Value of urinary excretion of microalbumin in predicting glomerular lesions in children with isolated microscopic hematuria

Identification of Protein-Coding Gene Structure and Protein-Related Genes and Their Splicing Sites in Kidney Stone Disease: A Protein Big Data Analysis

The study of protein-coding gene structure and protein-related genes in kidney stone disease is used for accurate identification of splicing sites and accurate location of gene exon boundaries, which is one of the difficulties and key problems in understanding the genome and discovering new genes. Prediction techniques based on signal characteristics of conserved sequences around splicing sites, such as the weighted array model (WAM), are widely used. On this basis, several other features that can be used for splicing site recognition (such as the base composition of splicing site upstream and downstream sequences, the change of signal and base composition of upstream and downstream sequences with the C + G content of adjacent sequences) were mined further, and a model was developed to describe these features. In this study, a log-linear model that can effectively integrate these features for splicing site recognition was designed, and a SpliceKey programme was developed. The findings reveal that SpliceKey's splicing site identification accuracy is not only much better than the WAM approach, but also better than DGSplice.

Efficacy and Safety of Tacrolimus in the Treatment of Pediatric Henoch-Schönlein Purpura Nephritis

BACKGROUND

Children with severe Henoch-Schönlein purpura nephritis (HSPN) may progress to end-stage renal disease without appropriate treatment.

OBJECTIVE

This study aimed to investigate the efficacy and safety of tacrolimus combined with glucocorticoids in the treatment of pediatric HSPN.

METHODS

A total of 87 HSPN patients with urinary protein ≥ 0.75 g/24 h received standard of care, including angiotensin II receptor blockers/angiotensin-converting enzyme inhibitors and glucocorticoids. Patients were divided into three groups and additionally received tacrolimus (n = 30), cyclophosphamide (n = 31), or mycophenolate mofetil (MMF) (n = 26). We monitored outcome measures, including proteinuria, hematuria, and renal function and analyzed the efficacy and side effects in each group.

RESULTS

At 2-month follow-up, the overall efficacy was 93.3%, 83.9%, and 61.5% for tacrolimus, cyclophosphamide, and MMF, respectively (P < 0.05). Urinary protein significantly decreased for all groups. Urinary red blood cell counts significantly decreased for patients treated with tacrolimus (P < 0.001) and cyclophosphamide (P < 0.05), whereas no significant decrease was seen for those receiving MMF (P = 0.09). Although urine β2-microglobulin significantly decreased following 2 months of treatment with all medications, efficacy was greater with tacrolimus than with cyclophosphamide and MMF (P < 0.001). Major adverse events were respiratory and urinary infections, with MMF having the highest infection rate. The cyclophosphamide group also experienced additional adverse events, including arrhythmia, hemorrhagic cystitis, leukocytosis, thrombocytopenia, and hyperglycemia.

CONCLUSIONS

These results indicate that tacrolimus is more effective at reducing proteinuria and hematuria and improving renal function, with relatively milder side effects, in the treatment of pediatric HSPN.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2200055323, retrospectively registered on January 7, 2022.

Laboratory Findings After Urinary Tract Infection and Antimicrobial Prophylaxis in Children With Vesicoureteral Reflux

It is a common practice to monitor blood tests in patients receiving long-term trimethoprim-sulfamethoxazole (TMP-SMZ) prophylaxis for recurrent urinary tract infections. This multicenter, randomized, placebo-controlled trial enrolled 607 children aged 2 to 71 months with vesicoureteral reflux diagnosed after symptomatic urinary tract infection. Study participants received TMP-SMZ (n = 302) or placebo (n = 305) and were followed for 2 years. Serum electrolytes (n ≥ 370), creatinine (n = 310), and complete blood counts (n ≥ 206) were measured at study entry and at the 24-month study conclusion. We found no significant electrolyte, renal, or hematologic abnormalities when comparing the treatment and placebo groups. We observed changes in several laboratory parameters in both treatment and placebo groups as would normally be expected with physiologic maturation. Changes were within the normal range for age. Long-term use of TMP-SMX had no treatment effect on complete blood count, serum electrolytes, or creatinine. Our findings do not support routine monitoring of these laboratory tests in children receiving long-term TMP-SMZ prophylaxis.

Simplified Algorithm for Evaluation of Proteinuria in Clinical Practice: How should A Clinician Approach?

Background

Proteinuria is a common laboratory finding among children and adolescents. It can be identified as either a transient or a persistent finding and can represent a benign condition or a serious disease.

