Urine specific gravity, pyuria, and neutrophil gelatinase-associated lipocalin for identifying urinary tract infection in young children

BACKGROUND

To determine whether urine neutrophil gelatinase-associated lipocalin (uNGAL) might be superior to pyuria for detecting urinary tract infection (UTI) regardless of urine specific gravity (SG) in young children.

METHODS

We conducted a retrospective analysis of children aged < 3 years who were evaluated for UTI with urinalysis, urine culture, and uNGAL measurements during a 5-year period. Sensitivity, specificity, likelihood ratios (LRs), predictive values (PVs), area under the curves (AUCs) of uNGAL cut-off levels, and various microscopic pyuria thresholds for detecting UTI were calculated for dilute (SG < 1.015) and concentrated urine (SG ≥ 1.015).

RESULTS

Of 456 children included, 218 had UTI. The diagnostic value of urine white blood cell (WBC) concentration to define UTI changed with urine SG. For detecting UTI, uNGAL cut-off of 68.4 ng/mL had higher AUC values than pyuria ≥ 5 WBCs/high power field (HPF) for dilute and concentrated urine samples (both P < 0.05). Positive LR and PV and specificity of uNGAL were all greater than those of pyuria ≥ 5 WBCs/HPF regardless of urine SG, although the sensitivity of pyuria ≥ 5 WBCs/HPF was higher than that of uNGAL cut-off for dilute urine (93.8% vs. 83.5%) (P < 0.05). At uNGAL ≥ 68.4 ng/mL and ≥ 5 WBCs/HPF, posttest probabilities of UTI were 68.8% and 57.5% for dilute urine and 73.4% and 57.3% for concentrated urine, respectively.

CONCLUSIONS

Urine SG can affect the diagnostic performance of pyuria for detecting UTI and uNGAL might be helpful for identifying UTI regardless of urine SG in young children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Genetic diagnosis of kidney disease by whole exome sequencing and its clinical application

The genetic spectrum of genetic kidney diseases (GKD) and the application of genetic diagnoses to patient care were assessed by whole exome sequencing (WES) of the DNA of 172 pediatric or adult patients with various kidney diseases. WES diagnosed genetic diseases in 63 (36.6%) patients. The diagnostic yields in patients with glomerulopathy were 33.8% (25/74 pts) due to variants in 10 genes, 58.8% (20/34) in patients with tubulointerstitial disease due to variants in 18 genes, 33.3% (15/45) in patients with cystic disease/ciliopathy due to variants in 10 genes, 18.2% (2/11) in patients with congenital anomalies of the kidneys and urinary tract (CAKUT) due to variants in two genes, and 12.5% (1/8) in patients with end stage kidney disease (ESKD). The diagnosis rate was high in patients aged <1-6 years (46-50.0%), and low in patients aged ≥40 years (9.1%). Renal phenotype was reclassified in 10 (15.9%) of 63 patients and clinical management altered in 10 (15.9%) of 63 patients after genetic diagnosis. In conclusion, these findings demonstrated the diagnostic utility of WES and its effective clinical application in patients, with various kinds of kidney diseases, across the different age groups.

Exposure to airborne particulate matter induces renal tubular cell injury in vitro: the role of vitamin D signaling and renin-angiotensin system

Background

Exposure to air pollution can interfere with the vitamin D endocrine system. This study investigated the effects of airborne particulate matter (PM) on renal tubular cell injury in vitro and explored the underlying mechanisms.

Methods

HK-2 human renal proximal tubule cells were treated with PM with or without 1,25(OH)₂D₃ analog, 19-Nor-1,25(OH)₂D₂ (paricalcitol, 10 nM) for 48 h. The dose- and time-dependent cytotoxicity of PM with or without paricalcitol was determined via cell counting kit-8 assay. Cellular oxidative stress was assessed using commercially available enzyme-linked immunosorbent assay kits. The protein expression of vitamin D receptor (VDR), cytochrome P450(CYP)27B1, CYP24A1, renin, angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1), nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-kB (NF-kB), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 was determined.

Results

PM exposure decreased HK-2 cell viability in a dose- and time-dependent manner. The activities of superoxide dismutase and malondialdehyde in HK-2 cells increased significantly in the group exposed to PM. PM exposure decreased VDR and Nrf2, while increasing CYP27B1, renin, ACE, AT1, NF-kB, TNF-α, and IL-6. The expression of VDR, CYP27B1, renin, ACE, AT1, and TNF-α was reversed by paricalcitol treatment. Paricalcitol also restored the cell viability of PM-exposed HK-2 cells.

