The value of newborn urinary proteome analysis in the evaluation and management of ureteropelvic junction obstruction: a cost-effectiveness study

Current status and future directions of application of urine proteomics in neonatology

With continuous advancements in mass spectrometry technology, researchers increasingly utilize this method to investigate the molecular mechanisms underlying various diseases, and to identify novel diagnostic and therapeutic strategies. Among proteomics applications, urinary proteomics stands out for its non-invasive nature, making it particularly suitable for vulnerable populations like neonates. This review provides a comprehensive overview of recent research on urinary proteomics in the field of neonatology. It summarizes findings from numerous studies, illustrating how urinary proteomic profiles provide critical insights into neonatal health and disease. By identifying specific protein biomarkers in urine, researchers can gain insights into the early detection and monitoring of neonatal diseases, potentially leading to more timely and effective interventions. As technology evolves, the sensitivity and accuracy of proteomic analyses are expected to improve, opening new avenues for research and clinical applications.

Crowdsourcing utility estimation for spina bifida in the general population

INTRODUCTION

Cost-utility analyses (CUA) are useful when the treatment conditions depend on patient preferences that are in turn dependent on health state utility value. Spina bifida (SB) is an example of such a preference-sensitive condition. Historically, the SB utility value for CUA has been gathered via a traditional face-to-face interview. However, due to funding and time constrains, utility estimation via online crowdsourcing has recently gained popularity. Our aim was to estimate the utility value for a generic SB health state using a validated online tool.

METHODS

A cross-sectional survey of American adults was conducted using the time-trade-off (TTO) method. Participants were recruited from an online crowdsourcing interface, Amazon's Mechanical Turk (mTurk). Demographic information and prior knowledge of SB were assessed. Respondents were provided a written passage and an online video explaining SB and its potential associated comorbidities. Participants were queried on hypothetical ascending time-trades from a child-parent dyad perspective to determine the utility of a SB health state in an affected 6-year-old child. Respondents were also asked to indicate the percentage of time traded from their life in relation to their child's. Utility estimates were then calculated and compared using bivariate and multivariate analyses.

RESULTS

We obtained 503 responses (85% response rate). Mean respondent age was 34 (± 11); 247 (49%) were female; 386 (77%) were white; 189 (38%) were married, and 234 (46%) had children. Mean proportion of longevity traded by participants in the dyadic interaction was 66% (± 27) from the parent's life. Only 51 respondents (9%) reported having "ample" prior knowledge of SB; 8 respondents (0.02%) had SB themselves. Few others had previous experience with SB or myelomeningocele either in a child (4, 1%), or friend/relative (28, 5%). Compared with a perfect health state of 1.0, we found mean utilities of 0.85 (± 0.20) for SB.

CONCLUSIONS

Utility estimation for SB is feasible through crowdsourcing, and the resultant values are similar to previous estimates using traditional techniques. Subjects view the SB health state to be inferior to perfect health.

The nephrologist of tomorrow: towards a kidney-omic future

Omics refers to the collective technologies used to explore the roles and relationships of the various types of molecules that make up the phenotype of an organism. Systems biology is a scientific discipline that endeavours to quantify all of the molecular elements of a biological system. Therefore, it reflects the knowledge acquired by omics in a meaningful manner by providing insights into functional pathways and regulatory networks underlying different diseases. The recent advances in biotechnological platforms and statistical tools to analyse such complex data have enabled scientists to connect the experimentally observed correlations to the underlying biochemical and pathological processes. We discuss in this review the current knowledge of different omics technologies in kidney diseases, specifically in the field of pediatric nephrology, including biomarker discovery, defining as yet unrecognized biologic therapeutic targets and linking omics to relevant standard indices and clinical outcomes. We also provide here a unique perspective on the field, taking advantage of the experience gained by the large-scale European research initiative called "Systems Biology towards Novel Chronic Kidney Disease Diagnosis and Treatment" (SysKid). Based on the integrative framework of Systems biology, SysKid demonstrated how omics are powerful yet complex tools to unravel the consequences of diabetes and hypertension on kidney function.