Methods

Pertinent medical literature for asymptomatic proteinuria in children and adolescents published in English was searched between January 1980 and May 2017 using PubMed, MEDLINE, EMBASE, and Google Scholar research databases. Of the 64 reviewed articles, 24 studies were eligible for inclusion.

Results

Random spot urine protein-to-creatinine (PCR) ratio is widely used to reliably detect proteinuria. The normal value for the spot PCR in children aged 2 years or older is less than 0.3. In children aged below 2 years, the PCR can be as high as 0.5. Orthostatic proteinuria is defined as urine PCR greater than 0.3 detected in a urine specimen during the daytime activity but less than 0.3 on the first morning void specimen. PCR above 3.0 signifies heavy proteinuria as seen in nephrotic syndrome. Orthostatic proteinuria is a frequent cause of proteinuria in asymptomatic children and adolescents, which require no specific therapy except for health maintenance follow-up. Pediatric nephrologist referral is indicated when the proteinuria is constant and persists over 6 months or is associated with hematuria, hypertension, or renal dysfunction.

Conclusions

We provide a simplified diagnostic algorithm for evaluation of proteinuria in primary care adolescents who appear well and in whom proteinuria is incidentally discovered during a routine examination.

Baseline urinalysis values in common bottlenose dolphins under human care in the Caribbean

Urinalysis is a rapid, simple, inexpensive, and reliable test that documents urine abnormalities reflecting various types of renal, hormonal, or metabolic diseases. Urinalysis could assist proper monitoring of the health of dolphins under human care; however, normal baseline values for dolphin urinalysis have not been reported, to our knowledge. We sampled urine from 193 common bottlenose dolphins ( Tursiops truncatus), living under human care in 24 Caribbean dolphinariums, by voluntary free-catch and analyzed the urine for chemical and microscopic variables using multi-agent dry reagent chemistry dipstick test strips, dedicated pH reagent strips, and unstained sediment slides. Most urine was clear, pale yellow to dark yellow, and had a fishy odor. Dipstick glucose, bilirubin, ketones, and nitrites were negative in all dolphins. The urine pH was acidic ( x¯ ± SD; 5.88 ± 0.58) and specific gravity (SG) was 1.035 ± 0.008. Most animals had 0-2 red blood cells and white blood cells per 40× field, and were negative for proteins. On microscopic sediment, 42.7% of samples had few-to-many squamous epithelial cells; hyaline and epithelial casts were observed only rarely. Crystals were observed in 36.6% of the samples; most were calcium oxalate dihydrate (48.2%) and amorphous urates (42.4%). The values obtained in our study can be used as a reference for health monitoring of dolphins in dolphinariums, and to monitor renal conditions and function in dolphins being rehabilitated or under human care.

Renal histological features of school-age children with asymptomatic haematuria and/or proteinuria: a multicenter study

AIM

The risk of asymptomatic haematuria and/or proteinuria development into chronic progressive glomerulonephritis (CPG) is unclear. The indications for renal biopsy and follow-up on these asymptomatic children remain controversial.

METHODS

A multicenter, retrospective study was performed to investigate the renal histological features of school-age children with asymptomatic urine abnormalities.

RESULTS

A total of 112 asymptomatic children's renal biopsy data were studied. Most of the children (71%) received a renal biopsy because of isolated microscopic haematuria (IH), and these children were predominantly (60%) proven to have only mild lesions in the glomeruli. Approximately 30% of the children were biopsied because of asymptomatic proteinuria with or without microscopic haematuria (HP or isolated asymptomatic proteinuria (IP)), and these children were mostly (44-83%) indicated to have CPG, such as IgA nephropathy, focal segmental glomerulosclerosis, and Alport syndrome. The junior high school students had a greater percentage of HP than the primary school children. IgA nephropathy was the most common diagnosis in children who received renal biopsy because of HP.

CONCLUSIONS

Our findings indicate that IP and especially HP may have a high risk of development into CPG. IH, however, has a relatively low risk of severe histological lesions. Thus, IH per se might not be suggested as an indication for early renal biopsy. Long-term follow-up is necessary for these asymptomatic children.

Microalbuminuria in children with urinary tract infection

Purpose

Microalbuminuria is defined as increased urinary albumin excretion (30-300 mg/day) or microalbumin/creatinine ratio (30-300 mg/g) in a spot urine sample. Although microalbuminuria is a predictor of clinical nephropathy and cardiomyopathy, few studies have investigated microalbuminuria in children with urinary tract infection (UTI).

