Use of protein:creatinine ratio measurements on random urine samples for prediction of significant proteinuria: a systematic review

Handheld Biosensor System Based on a Gradient Grating Period Guided-Mode Resonance Device

Handheld biosensors have attracted substantial attention for numerous applications, including disease diagnosis, drug dosage monitoring, and environmental sensing. This study presents a novel handheld biosensor based on a gradient grating period guided-mode resonance (GGP-GMR) sensor. Unlike conventional GMR sensors, the proposed sensor's grating period varies along the device length; hence, the resonant wavelength varies linearly along the device length. If a GGP-GMR sensor is illuminated with a narrow band of light at normal incidence, the light resonates and reflects at a specific period but transmits at other periods; this can be observed as a dark band by using a complementary metal oxide semiconductor (CMOS) underneath the sensor. The concentration of a target analyte can be determined by monitoring the shift of this dark band. We designed and fabricated a handheld device incorporating a light-emitting diode (LED) light source, the necessary optics, an optofluidic chip with an embedded GGP-GMR sensor, and a CMOS. LEDs with different beam angles and bandpass filters with different full width at half maximum values were investigated to optimize the dark band quality and improve the accuracy of the subsequent image analysis. Substrate materials with different refractive indices and waveguide thicknesses were also investigated to maximize the GGP-GMR sensor's figure of merit. Experiments were performed to validate the proposed handheld biosensor, which achieved a limit of detection (LOD) of 1.09 × 10-3 RIU for bulk solution measurement. The sensor's performance in the multiplexed detection of albumin and creatinine solutions at concentrations of 0-500 μg/mL and 0-10 mg/mL, respectively, was investigated; the corresponding LODs were 0.66 and 0.61 μg/mL.

The correlation of spot urinary protein-to-creatinine ratio with 24-h urinary protein excretion in various glomerulopathies

BACKGROUND

Proteinuria is an important and well-known biomarker of many forms of kidney injury. Its quantitation is of particular importance in the diagnosis and management of glomerular diseases. Its quantification can be done by several methods. Among these, the measurement of 24-h urinary protein excretion is the gold standard method. However, it is cumbersome, time-consuming, and inconvenient for patients and is not completely foolproof. Many alternative methods have been tested over time albeit with conflicting results. Among the latter, the measurement of urine protein-to-creatinine ratio (uPCR) in single-voided urinary samples is widely used. The majority of studies found a good correlation between uPCR in single urine samples with 24-h urinary protein estimation, whereas others did not.

AIM

To investigate the correlation of spot uPCR with 24-h urinary protein estimation in patients suffering from different forms of glomerulopathies at a single large-volume nephrological center in Pakistan.

METHODS

This cross-sectional, observational study was conducted at the Department of Nephrology, Sindh Institute of Urology and Transplantation, Karachi, Pakistan from September 2017 to March 2018. All newly presenting adult patients with proteinuria who were being investigated for suspected glomerulonephritis and persistent proteinuria with ages between 18 to 60 years were enrolled. All patients were given detailed advice regarding 24-h urine collection starting at 7:00 AM for total protein and creatinine excretion estimations. A spot urine sample was collected the next day at the time of submission of a 24-h urine sample for measuring uPCR along with a blood sample. The data of patients were collected in a proforma. SPSS version 20.0 was used for statistical analysis.

RESULTS

A total of 157 patients were included. Their mean age was 30.45 ± 12.11 years. There were 94 (59.8%) males and 63 (40.2%) females. The mean 24-h urinary protein excretion was 3192.78 ± 1959.79 mg and the mean spot uPCR was 3.16 ± 1.52 in all patients. A weak but significant correlation was observed between spot uPCR and 24-h urinary protein excretion (r = 0.342, P = 0.01) among all patients. On subgroup analysis, a slightly better correlation was found in patients older than 47 years (r = 0.78), and those with body mass index > 25 kg/m2 (r = 0.45). The Bland and Altman's plot analysis comparing the differences between spot uPCR and 24-h protein measurement also showed a wide range of the limits of agreement between the two methods.

CONCLUSION

Overall, the results from this study showed a significant and weakly positive correlation between spot uPCR and 24-h urinary protein estimation in different forms of glomerulopathies. The agreement between the two methods was also poor. Hence, there is a need for careful interpretation of the ratio in an unselected group of patients with kidney disease.

Gradient Guided-Mode Resonance Biosensor with Smartphone Readout

Integrating biosensors with smartphones is becoming an increasingly popular method for detecting various biomolecules and could replace expensive laboratory-based instruments. In this work, we demonstrate a novel smartphone-based biosensor system with a gradient grating period guided-mode resonance (GGP-GMR) sensor. The sensor comprises numerous gratings which each correspond to and block the light of a specific resonant wavelength. This results in a dark band, which is observed using a CCD underneath the GGP-GMR sensor. By monitoring the shift in the dark band, the concentration of a molecule in a sample can be determined. The sensor is illuminated by a light-emitting diode, and the light transmitted through the GGP-GMR sensor is directly captured by a smartphone, which then displays the results. Experiments were performed to validate the proposed smartphone biosensor and a limit of detection (LOD) of 1.50 × 10-3 RIU was achieved for sucrose solutions. Additionally, multiplexed detection was demonstrated for albumin and creatinine solutions at concentrations of 0-500 and 0-1 mg/mL, respectively; the corresponding LODs were 1.18 and 20.56 μg/mL.

Hyaluronic acid-British anti-Lewisite as a safer chelation therapy for the treatment of arthroplasty-related metallosis

Cobalt-containing alloys are useful for orthopedic applications due to their low volumetric wear rates, corrosion resistance, high mechanical strength, hardness, and fatigue resistance. Unfortunately, these prosthetics release significant levels of cobalt ions, which was only discovered after their widespread implantation into patients requiring hip replacements. These cobalt ions can result in local toxic effects-including peri-implant toxicity, aseptic loosening, and pseudotumor-as well as systemic toxic effects-including neurological, cardiovascular, and endocrine disorders. Failing metal-on-metal (MoM) implants usually necessitate painful, risky, and costly revision surgeries. To treat metallosis arising from failing MoM implants, a synovial fluid-mimicking chelator was designed to remove these metal ions. Hyaluronic acid (HA), the major chemical component of synovial fluid, was functionalized with British anti-Lewisite (BAL) to create a chelator (BAL-HA). BAL-HA effectively binds cobalt and rescues in vitro cell vitality (up to 370% of cells exposed to IC50 levels of cobalt) and enhances the rate of clearance of cobalt in vivo (t1/2 from 48 h to 6 h). A metallosis model was also created to investigate our therapy. Results demonstrate that BAL-HA chelator system is biocompatible and capable of capturing significant amounts of cobalt ions from the hip joint within 30 min, with no risk of kidney failure. This chelation therapy has the potential to mitigate cobalt toxicity from failing MoM implants through noninvasive injections into the joint.

Renal tubular response to titanium dioxide nanoparticles exposure

Titatinum dioxide nanoparticles (TiO2-NPs) are frequently used in several areas. Titanium alloys are employed in orthopedic and odontological surgery (such as hip, knee, and teeth implants). To evaluate the potential acute toxic effects of titanium pieces implantations and in other sources that allow the systemic delivery of titanium, parenteral routes of TiO2-NPs administration should be taken into account. The present study evaluated the impact of subcutaneous administration of TiO2-NPs on renal function and structure in rats. Animals were exposed to a dose of 50 mg/kg b.w., s.c. and sacrificed after 48 h. Titanium levels were detected in urine (135 ± 6 ηg/mL) and in renal tissue (502 ± 40 ηg/g) employing inductively coupled plasma mass spectrometry. An increase in alkaline phosphatase activity, total protein levels, and glucose concentrations was observed in urine from treated rats suggesting injury in proximal tubule cells. In parallel, histopathological studies showed tubular dilatation and cellular desquamation in these nephron segments. In summary, this study demonstrates that subcutaneous administration of TiO2-NPs causes acute nephrotoxicity evidenced by functional and histological alterations in proximal tubule cells. This fact deserves to be mainly considered when humans are exposed directly or indirectly to TiO2-NPs sources that cause the systemic delivery of titanium.

Neutrophils' Contribution to Periodontitis and Periodontitis-Associated Cardiovascular Diseases

Neutrophils represent the primary defense against microbial threats playing a pivotal role in maintaining tissue homeostasis. This review examines the multifaceted involvement of neutrophils in periodontitis, a chronic inflammatory condition affecting the supporting structures of teeth summarizing the contribution of neutrophil dysfunction in periodontitis and periodontal-related comorbidities. Periodontitis, a pathological condition promoted by dysbiosis of the oral microbiota, is characterized by the chronic inflammation of the gingiva and subsequent tissue destruction. Neutrophils are among the first immune cells recruited to the site of infection, releasing antimicrobial peptides, enzymes, and reactive oxygen species to eliminate pathogens. The persistent inflammatory state in periodontitis can lead to aberrant neutrophil activation and a sustained release of proinflammatory mediators, finally resulting in tissue damage, bone resorption, and disease progression. Growing evidence now points to the correlation between periodontitis and systemic comorbidities. Indeed, the release of inflammatory mediators, immune complexes, and oxidative stress by neutrophils, bridge the gap between local and systemic immunity, thus highlighting neutrophils as key players in linking periodontal inflammation to chronic conditions, including cardiovascular diseases, diabetes mellitus, and rheumatoid arthritis. This review underscores the crucial role of neutrophils in the pathogenesis of periodontitis and the complex link between neutrophil dysfunction, local inflammation, and systemic comorbidities. A comprehensive understanding of neutrophil contribution to periodontitis development and their impact on periodontal comorbidities holds significant implications for the management of oral health. Furthermore, it highlights the need for the development of novel approaches aimed at limiting the persistent recruitment and activation of neutrophils, also reducing the impact of periodontal inflammation on broader health contexts, offering promising avenues for improved disease management and patient care.

