinary EGF (uEGF) was observed in patients with UUTO compared to control group. A significant difference of uEGF level and uEGF/uMCP1 ratio was observed between mild compared to moderate/severe UUTO.

CONCLUSIONS

Utilization of the urinary biomarker MCP1, EGF and uEGF/uMCP1 ratio in patients with UUTO can adequately be used as a simple, efficacious and noninvasive way in diagnosis of UUTO.

Comparing accuracy of urinary biomarkers in differentiation of ureteropelvic junction obstruction from nonobstructive dilatation in children

Multiple urinary biomarkers have been reported in differentiation of nonobstructive dilatation (NOD) from ureteropelvic junction obstruction (UPJO). In this meta-analysis, we compared the accuracy of common urinary biomarkers applicable to UPJO. A systematic literature review of electronic databases was conducted for: (UPJO) OR (NOD) AND (urinary biomarkers) AND (children) for articles published in the last decade. PRISMA guidelines were used to exclude duplicate and erroneous articles. Meta-analysis involved risk of bias analysis, heterogeneity assessment, and comparison of sensitivity/specificity by forest plot analysis using MetaXL 5.3. Among the 264 articles analyzed, 19 articles met the inclusion criteria and reported the following: neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemotactic protein-1 (MCP1), carbohydrate antigen 19-9 (CA 19-9), kidney injury molecule (KIM1), epidermal growth factor (EGF), and interferon gamma induced protein-10 (IP10). There was substantial heterogeneity among articles. There was wide variation in applied cut-offs among studies. Overall sensitivity was highest at 87% for CA 19-9 while overall specificity was highest at 76% for NGAL. Overall accuracy was highest at 78% for CA 19-9 followed by 77% for NGAL and 75% for KIM1. In this meta-analysis, the overall accuracy was highest for CA 19-9 followed by NGAL and KIM1. The small number of studies for CA 19-9 and considerable heterogeneity for all should be considered while interpreting these findings. Based on the current meta-analysis, we support a panel of biomarkers combining NGAL, KIM, and CA 19-9 for the best diagnostic accuracy of UPJO in children.

The characteristics and influencing factors of fever in postoperative patients undergoing percutaneous nephrolithotomy: A retrospective analysis

Percutaneous nephrolithotomy (PCNL) is commonly used for the treatment of upper urinary calculi in clinical setting, and fever is a common complication after PCNL. It is necessary to evaluate the risk factors of fever in patients undergoing PCNL, to provide insights into the management of PCNL.Patients who underwent PCNL in our hospital from January 2018 to August 2020 were included. The clinical data of postoperative fever and no fever patients were collected and assessed. Logistic regression analyses were conducted to analyze the risk factors for fever in patients undergoing PCNL.A total of 276 patients undergoing PCNL were included, the incidence of postoperative fever for patients undergoing PCNL was 19.39%. No significant differences in the gender, body mass index, alcohol drinking, smoking, hypertension, hyperlipidemia, intraoperative blood infusion, length of hospital stay between fever patients, and no fever patients were found (all P > .05). There were significant differences in the age, diabetes, size of stones, duration of surgery between fever patients, and no fever patients (all P < .05). Age ≥60 years (odds ratio [OR] 2.143, 95% confidence interval [CI] 1.101∼3.264), diabetes (OR 2.218, 95% CI 1.176∼4.642), size of stone ≥2 cm (OR 1.428, 95%CI 1.104∼2.055), duration of surgery ≥100 minutes (OR 1.334, 95% CI 1.015∼1.923) were the risk factors for fever in patients with PCNL (all P < .05). Escherichia coli (48.44%), Staphylococcus aureus (18.75%), and Candida albicans (10.93%) were the top 3 pathogenic bacteria of urine culture.Fever is one of the common complications after PCNL. Patients with high-risk factors should be given full attentions and take corresponding preventive measures targeted on risks.

Risk factors for urinary infection after retrograde upper urinary lithotripsy: Implication for nursing

ABSTRACT

There are needs to evaluate the risk factors for urinary infection after retrograde upper urinary lithotripsy, to provide insights into the management and nursing care of patients with retrograde upper urinary lithotripsy.Patients who received retrograde upper urinary lithotripsy with a Foley 20 urinary tube insertion from June 1, 2019 to December 31, 2020 in our hospital were selected. Patients were grouped urinary infection and no infection group according to the culture results of urine, and the clinical data of the 2 groups of patients were collected and compared. Single factor and logistic regression analysis were used to analyze the risk factors of urinary tract infection after retrograde upper urinary lithotripsy.Four hundred ten patients with retrograde upper urinary lithotripsy were included, of whom 62 patients had the urinary tract infection, the incidence of urinary tract infection was 15.12%. There were significant differences in the gender, age, diabetes, stone diameter, duration of urinary tube insertion and duration of surgery between infection and no-infection group (all P < .05). The Escherichia coli (62.90%) was the most commonly seen bacterial in patients with urinary tract infection. Female (odds ratio [OR]: 1.602, 95% confidence interval 95% [CI]: 1.132∼2.472), age >50 years (OR: 2.247, 95% CI: 1.346∼3.244), diabetes (OR: 2.228, 95% CI: 1.033∼3.451), stone diameter ≥2 cm (OR: 2.152, 95% CI: 1.395∼3.099), duration of urinary tube insertion ≥3 days (OR: 1.942, 95% CI:1.158∼2.632), duration of surgery ≥90 minutes (OR: 2.128, 95% CI: 1.104∼3.846) were the independent risk factors for the postoperative urinary tract infection in patients with retrograde upper urinary lithotripsy (all P < .05).The incidence of urinary tract infection in patients undergoing retrograde upper urinary lithotripsy was high, counteractive measures targeted on those risk factors are needed to prevent and reduce the postoperative urinary infection in clinical settings.

Hepatic and renal expression of Oatp1 in obstructive uropathy. First detection of Oatp1 in urine, a potential biomarker

Obstructive renal diseases affect renal function and kidney integrity. Nevertheless, little is known about its systemic or extra-renal effects. The organic anion transporting polypeptide 1 (Oatp1) is a carrier expressed in liver and kidneys. In this study, the hepatic and renal expression of Oatp1 was evaluated in rats with obstructive nephropathy. Moreover, the urinary excretion of Oatp1 (Oatp1u ) was evaluated as a potential biomarker for this pathology. Male Wistar rats with bilateral ureteral obstruction for 5 hours (BUO5), 24 hours (BUO24) or sham operated were used. After 24 hours of ureteral releasing, liver and kidney functional parameters, histopathology, Oatp1 tissular expression and Oatp1u were evaluated. For Oatp1u evaluation two groups were added; BUO1 and BUO2 (1 and 2 hours of ureteral obstruction, respectively). Both liver and kidney functional parameters and histopathological studies showed alterations in BUO5 and BUO24. In hepatic homogenates, Oatp1 significantly decreased in BUO groups and in total liver membranes no modifications were observed. In renal homogenates, Oatp1 significantly decreased in BUO groups, but in apical kidney membranes, its expression was increased. Oatp1u was only detected in BUO groups, even in those (BUO1, BUO2) in which no alterations in the traditional parameters of renal function were observed. Modulations in liver and renal expression of Oatp1 could be an organism strategy to attenuate the effects of the disease and an attempt to maintain the complex organ cross-talk between liver and kidneys. Oatp1u could be a new, early and specific biomarker of obstructive nephropathy.