Conclusion

Our findings indicate that exposure to PM induces renal proximal tubular cell injury, concomitant with alteration of vitamin D endocrine system and renin angiotensin system. Vitamin D could attenuate renal tubular cell damage following PM exposure by suppressing the renin-angiotensin system and by partially inhibiting the inflammatory response.

The Delivery of the Recombinant Protein Cocktail Identified by Stem Cell-Derived Secretome Analysis Accelerates Kidney Repair After Renal Ischemia-Reperfusion Injury

Recent advances in cell therapy have shown the potential to treat kidney diseases. As the treatment effects of the cell therapies are mainly attributed to secretomes released from the transplanted cells, the delivery of secretomes or conditioned medium (CM) has emerged as a promising treatment option for kidney disease. We previously demonstrated that the controlled delivery of human placental stem cells (hPSC)-derived CM using platelet-rich plasma (PRP) ameliorated renal damages and restored kidney function in an acute kidney injury (AKI) model in rats. The proteomics study of the hPSC-CM revealed that hPSC secrets several proteins that contribute to kidney tissue repair. Based on our results, this study proposed that the proteins expressed in the hPSC-CM and effective for kidney repair could be used as a recombinant protein cocktail to treat kidney diseases as an alternative to CM. In this study, we analyzed the secretome profile of hPSC-CM and identified five proteins (follistatin, uPAR, ANGPLT4, HGF, VEGF) that promote kidney repair. We investigated the feasibility of delivering the recombinant protein cocktail to improve structural and functional recovery after AKI. The pro-proliferative and anti-apoptotic effects of the protein cocktail on renal cells are demonstrated in vitro and in vivo. The intrarenal delivery of these proteins with PRP ameliorates the renal tubular damage and improved renal function in the AKI-induced rats, yielding similar therapeutic effects compared to the CM delivery. These results indicate that our strategy may provide a therapeutic solution to many challenges associated with kidney repair resulting from the lack of suitable off-the-shelf regenerative medicine products.

Obesity and chronic kidney disease: prevalence, mechanism, and management

The prevalence of childhood obesity is increasing worldwide at an alarming rate. While obesity is known to increase a variety of cardiovascular and metabolic diseases, it also acts as a risk factor for the development and progression of chronic kidney disease (CKD). During childhood and adolescence, severe obesity is associated with an increased prevalence and incidence of the early stages of kidney disease. Importantly, children born to obese mothers are also at increased risk of developing obesity and CKD later in life. The potential mechanisms underlying the association between obesity and CKD include hemodynamic factors, metabolic effects, and lipid nephrotoxicity. Weight reduction via increased physical activity, caloric restriction, treatment with angiotensin-converting enzyme inhibitors, and judicious bariatric surgery can be used to control obesity and obesity-related kidney disease. Preventive strategies to halt the obesity epidemic in the healthcare community are needed to reduce the widespread deleterious consequences of obesity including CKD development and progression.

Urinary neutrophil gelatinase-associated lipocalin: a marker of urinary tract infection among febrile children

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a valuable biomarker of urinary tract infection (UTI) in children.

PURPOSE

This study aimed to compare the diagnostic accuracy of urinary NGAL (uNGAL) with those of serum C-reactive protein (CRP) and white blood cell (WBC) count for predicting UTI and acute pyelonephritis (APN) in febrile children.

METHODS

The medical charts of children undergoing uNGAL measurements between November 2017 and August 2019 were retrospectively reviewed. Patients with a suspected or diagnosed UTIs were included. The diagnostic accuracies of uNGAL, serum CRP, and WBC count for detecting UTI and APN were investigated. Independent predictors of UTI and APN were investigated using multivariable logistic regression analyses.

RESULTS

A total of 321 children were enrolled in this study. The uNGAL levels were higher in the UTI group (n=157) than in the non-UTI group (n=164) (P<0.05). Among children with a UTI, uNGAL levels were higher in the APN group (n=70) than, the non-APN group (n=87) (P<0.05). In the multivariate analysis, uNGAL was independently associated with UTI and APN (both P<0.05). Serum CRP and WBC count were not correlated with the presence of UTI and APN. Receiver operating curve analyses showed that the uNGAL level had the highest area under the curve (AUC) for predicting UTI and APN, respectively (AUC, uNGAL vs. CRP vs. WBC count, 0.860 vs. 0.608 vs. 0.669 for UTI; 0.780 vs. 0.680 vs. 0.639 for APN, all P<0.05, respectively). The predictive values and likelihood ratios of uNGAL were superior to those of serum CRP and WBC count for detecting UTI and APN at each cutoff level.