Consensus Statements from the Diabetologists & Endocrinologists Alliance for the Management of People with Hypertension and Type 2 Diabetes Mellitus

Hypertension and type 2 diabetes mellitus (T2DM) are important, intertwined public health issues. People with both conditions face significantly elevated risks of cardiovascular (CV) and renal complications. To optimize patient care, a multidisciplinary expert panel met to review recent evidence on optimal blood pressure (BP) targets, implications of albuminuria, and treatment regimens for hypertensive patients with T2DM, with the aim of providing recommendations for physicians in Hong Kong. The panel reviewed the relevant literature, obtained by searching PubMed for the publication period from January 2015 to June 2021, to address five discussion areas: (i) BP targets based on CV/renal benefits; (ii) management of isolated systolic or diastolic hypertension; (iii) roles of angiotensin II receptor blockers; (iv) implications of albuminuria for CV/renal events and treatment choices; and (v) roles and tools of screening for microalbuminuria. The panel held three virtual meetings using a modified Delphi method to address the discussion areas. After each meeting, consensus statements were derived and anonymously voted on by every panelist. A total of 17 consensus statements were formulated based on recent evidence and expert insights regarding cardioprotection and renoprotection for hypertensive patients with T2DM.

Vital NETosis vs. suicidal NETosis during normal pregnancy and preeclampsia

Background: NETosis occurs in the context of infection or inflammation and results in the expulsion of decondensed DNA filaments called NETs (Neutrophil Extracellular Traps) into the extracellular environment. NETosis activates coagulation and contributes to the thrombotic risk of inflammatory diseases. To date, two mechanisms of NETosis have been identified: suicidal NETosis, in which neutrophils die after expelling the filaments; and vital NETosis, in which expulsion appears without altering the membrane. Human pregnancy is associated with a mild pro-inflammatory state, which is increased in the event of complications such as preeclampsia (PE). NETosis has been observed in these situations, but the mechanism of its production has not yet been studied. The aim of our study was to evaluate the balance of vital vs. suicidal NETosis in normal pregnancy and in PE. Patients/Methods: Neutrophils from healthy volunteers were stimulated with plasma from normal pregnancies (n = 13) and from women developing preeclampsia (n = 13). Immunofluorescent labelling was performed to determine the percentages and origin of NETs in both groups. Inhibition with suicidal or vital NETosis inhibitors was also performed to validate our results. Results: We found a significant increase in NETs in women with PE compared to women with normal pregnancies. We showed that vital and non-vital NETosis are present in normal and preeclamptic pregnancies. We demonstrated that the higher proportion of NETs observed in PE was due to non-vital NETosis whose main component is represented by suicidal NETosis. Discussion: These results suggest the important part of non-vital NETosis in the pathophysiology of PE.

From Bench to Bedside: Clinical and Biomedical Investigations on Hepatitis C Virus (HCV) Genotypes and Risk Factors for Albuminuria

An extrahepatic manifestation of nephropathies can be a feature of the chronic hepatitis C virus (HCV) infection. Albuminuria is a major risk factor for nephropathies and chronic kidney disease (CKD). The correlation between HCV genotypes and albuminuria is still unclear. In this study, investigations have been done for the biomedical tools and methodologies used in the National Health and Nutrition Examination Survey (NHANES) public database. We searched the 2007−2016 NHANES public database to retrieve data regarding the different HCV genotypes and clinical scenarios. This study attempted to investigate the impacts of HCV genetic diversity, associated comorbidities, and racial differences on albuminuria. The urine albumin/creatinine ratio (ACR) was the primary endpoint. Among 40,856 participants, 336 participants with positive and 237 with negative HCV RNA tests were analyzed, excluding 14,454 participants with negative HCV antibodies and 25,828 which were missed. After controlling for sex, race, education level, smoking, diabetes mellitus, hepatitis B, alcohol use, and body mass index (BMI) with a generalized linear equation, HCV genotype 2 was more likely than any other genotype to cause albuminuria based on the urine ACR (p < 0.001). The generalized linear equation also demonstrated a significantly higher urine ACR, including hepatitis B (p < 0.001), diabetes mellitus (p < 0.001), and smoking (p = 0.026). In summary, the patients with HCV genotype 2 presented with increased albuminuria in comparison with other HCV genotypes in this 10-year retrospective analysis. HCV infection could be a risk factor of CKD; early diagnosis and appropriate treatment may improve clinical outcomes.

Hura crepitans Seeds for Control of Eimeria spp. in Lambs as an Alternative to Conventional Therapies

To evaluate the anticoccidial effect of the Hura crepitans seed, 21 cross-breed lambs, 23 ± 3 kg live weight (PV) and 70 ± 6 days old, were used. Animals were housed individually in raised wire-mesh pens, with individual water troughs and feeders. Lambs were randomly divided into three groups (n = 7) that received different doses of Hura crepitans seeds: 4 g/kg B.W. (group 1), 6 g/kg B.W. (group 2) and 0 g/kg B.W. (control group or group 0). The treatment was administered at the beginning of the experiment once orally and the study lasted 21 days. Stool samples were taken for quantitative analysis of oocysts using the McMaster technique and blood for haematological and biochemical analysis. Lambs that received the seeds showed a higher excretion of coccidia oocysts between days 5 and 7 after treatment (p < 0.05) due to the antiparasitic effect of these seeds, without affecting their productive performance (daily feed intake (DFI)- total weight gain (TWG), daily weight gain (DWG)). In addition, the daily feed consumption (DFC) and dry matter intake (DMI) were similar between the groups. The analysed enzymes (ALT, AST, GGT and FA) and creatinine showed reference values. Only the urea and BUN levels were slightly increased, but without statistical difference between the groups. Therefore, the Hura crepitans seed, at doses of 4 and 6 g/kg, favours the expulsion of coccidial oocysts, without affecting either the health or the productive behaviour of lambs.

The diagnostic value of native kidney biopsy in low grade, subnephrotic, and nephrotic range proteinuria: A retrospective cohort study

Background

In nephrotic range proteinuria of adult-onset, kidney biopsy is the diagnostic gold standard in determining the underlying cause of disease. However, in low grade or subnephrotic proteinuria the diagnostic value of kidney biopsy as first-line diagnostics is less well established.

Methods

We conducted a retrospective analysis of all native kidney biopsies at our institution (n = 639) between 01/2012 and 05/2021 for comparison of histological diagnoses and clinical outcomes stratified by amount of proteinuria at the time of kidney biopsy: A: <300mg/g creatinine (low grade), B: 300-3500mg/g creatinine (subnephrotic), C >3500mg/g creatinine (nephrotic).

Results

Nephrotic range proteinuria was associated with the highest frequency (49.3%) of primary glomerulopathies followed by subnephrotic (34.4%) and low grade proteinuria (37.7%). However, within the subnephrotic group, the amount of proteinuria at kidney biopsy was linearly associated with renal and overall survival (HR 1.05 per Δ100mg protein/g creatinine (95% CI: 1.02–1.09, p = 0.001)) independent of present histological diagnoses and erythrocyturia.

Conclusion

Frequency of primary glomerulopathies supports to perform kidney biopsy in patients with subnephrotic proteinuria. These patients have a substantial risk of ESKD and death upon follow-up. Therefore, diagnostic accuracy including histopathology is essential to guide personalized treatment and avert detrimental courses.

Correlation between Random Urinary Protein-to-creatinine Ratio and 24-h Urinary Protein Excretion in Preeclampsia

This study aimed to determine the correlation between random urinary protein-to-creatinine ratio in single-voided urine samples and 24-h urinary protein excretion in pregnant women with preeclampsia. A cross-sectional study was conducted at the Department of Gynecology and Obstetrics, Abbasi Shaheed Hospital, Karachi, Pakistan, from July 2019 to June 2020. Fifty women with singleton pregnancy after 20 weeks of gestation with hypertension and 2+ proteinuria or more, according to a dipstick test, were included. Those with chronic hypertension; preexisting renal disease; gestational diabetes; eclampsia; hemolysis, elevated liver enzymes, a low platelet count syndrome; and coexisting urinary tract infections were excluded. Two random urine samples taken at 9:00 a.m. and 2:00 p.m. and 24-h urine samples were collected to evaluate the random urinary protein-to-creatinine and the 24-h protein excretion, respectively. The correlation coefficient (r) between them was calculated using Pearson's correlation test. The patients' mean age was 28.58 ± 5.09 years and their mean gestational age was 32.74 ± 4.44 weeks. Twenty-eight (56%) women were primigravidas, and 22 (44%) were multiparous. The average serum creatinine was 0.80 ± 0.16 mg/dL. The mean random urinary protein-to-creatinine ratio was 0.93 ± 0.7 mg/mg, and the mean 24-h urine was 481.08 ± 20.10 mL. A strong positive correlation was found between the protein-to-creatinine ratio and 24-h urinary protein excretion (r = 0.655; P = 0.01). We concluded that the protein-to-creatinine ratio in spot urine samples could be used as an alternative to in 24-h collection of urine to determine protein excretion in preeclamptic pregnant women.