Evaluation and fetal intervention in severe fetal hydronephrosis

PURPOSE OF REVIEW

Fetal hydronephrosis secondary to congenital anomalies of the kidney and urinary tract (CAKUT) can adversely affect neonates in the postnatal period with long-term consequences. A prenatal diagnosis of CAKUT can have an early fetal intervention to minimize these consequences. This review aims to provide an overview of the possible fetal intervention with severe hydronephrosis.

RECENT FINDINGS

Clinical course and outcomes of CAKUT are predicted based on biochemical markers and radiological findings. In spite of advancements and accurately diagnosing the severity of hydronephrosis, there are many controversies surround on selection of cases with antenatal hydronephrosis (ANH) that will benefit from fetal intervention. Despite better diagnosis and techniques fetal intervention is limited to mainly lower urinary tract obstruction patients to improve amniotic fluid volume and assist in lung development.

SUMMARY

ANH can potentially detect the severity of congenital renal anomalies but unable to recognize a specific disease. A multidisciplinary approach is required to diagnose and properly stage cases of severe CAKUT and potential surgical intervention can be considered.

Regulatory T Cells Accelerate the Repair Process of Renal Fibrosis by Regulating Mononuclear Macrophages

BACKGROUND

We aimed to investigate the mechanisms of renal fibrosis and explore the effect of CD4+CD25+Foxp3+ regulatory T cells (Treg) on renal fibrosis after the obstruction was removed.

METHODS

Fifty-five C57BL/6 mice were randomly divided into three groups: the unilateral ureteral obstruction (UUO) group, the relief for unilateral ureteral obstruction (RUUO) group, and the RUUO+Treg group. Renal fibrosis indexes of RUUO mice were evaluated using hematoxylin and eosin (HE) and, Masson staining and immunohistochemistry after CD4+CD25+Treg cells were injected into the tail vein at the moment of recanalization. We detected the levels of Treg, M1, and M2 markers by flow cytometry, and the levels of transforming growth factor (TGF)-β1, interleukin (IL)-1β, IL-6 and IL-10 using ELISA.

RESULTS

The tubular necrosis score, AO value of α-SMA (smooth muscle actin), and collagen area on the 3rd and 14th days post RUUO were up-regulated compared with the 7th day post RUUO (P<0.05). After injection of Treg via tail vein, the tubular necrosis score, AO value of α-SMA, TGF-β1 level, and collagen area in the RUUO+Treg group on the 14th day were down-regulated compared with the RUUO group (P<0.05). Moreover, Treg could transform M1 macrophages into M2 macrophages, manifesting as up-regulated expression of CD206 compared with the RUUO group (P<0.05). Treg could also down-regulate the secretion of IL-6 and IL-1β while up-regulating the secretion of IL-10 in vitro compared with the M1 group (P<0.05).

CONCLUSIONS

The kidney could deteriorate into a state of injury and fibrosis after the obstruction was removed, and Treg could effectively protect the kidney function.

Renoprotective effect of platelet-rich plasma in obstructive uropathy

PURPOSE

To investigate the effect of platelet-rich plasma (PRP) in reducing renal injury in ureteral obstruction.

METHODS

Twenty-four Wistar Albino rats were randomized and divided into four groups as the donor (n = 6), sham (n = 6), saline (n = 6), and PRP (n = 6). Blood was obtained from the donor group by cardiac puncture and PRP was prepared. 2 cc blood was sampled from other groups to measure blood-urea nitrogen and creatinine levels. Baseline renal scintigraphy was performed. An abdominal midline incision was made and the left ureter was exposed in the sham group. Saline infusion was given to the kidneys of the saline group after left ureteral obstruction, while PRP was given to the PRP group. On postoperative Day 7, control biochemical and scintigraphic evaluations were performed and left nephrectomies were done. Left kidneys were evaluated histopathologically.

RESULTS

DMSA measurements in the sham group were found to be significantly higher than the saline and PRP groups (p = 0.001 and p = 0.024, respectively). There were no significant differences between the saline and PRP groups (p = 0.525 and p > 0.05, respectively). Histopathologically, no significant difference was observed between the saline and PRP groups (p = 0.320), while the scores of the sham group were significantly higher than the saline and PRP groups (p = 0.02 and p = 0.001, respectively).

CONCLUSION

Our study results suggest that PRP may be effective in preventing ureteral obstruction-induced renal injury.

Naringin attenuates renal interstitial fibrosis by regulating the TGF-β/Smad signaling pathway and inflammation

Interstitial fibrosis is a typical feature of all progressive renal diseases. The process of fibrosis is frequently coupled with the presence of pro-fibrotic factors and inflammation. Naringin is a dihydroflavone compound that has been previously reported to exhibit anti-fibrotic effects in the liver, where it prevents oxidative damage. In the present study, a rat model of renal interstitial fibrosis and fibrosis cell model were established to evaluate the effects of naringin on inflammatory proteins and fibrosis markers in kidney of rats and NRK-52E cells, and to elucidate the role of the TGF-β/Smad signaling pathway in this mechanism. Compared with those in fibrotic NRK-52E cells that were stimulated by transforming growth factor-β (TGF-β), gene expression levels of α-smooth muscle actin (α-SMA), collagen 1 (COL1A1), collagen 3 (COL3A1), interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) were all found to be significantly decreased in fibrotic NRK-52E cells following treatment with naringin (50, 100 and 200 ng/ml). Results from the histopathological studies showed that naringin treatment preserved the renal tissue structure and reduced the degree of fibrosis in the kidney tissues of rats that underwent unilateral ureteral obstruction (UUO). In addition, naringin administration reduced the expression of α-SMA, COL1A1, COL3A1, IL-1β, IL-6 and TNF-α in the kidneys of rats following UUO. The current study, using western blot analysis, indicated that naringin also downregulated the activation of Smad2/3 and the expression of Smad4, high-mobility group protein B1, activator protein-1, NF-κB and cyclooxygenase-2 whilst upregulating the expression of Smad7 in fibrotic NRK-52E cells and rats in the UUO group. In conclusion, naringin could antagonize renal interstitial fibrosis by regulating the TGF-β/Smad pathway and the expression of inflammatory factors.

Trans-uretero-cystic external urethral stent for urinary diversion in pediatric laparoscopic pyeloplasty: A novel approach

PURPOSE

We present a new approach for urine drainage in pediatric patients following laparoscopic pyeloplasty, the trans-uretero-cystic external urethral stent (TEUS).