CONCLUSION

UNGAL may be more useful than serum CRP and WBC count for identifying and assessing UTI in febrile children.

Impact of early-life weight status on urinary tract infections in children: a nationwide population-based study in Korea

OBJECTIVES

We aimed to evaluate the association between early-life weight status and urinary tract infection (UTI) risk in children.

METHODS

A nationwide study was conducted using Korean National Health Screening (NHS) data and National Health Insurance Service data. A sample cohort was selected using data from the 2014 and 2015 NHS for infants and children (4-71 months) and followed up until the end of 2017. Participants were divided into 4 groups (underweight, normal weight, overweight, and obese) based on the weight-for-age (< 2 years) or body mass index (≥ 2 years). Hazard ratios (HRs) with 95% confidence intervals (CIs) for developing UTIs, cystitis, and acute pyelonephritis (APN) were calculated using a Cox proportional hazard model.

RESULTS

Of 1,653,106 enrolled children, 120,142 (7.3%) developed UTIs, cystitis, and APN during follow-up. The underweight, overweight, and obese groups had higher risks of UTIs than the reference group after adjusting for age, sex, birth weight, and preterm birth. Between 2 years and 6 years of age, boys with underweight had a high risk of UTI and APN, while girls with overweight and obesity revealed elevated risks of UTIs, cystitis, and APN. The HRs for APN in boys with underweight and in girls with obesity were 1.46 (95% CI, 1.03 to 2.07) and 1.41 (95% CI, 1.13 to 1.75), respectively, after adjusting for age, sex, birth weight, and preterm birth. The incidence of APN did not decrease with age in underweight and obese children aged 2-6 years.

CONCLUSIONS

Children with underweight, overweight, and obesity may be at high risk for UTIs.

Angiotensin inhibition and cellular senescence in the developing rat kidney

Cellular senescence is important for the maintenance of tissue homeostasis during normal development. In this study, we aimed to investigate the effect of renin angiotensin system (RAS) blockade on renal cell senescence in the developing rat kidney. Newborn rat pups were treated with enalapril (30 mg/kg/day) or vehicle for seven days after birth. We investigated the intrarenal expressions of cell cycle regulators p21 and p16 with immunoblots and immunohistochemistry at postnatal day 8. For the determination of renal cellular senescence, immunostaining for senescence-associated β-galactosidase (SA-β-gal) and telomerase reverse transcriptase (TERT) was also performed. Enalapril treatment showed significant alterations in cellular senescence in neonatal rat kidneys. In the enalapril-treated group, intrarenal p16 and p21 protein expressions decreased compared to controls. The expressions of both p21 and p16 were reduced throughout the renal cortex and medulla of enalapril-treated rats. The immunoreactivity of TERT in enalapril-treated kidneys was also weaker than that in control kidneys. Control kidneys revealed a clear positive SA-β-gal signal in the cortical tubules; however, SA-β-gal activity was noticeably lower in the enalapril-treated kidneys than in control kidneys. Interruption of the RAS during postnatal nephrogenesis may disrupt physiologic renal cellular senescence in the developing rat kidney.

Associations of Plasma Neutrophil Gelatinase-associated Lipocalin, Anemia, and Renal Scarring in Children with Febrile Urinary Tract Infections

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL), a bacteriostatic agent, is known to inhibit erythropoiesis leading to anemia. We aimed to investigate the associations of NGAL, anemia, and renal scarring in children with febrile urinary tract infections (UTIs).

METHODS

We retrospectively reviewed the medical records of 261 children with febrile UTIs. The relationship between the presence of anemia and plasma NGAL levels was investigated. NGAL performance in comparison with serum C-reactive protein (CRP) at admission and after 72 hours of treatment was also evaluated for the prediction of renal scarring as well as acute pyelonephritis (APN) and vesicoureteral reflux (VUR).