Methods

Therefore, we compared the spot urine microalbumin/creatinine ratio in pediatric UTI patients with that of control subjects. We investigated the correlation between the ratio in children with UTI and age, height, weight, blood pressure, glomerular filtration rate (GFR), hematuria, vesicoureteral reflux, renal parenchymal defect, and renal scar, and its predictability for UTI complications.

Results

We studied 66 patients (42 boys, 24 girls) and 52 healthy children (24 boys, 28 girls). The mean microalbumin/creatinine ratio in UTI patients was statistically significantly increased compared to the control group (340.04±321.36 mg/g (38.47±36.35 mg/mmol) in patient group vs. 225.68±154.61 mg/g (25.53±17.49 mg/mmol) in control group, P=0.0141). The mean value of spot urine microalbumin/creatinine ratio (384.70±342.22 mg/g (43.47±37.67 mg/mmol) in patient group vs. 264.92±158.13 mg/g (29.94±17.86 mg/mmol) in control group, P=0.0341) in 1-23 months age patient group showed statistically significant increase compared to control group. Microalbumin/creatinine ratio showed negative correlation to age (r=-0.29, P=0.0167), body surface area (BSA) (r=-0.29, P=0.0173) and GFR (r=-0.26, P=0.0343). The presence of hematuria (P=0.0169) was found to be correlated.

Conclusion

The spot urine microalbumin/creatinine ratio in children with UTI was significantly greater than that in normal children, and it was positively correlated with GFR. This ratio is a potential prescreening and prognostic marker in UTI patients. Further studies are required to validate the predictability of microalbuminuria in pediatric UTI patients.

Renal gangliosides are involved in lead intoxication

The biological effects of lead are well defined; however, neither the risk exposure level nor the subcellular mechanism of its action is completely clear. The present work was undertaken to investigate the effects of low level and long term lead exposure on the composition and expression of rat renal gangliosides. In order to identify ganglioside expression, frozen sections of kidneys were stained with monoclonal antibodies GMB16 (GM1 specific), GM28 (GM2 specific), AMR-10 (GM4 specific) and CDW 60 (9-O-Ac-GD3 specific). Strong reactivity was observed for GMB28, AMR-10 and CDW 60, while GMB16 developed only weak labelling in treated kidney compared with the control. The alterations in the expression of renal gangliosides observed by immunohistochemistry were accompanied by quantitative and qualitative changes in the thin layer chromatography of total gangliosides isolated from kidney tissues. Lead treatment produced a significant increase in 9-O-Ac GD3, a ganglioside involved in apoptotic processes. In agreement with this result, a significant decrease in the number of apoptotic glomerular cells was observed with the TUNEL assay. These findings lead us to suggest that alterations in renal gangliosides produced by low level lead exposure are associated with the apoptotic processes that take place in the kidney. These findings provide evidence that low level and long term lead exposure produces renal ganglioside alterations with urinary microalbumin excretion. The results suggest that lead levels within the limits of biological tolerance already cause molecular renal damage without clinical signs of toxicity.

Efficacy of urine screening at school: experience in Shanghai, China

To explore the prevalence of hematuria or proteinuria in school children in Shanghai and to evaluate the screening methods, we conducted urine screening in more than 40,000 school children between 2003 and 2005. Children were tested with dipsticks read manually (method A) or dipsticks read by machines (method B) combined with a sulfosalicylic acid test or microscopy. Some children were tested once, and others who had abnormal results in the first screening were tested again 2 weeks later. The prevalence of urine abnormalities in the first screening was more than 5.00% and of the second screening about 1.00%. Either method B or testing two urine samples for each child had higher specificity. As to the direct cost, that of screening twice with method A was lower than just screening once with method B. So using method A to screen twice for each child was not only convenient and economical, but also could reduce the false positive rate effectively. More than 10 months of follow-up diagnosed two cases of IgA nephropathy. Asymptomatic chronic renal diseases in school children could be detected through school urine screening. For Shanghai, China, screening twice using method A might be the best choice.