METHODS

We retrospectively identified 85 children who underwent laparoscopic pyeloplasty from July 2015 to June 2017. The included children were assigned to group A (double-J stent) or group B (TEUS). In group A, the double-J stent was removed by a cystoscopy under anesthesia after 1 month, while in group B, the external stent was removed after 5 to 7 days. We examined the durations of operation, hospital stay and the frequency of stent-related complications including urinary leakage, stent dislocation, stent occlusion, and urinary tract infection.

RESULTS

The operation time was significantly longer for patients in group B than for those in group A. No significant difference was observed between the groups regarding stent-related complications. In group A, 4 patients need auxiliary stent re-insertion for the management of complications, 2 developed urinary tract infection, and 2 had stent occlusion. In group B, none needed auxiliary stent re-insertion for complications and avoided re-operation.

CONCLUSIONS

In children, the outcome of external stent implantation was similar to that using double-J stent, and the use of the former approach may be beneficial for younger children.

Utility of urinary organic anion transporter 5 as an early biomarker of obstructive nephropathy

Ureteral obstruction is a relevant cause of kidney damage. The traditional parameters used in clinical practice for the detection of renal injury are insensitive and non-specific for the diagnosis of obstructive renal disease. The organic anion transporter 5 (Oat5) is a carrier expressed exclusively in the kidney. In this study, the Oat5 urinary excretion (Oat5u ) was evaluated as a potential biomarker of obstructive nephropathy, comparing it with traditional markers of renal function and with neutrophil gelatinase-associated lipocalin in urine (NGALu ), a more recent biomarker of renal pathology. Bilateral ureteral obstruction (BUO) was induced in male Wistar rats, by complete ligation of ureters for 1 hour (BUO1), 2 hours (BUO2), 5 hours (BUO5), or 24 hours (BUO24). After 24 hours of ureteral releasing, urea and creatinine plasma concentrations, creatinine clearance, urinary total proteins, urinary glucose, and alkaline phosphatase activities in urine were evaluated. Oat5 and NGAL levels were assessed in urine samples by immunoblotting. All parameters of renal function were altered in the BUO24 and some also in BUO5, while the Oat5u increased in all of the experimental groups analyzed. After a long time of ureteral obstruction (BUO24), the urinary excretion of Oat5 markedly increased, in parallel with the alteration in the other parameters evaluated. Nevertheless, in BUO1 and BUO2, Oat5u appeared as the only parameter modified. Therefore, Oat5u could be proposed as a novel early biomarker of ureteral obstruction, with the additional potential to inform about the severity of the obstructive injury suffered by the kidney.

Impact of successful pediatric ureteropelvic junction obstruction surgery on urinary HIP/PAP and BD-1 levels

INTRODUCTION

In the pediatric patient whose ureteropelvic junction obstruction (UPJO) is not always symptomatic, imaging is the most common means of detecting surgical success. There is interest, however, in other means of post-operative monitoring. A panel of antimicrobial peptides (AMPs) has been previously found to be elevated in UPJO, but the impact of surgical correction on these AMPs is unknown.

OBJECTIVE

To determine if elevated levels of candidate urinary AMP biomarkers of urinary tract obstruction decrease following UPJO repair.

STUDY DESIGN

Pediatric patients undergoing surgical correction of an UPJO were recruited for participation. Bladder urine from uninfected consenting/assenting patients was collected immediately prior to surgery and then at least 6 months afterward. Based on prior studies demonstrating significant elevation of beta defensin 1 (BD-1), hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), cathelicidin (LL-37), and neutrophil gelatinase-associated lipocalin (NGAL) in patients with UPJO versus control patients, we performed enzyme-linked immunosorbent assays on these four AMPs to compare their expression before and after surgical intervention. If found to significantly decrease, AMP levels were compared to healthy controls. AMP levels were normalized to urine creatinine. Results were analyzed with paired t test or Wilcoxon test using Graphpad software. Correlation was calculated using Pearson or Spearman correlation. A p-value of <0.05 was considered significant.

RESULTS

13 UPJO patients were included in this study; 9 were male (69%). Age at surgery was a median of 4.3 years (average 6.1, range 0.4-18.4 years). Follow-up urine samples were collected a median of 27.4 months after surgery (average 27.4; range 7.8-45.3 months). All 13 patients had clinical improvement and/or signs of improved hydronephrosis on post-operative imaging. HIP/PAP and BD-1 significantly decreased in post-surgical samples compared to pre-surgical samples (p = 0.02 and 0.01, respectively); NGAL and LL-37 did not significantly change. Overall, HIP/PAP decreased in 12 patients (92%) and BD-1 decreased in 11 patients (85%). BD-1 levels after successful repair were not different from healthy controls (p = 0.06).

DISCUSSION

Urinary biomarkers of obstruction should detect significant obstructive pathology as well as reflect its resolution. This would enable their use in post-operative monitoring and augment current methods of determining successful surgical outcome through imaging.

CONCLUSIONS

The AMPs HIP/PAP and BD-1 are significantly elevated in UPJO but then significantly decrease after pyeloplasty, with BD-1 returning to healthy control levels. As a result, these AMPs could serve as markers of successful surgical intervention.

Risk factors for obstructive complications after endoscopic correction of vesico-ureteral reflux using polyacrylate polyalcohol copolymer

Use of polyacrylate-polyalcohol copolymer (PPC) after endoscopic correction (EC) of vesico-ureteral reflux (VUR) is highly effective but is associated with a higher risk of obstructive complications (OC) compared with other implants. We undertook a STROBE compliant retrospective investigation and studied the OC risk factors to increase the practical safety of PPC.Overall, 798 patients (464 [58.1%] girls and 334 [41.9%]) boys) from 5 hospitals in whom PPC was routinely used were evaluated retrospectively. The patients were subdivided into 2 groups. Group I consisted of 754 (94.5%) children (449 [59.5%] girls and 305 [40.5%] boys) without OC. Median age was 41 months [Q1: 18.0; Q3: 81.0]. Group II comprised 44 (5.5%) patients (29 [65.9%] boys and 15 [34.1%] girls) experiencing OC, and their median age was 21.5 months [Q1: 12.0; Q3: 43.0]. Clinical and renal ultrasound examinations were carried out 1 day and 1 month after EC, and then every 6 months after EC. At the follow-up examination approximately 6 months after EC, voiding cysto-urethrography (VCUG) was performed. All patients with OC underwent diuretic renography.OC occurred in 44 (5.5%) of 798 children, in some cases as late as 60 months after endoscopic injection of the bulking agent PPC for correction of VUR. Univariate analysis revealed that younger age (P < .001), higher grade of VUR (P < .001), male gender (P < .001), second injection (P = .003), and EC injection using hydrodistension implantation technique (HIT; P < .001) represented significant risk factors. At multivariate analysis, only male gender (P = .0078), younger age (P = .0044), HIT technique (P < .0001), and second injection (P = .04) represented significant risk factors for the occurrence of OC.We identified young age, male gender, high reflux grade, HIT technique, and second endoscopic injections as factors associated with the risk of OC after EC of VUR using PPC as a bulking agent. Thus, patients who have undergone EC with PPC must be monitored sonographically for occurrence of OC for at least 60 months after the intervention.