RESULTS

Plasma NGAL levels were elevated in patients with anemia compared with those without anemia. Multiple linear regression analysis showed an inverse relationship between NGAL levels and erythrocyte counts (standard β = -0.397, P < 0.001). Increased NGAL, but not CRP, was independently associated with the presence of anemia (odds ratio [OR], 2.37; 95% confidence interval [CI], 1.07-5.27; P < 0.05). Receiver operating curve analyses showed good diagnostic profiles of pre- and post-treatment NGAL for identifying APN, VUR, and renal scarring (all P < 0.05). For detecting renal scars, the area under the curve of post-treatment NGAL (0.730; 95% CI, 0.591-0.843) was higher than that of post-treatment CRP (0.520; 95% CI, 0.395-0.643; P < 0.05). The presence of anemia and elevated NGAL at admission (> 150 ng/mL) were independent risk factors for renal scarring in children with febrile UTIs. With anemia, NGAL levels increased consecutively in children with febrile UTI without renal involvement, with APN without scar, and with APN with renal scarring.

CONCLUSION

Increased plasma NGAL levels may be associated with the presence of anemia and renal scarring in children with febrile UTIs.

Controlled Delivery of Stem Cell-Derived Trophic Factors Accelerates Kidney Repair After Renal Ischemia-Reperfusion Injury in Rats

Renal disease is a worldwide health issue. Besides transplantation, current therapies revolve around dialysis, which only delays disease progression but cannot replace other renal functions, such as synthesizing erythropoietin. To address these limitations, cell‐based approaches have been proposed to restore damaged kidneys as an alternative to current therapies. Recent studies have shown that stem cell‐derived secretomes can enhance tissue regeneration. However, many growth factors undergo rapid degradation when they are injected into the body in a soluble form. Efficient delivery and controlled release of secreting factors at the sites of injury would improve the efficacy in tissue regeneration. Herein, we developed a gel‐based delivery system for controlled delivery of trophic factors in the conditioned medium (CM) secreted from human placental stem cells (HPSCs) and evaluated the effect of trophic factors on renal regeneration. CM treatment significantly enhanced cell proliferation and survival in vitro. Platelet‐rich plasma (PRP) was used as a delivery vehicle for CM. Analysis of the release kinetics demonstrated that CM delivery through the PRP gel resulted in a controlled release of the factors both in vitro and in vivo. In an acute kidney injury model in rats, functional and structural analysis showed that CM delivery using the PRP gel system into the injured kidney minimized renal tissue damage, leading to a more rapid functional recovery when compared with saline, CM, or vehicle only injection groups. These results suggest that controlled delivery of HPSC‐derived trophic factors may provide efficient repair of renal tissue injury. stem cells translational medicine2019;8:959&970

Angiotensin inhibition in the developing kidney; tubulointerstitial effect

BACKGROUND

Renin-angiotensin system (RAS) blockade during nephrogenesis causes a broad range of renal mal-development. Here, we hypothesized that disruption of renal lymphangiogenesis may contribute to tubulointerstitial alterations after RAS blockade during kidney maturation.

METHODS

Newborn rat pups were treated with enalapril (30 mg/kg/day) or vehicle for 7 days after birth. Lymphangiogenesis was assessed via immunostaining and/or immunoblots for vascular endothelial growth factor (VEGF)-C, VEGF receptor (VEGFR)-3, Podoplanin, and Ki-67. The intrarenal expression of fibroblast growth factor (FGF)-1, FGF-2, FGF receptor (R)-1, α-smooth muscle actin (α-SMA), and fibroblast-specific protein (FSP)-1 was also determined. Sirius Red staining was performed to evaluate interstitial collagen deposition.

RESULTS

On postnatal day 8, renal lymphangiogenesis was disrupted by neonatal enalapril treatment. The expression of podoplanin and Ki-67 decreased in enalapril-treated kidneys. While the expression of VEGF-C was decreased, the levels of VEGFR-3 receptor increased following enalapril treatment. Enalapril treatment also reduced the renal expression of FGF-1, FGF-2, and FGFR-1. Enalapril-treated kidneys exhibited profibrogenic properties with increased expression of α-SMA and FSP-1 and enhanced deposition of interstitial collagen.

CONCLUSION

Enalapril treatment during postnatal renal maturation can disrupt renal lymphangiogenesis along with tubulointerstitial changes, which may result in a pro-fibrotic environment in the developing rat kidney.