Association Between Urinary Protein-to-Creatinine Ratio and Chronic Kidney Disease Progression: A Secondary Analysis of a Prospective Cohort Study

Objective

Studies on the association between urinary protein-to-creatinine ratio (UPCR) and chronic kidney disease (CKD) progression are limited. This study aimed to investigate the relationship between UPCR and CKD progression in a Japanese population.

Methods

The present research was a secondary analysis of a prospective cohort study. Eight hundred and ninety-six subjects from the research of CKD-ROUTE in Japan were included. All the patients were new visitors or first referred to the participating centers of nephrology between October 2010 and December 2011. The target-independent variable was UPCR measured at baseline. The dependent variable was CKD progression and the estimated glomerular filtration rate (eGFR) changes during follow-up. We used Cox proportional hazards regression to investigate the association between UPCR and CKD progression risk. To address UPCR and CKD progression's non-linearity, a multivariate Cox proportional hazards regression analysis with cubic spline functions model and smooth curve fitting (penalized spline method) were conducted. We further used a generalized linear mixed model to explore the relationship between UPCR and the changes of eGFR.

Result

The mean age of the included patients was 67.2 ± 13.4 years old. Two hundred and thirty-four people occurred CKD progression during follow-up. The present study showed that UPCR was independently associated with CKD progression in the multivariate analysis [HR = 1.164, 95% CI (1.116, 1.215)]. The non-linear relationship between UPCR and CKD progression was explored in a dose-dependent manner, with an obvious inflection point of 1.699. Furthermore, our findings indicated that the tendency of the effect sizes on both the left and right sides of the inflection point was not consistent [left HR: 4.377, 95% CI (2.956, 6.483); right HR: 1.100, 95% CI (1.049–1.153)]. Using the linear mixed-effects regression model, we found that UPCR was an independent predictor of the longitudinal changes in eGFR (p < 0.001 for the interaction term with time).

Conclusion

This study demonstrates a nonlinear positive relationship between UPCR and CKD progression in the Japanese population. UPCR is also an independent predictor of the longitudinal changes in eGFR.

Chronic Kidney Disease in the Transgender, Nonbinary, or Gender Diverse Person

Nephrologists are increasingly providing care to transgender, nonbinary, and gender diverse (TNBGD) individuals with chronic kidney disease. This narrative review discusses the care of TNBGD individuals from a nephrology perspective. TNBGD individuals are under-represented in the nephrology literature. TNBGD individuals are at an increased risk of adverse outcomes compared with the cisgender population including mental health, cardiovascular disease, malignancy, sexually transmitted infections, and mortality. Gender-affirming hormone therapy (GAHT) with estradiol in transfeminine individuals potentially increases the risk of venous thromboembolism and cardiovascular disease. GAHT with testosterone in transmasculine individuals potentially increases the risk of erythrocytosis and requires careful monitoring. GAHT modifies body composition and lean muscle mass, which in turn influence creatinine generation and excretion, which may impact the performance of estimated glomerular filtration rate (GFR) equations and the estimation of 24-hour urine values from spot urine albumin/protein to creatinine ratios. There are limited studies regarding TNBGD individuals with chronic kidney disease. Additional research is needed to evaluate the effects of GAHT on GFR and biomarkers of kidney function and the performance of the estimated GFR equation in TNBGD populations.

Comparison of 24-h Urine Protein, Urine Albumin-to-Creatinine Ratio, and Protein-to-Creatinine Ratio in IgA Nephropathy

Background

Proteinuria is a strong risk factor for renal outcomes in IgA nephropathy. Random urine protein-to-creatinine ratio (PCR), random albumin-to-creatinine ratio (ACR), and 24-h urine protein excretion (24-h UP) have been widely used in clinical practice. However, the measurement which is the best predictor of long-term renal outcomes remains controversial. This study aimed to compare the three measurements in IgA nephropathy.

Methods

We conducted a retrospective study of 766 patients with IgA nephropathy. The associations among baseline ACR, PCR, and 24-h UP with chronic kidney disease (CKD) progression event, defined as 50% estimated glomerular filtration rate (eGFR) decline or end stage kidney disease (ESKD), were tested and compared.

Results

In this study, ACR, PCR, and 24-h UP showed high correlation (r = 0.671-0.847, P < 0.001). After a median follow-up of 29.88 (14.65-51.65) months, 51 (6.66%) patients reached the CKD progression event. In univariate analysis, ACR performed better in predicting the prognosis of IgA nephropathy, with a higher area under the receiver operating curve (ROC) curve than PCR and 24-h UP. After adjustment for traditional risk factors, ACR was most associated with composite CKD progression event [per log-transformed ACR, hazard ratio (HR): 2.82; 95% (95% CI): 1.31-6.08; P = 0.008].

Conclusions

In IgA nephropathy, ACR, PCR, and 24-h UP had a high correlation. ACR performed better in predicting the prognosis of IgA nephropathy.

Urinary Dipstick Is Not Reliable as a Screening Tool for Albuminuria in the Emergency Department—A Prospective Cohort Study

Albuminuria is a sensitive marker for renal dysfunction. Urinary dipstick tests are frequently used to screen for urinary abnormalities in the emergency department (ED). The aim of this prospective cohort study is to evaluate the usefulness of urinary dipstick testing as a screening tool for albuminuria in the ED setting and to determine the persistency of albuminuria identified in the acute setting. Urinary dipstick tests and spot urine samples were obtained simultaneously for analysis of the urinary albumin-creatinine ratio (ACR). Participants with positive dipsticks for protein were invited for a second urinalysis four to six weeks after admission. The study included 234 patients admitted to the ED. Urinalysis was performed on 178 patients of which 46% (n = 82) had positive urinary dipstick tests for proteinuria. The sensitivity and specificity of the dipstick test were low (72.7% and 55.7% respectively) when compared to the ACR. Of the 82 patients with positive dipsticks at admission, 35 were available for follow-up. We observed a significant reduction in ACR at follow-up when compared to ACR at admission (p = 0.004). This paper concludes that urinary dipstick tests are not a reliable means to screen for albuminuria in the ED setting.

Soluble CD146 is increased in preeclampsia and interacts with galectin-1 to regulate trophoblast migration through VEGFR2 receptor

OBJECTIVE

To explore the regulatory role of soluble CD146 (sCD146) and its interaction with galectin-1 (Gal1) in placenta-mediated complications of pregnancy.

DESIGN

Prospective pilot and experimental studies.

SETTING

University-affiliated hospital and academic research laboratory.

PATIENT(S)

One hundred fifteen women divided into three groups: 30 healthy, nonpregnant women, 50 women with normal pregnancies, and 35 with placenta-mediated pregnancy complications.

INTERVENTION(S)

Wound-healing experiments were conducted to study trophoblast migration.

MAIN OUTCOME MEASURE(S)

Quantification of sCD146 and Gal1 by enzyme-linked immunosorbent assay. Analysis of trophoblast migration by wound closure.

RESULT(S)

Concomitant detection of sCD146 and Gal1 showed lower sCD146 and higher Gal1 concentrations in women with normal pregnancies compared with nonpregnant women. In addition, follow-up of these women revealed a decrease in sCD146 associated with an increase in Gal1 throughout pregnancy. In contrast, in women with preeclampsia, we found significantly higher sCD146 concentrations compared with women with normal pregnancies and no modification of Gal1. We emphasize the opposing effects of sCD146 and Gal, since, unlike Gal1, sCD146 inhibits trophoblast migration. Moreover, the migratory effect of Gal1 was abrogated with the use of an anti-CD146 blocking antibody or the use of small interfering RNA to silence VEGFR2 expression. This suggests that trophoblast migration is mediated though the interaction of Gal1 with CD146, further activating the VEGFR2 signaling pathway. Significantly, sCD146 blocked the migratory effects of Gal1 on trophoblasts and inhibited its secretion, suggesting that sCD146 acts as a ligand trap.

CONCLUSION(S)

Soluble CD146 could be proposed as a biomarker in preeclampsia and a potential therapeutic target.

CLINICAL TRIAL REGISTRATION NUMBER

NCT 01736826.

Associations between Sex and Risk Factors for Predicting Chronic Kidney Disease

Gender is an important risk factor in predicting chronic kidney disease (CKD); however, it is under-researched. The purpose of this study was to examine whether gender differences affect the risk factors of early CKD prediction. This study used data from 19,270 adult health screenings, including 5101 with CKD, to screen for 11 independent variables selected as risk factors and to test for the significant effects of statistical Chi-square test variables, using seven machine learning techniques to train the predictive models. Performance indicators included classification accuracy, sensitivity, specificity, and precision. Unbalanced category issues were addressed using three extraction methods: manual sampling, the synthetic minority oversampling technique, and SpreadSubsample. The Chi-square test revealed statistically significant results (p < 0.001) for gender, age, red blood cell count in urine, urine protein (PRO) content, and the PRO-to-urinary creatinine ratio. In terms of classifier prediction performance, the manual extraction method, logistic regression, exhibited the highest average prediction accuracy rate (0.8053) for men, whereas the manual extraction method, linear discriminant analysis, demonstrated the highest average prediction accuracy rate (0.8485) for women. The clinical features of a normal or abnormal PRO-to-urinary creatinine ratio indicated that PRO ratio, age, and urine red blood cell count are the most important risk factors with which to predict CKD in both genders. As a result, this study proposes a prediction model with acceptable prediction accuracy. The model supports doctors in diagnosis and treatment and achieves the goal of early detection and treatment. Based on the evidence-based medicine, machine learning methods are used to develop predictive model in this study. The model has proven to support the prediction of early clinical risk of CKD as much as possible to improve the efficacy and quality of clinical decision making.