Renal injury in neonates: use of "omics" for developing precision medicine in neonatology

Preterm birth is associated with increased risks of morbidity and mortality along with increased healthcare costs. Advances in medicine have enhanced survival for preterm infants but the overall incidence of major morbidities has changed very little. Abnormal renal development is an important consequence of premature birth. Acute kidney injury (AKI) in the neonatal period is multifactorial and may increase lifetime risk of chronic kidney disease.Traditional biomarkers in newborns suffer from considerable confounders, limiting their use for early identification of AKI. There is a need to develop novel biomarkers that can identify, in real time, the evolution of renal dysfunction in an early diagnostic, monitoring and prognostic fashion. Use of "omics", particularly metabolomics, may provide valuable information regarding functional pathways underlying AKI and prediction of clinical outcomes.The emerging knowledge generated by the application of "omics" (genomics, proteomics, metabolomics) in neonatology provides new insights that can help to identify markers of early diagnosis, disease progression, and identify new therapeutic targets. Additionally, omics will have major implications in the field of personalized healthcare in the future. Here, we will review the current knowledge of different omics technologies in neonatal-perinatal medicine including biomarker discovery, defining as yet unrecognized biologic therapeutic targets, and linking of omics to relevant standard indices and long-term outcomes.

Economic analysis of continuous antibiotic prophylaxis for prevention of urinary tract infections in infants with high-grade hydronephrosis

BACKGROUND

For infants with hydronephrosis, continuous antibiotic prophylaxis (CAP) may reduce urinary tract infections (UTIs); however, its value remains controversial. Recent studies have suggested that neonates with severe obstructive hydronephrosis are at an increased risk of UTIs, and support the use of CAP. Other studies have demonstrated the negligible risk for UTIs in the setting of suspected ureteropelvic junction obstruction and have highlighted the limited role of CAP in hydronephrosis. Furthermore, economic studies in this patient population have been sparse.

OBJECTIVE

This study aimed to evaluate whether the use of CAP is an efficient expenditure for preventing UTIs in children with high-grade hydronephrosis within the first 2 years of life.

STUDY DESIGN

A decision model was used to estimate expected costs, clinical outcomes and quality-adjusted life years (QALYs) of CAP versus no CAP (Fig. 1). Cost data were collected from provincial databases and converted to 2013 Canadian dollars (CAD). Estimates of risks and health utility values were extracted from published literature. The analysis was performed over a time horizon of 2 years. One-way and probabilistic sensitivity analyses were carried out to assess uncertainty and robustness.

RESULTS

Overall, CAP use was less costly and provided a minimal increase in health utility when compared to no CAP (Table). The mean cost over two years for CAP and no CAP was CAD$1571.19 and CAD$1956.44, respectively. The use of CAP reduced outpatient-managed UTIs by 0.21 infections and UTIs requiring hospitalization by 0.04 infections over 2 years. Cost-utility analysis revealed an increase of 0.0001 QALYs/year when using CAP. The CAP arm exhibited strong dominance over no CAP in all sensitivity analyses and across all willingness-to-pay thresholds.

DISCUSSION

The use of CAP exhibited strong dominance in the economic evaluation, despite a small gain of 0.0001 QALYs/year. Whether this slight gain is clinically significant remains to be determined. However, small QALY gains have been reported in other pediatric economic evaluations. Strengths of this study included the use of data from a recent systematic review and meta-analysis, in addition to a comprehensive probabilistic sensitivity analysis. Limitations of this study included the use of estimates for UTI probabilities in the second year of life and health utility values, given that they were lacking in the literature. Spontaneous resolution of hydronephrosis and surgical management were also not implemented in this model.

CONCLUSION

To prevent UTIs within the first 2 years of life in infants with high-grade hydronephrosis, this probabilistic model has shown that CAP use is a prudent expenditure of healthcare resources when compared to no CAP.