Useful indicators for performing renal biopsy in adult patients with isolated microscopic haematuria

Among adult patients with isolated microscopic haematuria (IMH) which is defined as persistent microscopic haematuria but without proteinura, hypertension, renal insufficiency, urinary tract infection or structural abnormality of the urinary tract, some patients have chronic glomerulonephritis (CGN), in whom early diagnosis by renal biopsy is beneficial to timely intervention. Nevertheless, a considerable number of patients with optimistic prognosis [e.g. thin basement membrane nephropathy (TBMN)] undergo invasive and needless renal biopsy. Indicators for weighing the necessity of renal biopsy would be clinically significant. To investigate the value of urinary albumin/creatinine ratio (UACR), serum IgA level, serum C3 level and serum IgA to C3 ratio in predicting the necessity of renal biopsy for adult patients with IMH, 216 patients were studied retrospectively. Patients were divided into: (CGN group, n=137), (TBMN group, n=56) and normal biopsy (normal group, n=23). Of all patients, 131 (61%) evidenced microalbuminuria (UACR=30-299 mg/g) and 85 (39%) had normoalbuminuria (UACR<30 mg/g). The mean value of UACR in CGN group was higher (96+/-17 mg/g) compared with that in TBMN (20+/-4 mg/g, p<0.01) or normal (18+/-3 mg/g, p<0.01) group. The mean values of serum IgA and serum IgA/C3 ratio in patients with IgA nephropathy (IgAN) were significantly higher than those with non-IgAN (380+/-103:217+/-99 mg/dl, p<0.01; 4.5+/-1.2 : 2.4+/-0.9, p<0.01). The odds ratio for distinguishing IgAN from non-IgAN was significantly correlated with serum IgA level and serum IgA to C3 ratio. For adult patients with IMH, UACR, serum IgA level and serum IgA to C3 ratio are non-invasive markers for predicting the necessity of renal biopsy.

Profiling proteinuria in pediatric patients

This study was designed to characterize proteinuria in children with kidney disease. Random urine samples from 250 pediatric patients were examined by quantitative measures of total protein (pr), albumin (Alb), and creatinine (cr). Patient diagnoses were subjectively categorized as "Glomerular" (GD) or "Tubulo-interstitial" disease (TD) in origin. Proteinuria was quantitated by the random urine protein-to-creatinine (Upr/cr) ratio, and glomerular proteinuria was assessed as the albumin-to-creatinine ratio (Ualb/cr) and percentage albuminuria (%Alb=Alb/pr*100). The non-albumin fraction (1-Alb/pr) includes low-molecular-weight proteins and micro- and macroglobulins. Of the 250 patients, 112 (45%) had GD and 138 (55%) had TD. Both proteinuria and albuminuria correlated with a decline in glomerular filtration rate (GFR) (r=-0.4; p<0.0001). Those with GD averaged significantly greater %Alb than those with TD at all levels of proteinuria (p<0.0001). With loss in GFR, %Alb increased significantly in patients with TD (18+/-13 to 47+/-30%; p<0.001) and GD (56+/-26 to 74+/-15%; p<0.01), respectively. The %Alb at all levels of GFR averaged <50% in those with TD and >50% in those with GD. In conclusion, random Ualb/cr, Upr/cr, and %Alb provide a simple and inexpensive assessment of proteinuria and may profile renal disease activity and response to therapy in pediatric patients.

Daily urinary interleukin-11 excretion correlated with proteinuria in IgA nephropathy and lupus nephritis

Interleukin-11 (IL-11) is a multifunctional cytokine with both thrombopoietic and anti-inflammatory effects. In an animal study IL-11 was shown to reduce proteinuria in mice with necrotizing glomerulonephritis. The purpose of this current study is to explore the role of IL-11 in human glomerulonephritis. Subjects of this study were patients with proteinuria (daily urine protein excretion >40 mg/m2 per hour) and underlying pathology of IgA nephropathy (IgAN) (n=20), lupus nephritis (LN) (n=40), and idiopathic nephrotic syndrome (INS) (n=68). Daily urinary IL-11 level was measured by enzyme-linked immunosorbent assay (ELISA). Correlation between urinary IL-11 and urinary protein was determined by Pearson's correlation coefficient. Another five patients with serial data of urinary protein, IL-11 and IL-11 messenger RNA (mRNA) expression in urine sediment are presented. The correlation between urinary IL-11 and daily urinary protein was significant for patients with IgAN (r=0.596, P=0.006) and LN (r=0.630, P<0.001), but not for patients with INS (r=0.030, P=0.812). Serial data revealed the same correlation. Furthermore, the peak of urinary IL-11 mRNA preceded that of urinary IL-11. We conclude that daily urinary IL-11 excretion is correlated with urinary protein loss in nephritis having local T helper (Th)1 predominant immune response, such as IgAN and LN. Local IL-11 production may serve as a counter cytokine against Th1-mediated inflammation.