Perioperative acute kidney injury: Stratification and risk reduction strategies

Perioperative acute kidney injury (AKI) is associated with increased morbidity and mortality. Patient comorbidities, the type of surgery, timing of surgery, and exposure to nephrotoxins are important contributors for developing acute kidney injury. Urgent or emergent surgery, cardiac, and organ transplantation procedures are associated with a higher risk of acute kidney injury. Nephrotoxic drugs, contrast dye, and diuretics can worsen preexisting kidney dysfunction or act as an additive and/or synergistic insult to perioperative injury. A history of preoperative chronic kidney disease is the main risk factor for developing AKI, conferring as much as a 10-fold risk. However, beyond the preoperative renal function, the development of AKI is a complex phenomenon that involves a combination of patient-related and surgery-related factors.

Effect of ureteral calculus in outpatients receiving semirigid ureteroscope laser lithotripsy

The surgical outcomes of patients with single ureteral stones who had undergone ureteroscopic Holmium laser lithotripsy as outpatients and compare them with those of patients who had received the same procedure as inpatients. Records were obtained from January 2012 to December 2016 for selected patients who had undergone the above mentioned procedure at our institution. Patients were excluded if their ECOG performance status was ≥2, presented with multiple stones or concomitant renal stones, had histories of cancer or congenital urinary system abnormalities, or had undergone urinary system reconstruction surgery. Patients could decide whether to receive the procedure as an outpatient or inpatient. All surgeries were performed by a single surgeon. Patients preoperative, operative, and postoperative data were recorded. The clinical results, such as urinary tract infection, analgesic requirement, rate of returning to the emergency room, stone clearance, surgical complications, and medical expenditure for the treatment courses were analyzed and compared between the 2 cohorts. In total, 303 patients met the inclusion criteria. Among them, 119 patients decided to receive ureteroscopic laser lithotripsy as outpatients, whereas 184 decided to be inpatients. The outpatient cohort was younger (P < .001), had smaller stone diameters (P < .001), and fewer comorbidity factors (P = .038). Patients with a history of stone manipulation favored receiving the procedure under admission (P < .001). After 1:1 propensity score matching, no significant differences were discovered between the cohorts with regard to operative time, rate of lithotripsy failure, and operative complications. Furthermore, rates of stone clearance, post-op urinary tract infection, analgesic requirement, and returning to the emergency room were comparable between the 2 groups. However, the medical expenditure was significantly lower in the outpatient cohort (P < .001). Our data revealed that outpatient ureteroscopic lithotripsy with a Holmium laser was more economical compared with the inpatient group and achieved favorable outcomes for patients with a single ureteral stone.

Evaluation of dynamic thiol-disulphide homeostasis in obstructive uropathy

PURPOSE

To evaluate the ability of thiol-disulphide homeostasis to predict renal injury in ureteral obstruction by matching renal scintigraphy and pathological findings in an experimental rat model.

METHODS

24 rats were randomized and divided into 3 groups as sham, partial and complete. Blood samples for biochemical evaluations and dimercaptosuccinic acid (DMSA) renal scintigraphy were performed at the beginning and on the 7th day postoperatively. Only a midline abdominal incision was done in sham group. Left ureter of partial group was dissected and gently buried into the psoas muscle. In complete group, left ureter was dissected and ligated.

RESULTS

Statistically significant association was found between left kidney function loss percentage, native thiol, total thiol and creatinine alterations and pathological EGTI (Endothelial, Glomerular, Tubular, Interstitial) scores (r = - 0.867, r = - 0.815, r = 0.745, r = - 0.911; p = 0.000). Statistically significant difference was detected between groups in terms of postoperative native thiol and total thiol values (p = 0.000, p = 0.001). There was also a significant difference in preoperative and postoperative comparisons of these parameters in partial and complete obstruction groups (p = 0.012, p = 0.018). There was a significant difference in terms of postoperative disulphide/native thiol and native thiol/total thiol ratios in complete obstruction group compared to other groups (p₁ = 0.011, p₂ = 0.040; p₁ = 0.015, p₂ = 0.028).

CONCLUSIONS

Association with scintigraphic and pathological results empowers the value of this parameter. Disulphide/native thiol and native thiol/total thiol ratios indicate complete obstruction. These findings may shed light to more comprehensive studies.

Potential Prognostic Markers of Acute Kidney Injury in the Early Phase of Acute Pancreatitis

Acute kidney injury (AKI) is a serious complication of acute pancreatitis (AP), which occurs in up to 70% of patients with severe AP and significantly increases the risk of mortality. At present, AKI is diagnosed based on dynamic increase in serum creatinine and decreased urine output; however, there is a need for earlier and more accurate biomarkers. The aim of the study was to review current evidence on the laboratory tests that were studied as the potential biomarkers of AKI in AP. We also briefly summarized the knowledge coming from the studies including sepsis or ICU patients since severe acute pancreatitis is associated with systemic inflammation and organ failure. Serum cystatin C and serum or urine NGAL have been shown to predict or diagnose AKI in AP; however, this evidence come from the single center studies of low number of patients. Other markers, such as urinary kidney injury molecule-1, cell cycle arrest biomarkers (tissue inhibitor metalloproteinase-2 and urine insulin-like growth factor-binding protein 7), interleukin-18, liver-type fatty acid-binding protein, or calprotectin have been studied in other populations suffering from systemic inflammatory states. In AP, the potential markers of AKI may be significantly influenced by either dehydration or inflammation, and the impact of these factors may be difficult to distinguish from kidney injury. The subject of AKI complicating AP is understudied. More studies are needed, for both exploratory (to choose the best markers) and clinical (to evaluate the diagnostic accuracy of the chosen markers in real clinical settings).

Cumulative sum analysis of learning curve for video-assisted mini-laparotomy partial nephrectomy in renal cell carcinoma

Video-assisted mini-laparotomy surgery (VAMS), a hybrid of open and laparoscopic surgical techniques, is an important surgical approach in the field of partial nephrectomy. The learning curve for VAMS partial nephrectomy has not been studied to date; we therefore, evaluated this learning curve.We prospectively evaluated 20 consecutive patients who underwent VAMS partial nephrectomy performed by a single surgeon (YEY) between March 2015 and December 2016. The learning curve was evaluated using the cumulative sum method. The measure of surgical performance was composed of 3 parameters (total operation time [Op time], warm ischemic time [WIT], and estimated blood loss [EBL]).Among the 20 patients who underwent VAMS partial nephrectomy, the mean age was 54.6 years. The mean Op time and WIT were 172.5 and 28.8 minutes, respectively. The learning curve for the Op time, WIT, and EBL consisted of 3 unique phases: phase 1 (the first 7 cases), phase 2 (the next 5 to 7 cases), and phase 3 (all subsequent cases). Phase 1 represents the initial learning curve, and the phase 2 plateau represents the period of expert competency. Phase 3 represents when one is competent in VAMS partial nephrectomy.The learning curve for VAMS partial nephrectomy is relatively short and after a learning curve of approximately 7 cases, the surgeon became familiar with VAMS partial nephrectomy; after 12 to 14 cases, the surgeon became competent in this procedure.