Improving the urine spot protein/creatinine ratio by the estimated creatinine excretion to predict proteinuria in pediatric kidney transplant recipients

BACKGROUND

Since the daily creatinine excretion rate (CER) is directly affected by muscle mass, which varies with age, gender, and body weight, using the spot protein/creatinine ratio (Spot P/Cr) follow-up of proteinuria may not always be accurate. Estimated creatinine excretion rate (eCER) can be calculated from spot urine samples with formulas derived from anthropometric factors. Multiplying Spot P/Cr by eCER gives the estimated protein excretion rate (ePER). We aimed to determine the most applicable equation for predicting daily CER and examine whether ePER values acquired from different equations can anticipate measured 24 h urine protein (m24 h UP) better than Spot P/Cr in pediatric kidney transplant recipients.

METHODS

This study enrolled 23 children with kidney transplantation. To estimate m24 h UP, we calculated eCER and ePER values with three formulas adapted to children (Cockcroft-Gault, Ghazali-Barratt, and Hellerstein). To evaluate the accuracy of the methods, Passing-Bablok and Bland-Altman analysis were used.

RESULTS

A statistically significant correlation was found between m24 h UP and Spot P/Cr (p < .001, r = 0.850), and the correlation was enhanced by multiplying the Spot P/Cr by the eCER equations. The average bias of the ePER formulas adjusted by the Cockcroft-Gault, Ghazali-Barratt, and Hellerstein equations were -0.067, 0.031, and 0.064 g/day, respectively, whereas the average bias of Spot P/Cr was -0.270 g/day obtained by the Bland-Altman graphics.

CONCLUSION

Using equations to estimate eCER may improve the accuracy and reduce the spot urine samples' bias in pediatric kidney transplantation recipients. Further studies in larger populations are needed for ePER reporting to be ready for clinical practice.

Reference values of urine protein/creatinine ratio in healthy Dalian adults

Background

The urine protein/creatinine ratio (UPCR) is commonly used in current clinical practice. However, there are only few published clinical data on UPCR from large cohorts of Chinese adults. This study aimed to determine the overall and age‐ and sex‐specific UPCR reference values for healthy Dalian adults.

Methods

According to the Clinical & Laboratory Standards Institute EP28‐A3c guidelines, 1321 healthy Dalian adults (646 men and 675 women) aged 20–69 years were enrolled. Urine protein and creatinine levels were analyzed in the random morning spot urine samples, and UPCR was calculated. The 95th percentile of the UPCR was used as the normal upper limit. The Mann–Whitney U test was used to test differences among groups.

Results

The UPCR reference value was 141.7 mg/g for the entire cohort, 128.7 mg/g for men, and 150.8 mg/g for women. In addition, women had relatively higher UPCR values than men in the same age group. We also compared the UPCR reference values between different estimated glomerular filtration rate (eGFR) groups and found that women had significantly higher UPCR values than men in the normal eGFR groups.

Conclusions

This study provides the overall and age‐ and sex‐specific UPCR reference values for healthy Dalian adults.

Apolipoprotein-1 risk variants and associated kidney phenotypes in an adult HIV cohort in Nigeria

HIV-positive adults are at risk for various kidney diseases, and apolipoprotein 1 (APOL1) high-risk genotypes increase this risk. This study aimed to determine the prevalence and ethnic distribution of APOL1 risk genotypes among a cohort of HIV-positive Nigerian adults and explore the relationship between APOL1 risk variant status with albuminuria and estimated glomerular filtration rate (eGFR). We conducted a cross-sectional study among 2 458 persons living with HIV who attended an HIV clinic in northern Nigeria and had received antiretroviral therapy for a minimum of six months. We collected two urine samples four-eight weeks apart to measure albumin excretion, and blood samples to measure eGFR and determine APOL1 genotype. The frequency of APOL1 high-risk genotype was 6.2%, which varied by ethnic group: Hausa/Fulani (2.1%), Igbo (49.1%), and Yoruba (14.5%). The prevalence of microalbuminuria (urine/albumin creatinine ratio 30- 300 mg/g) was 37%, and prevalence of macroalbuminuria (urine/albumin creatinine ratio over 300 mg/g) was 3%. The odds of microalbuminuria and macroalbuminuria were higher for participants with the APOL1 high-risk genotype compared to those carrying the low-risk genotype ([adjusted odds ratio 1.97, 95% confidence interval 1.37-2.82] and [3.96, 1.95-8.02] respectively). APOL1 high-risk genotype participants were at higher risk of having both an eGFR under 60 ml/min/1.73m2 and urine/albumin creatinine ratio over 300 mg/g (5.56, 1.57-19.69). Thus, we found a high proportion of HIV-positive, antiretroviral therapy-experienced, and largely virologically suppressed adults had microalbuminuria. Hence, although the high-risk APOL1 genotype was less prevalent than expected, it was strongly associated with some level of albuminuria.

Effectiveness of the rapid emergency medicine score and the rapid acute physiology score in prognosticating mortality in patients presenting to the emergency department with COVID-19 symptoms

Objective

We investigated the effectiveness of the Rapid Emergency Medicine Score and the Rapid Acute Physiology Score in identifying critical patients among those presenting to the emergency department with COVID-19 symptoms.

Material and methods

This prospective, observational, cohort study included patients with COVID-19 symptoms presenting to the emergency department over a two-month period. Demographics, clinical characteristics, and the data of all-cause mortality within 30 days after admission were noted, and the Rapid Emergency Medicine Score and the Rapid Acute Physiology Score were calculated by the researchers. The receiver operating characteristic curve analysis was performed to determine the discriminative ability of the scores.

Results

A total of 555 patients with a mean of age of 49.4 ± 16.8 years were included in the study. The rate of 30-day mortality was 3.9% for the whole study cohort, 7.2% for the patients with a positive rt-PCR test result for SARS-CoV-2, and 1.2% for those with a negative rt-PCR test result for SARS-CoV-2. In the group of patients with COVID-19 symptoms, according to the best Youden's index, the cut-off value for the Rapid Emergency Medicine Score was determined as 3.5 (sensitivity: 81.82%, specificity: 73.08%), and the area under curve (AUC) value was 0.840 (95% confidence interval 0.768–0.913). In the same group, according to the best Youden's index, the cut-off value for the Rapid Acute Physiology Score was 2.5 (sensitivity: 90.9%, specificity: 97.38%), and the AUC value was 0.519 (95% confidence interval 0.393–0.646).

Conclusion

REMS is able to predict patients with COVID-19-like symptoms without positive rt-PCR for SARS-CoV-2 that are at a high-risk of 30-day mortality. Prospective multicenter cohort studies are needed to provide best scoring system for triage in pandemic clinics.

Comparison of Patients with Hospital-Recorded Nephrotic Syndrome and Patients with Nephrotic Proteinuria and Hypoalbuminemia: A Nationwide Study in Denmark

Background

Registry-based studies of nephrotic syndrome (NS) may only include a subset of patients with biochemical features of NS. To address this, we compared patients with laboratory-recorded nephrotic proteinuria and hypoalbuminemia to patients with hospital-recorded NS.

Methods

We identified adult patients with first-time hospital-recorded NS (inpatients, outpatients, or emergency-room visitors) in the Danish National Patient Registry and compared them with adults with first-time recorded nephrotic proteinuria and hypoalbuminemia in Danish laboratory databases during 2004-2018, defining the date of admission or laboratory findings as the index date. We characterized these cohorts by demographics, comorbidity, medication use, and laboratory and histopathologic findings.

Results

We identified 1139 patients with hospital-recorded NS and 5268 patients with nephrotic proteinuria and hypoalbuminemia; of these, 760 patients were identified in both cohorts. Within 1 year of the first record of nephrotic proteinuria and hypoalbuminemia, 18% had recorded hospital diagnoses indicating the presence of NS, and 87% had diagnoses reflecting any kind of nephropathy. Among patients identified with nephrotic proteinuria and hypoalbuminemia, their most recent eGFR was substantially lower (median of 35 versus 61 ml/min per 1.73 m²), fewer underwent kidney biopsies around the index date (34% versus 61%), and the prevalence of thromboembolic disease (25% versus 17%) and diabetes (39% versus 18%) was higher when compared with patients with hospital-recorded NS.

Conclusions

Patients with nephrotic proteinuria and hypoalbuminemia are five-fold more common than patients with hospital-recorded NS, and they have a lower eGFR and more comorbidities. Selective and incomplete recording of NS may be an important issue when designing and interpreting studies of risks and prognosis of NS.