Genetic Contributions to Childhood Obesity: Association of Candidate Gene Polymorphisms and Overweight/Obesity in Korean Preschool Children

This study was aimed to investigate the association of candidate gene polymorphisms and obesity or overweight in young Korean children. A total of 190 Korean preschool children (96 control, 48 overweight, and 46 obese children) were genotyped for the angiotensin converting enzyme (ACE) insertion (I)/deletion (D), angiotensin II type 2 receptor (AT2) C3123A, transforming growth factor (TGF)-β1 T869C, vascular endothelial growth factor (VEGF) T460C, and tumor necrosis factor (TNF)-α G308A polymorphisms. No differences were found among the groups with respect to age, sex, birth weight, blood pressure levels, and serum concentrations of glucose and total cholesterol. Obese children showed a higher incidence of ACE DD genotype and D allelic frequency compared to the controls (odds ratio [OR], 2.7, 95% confidence interval [CI], 1.01-7.21; OR, 2.5, 95% CI, 1.49-4.19; all P < 0.05). The frequency of TC genotype and C allele in the TGF-β1 T869C polymorphism (OR, 2.08, 95% CI, 1.01-4.27; OR, 1.93, 95% CI, 1.15-3.21) and that in the VEGF T460C polymorphism (OR, 2.5, 95% CI, 1.19-5.28; OR, 2.15, 95% CI, 1.26-3.68) was also higher in obese children than in control subjects (all P < 0.05). Overweight children exhibited a higher frequency of the A allele in the AT2 C3123A polymorphism compared to the controls (OR, 1.72, 95% CI, 1.03-2.88, P < 0.05). There were no differences in the TNF-α G308A polymorphism among the groups. The ACE I/D, AT2 C3123A, TGF-β1 T869C, and VEGF T460C polymorphisms can affect susceptibility to obesity or overweight in Korean children.

Eosinophilic gastroenteritis in an 18-year-old male with prolonged nephrotic syndrome

Eosinophilic gastroenteritis is a rare disease characterized by prominent eosinophilic tissue infiltration of the gastrointestinal tract. Here, we report a case of eosinophilic gastroenteritis in an 18-year-old patient with prolonged nephrotic syndrome who presented with abdominal pain and peripheral hypereosinophilia. During the previous 2 years, he had visited local Emergency Department several times because of epigastric pain and nausea. He had been treated with steroid-dependent nephrotic syndrome since 3 years of age. Tests ruled out allergic and parasitic disease etiologies. Gastroduodenoscopy with biopsy revealed marked eosinophilic infiltration in the duodenum. Renal biopsy findings indicated minimal change disease spectrum without eosinophilic infiltration. The oral deflazacort dosage was increased, and the patient was discharged after abdominal pain resolved. To our knowledge, this is the first report of eosinophilic gastroenteritis in a patient with minimal change disease.

Impaired angiogenesis in the enalapril-treated neonatal rat kidney

PURPOSE

Nephrogenesis is normally accompanied by a tightly regulated and efficient vascularization. We investigated the effect of angiotensin II inhibition on angiogenesis in the developing rat kidney.

METHODS

Newborn rat pups were treated with enalapril (30 mg/kg/day) or vehicle (control) for 7 days after birth. Renal histological changes were checked using Hematoxylin & Eosin staining. We also investigated the intrarenal expression of vascular endothelial growth factor (VEGF)-A, VEGF receptor 1 (VEGFR1), VEGFR2, platelet-derived growth factor (PDGF)-B, and PDGF receptor-β with Western blotting and immunohistochemical staining at postnatal day 8. Expression of the endothelial cell marker CD31 was examined to determine glomerular and peritubular capillary density.

RESULTS

Enalapril-treated rat kidneys showed disrupted tubules and vessels when compared with the control rat kidneys. In the enalapril-treated group, intrarenal VEGF-A protein expression was significantly higher, whereas VEGFR1 protein expression was lower than that in the control group (P<0.05). The expression of VEGFR2, PDGF-B, and PDGF receptor-β was not different between the 2 groups. The increased capillary CD31 expression on the western blots of enalapril-treated rat kidneys indicated that the total endothelial cell protein level was increased, while the cortical capillary density, assessed using CD31 immunohistochemical staining, was decreased.

CONCLUSION

Impaired VEGF-VEGFR signaling and altered capillary repair may play a role in the deterioration of the kidney vasculature after blocking of angiotensin II during renal development.

Evaluation of new American Academy of Pediatrics guideline for febrile urinary tract infection

PURPOSE

To evaluate the practical applications of the diagnosis algorithms recommended by the American Academy of Pediatrics urinary tract infection (UTI) guideline.

METHODS

We retrospectively reviewed the medical records of febrile UTI patients aged between 2 and 24 months. The patients were divided into 3 groups: group I (patients with positive urine culture and urinalysis findings), group II (those with positive urine culture but negative urinalysis findings), and group III (those with negative urine culture but positive urinalysis findings). Clinical, laboratory, and imaging results were analyzed and compared between the groups.