Uromodulin deficiency alters tubular injury and interstitial inflammation but not fibrosis in experimental obstructive nephropathy

Human GWAS and Mendelian genetic studies have linked polymorphic variants and mutations in the human uromodulin gene (UMOD) with chronic kidney disease. The primary function of this kidney‐specific and secreted protein remains elusive. This study investigated whether UMOD deficiency modified responses to unilateral ureteral obstruction (UUO)‐induced kidney injury. Kidneys harvested from groups of wild‐type (UMOD+/+) and knockout (UMOD−/−) male mice (n = 7–10 each) were studied on days 7, 14, and 21. Compared to sham kidneys, UMOD protein levels increased 9–13x after UUO and were associated with increased urinary UMOD levels. Kidney KIM‐1 protein levels were higher in the UMOD−/− groups at all time‐points (4–14x). The UMOD−/− groups also had higher KIM‐1 kidney‐to‐urine relative ratios (5–35x). In vitro studies using KIM‐1 expressing 769‐P cells showed lower KIM‐1 levels in the presence of UMOD protein. Levels of proapoptotic genes and the epithelial cell apoptotic protein marker M30 were significantly lower in the UMOD−/− groups. Both M30 and KIM‐1 colocalized with intraluminal UMOD protein deposits. Interstitial inflammation was less intense in the UMOD−/− groups. Renal fibrosis severity (kidney collagen mRNA and protein) was similar in both genotypic groups on days 7, 14, and 21. Our findings suggest a role for UMOD‐dependent inhibition of KIM‐1 expression and its apoptotic cell scavenging responses during chronic obstruction‐associated tubular injury.

Atypical Causes of Urinary Tract Obstruction

Acute kidney injury due to urinary tract obstruction invariably suggests lower urinary tract obstruction or bilateral ureteric obstruction since obstruction of a single kidney while the contralateral kidney is normal and not obstructed would not cause a perceptible rise in creatinine. Assuming a total body volume of 42 L, 70 kg male that generates approximately 1400 mg of creatinine daily (20 mg/kg/day) who has complete urinary tract obstruction would experience a 3.33 mg/dL per day increase in serum creatinine. Thus, for an individual who had prior normal renal function and who presents with a creatinine of 30 mg/dL, one could surmise that the obstructive pathology had lasted at least 10 days. However, the rise in serum creatinine is a poor marker of renal injury and subsequent prognosis. Urinary tract obstruction leading to AKI can be due to a variety of causes, and its management is tailored to the underlying etiology. This case series describes the varied clinical course of four patients at our center who experienced AKI from atypical causes of obstructive uropathy. Current and future diagnostic modalities and caveats in the treatment of this disease entity are also discussed.

Elevated urinary lipocalin-2, interleukin-6 and monocyte chemoattractant protein-1 levels in children with congenital ureteropelvic junction obstruction

INTRODUCTION

In children with congenital ureteropelvic junction obstruction (UPJO), urinary biomarkers could assist in the diagnosis of renal damage or kidneys at risk for damage. Urinary levels of interleukin-6 (IL6), neutrophil gelatinase-associated lipocalin (LCN2), monocyte chemoattractant protein-1 (MCP1), and transforming growth factor-β1 (TGFB1) proteins have been correlated with renal damage in several contexts. Whether they might be useful non-invasive biomarkers of obstructive nephropathy due to unilateral and bilateral congenital UPJO was tested.

PATIENTS AND METHODS

A cohort study was performed at People's Hospital of Xinjiang Uygur Autonomous Region in China. Bladder urine samples from 17 patients with UPJO were obtained before surgical intervention and from 17 healthy age-matched controls. Levels of IL6, LCN2, MCP1, and TGFB1 were determined by enzyme-linked immunosorbent assay and normalized to urinary creatinine levels.

RESULTS

Levels of urinary LCN2, MCP1, and IL6 were significantly elevated in the urine from individuals with UPJO compared with controls (P = 0.0003, P = 0.0003, and P = 0.0073, respectively). Children with bilateral UPJO (n = 5) showed significantly higher levels of IL6, LCN2, and MCP1 protein in their urine compared with controls or those with unilateral UPJO (n = 12; P = 0.007, P < 0.0001, and P = 0.0002, respectively). Combining LCN2 and MCP1 slightly improved biomarker performance.

DISCUSSION

Urinary biomarkers could be used in obstructed patients to monitor for renal damage and might find particular utility on patients with bilateral UPJO. Monitoring urinary biomarkers and imaging features in untreated patients could provide insights into the natural history of renal damage due to obstruction and will be necessary to test their performance characteristics as biomarkers.

CONCLUSIONS

Urinary levels of LCN2 and MCP1 protein are promising biomarkers monitoring children with UPJO, particularly in those with bilateral disease.

The correlation between affected renal function and affected renal residual volume: A retrospective outcome of laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking-up for localized renal tumors

Laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking (SRPN) has been widely used in the treatment of localized renal tumors. However, the impact of ischemia-reperfusion injury (IRI) during SRPN remains controversial. This study aims to evaluate the correlation between affected renal function and affected renal volume after SRPN for localized renal tumor treatment, explore the effect of IRI on renal function after SRPN.A total of 39 patients who underwent SRPN for localized renal tumor from June 2009 to April 2012 were reviewed. These patients were followed-up for 5 years. The preoperative affected renal glomerular filtration rate (aGFRpre), postoperative affected renal glomerular filtration rate (aGFRpost), preoperative affected renal volume (aVolpre), and postoperative affected renal volume (aVolpost) were collected during the follow-up period. The correlation between aGFRpost/aGFRpre and aVolpost/aVolpre was compared.A total of 33 patients were successfully followed up. After 3, 6, 12, 24, and 60 months, aGFRpost was 34.6 ± 4.6, 34.7 ± 4.8, 34.9 ± 4.4, 35.1 ± 4.4, and 35.2 ± 4.2 mL/min. The correlation coefficients between aGFRpost/aGFRpre and aVolpost/aVolpre were 0.659 (P = .000), 0.667 (P = .000), 0.663 (P = .000), 0.629 (P = .000), and 0.604 (P = .000), respectively. The limitation of this study was the small cohort size.For the localized renal tumor, aGFRpost was associated with aVolpost, but was not associated with intraoperative factors, such as the time of clamping of the affected segmental renal artery. As a part of nephrons, the resected tumor tissue caused the lack of inherent nephrons, resulting in the loss of renal function. More nephrons should be maintained before resecting the tumor completely during SRPN.Trial registration: ChiCTR-RRC-17011418.