First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

BACKGROUND

Quantification of proteinuria in kidney transplant recipients is important for diagnostic and prognostic purposes. Apart from correlation tests, there have been few evaluations of spot urine protein measurements in kidney transplantation.

METHODS

In this cross-sectional study involving 151 transplanted patients, we investigated measures of agreement (bias and accuracy) between the estimated protein excretion rate (ePER), determined from the protein-to-creatinine ratio in the first and second morning urine, and 24-h proteinuria and studied their performance at different levels of proteinuria. Measures of agreement were reanalyzed in relation to allograft histology in 76 patients with kidney biopsies performed for cause before enrolment in the study.

RESULTS

For ePER in the first morning urine, percent bias ranged from 1 to 28% and accuracy (within 30% of 24-h collection) ranged from 56 to 73%. For the second morning urine, percent bias ranged from 2 to 11%, and accuracy ranged from 71 to 78%. The accuracy of ePER (within 30%) in first and second morning urine progressively increased from 56 and 71% for low-grade proteinuria (150-299 mg/day) to 60 and 74% for moderate proteinuria (300-999 mg/day), and to 73 and 78% for high-grade proteinuria (≥1000 mg/day). Measures of agreement were similar across histologic phenotypes of allograft injury.

CONCLUSIONS

The ability of ePER to accurately predict 24-h proteinuria in kidney transplant recipients is modest. However, accuracy improves with an increase in proteinuria. Given the similar accuracy of ePER measurements in first and second morning urine, second morning urine can be used to monitor protein excretion.

Urinary miRNA profiles discriminate between obstruction-induced bladder dysfunction and healthy controls

Urgency, frequency and incomplete emptying are the troublesome symptoms often shared between benign prostatic obstruction-induced (BLUTD) and neurogenic (NLUTD) lower urinary tract dysfunction. Previously, using bladder biopsies, we suggested a panel of miRNA biomarkers for different functional phenotypes of the bladder. Urine is a good source of circulating miRNAs, but sex- and age-matched controls are important for urinary metabolite comparison. In two groups of healthy subjects (average age 32 and 57 years old, respectively) the total protein and RNA content was very similar between age groups, but the number of secreted extracellular vesicles (uEVs) and expression of several miRNAs were higher in the young healthy male volunteers. Timing of urine collection was not important for these parameters. We also evaluated the suitability of urinary miRNAs for non-invasive diagnosis of bladder outlet obstruction (BOO). A three urinary miRNA signature (miR-10a-5p, miR-301b-3p and miR-363-3p) could discriminate between controls and patients with LUTD (BLUTD and NLUTD). This panel of representative miRNAs can be further explored to develop a non-invasive diagnostic test for BOO. The age-related discrepancy in the urinary miRNA content observed in this study points to the importance of selecting appropriate, age-matched controls.

Proteinuria in COVID-19

Upper respiratory and pulmonary diseases are the primary manifestations of coronavirus disease 2019 (COVID-19). However, kidney involvement has also been recognized and extensively described. A large percentage of affected patients present with acute kidney injury (AKI). However, specific phenotypic aspects of AKI or other renal manifestations of COVID-19 remain sparsely characterized. Many reports indicate that proteinuria can be detected in AKI associated with COVID-19 (CoV-AKI) despite CoV-AKI being largely described as a form of acute tubular injury. On the other hand, individuals of African ancestry with the high-risk APOL1 genotype are uniquely at risk of developing collapsing glomerulopathy when they are infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the entity now known as COVID-19-associated nephropathy (COVAN). Patients with COVAN typically present with nephrotic-range proteinuria. The exact incidence of proteinuria in COVID-19 is unclear due to heterogeneity in the frequency with which proteinuria has been assessed in cases of COVID-19, as well as methodological differences in the way proteinuria is measured and/or reported. In this review we discuss the current evidence of proteinuria as a manifestation of COVID-19 and elaborate on potential pathophysiological mechanisms associated with it.

Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria

Proteinuria is an important prognostic marker in the diagnosis and management of kidney diseases. Sulfosalicylic acid method (SSA) is a simple, low cost, qualitative test, widely used to assess proteinuria. The aim of this study was to optimize SSA test as a quantitative screening tool to assess proteinuria at lower excretory levels which would facilitate the screening and early diagnosis of renal impairment using protein-to-creatinine ratio (PCR). The study was conducted in two phases. In phase I, optimum SSA percentage to detect low-grade proteinuria was selected by comparing the performance of 3%, 6%, and 25% SSA methods in manual spectrophotometric analysis. In phase II, clinical applicability of the optimized method was evaluated using retained urine samples of patients with chronic kidney disease (CKD) assessed for urine protein by the pyrogallol red (PGR) method in a tertiary care hospital in Sri Lanka. Optimized 25% SSA protein-to-creatinine ratio (PCR) was compared with PGR PCR and albumin-to-creatinine ratio (ACR). Sensitivity, specificity, degree of agreement, correlation, and diagnostic accuracy were evaluated. Turbidimetric analysis using 25% SSA was linear in the range 3–50 mg/dL giving the highest analytical sensitivity. The test yielded a sensitivity of 86.5% and specificity of 96.5% and a degree of agreement of 5 mg/dL with the PGR method. Optimal cut-off for 25% SSA PCR in receiver operating characteristic analysis was 166 mg/g. Spearman's correlation coefficient for 25% SSA PCR versus ACR was r = 0.823, p < 0.0001, and for 25% SSA PCR versus PGR PCR was r = 0.913, p < 0.0001. The 25% SSA PCR has a sensitivity of 92% against ACR, the current prognostic marker for proteinuria in patients with CKD. The 25% SSA test is a simple method, and it performs satisfactorily as a screening test with a cut-off for PCR optimized at 166 mg/g. The test merits further evaluation due to its low cost.

NETosis Markers in Pregnancy: Effects Differ According to Histone Subtypes

NETosis is an innate immune response occurring after infection or inflammation: activated neutrophils expel decondensed DNA in complex with histones into the extracellular environment in a controlled manner. It activates coagulation and fuels the risk of thrombosis. Human pregnancy is associated with a mild proinflammatory state characterized by circulatory neutrophil activation which is further increased in complicated pregnancies, placenta-mediated complications being associated with an increased thrombotic risk. This aberrant activation leads to an increased release of nucleosomes in the blood flow. The aim of our study was to initially quantify nucleosome-bound histones in normal pregnancy and in placenta-mediated complication counterpart. We analyzed the role of histones on extravillous trophoblast function. Circulating nucleosome-bound histones H3 (Nu.QH3.1, Nu.QH3PanCit, Nu.QH3K27me3) and H4 (Nu.QH4K16Ac) were increased in complicated pregnancies. In vitro using the extravillous cell line HTR-8/SVNeo, we observed that free recombinant H2B, H3, and H4 inhibited migration in wound healing assay, but only H3 also blocked invasion in Matrigel-coated Transwell experiments. H3 and H4 also induced apoptosis, whereas H2B did not. Finally, the negative effects of H3 on invasion and apoptosis could be restored with enoxaparin, a low-molecular-weight heparin (LMWH), but not with aspirin. Different circulating nucleosome-bound histones are increased in complicated pregnancy and this would affect migration, invasion, and induce apoptosis of extravillous trophoblasts. Histones might be part of the link between the risk of thrombosis and pregnancy complications, with an effect of LMWH on both.

Gradient Waveguide Thickness Guided-Mode Resonance Biosensor

Portable systems for detecting biomolecules have attracted considerable attention, owing to the demand for point-of-care testing applications. This has led to the development of lab-on-a-chip (LOC) devices. However, most LOCs are developed with a focus on automation and preprocessing of samples; fluorescence measurement, which requires additional off-chip detection instruments, remains the main detection method in conventional assays. By incorporating optical biosensors into LOCs, the biosensing system can be simplified and miniaturized. However, many optical sensors require an additional coupling device, such as a grating or prism, which complicates the optical path design of the system. In this study, we propose a new type of biosensor based on gradient waveguide thickness guided-mode resonance (GWT-GMR), which allows for the conversion of spectral information into spatial information such that the output signal can be recorded on a charge-coupled device for further analysis without any additional dispersive elements. A two-channel microfluidic chip with embedded GWT-GMRs was developed to detect two model assays in a buffer solution: albumin and creatinine. The results indicated that the limit of detection for albumin was 2.92 μg/mL for the concentration range of 0.8–500 μg/mL investigated in this study, and that for creatinine it was 12.05 μg/mL for the concentration range of 1–10,000 μg/mL. These results indicated that the proposed GWT-GMR sensor is suitable for use in clinical applications. Owing to its simple readout and optical path design, the GWT-GMR is considered ideal for integration with smartphones or as miniaturized displays in handheld devices, which could prove beneficial for future point-of-care applications.

Biochemical markers for severity and risk in GBA and LRRK2 Parkinson's disease

BACKGROUND

The phenotype of Parkinson's disease (PD) is variable with mutations in genes such as LRRK2 and GBA explaining part of this heterogeneity. Additional genetic and environmental factors contribute to disease variability.

OBJECTIVE

To assess the association between biochemical markers, PD severity and probability score for prodromal PD, among GBA and LRRK2 mutation carriers.