Proteomic urinary biomarker approach in renal disease: from discovery to implementation

Biomarkers hold the promise of significantly improving health care by enabling prognosis and diagnosis with improved accuracy, and at earlier points in time. Previous results have indicated that single biomarkers are not suitable to describe complex diseases such as kidney disease. Here we provide an update on the progress of urinary proteomics-based studies and strategies to develop biomarker-based classifiers that tolerate instability and inconsistency of individual biomarkers. The examples focus on two major fields in nephrology: chronic kidney disease in the adult population and obstructive nephropathies in the pediatric population. When employed adequately, urinary proteomics demonstrates a clear value in kidney disease, indicating that the current status quo ruling for decades now could be changed by applying modern "omics" approaches. However, while research is able to deliver these useful tools for patient management, the issues associated with implementation are not yet solved. Active engagement of the relevant clinical professional societies, as well as patient's organizations, might help to implement these omics approaches that have shown a clear benefit for the patient.

Clinical proteomics in obstetrics and neonatology

Clinical proteomics has been applied to the identification of biomarkers of obstetric and neonatal disease. We will discuss a number of encouraging studies that have led to potentially valid biomarkers in the context of Down's syndrome, preterm birth, amniotic infections, preeclampsia, intrauterine growth restriction and obstructive uropathies. Obtaining noninvasive biomarkers (e.g., from the maternal circulation, urine or cervicovaginal fluid) may be more feasible for obstetric diseases than for diseases of the fetus, for which invasive methods are required (e.g., amniotic fluid, fetal urine). However, studies providing validated proteomics-identified biomarkers are limited. Efforts should be made to save well-characterized samples of these invasive body fluids so that many valid biomarkers of pregnancy-related diseases will be identified in the coming years using proteomics based analysis upon adoption of 'clinical proteomics guidelines'.

Glomerular filtration rate and urine osmolality in unilateral ureteropelvic junction obstruction

Background:

Renal maldevelopment, interstitial fibrosis, ischemic atrophy, decreased glomerular filtration rate (GFR), and renal blood flow (RBF) are inevitable consequences of chronic kidney obstruction that only partially improve after early intervention. There are only few studies that evaluated urine osmolality in affected kidney and its correlation with short-term outcome.

Materials and Methods:

Thirty patients (age<1 year) with unilateral ureteropelvic junction obstruction (UUPJO) were enrolled in this study. UUPJO was confirmed using Technetium 99 isotope scans and the patients were indicated to be operated afterward. Urine and blood samples were obtained before, 24, 48, and 72 h after the surgery. The serum level of blood urea nitrogen, creatinine, and glucose were measured. GFR, urine osmolality (measured and calculated), and urine specific gravity were determined too.

Results:

Cortical thickness of hydronephrotic kidney was significantly increased 6 months after the surgery. GFR was significantly increased 72-h postsurgery compared to before operation.

Neither means of calculated nor of measured urine osmolalities were significantly different in various stages. The last calculated urine osmolality (72 h) had significant correlation with the last measured osmolality (72 h); r=0.962, P=0.0001. The last GFR (72 h) had positive significant correlation with GFR before the surgery and GFRs at 24 and 48 h postsurgery.

Using regression tests, only the before surgery GFR was the predictor of the last GFR(72 h).

Conclusion:

In UUPJO the measured and calculated urine osmolality of the affected kidney did not differ. In addition, GFR before surgery should be considered as the predictor of the GFR shortly after repair.

How to get proteomics to the clinic? Issues in clinical proteomics, exemplified by CE-MS

Clinical proteomics is defined as application of proteome analysis aiming at improving the current clinical situation. As such, the success of clinical proteomics should be assessed based on the clinical impact following implementation of the findings. While we have experienced significant technological advancements in mass spectrometry in the last years, based on the above measure, this has not at all resulted in similar advancements in clinical proteomics. Although a large number of proteomic biomarkers have been described, most of them were not subsequently validated, and certainly have had no impact in clinical decision making as yet. Under the current conditions, it appears likely that the situation will not change significantly: we will be flooded by reports on biomarkers, but not see any implementation. In this article, some key issues in proteomic biomarker research are pinpointed, based on the experience with CE-MS, likely also holding true for biomarkers resulting from other analysis domains.