Focal therapy versus robot-assisted partial nephrectomy in the management of clinical T1 renal masses: A systematic review and meta-analysis

BACKGROUND

Robot-assisted partial nephrectomy (RPN) and focal therapy (FT) have both been successfully employed in the management of small renal masses. However, despite this being the era of minimally invasive surgery, few comparative studies exist on RPN and FT. The aim of our study is to review perioperative, renal functional and oncologic outcomes of FT and RPN in cT1 renal masses.

METHODS

Literature published in Medline, EMBASE, and Cochrane Library databases up to April 22, 2018, was systematically searched. We included literature comparing outcomes of FT (radiofrequency ablation, cryoablation, microwave ablation, and irreversible electroporation) and RPN. Studies that reported only on laparoscopic partial nephrectomy or open partial nephrectomy, and review articles, editorials, letters, or cost analyses were excluded. In total, data from 1166 patients were included.

RESULTS

From 858 total articles, 7 nonrandomized, observational studies were included. Compared with RPN, FT was associated with a significantly lower decrease of estimated glomerular filtration rate (weighted mean difference [WMD] -8.06 mL/min/1.73 m; confidence interval [CI] -15.85 to -0.26; P = .04), and lower estimated blood loss (WMD -49.61 mL; CI -60.78 to -38.45; P < .001). However, patients who underwent FT had a significantly increased risk of local recurrence (risk ratio [RR] 9.89; CI 4.24-23.04; P < .001) and distant metastasis (RR 6.42; CI 1.70-24.33; P = .006). However, operative times, lengths of stay, and complication rates were revealed to be similar between FT and RPN.

CONCLUSION

RPN has a substantial advantage in preventing cancer recurrence. However, in the era of minimally invasive surgery, FT has advantages in renal function preservation and less bleeding. Long-term follow-up for survival rates and comparative analysis of microwave ablation and irreversible electroporation are needed to extend FT for patients with significant morbidities and for those who need sufficient renal function preservation with minimal bleeding.

Dicer deficiency in proximal tubules exacerbates renal injury and tubulointerstitial fibrosis and upregulates Smad2/3

Renal fibrosis is a common pathological feature in chronic kidney disease (CKD), including diabetic kidney disease (DKD) and obstructive nephropathy. Multiple microRNAs have been implicated in the pathogenesis of both DKD and obstructive nephropathy, although the overall role of microRNAs in tubular injury and renal fibrosis in CKD is unclear. Dicer (a key RNase III enzyme for microRNA biogenesis) was specifically ablated from kidney proximal tubules in mice via the Cre-lox system to deplete micoRNAs. Proximal tubular Dicer knockout (PT- Dicer KO) mice and wild-type (WT) littermates were subjected to streptozotocin (STZ) treatment to induce DKD or unilateral ureteral obstruction (UUO) to induce obstructive nephropathy. Renal hypertrophy, renal tubular apoptosis, kidney inflammation, and tubulointerstitial fibrosis were examined. Compared with WT mice, PT- Dicer KO mice showed more severe tubular injury and renal inflammation following STZ treatment. These mice also developed higher levels of tubolointerstitial fibrosis. Meanwhile, PT- Dicer KO mice had a significantly higher Smad2/3 expression in kidneys than WT mice (at 6 mo of age) in both control and STZ-treated mice. Similarly, UUO induced more severe renal injury, inflammation, and interstitial fibrosis in PT- Dicer KO mice than WT. Although we did not detect obvious Smad2/3 expression in sham-operated mice (2-3 mo old), significantly more Smad2/3 was induced in obstructed PT- Dicer KO kidneys. These results supported a protective role of Dicer-dependent microRNA synthesis in renal injury and fibrosis development in CKD, specifically in DKD and obstructive nephropathy. Depletion of Dicer and microRNAs may upregulate Smad2/3-related signaling pathway to enhance the progression of CKD.

Kidney atrophy vs hypertrophy in diabetes: which cells are involved?

One of the first structural changes in diabetic nephropathy (DN) is the renal enlargement. These changes resulted in renal hypertrophy in both glomerular and tubular cells. Shrink in the kidney size, which described as kidney atrophy resulted from the loss of nephrons or abnormal nephron function and lead to loss of the kidney function. On the other hand, increase in kidney size, which described as hypertrophy resulted from increase in proximal tubular epithelial and glomerular cells size. However overtime, tubular atrophy and tubulointerstitial fibrosis occurs as subsequent changes in tubular cell hypertrophy, which is associated with the infiltration of fibroblast cells into the tubulointerstitial space. The rate of deterioration of kidney function shows a strong correlation with the degree of tubulointerstitial fibrosis. A consequence of long-standing diabetes/hyperglycemia may lead to major changes in renal structure that occur but not specific only to nephropathy. Identifying type of cells that involves in renal atrophy and hypertrophy may help to find a therapeutic target to treat diabetic nephropathy. In summary, the early changes in diabetic kidney are mainly includes the increase in tubular basement membrane thickening which lead to renal hypertrophy. On the other hand, only renal tubule is subjected to apoptosis, which is one of the characteristic morphologic changes in diabetic kidney to form tubular atrophy at the late stage of diabetes.

Urinary antimicrobial peptides: Potential novel biomarkers of obstructive uropathy

INTRODUCTION

Antimicrobial peptides (AMPs) have historically been evaluated for their role in protecting against uropathogens. However, there is mounting evidence to support their expression in noninfectious injury, with unclear meaning as to their function. It is possible that AMPs represent urothelial injury. Urinary tract obstruction is known to alter the urothelium; however, AMPs have not been evaluated for expression in this noninfectious injury.

OBJECTIVE

A pilot study to compare urinary AMP expression in children undergoing surgical intervention for ureteropelvic junction obstruction (UPJO) with nonobstructed controls.

STUDY DESIGN

Bladder urine was collected from consenting/assenting pediatric patients with UPJO at intervention. Control bladder urines were obtained from age-matched and sex-matched healthy children without known obstruction or infection. Enzyme-linked immunosorbent assays were run for the following AMPs: β defense 1 (BD-1), neutrophil gelatinase-associated lipocalin (NGAL), cathelicidin (LL-37), hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), and human α defensin 5 (HD-5); and normalized to urine creatinine. Results were analyzed with Student's t-test or Mann-Whitney U test, when appropriate, and receiver operating characteristic curves. A P-value of <0.05 was considered significant.

RESULTS

Thirty bladder urine samples were obtained from children with UPJO at the time of decompressive intervention. Mean patient age was 4.7 years (range 0.3-18.4); 20 (67%) patients were male. Fifteen bladder urine samples were obtained from age-matched and sex-matched controls. Urinary AMP levels were significantly higher in UPJO patients than controls for BD-1 (P = 0.015), NGAL (P < 0.001), LL-37 (P < 0.001), and HIP/PAP (P = 0.046). Optimal threshold values of these AMPs were determined, with each demonstrating significant odds ratios of predicting urinary obstruction.