METHODS

Levels of uric acid, vitamin D, C-reactive protein, microalbumin/creatinine ratio (ACR), white blood count (WBC), hemoglobin, platelets, neutrophil/lymphocyte ratio and estimated glomerular filtration rate (eGFR) were assessed from patients with PD and non-manifesting carriers (NMC) of mutations in GBA and LRRK2, together with disease related questionnaires enabling the construction of the MDS prodromal probability score.

RESULT

A total of 241 patients with PD: 105 idiopathic PD (iPD), 49 LRRK2-PD and 87 GBA-PD and 412 non-manifesting subjects; 74 LRRK2-NMC, 118 GBA-NMC and 220 non-manifesting non-carriers (NMNC), participated in this study. No significant differences in biochemical measures were detected among patients with PD or non-manifesting carriers. Among GBA-PD patients, worse motor performance was associated with ACR (B = 4.68, 95% CI (1.779-7.559); p = 0.002). The probability score for prodromal PD among all non-manifesting participants was associated with eGFR; NMNC (B = - 0.531 95% CI (- 0.879 to - 0.182); p < 0.001, LRRK2-NMC (B = - 1.014 95% CI (- 1.663 to - 0.366); p < 0.001) and GBA-NMC (B = - 0.686 95% CI (1.300 to - 0.071); p = 0.029).

CONCLUSION

Sub-clinical renal impairment is associated with increased likelihood for prodromal PD regardless of genetic status. While the mechanism behind this finding needs further elucidation, it suggests that kidney function might play a role in PD pathogenesis.

Placenta-mediated complications: Nucleosomes and free DNA concentrations differ depending on subtypes

BACKGROUND

Placenta-mediated pregnancy complications generate short- and long-term adverse medical outcomes for both the mother and the fetus. Nucleosomes and free DNA (fDNA) have been described in patients suffering from a wide range of inflammatory conditions.

OBJECTIVE

The objective of our study was to compare nucleosomes and fDNA circulating levels during pregnancy and particularly in women developing a placenta-mediated complication according to the subtype (preeclampsia or intrauterine growth restriction) (NCT01736826).

PATIENTS/METHODS

A total of 115 women were prospectively included in the study across three groups: 30 healthy non-pregnant women, 50 with normal pregnancy, and 35 with a complicated pregnancy. Blood samples were taken up to every 4 weeks for several women with normal pregnancy and nucleosomes and fDNA were quantified using enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively.

RESULTS

We show that nucleosomes and fDNA concentrations significantly increase during normal pregnancy, with concentrations at delivery differing between the two groups. Interestingly, we show that concentrations differ according to the type of placenta-mediated complications, with higher levels in preeclampsia compared to intrauterine growth restriction.

CONCLUSIONS

These data suggest that nucleosomes and fDNA may be additional actors participating in placenta-mediated pregnancy complications.

Association of Diet Quality Indices with Longitudinal Changes in Kidney Function in U.S. Hispanics/Latinos: Findings from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

Background

Recent studies suggest an association between diet quality and incident CKD. However, Hispanics/Latinos were under-represented in these studies. We examined the relationship of diet quality with change in kidney function in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Methods

Individuals who participated in HCHS/SOL visits 1 (2008-2011) and 2 (2014-2017) were analyzed (n=9921). We used Alternate Healthy Eating Index 2010 (AHEI-2010), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean Diet (MeDS) scores as measures of dietary quality. Scores were calculated from two 24-hour dietary recalls administered at visit 1 and categorized into quartiles of each dietary score (higher quartiles correspond to a healthier diet). Kidney function was assessed at both visits using eGFR and urine albumin-creatinine ratio (UACR). Annualized change was computed as the difference in eGFR or UACR between visits divided by follow-up time in years. Weighted linear-regression models were used to examine the association between quartiles of each dietary quality index and annualized change in eGFR and UACR, adjusted for potential confounders.

Results

At visit 1, the mean (SD) age of participants was 41 (0.28) years, and 56% were female. The baseline mean eGFR was 107.1 ml/min per 1.73 m², and baseline median UACR was 6.1 mg/g. On average, eGFR declined by 0.65 ml/min per 1.73 m² per year, and UACR increased by 0.79 mg/g per year over a 6-year period. Lower AHEI-2010 quartiles were associated with eGFR decline in a dose-response manner (P trend=0.02). Higher AHEI-2010 quartiles showed a trend toward lower annualized change in UACR, but the result did not reach significance. Neither MeDS nor DASH scores were associated with eGFR decline or change in UACR.

Conclusions

Unhealthy diet, assessed at baseline by AHEI-2010, was associated with kidney-function decline over 6 years. Improving the quality of foods and nutrients according to the AHEI-2010 may help maintain kidney function in the Hispanic/Latino community.

24-h Urine Collection: A Relevant Tool in CKD Nutrition Evaluation

Dietary management is a cornerstone of Chronic Kidney Disease (CKD) monitoring, and dietary surveys often difficult to perform. We studied in a CKD patient cohort with two years follow-up, whether validated 24-h urine ionogram would be a relevant tool for diet evaluation and compliance. We included 404 non-dialysis CKD patients, with three evaluations, including repeated measurements of fractional renal creatinine clearance and 24-h urine collection. Completeness of the 24-h urine collection, assessed by daily urine creatinine excretion extrapolated from fractional creatinine clearance, was 64.6%, 75.5%, and 78.2% at the first, second, and third visits, respectively. One hundred sixty-eight patients (41.6%) had three complete collections, with a measured glomerular filtration of 42.3 mL/min/1.73 m² at baseline and prevalence of anemia and secondary hyperparathyroidism of 13.9% and 26.2%, respectively, increasing during follow-up to 15% and 31.5% (p < 0.001 and p < 0.001). The urine analysis showed at baseline a urine volume of above 2 L/day, and estimated sodium and protein intake within targets in 51.6% and 40.3% of cases, which improved during follow-up only for protein (to 45.9%, p < 0.0001). Our data suggest that a 24-h urine ionogram is an interesting, reliable tool in CKD patients for dietary monitoring to achieve target recommendation noteworthy salt and protein intake.

Comparisons of Dipstick Test, Urine Protein-to-Creatine Ratio, and Total Protein Measurement for the Diagnosis of Preeclampsia

Preeclampsia affects 2–5% of pregnant women and is one of the leading causes of maternal and perinatal morbidity and mortality. We aimed to extensively evaluate proteinuria in women with preeclampsia and to determine the analytical sensitivity and specificity of and the cutoff values for urine protein-to-creatinine ratio (UPCR) and total protein in 24 h urine samples. This study included 88 women. We used the urine dipstick test, UPCR, and total protein measurement in a 24 h urine sample. The patients were divided in gestational hypertension (GH, n = 44) and preeclampsia (PE, n = 44) groups. In the GH group, 25% (11/44) of the patients presented incidentally positive results. UPCR and total protein in 24 h urine specimens were increased in the GH group compared to the PE group. Receiver operating characteristic analysis showed a UPCR cutoff of 30 mg/mmol as significant for preeclampsia, while the sensitivity and specificity were 89% (95% CI, 75–97) and 100% (95% CI, 87–100), respectively. In the 24 h urine protein test, sensitivity and specificity were 80% (95% CI, 61–92) and 100% (95% CI, 88–100), respectively, for the cutoff value of 0.26 g/24 h. In comparison to the other commonly used tests here considered, UPCR determination is a reliable, relatively faster, and equally accurate method for the quantitation of proteinuria, correlates well with 24 h urine protein estimations, and could be used as an alternative to the 24 h proteinuria test for the diagnosis of preeclampsia.

Effect of a Single Intravitreal Bevacizumab Injection on Proteinuria in Patients With Diabetes

Purpose

Proteinuria is the second most common complication after hypertension after systemic administration of bevacizumab. Therefore we aimed to analyze the effect of intravitreal bevacizumab (IVB) injection on proteinuria in patients with diabetes.

Methods

Patients scheduled to receive IVB injection from May 1, 2018, to December 31, 2018, were prospectively enrolled. In total, 53 patients with diabetes (26 with nonproliferative diabetic retinopathy and 27 with proliferative diabetic retinopathy) and 37 patients without diabetes were included. Urine tests were performed within 1 month of and 7 ± 1 days after IVB injection. Urinary protein, creatinine, and albumin concentrations were quantitatively measured, and urinary protein-to-creatinine ratio and urinary albumin-to-creatinine ratio (UACR) were calculated from these data before and after IVB injection.

Results

The mean urinary microalbumin concentrations and urinary protein-to-creatinine ratio were significantly higher in patients with diabetes, both before and after IVB injection. There were no differences between patients with nonproliferative diabetic retinopathy and proliferative diabetic retinopathy. About 80% of patients with diabetes showed improved albuminuria or at least no harmful effect in terms of albuminuria. Patients with deteriorated baseline UACR showed more residual increase in UACR after IVB injection (P < 0.05 in all groups).

Conclusions

Close monitoring of renal function after IVB might be needed in patients with diabetes according to the severity of nephropathy.

Translational Relevance

Our results may provide information regarding the renal function of IVB-treated patients with diabetes.

Correlation of urine protein/creatinine ratios to 24-h urinary protein for quantitating proteinuria in children

BACKGROUND

The purpose of this study was to evaluate the correlation and consistency between urine protein/creatinine ratio (UPCR) and 24-h urine protein (24HUPr) in children, and to determine cutoff values of UPCR relative to 24HUPr at 100 mg/m²/d (≥ 100 mg/m²/d as pathological proteinuria) and 1000 mg/m²/d (≥ 1000 mg/m²/d as nephrotic-range proteinuria).