Hydronephrosis: a view from the inside

Unilateral ureteropelvic junction obstruction (UPJO) is the most common prenatally detected disease leading to hydronephrosis. The obstructive anatomic lesion leads to varying degrees of hydronephrosis, ranging from no apparent effect on renal function to atrophy. Furthermore, the natural course of hydronephrosis varies from spontaneous resolution to progressive deterioration and may take upwards of 3 years for a kidney to declare itself. The objectives of this article are to update our knowledge regarding the evaluation and management of UPJO in depth and to discuss the emerging value of urinary proteome analysis to the clinical arena.

Urinary proteome analysis identifies infants but not older children requiring pyeloplasty

One out of every five children suffering from ureteropelvic junction obstruction (UPJO) requires pyeloplasty. This prevalence indicates an urgent necessity to identify high-grade UPJO as early as possible to avoid renal damage. A novel non-invasive proteomic urine test has recently been introduced that is able to detect these patients at an early stage. In the study reported here, we tested this approach to assess its use in our centre and to expand its application to older children. Twenty-seven children (median age 0.4 years, range 0.1-8.8 years) with hydronephrosis who had been scheduled a nuclear diuretic renal scan (DR) to identify urodynamically relevant UPJO were included in our prospective study. Patients with prior surgery of the urinary tract were excluded. The urinary proteome pattern was analysed using capillary electrophoresis coupled to mass spectrometry. Of the 27 children, 11 had a relevant UPJO diagnosed by the DR. In 19 children <1 year of age, urinary proteome analysis predicted obstruction with a sensitivity of 83% (5/6) and a specificity of 92% (12/13). However, in older patients, the sensitivity decreased to 20% (1/5) and specificity to 66% (2/3). Based on our results, the proteome pattern established by Decramer and co-workers predicts the need for surgery in infants but not in older children with UPJO.

Urinary proteome analysis and the management of ureteropelvic junction obstruction

Ureteropelvic junction obstruction (UPJO) detected prenatally may over time deteriorate and require surgery, improve, or remain stable, and it may take upwards of 3 years for its natural history to unfold. Clinical decisions for or against operative corrections are usually based on scintigraphy follow-up studies. A non-invasive method for facilitating clinical decisions has recently been presented: urinary proteome analysis utilizing capillary electrophoresis mass spectrometry (CE-MS) has been shown to predict the outcome of UPJO in newborns. The group that developed this assay has now validated their seminal findings and extended the investigations to older age groups (this issue). The results of the blinded analysis correctly identified patients with UPJO who underwent surgery with a sensitivity of 83% (5 of 6 patients) and a specificity of 92% (12 of 13 patients) in infants up to 1 year of age. The validity of the analysis was poor in children >1 year of age with unilateral UPJO. A large number of patients will be needed to answer the question of to what extent the normal variability of urinary proteomes overlap with the variability of the pattern in UPJO beyond early infancy.

Advances in urinary proteome analysis and biomarker discovery in pediatric renal disease

Recent progress in proteomic analysis and strategies for the identification of clinically useful biomarkers in biofluids has led to the identification of urine as an excellent non-invasive reservoir for biomarkers of disease. Urinary biomarkers have been identified and validated on independent cohorts in different high-incidence adult renal diseases, including diabetic nephropathy, chronic kidney disease and immunoglobulin A-nephropathy, but also in extrarenal disease, such as coronary artery disease. Unfortunately, this type of research is underrepresented in the pediatric population. Here, we present the rare studies in the pediatric population that identified potential clinically useful urinary biomarkers in ureteropelvic junction (UPJ) obstruction and renal Fanconi syndrome. These studies, although limited in number, clearly show the potential of urinary proteomics, especially in the pediatric population. It is anticipated that the advances made in the adult population, the lessons learned on the use of appropriate statistics and the inclusion of independent blinded validation cohorts in these types of studies will rapidly lead to clinical useful urinary biomarkers for other pediatric (renal) disease in a population where non-invasive analysis is particularly appreciated.