DISCUSSION

Certain urinary AMPs are altered even in noninfectious urinary tract pathology. This represents a novel induction of AMP expression, as the current study is the first to report elevations in BD-1 and HIP/PAP in urinary tract obstruction. This suggests other roles for these AMPs outside of their antimicrobial properties, and likely is a reflection of the urothelial and tubular stress resulting from obstructive uropathy.

CONCLUSIONS

Induction of AMPs BD-1, NGAL, LL-37, and HIP/PAP was found to occur in urinary tract obstruction. Further evaluation of AMP expression as a biomarker of uroepithelial injury outside of infection is indicated.

Markers of early progressive renal decline in type 2 diabetes suggest different implications for etiological studies and prognostic tests development

To identify determinants of early progressive renal decline in type 2 diabetes a range of markers was studied in 1032 patients enrolled into the 2nd Joslin Kidney Study. eGFR slopes estimated from serial measurements of serum creatinine during 5-12 years of follow-up were used to define early renal decline. At enrollment, all patients had normal eGFR, 58% had normoalbuminuria and 42% had albuminuria. Early renal decline developed in 6% and in 18% patients, respectively. As determinants, we examined baseline values of clinical characteristics, circulating markers: TNFR1, KIM-1, and FGF23, and urinary markers: albumin, KIM-1, NGAL, MCP-1, EGF (all normalized to urinary creatinine) and the ratio of EGF to MCP-1. In univariate analysis, all plasma and urinary markers were significantly associated with risk of early renal decline. When analyzed together, systolic blood pressure, TNFR1, KIM-1, the albumin to creatinine ratio, and the EGF/MCP-1 ratio remained significant with the latter having the strongest effect. Integration of these markers into a multi-marker prognostic test resulted in a significant improvement of discriminatory performance of risk prediction of early renal decline, compared with the albumin to creatinine ratio and systolic blood pressure alone. However, the positive predictive value was only 50% in albuminuric patients. Thus, markers in plasma and urine indicate that the early progressive renal decline in Type 2 diabetes has multiple determinants with strong evidence for involvement of tubular damage. However, new, more informative markers are needed to develop a better prognostic test for such decline that can be used in a clinical setting.

Postrenal acute kidney injury in a patient with unilateral ureteral obstruction caused by urolithiasis: A case report

RATIONALE

In patients with bilateral ureteral obstruction, the serum creatinine levels are often elevated, sometimes causing postrenal acute kidney injury (AKI). In contrast, those with unilateral ureteral obstruction present normal serum creatinine levels, as long as their contralateral kidneys are preserved intact. However, the unilateral obstruction of the ureter could affect the renal function, as it humorally influences the renal hemodynamics.

PATIENT CONCERNS

A 66-year-old man with a past medical history of hypertension and diabetes mellitus came to our outpatient clinic because of right abdominal dullness.

DIAGNOSES

Unilateral ureteral obstruction caused by a radio-opaque calculus in the right upper ureter and a secondary renal dysfunction.

INTERVENTIONS

As oral hydration and the use of calcium antagonists failed to allow the spontaneous stone passage, extracorporeal shock wave lithotripsy (ESWL) was performed.

OUTCOMES

Immediately after the passage of the stone, the number of red blood cells in the urine was dramatically decreased and the serum creatinine level almost returned to the normal range with the significant increase in glomerular filtration rate.

LESSONS

Unilateral ureteral obstruction by the calculus, which caused reflex vascular constriction and ureteral spasm in the contralateral kidney, was thought to be responsible for the deteriorating renal function.

The role of urinary KIM-1, NGAL, CA19-9 and β2-microglobulin in the assessment of ureteropelvic junction obstruction in adults

PURPOSE

The objective of this study is to evaluate the diagnostic properties of urinary biomarkers in adults with ureteropelvic junction obstruction: KIM-1, NGAL, CA19-9, and β2-microglobulin. We also assessed urinary biomarker concentrations following pyeloplasty.

MATERIAL AND METHODS

We prospectively studied adults from December 2013 to February 2015. We included 47 patients with a mean age of 38.6 ± 12.7 years. Each patient provided four samples of voided urine for biomarker measurement, one at pre-operative consultation and the others at 1, 3, and 6 months of post-operative follow-up. The control group consisted of 40 healthy individuals with no hydronephrosis on ultrasound evaluation.

RESULTS

KIM-1 had an area under the curve of 0.79 (95% CI 0.70-0.89), NGAL 0.71 (95% CI 0.61-0.83), CA19-9 0.70 (95% CI 0.60-0.81), and β2-microgloblin 0.61 (95% CI 0.50-0.73). KIM-1 was the most sensitive marker with a cut-off of 170.4 pg/mg creatinine (sensitivity 91.4%, specificity 59.1%), whereas CA19-9 was the most specific with a cut-off of 51.3 U/mg creatinine (sensitivity 48.9%, specificity 88.0%). Urinary concentrations of biomarkers decreased after pyeloplasty.

CONCLUSIONS

The evaluation of urinary biomarkers is useful in adults undergoing pyeloplasty. KIM-1, NGAL, and CA19-9 were elevated and significantly decreased after surgery.

Circulating kidney injury molecule-1 is a novel diagnostic biomarker for renal dysfunction during long-term adefovir therapy in chronic hepatitis B

The aim of this study was to evaluate serum kidney injury molecule-1 (KIM-1) as a new diagnostic marker of renal dysfunction in chronic hepatitis B (CHB) patients receiving long-term adefovir dipivoxil (ADV) treatment.We retrospectively enrolled 85 patients treated with ADV and 85 patients treated with entecavir (ETV) monotherapy, for at least 6 months. The 2 groups were matched for baseline age (± 5 years), sex, and estimated glomerular filtration rate (eGFR). Serum creatinine, cystatin C, and KIM-1 concentrations were measured, and eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine-cystatin C equation, at baseline and last follow-up.eGFR decreased by 10-20% from baseline in 11/85 (14.1%) patients, 20-30% in 5/85 (5.9%), and ≥ 30% in 2/85 (2.4%) patients treated with ADV. Serum KIM-1 was more significantly increased after ADV treatment 86.53 (10.20-355.40) pg/mL than ETV treatment 61.54 (10.53-200.56) pg/mL (P < 0.01). Furthermore, serum KIM-1 was positively correlated with serum cystatin C (r = 0.47; P < 0.001) and negatively correlated with eGFR (r = -0.46; P < 0.001). The area under the receiver operating characteristic curve (AUC-ROC) of serum KIM-1 for identifying renal dysfunction in all enrolled patients was 0.94 (95% confidence interval [95% CI], 0.87 to 1.02; P < 0.001), while the AUC-ROC of serum creatinine was only 0.82 (95% CI, 0.60 to 1.03; P < 0.01).Serum KIM-1 is a promising new diagnostic biomarker of renal dysfunction during long-term ADV therapy for CHB patients.