RESULTS

A total of 300 children were enrolled. The serum C-reactive protein level was lower in children in group II than in those in groups I and III (P<0.05). Children in group I showed a higher frequency of hydronephrosis than those in groups II and III (P<0.05). However, the frequencies of acute pyelonephritis (APN), vesicoureteral reflux (VUR), renal scar, and UTI recurrence were not different between the groups. In group I, recurrence of UTI and presence of APN were associated with the incidence of VUR (recurrence vs. no recurrence: 40% vs.11.4%; APN vs. no APN: 23.3% vs. 9.2%; P<0.05). The incidence of VUR and APN was not related to the presence of hydronephrosis.

CONCLUSION

UTI in febrile children cannot be ruled out solely on the basis of positive urinalysis or urine culture findings. Recurrence of UTI and presence of APN may be reasonable indicators of the presence of VUR.

Plasma neutrophil gelatinase-associated lipocalin predicts acute pyelonephritis in children with urinary tract infections

BACKGROUND

The identification of acute pyelonephritis (APN) is still a challenge.

METHODS

Patients admitted for their first urinary tract infection (UTI) were enrolled. Plasma neutrophil gelatinase-associated lipocalin (NGAL) levels were measured at admittance and after treatment. Laboratory, clinical, and imaging results were compared between children with and without APN.

RESULTS

A total of 123 patients were enrolled (53 APN and 70 lower UTI). After adjusting for age and gender, plasma NGAL levels were higher in the APN group than in the lower UTI group (233 (129-496) ng/ml vs. 71 (50.8-110) ng/ml, P < 0.001). NGAL levels were correlated with the serum levels of leukocytes, C-reactive protein, and creatinine, as well as fever duration (P < 0.05). Multivariable analysis revealed that log-transformed plasma NGAL was an independent predictor of APN (P < 0.05). Receiver operating curve analysis showed a good diagnostic profile of NGAL for identifying APN (area under the curve 0.864) with a best cut-off value of 102.5 ng/ml. The NGAL levels in both two groups decreased after treatment compared to levels before treatment (P < 0.001).

CONCLUSION

Plasma NGAL can be a sensitive predictor for identifying APN and monitoring the treatment response of pediatric UTI.

Predictive value of urinary and serum biomarkers in young children with febrile urinary tract infections

BACKGROUND

Early predictive biomarkers for the diagnosis and management of febrile urinary tract infections (UTIs) can be valuable diagnostic tools in children.

METHODS

The study cohort comprised 73 pediatric patients with febrile UTIs [46 with acute pyelonephritis (APN) and 27 with lower UTIs] and 56 healthy children. Urine neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury molecule-1 (uKIM-1) levels and serum cystatin C (sCysC) levels were measured.

RESULTS

The uNGAL/creatinine (Cr) and uKIM-1/Cr levels were higher in the UTI group than in the controls (P < 0.05). uNGAL/Cr and sCysC levels were higher in patients with APN than in those with lower UTIs (P < 0.05). uNGAL/Cr levels in both the APN and UTI groups decreased following the administration of antibiotics compared to those before treatment (P < 0.05). The uNGAL/Cr level was correlated with serum levels of white blood cells, C-reactive protein, CysC and with uKIM-1/Cr (P < 0.05). uKIM-1/Cr was also correlated with sCysC (P < 0.05). Receiver operating curve analyses showed good diagnostic profiles of uNGAL/Cr and uKIM-1/Cr for identifying UTIs [area under the curve (AUC) 0.9 and 0.66, respectively) and of uNGAL/Cr and sCysC for predicting APN (AUC 0.78 and 0.72, respectively).

CONCLUSIONS

Our results suggest that uNGAL, uKIM-1 and sCysC levels may be useful for predicting and managing febrile UTIs in children.

Differential modification of enalapril in the kidneys of lean and 'programmed' obese male young rats

OBJECTIVE

We investigated whether enalapril treatment could have beneficial effects on nutritionally-programmed renal changes in postnatally overfed young rats.

METHODS

Three or 10 male pups per mother were assigned to either the Obese or Lean groups during the first 21 days of life. These pups were treated with enalapril (Obese enalapril, OE; Lean enalapril, LE) or vehicle (Obese control, OC; Lean control, LC) between 15 and 28 days. All pups had their kidneys examined at 29 days.