METHODS

Three hundred sixty-six children were enrolled, including 81 controls, 109 with Henoch-Schönlein purpura nephritis, 167 with nephrotic syndrome, 5 with IgA nephropathy, and 4 with lupus nephritis. Patients were divided into three groups: normal group; non-nephrotic-range proteinuria group; nephrotic-range proteinuria group. The cutoff values of UPCR in predicting the different levels of proteinuria were determined using ROC curve analysis.

RESULTS

UPCR was positively correlated with 24HUPr (r = 0.915, p < 0.01). Bland-Altman diagrams showed that UPCR and 24HUPr had good consistency, and > 95% spots of UPCR and 24HUPr were within 95% confidence intervals. Relative to 24HUPr at 100 mg/m²/d, the cutoff value of UPCR (0.18 g/g Cr) had the highest sensitivity (94%) and specificity (98.8%) which is close to 0.2 g/g Cr as proposed by the American College of Rheumatology. Relative to 24HUPr at 1000 mg/m²/d, the cutoff value of UPCR (2.09 g/g Cr) had the highest sensitivity (92.1%) and specificity (92.1%) which is close to the 2.0 g/g Cr proposed in KDIGO guidelines.

CONCLUSIONS

UPCR showed strong correlation and consistency with 24HUPr for evaluating levels of proteinuria in children. UPCR < 0.2 g/g Cr can be considered a criterion for normal-range proteinuria. Instead of 24HUPr ≥ 1000 mg/m²/d, UPCR ≥ 2.0 g/g Cr can be considered a criterion for nephrotic-range proteinuria or nephrotic syndrome in children.

Diagnostic utility of protein to creatinine ratio (P/C ratio) in spot urine sample within routine clinical practice

The spot (random) urine protein to creatinine ratio (P/C ratio) is an alternative, fast and simple method of detecting and estimating the quantitative assessment of proteinuria. The aim of the work was to review the literature concerning the usefulness of spot urine P/C ratio evaluation in the diagnosis of proteinuria in the course of kidney disease, hypertension, gestational hypertension, preeclampsia, immunological diseases, diabetes mellitus, and multiple myeloma, and in the diagnosis of proteinuria in children. We searched the PubMed and Google Scholar databases using the following keywords: proteinuria, spot urine protein to creatinine ratio, spot urine P/C ratio, protein creatinine index, PCR (protein to creatinine ratio), P/C ratio and methods, Jaffe versus enzymatic creatinine methods, urine protein methods, spot urine protein to creatinine ratio versus ACR (albumin to creatinine ratio), proteinuria versus albuminuria, limitations of the P/C ratio. More weight was given to the articles published in the last 10-20 years. A spot urine P/C ratio >20 mg/mmol (0.2 mg/mg) is the most commonly reported cutoff value for detecting proteinuria, while a P/C ratio value >350 mg/mmol (3.5 mg/mg) confirms nephrotic proteinuria. The International Society for the Study of Hypertension in Pregnancy recommends a P/C ratio of 30 mg/mmol (0.3 mg/mg) for the classification of proteinuria in pregnant women at risk of preeclampsia. A high degree of correlation was observed between P/C ratio values and the protein concentration in 24-h urine collections. The spot urine P/C ratio is a quick and reliable test that can eliminate the need for a daily 24-h urine collection. However, in doubtful situations, it is still recommended to assess proteinuria in a 24-h urine collection. The literature review indicates the usefulness of the spot P/C ratio in various disease states; therefore, this test should be available in every laboratory. However, the challenge for the primary care physician is to know the limitations of the methods used to determine the protein and creatinine concentrations that are used to calculate the P/C ratio. Moreover, the P/C ratio cutoff used should be determined in individual laboratories because it depends on the patient population and the laboratory methodologies.

Spot urine protein-to-creatinine ratio as a diagnostic test in pre-eclampsia: A gold standard?

OBJECTIVE

To determine the diagnostic accuracy and optimal threshold of the spot protein-to-creatinine ratio (PCR) compared to the gold standard, 24-hour proteinuria (24HP) in patients with suspected pre-eclampsia.

METHODS

A prospective observational study was performed from June 2015 to May 2017 consisting of patients hospitalized for suspected pre-eclampsia in a tertiary care referral center. To compare the two diagnostic tests, a spot urine sample was obtained to perform the PCR before starting the collection of the 24HP. Only patients who had both tests were analyzed.

RESULTS

In total, 148 patients (216 samples) were included. The two tests were highly correlated (r=0.80, P<0.001). The receiver operating characteristic curve analysis and the area under the curve (AUC=0.92) highlighted the accuracy of PCR in diagnosing significant proteinuria and thus pre-eclampsia. The optimal cut-off using the Liu method was 56.9 mg/mmol (sensitivity=79.3%, specificity=91.5%).

CONCLUSION

The results suggest that PCR could replace 24HP when diagnosing proteinuria in pre-eclampsia. Moreover, it is a simple test, easy to realize and standardize, and cheap with no need for systematic hospitalization. The best cut-off should be chosen by thinking about the risks for adverse maternal and/or fetal outcomes. The test may help to optimize medical care in pre-eclampsia worldwide.

Proteinuria-take a closer look!

Proteinuria is a hallmark of kidney disease. Therefore, measurement of urine protein content plays a central role in any diagnostic work-up for kidney disease. In many cases, proteinuria analysis is restricted to the measurement of total protein content knowing that very high levels of proteinuria (nephrotic proteinuria) are characteristic of glomerular disease. Still, proteinuria can also be a manifestation of impaired tubular protein reabsorption or even be physiological. This review will discuss the physiology of renal protein handling and give guidance on a more sophisticated analysis of proteinuria differentiating albumin, low-molecular weight proteins and immunoglobulins. These non-invasive tests are available in most routine clinical laboratories and may guide the clinician in the diagnostic process before ordering far more expensive (molecular genetic testing) and/or invasive (kidney biopsy) diagnostics.

Disorders of the Urinary and Reproductive Systems in Ferrets

Urogenital lesions are relatively common in ferrets. Renal disease is diagnosed as in traditional small animal medicine; however, peculiarities in ferrets include physiologically low levels of creatinine. Renal cysts are very common in ferrets but are usually incidental findings. Uroliths are usually composed of struvite or cystine. Urethral obstruction in male ferrets is predominantly caused by adrenal-associated prostatic disease. Spontaneous cystitis is rare in ferrets. Primary reproductive disease is uncommon in ferrets in the United States where animals are usually neutered at 6 weeks of age. In other countries, ferrets either remain unneutered or are neutered at 5 to 6 months of age. Ferrets are seasonal breeders, and female are induced ovulators. Prolonged estrus and hyperestrogenism often causes profound bone marrow suppression.

Evaluation of Hypertension, Proteinuria, and Abnormalities of Body Weight in Italian Adolescents Participating in the World Kidney Days

INTRODUCTION

World Kidney Day (WKD) was promoted by the Italian Kidney Foundation and the Italian Society of Nephrology for raising awareness, detection, prevention, and treatment of kidney diseases. The Italian WKD focused on the "School Project" by screening students attending the fifth year of high school. The main goal of the "School Project" was to assess in healthy adolescents the presence of hypertension (HTN) and proteinuria; as well as to evaluate potential interrelations between overweight, obesity (both measured with different anthropometric methods), blood pressure (BP) levels, and proteinuria. The ancillary goal was to have an estimate of awareness on some nephrology topics.

METHODS

The study population consisted of 17- to 19-year-old students. HTN was defined as systolic BP (SBP) ≥140 mm Hg and/or diastolic BP (DBP) ≥90 mm Hg. Isolated systolic hypertension (ISH) was defined as SBP ≥140 mm Hg and DBP <90 mm Hg; isolated diastolic hypertension as SBP <140 mm Hg and DBP ≥90 mm Hg; systolic and diastolic hypertension as SBP ≥140 mm Hg and DBP ≥90 mm Hg; pre-hypertension as SBP >120 mm Hg but <140 mm Hg or DBP >80 mm Hg but <90 mm Hg; and optimal BP as SBP ≤120 mm Hg and DBP ≤80 mm Hg. Urine tests were performed with a dipstick; the subjects were regarded as proteinuric when the urine dipstick was positive (proteinuria ≥30 mg/dL). Body weight, height, and waist circumference (WC) were measured; body mass index (BMI), waist-to-height ratio (WHtR), and conicity index (Ci) were calculated. According to the BMI, the following classifications were adopted: underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), class-I obesity (30-34.9 kg/m2), class-II obesity (35-39.9 kg/m2), class-III obesity (≥40 kg/m2).

RESULTS

Data from 12,125 students (45.6% males) were evaluated. HTN was found in 1,349 participants (11.1%; 61.1% male), and ISH was present in 7.4%. Overweight (24.1%) and class-I (6%), -II (3.6%), and -III (1%) obesity were present in hypertensive participants. Compared to participants with normal BP, hypertensive participants had a higher BMI (p < 0.001), WC (p < 0.001), and WHtR (p < 0.001); whereas the Ci was not different (p = 0.527). Multivariate linear regression analysis showed that both WC and BMI were predictors of abnormal SBP and DBP (p < 0.001) both in males and females. Proteinuria was present in 14.8, 13.8, 14.7, and 14.7% of all normal weight, overweight, obese, and all subjects, respectively. In addition, no association was found between body weight, proteinuria, and BP.