Evaluation and management of hydronephrosis in the neonate

PURPOSE OF REVIEW

The prenatal detection of congenital anomalies of the kidney and urinary tract (CAKUT) has permitted the early management of these conditions. The aim of this review is to provide an overview of the management of neonates with antenatal hydronephrosis (ANH).

RECENT FINDINGS

In spite of the continuous advances in the understanding of the genetic basis, clinical course, and outcomes of CAKUT, there are still many controversies regarding the clinical significance, postnatal evaluation, and management of neonates with ANH. Mild ANH will often resolve spontaneously, whereas moderate to severe ANH is frequently associated with CAKUT.

SUMMARY

ANH is a surrogate marker of potential congenital renal anomalies, but usually cannot identify a specific disease. A multidisciplinary team approach is required to diagnose and treat these complex disorders. Currently nonsurgical management of CAKUT should be considered whenever possible for infants with ANH.

Urinary neutrophil gelatinase-associated lipocalin is associated with heavy metal exposure in welding workers

Metals cause nephrotoxicity with acute and/or chronic exposure; however, few epidemiological studies have examined impacts of exposure to metal fumes on renal injury in welding workers. In total, 66 welding workers and 12 office workers were recruited from a shipyard located in southern Taiwan. Urine samples from each subject were collected at the beginning (baseline) and end of the work week (1-week exposure). Personal exposure to PM_2.5 was measured. The 8-h mean PM_2.5 was 50.3 μg/m³ for welding workers and 27.4 μg/m³ for office workers. iTRAQs coupled with LC-MS/MS were used to discover the pathways in response to welding PM_2.5 in the urine, suggesting that extracellular matrix (ECM)-receptor interactions are a critical mechanism. ECM-receptor interaction-related biomarkers for renal injury, kidney injury molecule (KIM)-1 and neutrophil gelatinase-associated lipocalin (NGAL), were significantly elevated in welding workers post-exposure, as well as were urinary Al, Cr, Mn, Fe, Co, and Ni levels. NGAL was more significantly associated with Al (r = 0.737, p < 0.001), Cr (r = 0.705, p < 0.001), Fe (r = 0.709, p < 0.001), and Ni (r = 0.657, p < 0.001) than was KIM-1, suggesting that NGAL may be a urinary biomarker for welding PM_2.5 exposure. Nephrotoxicity (e.g., renal tubular injury) may be an emerging concern in occupational health.

Kidney Injury Molecule-1 and Cardiovascular Diseases: From Basic Science to Clinical Practice

Despite the recent findings concerning pathogenesis and novel therapeutic strategies, cardiovascular disease (CVD) still stays the leading cause of morbidity and mortality in patients with renal dysfunction, especially acute kidney injury (AKI). Early detection of patients with impaired renal function with cardiovascular risk may help ensure more aggressive treatment and improve clinical outcome. Kidney injury molecule-1 (KIM-1) is a new, promising marker of kidney damage which is currently the focus of countless studies worldwide. Some recent animal and human studies established KIM-1 as an important marker of acute tubular necrosis (ATN) and reliable predictor of development and prognosis of AKI. Food and Drug Administration (FDA) in USA acclaimed KIM-1 as an AKI biomarker for preclinical drug development. Recent data suggest the importance of monitoring of KIM-1 for early diagnosis and clinical course not only in patients with various forms of AKI and other renal diseases but also in patients with cardiorenal syndrome, heart failure, cardiopulmonary bypass, cardiothoracic surgical interventions in the pediatric emergency setting, and so forth. The aim of this review article is to summarize the literature data concerning KIM-1 as a potential novel marker in the early diagnosis and prediction of clinical outcome of certain cardiovascular diseases.

Urine exoglycosidases are potential markers of renal tubular injury in children with ureteropelvic junction obstruction

AIM

Hydronephrosis caused by ureteropelvic junction obstruction (UPJO) is an important problem in children and young adults. The aim of this pilot study was to determine the urine profiles of a number of lysosomal exoglycosidases to see whether they indicated tubular renal damage in children with UPJO.

METHODS

We measured lysosomal exoglycosidases urine activities in 32 patients with UPJO, dividing them into three groups. The surgical group comprised 16 children with severe hydronephrosis who required surgery, the nonsurgical group comprised 16 patients with mild hydronephrosis, and the reference group comprised 42 healthy children. The following indicators were measured: N-acetyl-β-hexosaminidase and its A and B isoenzymes, α-fucosidase, β-galactosidase, α-mannosidase and β-glucuronidase.

RESULTS

The urine activities of all exoglycosidases were significantly higher in children with UPJO than children in the reference group (p < 0.01). A strong positive correlation was also found between most of the urine exoglycosidases and the urine albumin/creatinine ratio (p < 0.01).

CONCLUSION

Our findings demonstrated that children with UPJO showed increased renal activities of assessed exoglycosidases, which correlated positively with the urine albumin/creatinine ratio. A larger multicentre study is required to confirm the clinical applications of these observations.

Neutrophil gelatinase-associated lipocalin in kidney transplantation: A review

Neutrophil gelatinase-associated lipocalin (NGAL) is a protein expressed by kidney tubular cells in response to ischemia, but may also be an early indicator of immunological rejection, calcineurin inhibitor toxicity, obstructive nephropathy, subclinical tubulitis or infection. Although there is currently no evidence to support the routine serial measurement of blood or urinary NGAL to detect subclinical acute tubular injury, NGAL has the potential to provide useful information to those that care for kidney transplant recipients (KTRs). First, high urinary or serum NGAL concentrations shortly after transplantation are a predictor of delayed graft function and are associated with reduced graft function at one year. Secondly, among KTRs with previously stable graft function who then suffer acute graft dysfunction, a high urinary NGAL predicts graft loss at one year. If further refined, diagnostic tests based on NGAL levels may provide future useful clinical tools.

Novel biomarkers of acute kidney injury: Evaluation and evidence in urologic surgery

Patients undergoing urologic surgery are at risk of acute kidney injury (AKI) and consequently long-term deterioration in renal function. AKI is further associated with significantly higher odds of perioperative complications, prolonged hospital stay, higher mortality and costs. Therefore, better awareness and detection of AKI, as well as identification of AKI determinants in the urological surgery setting is warranted to pre-empt and mitigate further deterioration of renal function in patients at special risk. New consensus criteria provide precise definitions of diagnosis and description of the severity of AKI. However, they rely on serum creatinine (SCr), which is known to be an inaccurate marker of early changes in renal function. Therefore, several new urinary and serum biomarkers promise to address the gap associated with the use of SCr. Novel biomarkers may complement SCr measurement or most likely improve the diagnostic accuracy of AKI when used in combinations. However, novel biomarkers have to prove their clinical applicability, accuracy, and cost effectiveness prior to implementation into clinical practice. Most preferably, novel biomarkers should help to positively improve a patient’s long-term renal functional outcomes. The purpose of this review is to discuss currently available biomarkers and to review their clinical evidence within urologic surgery settings.