RESULTS

OC pups weighed more than those in the LC group between 7 and 28 days of age (P<0.05). Enalapril reduced body weights in rats from both the Obese and Lean groups between 22 and 28 days (P<0.05). Renal cell proliferation and apoptosis, glomerulosclerosis, and tubulointerstitial fibrosis were all increased by enalapril (P<0.05). Among the groups, renal cell apoptosis and serum creatinine were the highest in OE pups (P<0.05). Enalapril treatment resulted in contrasting molecular expression profiles involved in renal maturation and repair in the kidneys of the rats from the Lean and Obese groups.

CONCLUSION

Enalapril can differentially modulate renal molecular alterations in lean and postnatally overfed rats and may be not beneficial in obese young male rats.

A rapid plasma neutrophil gelatinase-associated lipocalin assay for diagnosis of acute pyelonephritis in infants with acute febrile urinary tract infections: a preliminary study

In infants with febrile urinary tract infection (UTI), the accurate rapid diagnosis of acute pyelonephritis (APN) would be valuable because early aggressive treatment reduces the risk of renal scarring. The objective of the study was to evaluate whether rapid plasma neutrophil gelatinase-associated lipocalin (NGAL) assay could be used as a diagnostic biomarker of renal parenchymal injury in infants with acute febrile UTI to distinguish APN at the bedside. This prospective observational study included 47 infants, who were admitted with a first episode of acute febrile UTI. Total UTI group was divided into the Cortical defect (UTI-CD, n = 24) group and Non-cortical defect (UTI-ND, n = 23) group, according to the result of renal scan. For the Control group, 15 infants who presented a febrile episode without any focus of bacterial infection were included. On admission, the median NGAL level (106.5 [60-476] ng/mL) in the UTI-CD group was significantly higher than that (60 [60-196] ng/mL) in the UTI-ND group and that (60 [60-197] ng/mL) in the Control group and was significantly decreased to 60 [60-306] ng/mL after an antibiotic treatment. The area under the receiver operating characteristic curves was 0.748 (95 % CI, 0.610-0.887; P = 0.003) for NGAL levels and 0.724 (95 % CI, 0.579-0.868; P = 0.009) for CRP levels. The best cutoff of NGAL level for detection of APN was founded to be 61.0 ng/mL (sensitivity, 75.0 %; specificity, 78.3 %). Although not a stand-alone test, the rapid determination of plasma NGAL level provides valuable information quickly, concerning the distinction of APN, for determining the clinical course of acute febrile UTI.

Overweight, hypertension and renal dysfunction in adulthood of neonatally overfed rats

Accelerated growth in early infancy has been associated with later cardiovascular and metabolic diseases. We investigated the influence of overnutrition during neonatal periods on the development of renal pathophysiological changes in adult offspring rats. Three or 10 male pups per mother were assigned to either the small litter (SL) or normal litter (NL) control groups during the first 21 days of life. The effects of early postnatal overnutrition on body weight, blood pressure and renal changes were determined at 3 and 6 months. Pups in the SL group weighed more than controls between 7 days and 6 months of age (P<.05). In the SL group, serum creatinine levels were higher at 3 and 6 months (P<.05), and at 6 months, blood pressure levels were higher than those of the controls (P<.05). The number of ED-1 positive macrophages in renal cortex and glomerulosclerosis index increased in the SL group at 3 and 6 months (P<.05). Additionally, cortical apoptotic cells increased in the SL group at 6 months (P<.05). Immunoblotting and immunohistochemistry showed that matrix metalloproteinase (MMP)-9 protein expressions decreased and tissue inhibitor of MMP-1, tumor necrosis factor-α, osteopontin and adiponectin expressions increased in the SL group at 3 months (P<.05). However, at 6 months, MMP-9 expression was elevated, and osteopontin expression remained elevated in the SL group (P<.05). Early postnatal overfeeding can lead to lasting overweight, hypertension and renal dysfunction and place a greater burden on the kidney.

Membranous nephropathy in a 13-year-old boy with common variable immunodeficiency

Various forms of hypogammaglobulinemia can occur in patients with autoimmune diseases and vice versa. We report a 13-yr-old boy with membranous nephropathy and common variable immunodeficiency. He presented with the nephrotic syndrome, pneumonia with bronchiectasis, and profound hypogammaglobulinemia. Renal biopsy showed diffusely thickened glomerular capillary walls with 'spikes' suggesting a membranous nephropathy. Secondary causes were ruled out by laboratory studies; however, heavy proteinuria persisted with steroid therapy. Cyclosporine and intravenous immunoglobulin were added, and the patient was discharged with decreased proteinuria. Hypogammaglobulinemia may have a deleterious impact on the immune dysregulation in some patients with membranous nephropathy.