CONCLUSION

This study shows that overweight and obesity were significantly associated to HTN in Italian adolescents. BMI and WC were predictors of SBP and DBP. The occurrence of proteinuria was quite similar to that of HTN, but it was not associated with anthropometric indicators or HTN.

Preeclampsia: Risk Factors, Diagnosis, Management, and the Cardiovascular Impact on the Offspring

Hypertensive disorders of pregnancy affect up to 10% of pregnancies worldwide, which includes the 3%–5% of all pregnancies complicated by preeclampsia. Preeclampsia is defined as new onset hypertension after 20 weeks’ gestation with evidence of maternal organ or uteroplacental dysfunction or proteinuria. Despite its prevalence, the risk factors that have been identified lack accuracy in predicting its onset and preventative therapies only moderately reduce a woman’s risk of preeclampsia. Preeclampsia is a major cause of maternal morbidity and is associated with adverse foetal outcomes including intra-uterine growth restriction, preterm birth, placental abruption, foetal distress, and foetal death in utero. At present, national guidelines for foetal surveillance in preeclamptic pregnancies are inconsistent, due to a lack of evidence detailing the most appropriate assessment modalities as well as the timing and frequency at which assessments should be conducted. Current management of the foetus in preeclampsia involves timely delivery and prevention of adverse effects of prematurity with antenatal corticosteroids and/or magnesium sulphate depending on gestation. Alongside the risks to the foetus during pregnancy, there is also growing evidence that preeclampsia has long-term adverse effects on the offspring. In particular, preeclampsia has been associated with cardiovascular sequelae in the offspring including hypertension and altered vascular function.

Location of glomerular immune deposits, not codeposition of immunoglobulin G, influences definitive renal outcomes in immunoglobulin A nephropathy

Background

It has been suggested that the prognosis of immunoglobulin (IgA) nephropathy (IgAN) is adversely affected if there is codeposition of IgG in the glomeruli or if immune deposits are present in the glomerular capillary walls. We sought to understand how these variables affect clinical outcome.

Methods

A total of 80 IgAN biopsies were retrospectively divided into groups: (i) IgA without IgG deposition versus IgA + IgG and (ii) immune deposits restricted to the mesangium versus mesangium and peripheral capillary walls (PCWs). The association of these groups with the composite primary outcome of renal replacement therapy, renal transplant, death or doubling of serum creatinine (SCr) concentration was determined. The change in estimated glomerular filtration rate (eGFR) was also assessed. Covariates examined were age, sex, race, SCr and proteinuria level at biopsy and at follow-up, duration of follow-up, treatment, Oxford score and presence of crescents.

Results

IgG codeposition showed a trend toward endocapillary hypercellularity (P = 0.082); there were no other baseline differences between the IgA (n = 55) and IgA + IgG (n = 25) groups. At a median follow-up time of 29 months, the combined primary outcome was reached in 24 patients, 16 with IgA and 8 with IgA + IgG (P = 0.82). Patients with immune deposits in the PCWs (n = 21) presented with higher baseline proteinuria than those with deposits limited to the mesangium (n = 59; P = 0.025), were more likely to have crescents/segmental glomerular necrosis on biopsy (P = 0.047) and were more likely to reach the combined primary outcome (P = 0.026). Biopsies with crescents/segmental glomerular necrosis were associated with endocapillary hypercellularity (P < 0.001).

Conclusions

In this multicenter IgAN cohort, IgG co-deposition and the location of glomerular immune deposits in the PCWs were both associated with greater histologic activity on renal biopsy, but only the location of glomerular immune deposits in the PCWs was associated with a significantly increased risk for end-stage renal disease, transplant, death and/or doubling of SCr.

Urinary 2,8-dihydroxyadenine excretion in patients with adenine phosphoribosyltransferase deficiency, carriers and healthy control subjects

BACKGROUND

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive disorder of adenine metabolism that results in excessive urinary excretion of the poorly soluble 2,8-dihydroxyadenine (DHA), leading to kidney stones and chronic kidney disease. The purpose of this study was to assess urinary DHA excretion in patients with APRT deficiency, heterozygotes and healthy controls, using a recently developed ultra-performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS) assay.

METHODS

Patients enrolled in the APRT Deficiency Registry and Biobank of the Rare Kidney Stone Consortium (http://www.rarekidneystones.org/) who had provided 24-h and first-morning void urine samples for DHA measurement were eligible for the study. Heterozygotes and healthy individuals served as controls. Wilcoxon-Mann-Whitney test was used to compare 24-h urinary DHA excretion between groups. Associations were examined using Spearman's correlation coefficient (r_s).

RESULTS

The median (range) 24-h urinary DHA excretion was 138 (64-292) mg/24 h and the DHA-to-creatinine (DHA/Cr) ratio in the first-morning void samples was 13 (4-37) mg/mmol in APRT deficiency patients who were not receiving xanthine oxidoreductase inhibitor therapy. The 24-h DHA excretion was highly correlated with the DHA/Cr ratio in first-morning void urine samples (r_s = 0.84, p < .001). DHA was detected in all urine samples from untreated patients but not in any specimens from heterozygotes and healthy controls.

CONCLUSIONS

High urinary DHA excretion was observed in patients with APRT deficiency, while urine DHA was undetectable in heterozygotes and healthy controls. Our results suggest that the UPLC-MS/MS assay can be used for diagnosis of APRT deficiency.

Comparison of Different Methods of Urinary Protein Excretion Measurement: Is the King Really Dead?

INTRODUCTION

Assessing proteinuria is of uttermost importance for a nephrologist. It is often indispensable to accurately quantify the amount of protein lost, hence complicated and time-consuming urine collections (the gold standard or "king" of methods - 24-h protein excretion rate [PER]) are often replaced by spot urinary protein to creatinine ratio (PCR). The aim of the study was to determine whether the latter can reliably compare to the gold standard and whether "timing" of a spot urine sample is essential.

METHODS

We performed a prospective, single-center study of 143 consecutive adult patients with glomerular proteinuria (a total of 187 cases). Protein and creatinine concentration was measured in 3 consecutive urine samples (starting with the first morning void) and a simultaneous 24-h urine collection. Agreement between 24-h PER and PCR was evaluated with Bland-Altman plots.

RESULTS

Compared to PER 3 consecutive PCRs were 0.86, 0.66, and 0.50 higher with wide limits of agreement respectively. The bias between 2 methods was influenced by sex, CKD stage, albumin concentration and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker treatment. In 24 participants, in whom at least 2 measurements at different time points were available, only 88% of differences were lower than the calculated repeatability coefficient.

CONCLUSIONS

Unfortunately although random PCR correlates with 24-h protein excretion, the scatter of differences increases as 24-h proteinuria rises (without any significant effect of the sampling time). The observed lack of agreement makes PCR an unsuitable parameter to correctly quantify proteinuria; it is also not useful for monitoring the amount of daily proteinuria in the same patient. Therefore, while searching for new markers, nephrologists can only say: "long live the king!"

Spot urine protein/creatinine ratio as a reliable estimate of 24-hour proteinuria in patients with immunoglobulin A nephropathy, but not membranous nephropathy

BACKGROUND

Proteinuria is known to be associated with both kidney function deterioration and cardiovascular diseases. While proteinuria estimation from 24-h urine samples has traditionally been considered as the standard method for assessment of the degree of urinary protein excretion, sample collection is associated with several technical problems such as inaccurate collection and the potential spread of drug-resistant pathogens. Therefore, the spot urine protein/creatinine ratio (PCR) assessment is currently recommended as an alternative. While the utility of PCR has been validated, studies on the association between spot urine PCR and 24-h proteinuria (24HP) in patients with chronic glomerular nephritis (CGN) and nephrotic syndrome (NS) are limited. This study aimed to evaluate whether an estimated result from a spot urine PCR could sufficiently approximate the daily urine protein excretion amount from a 24-h urine sample in patients with immunoglobulin A nephropathy (IgAN), minimal change disease (MCD), and membranous nephropathy- nephrotic syndrome (MN-NS).

METHODS

The study participants included 161 patients with IgAN, MCD, or MGN-NS at the Jikei University Kashiwa Hospital and Kanagawa Prefecture Shiomidai Hospital. The correlation between spot urine PCR and a 24-h urine protein was investigated using linear regression analysis with Spearman's correlation (r) coefficient and intraclass correlation coefficient (ICC).

RESULTS

While high correlation coefficients (r = 0.86, P < 0.001) and substantial agreement (ICC: 0.806, P < 0.001) were observed in patients with IgAN, similar correlations were not observed in patients with MCD or MN-NS. In the patients with MCD, r was 0.53 (P < 0.001), which signified a slight correlation, and in the patients with MN-NS, r was 0.289 (P = 0.17), which was not statistically significant.

CONCLUSIONS

This study revealed that spot urine PCR is a reliable estimate of 24HP value in patients with IgAN. In contrast, there is a considerable difference between the daily urine protein excretion amount based on a 24-h urine sample and that which is calculated from spot urine PCR in patients with NS.