Postnatal early overnutrition dysregulates the intrarenal renin-angiotensin system and extracellular matrix-linked molecules in juvenile male rats

Overnutrition during the perinatal period has been associated with susceptibility to obesity and related comorbidities. We examined the effects of postnatal early overnutrition on the development of juvenile obesity and the associated renal pathophysiological changes. Three or 10 pups per mother from rat pup litters were assigned to either the overnutrition or control groups during the first 21 days of life. The effects of overfeeding were measured at 28 days. The smaller male litter pups were heavier than the controls between 4 and 28 days after birth (P<.05). By 28 days of age, the kidney weight per body weight ratio decreased in the small litter group (P<.05). Circulating leptin levels increased in the small litter rats (P<.05). Overnutrition had no effect on renal cell proliferation, apoptosis, macrophages and glomerulosclerosis. In the immunoblots and immunohistochemistry, renin and angiotensin II type (AT) 2 receptor expression increased in the overfed rats (P<.05). By contrast, the plasminogen activator inhibitor (PAI)-1 and matrix metalloproteinase (MMP)-9 expression decreased in the overnutrition group (P<.05). The AT 1 receptor, tissue inhibitor of MMP-1, monocyte chemoattractant protein-1, tumor necrosis factor-α, osteopontin and adiponectin expression was not changed. Our data showed that postnatal early overfeeding led to hyperleptinemia, juvenile obesity and the acquired reset of renal maturation. Up-regulation of renin and AT2 and down-regulation of PAI-1 and MMP-9 might contribute to abnormal programming of renal growth in rats exposed to postnatal early overnutrition.

Cellular and RAS changes in the hearts of young obese rats

Obesity during childhood increases the risk of cardiac disease, hypertension, and other complications in adulthood. We investigated the cellular and renin-angiotensin system changes of the heart in obese young rats. We used Sprague-Dawley rats and early obesity was induced by overfeeding through adjusting the number of male pups per dam during the first 28 days of life. The body weight, heart weight, blood pressure, serum glucose, and blood pressure were assessed and we performed echocardiography, proliferating cell nuclear antigen (PCNA); assessment, apoptosis and Masson's trichrome staining, and Western blotting and the results were compared between the normal litter (NL, control) and the small litter (SL, obesity). There were no differences in blood pressure and serum glucose, but the body weight increased 61.2% and the interventricular septal thickness in diastole on the echocardiography was increased in the SL. There was hyperplasia of the PCNA cells and apoptotic cells without cellular hypertrophy or change of the amount of collagen in the SL. On Western blotting, rennin, and angiotensin II type 2 receptor (AT2R) were increased without a change of angiotensin II type 1 receptor (AT1R) in the SL. Early obesity caused echocardiographically detected septal hypertrophy and an increase of cellular turnover. Renin and AT2R were upregulated without a change of AT1R and the increase of AT2R was regarded as a cardioprotective effect against the pathologic conditions caused by the early obesity.

Spironolactone and enalapril differentially up-regulate the expression of VEGF and heme oxygenase-1 in the neonatal rat kidney

Both the renin-angiotensin-aldosterone system (RAAS) and hypoxia are vital physiological factors involved in the control of nephrogenesis and vascularization. We investigated the relationship between RAAS and hypoxia in the developing kidney. The expression of VEGF and heme oxygenase (HO)-1 related with the oxygen was analyzed in the enalapril- or spironolactone-treated neonatal rat kidneys. Enalapril (30 mg/kg/d) or spironolactone (200 mg/kg/d) was administered to newborn rat pups for 7 d. The newborn rats were injected i.p. with pimonidazole (200 mg/kg), a marker of severe tissue hypoxia, 1 h before killing. VEGF and HO-1 protein expression was significantly increased by immunoblots and immunohistochemistry in both the enalapril- and spironolactone-treated kidneys, compared with the controls (p < 0.05). HO-1 mRNA expression was increased in the spironolactone-treated group (p < 0.05). The immunoactivity of pimonidazole was not different from that of the controls in the enalapril-treated group, whereas it was increased in the spironolactone-treated group. The results of this study indicate that aldosterone blockade or angiotensin II inhibition in the developing rat kidney up-regulated renal VEGF and HO-1 expression regardless of the hypoxic conditions and may differentially modulate VEGF and HO-1 production.

Hepatic and pulmonary nodular lesions in pediatric urinary tract infections

One of the major goals in investigating children with urinary tract infection (UTI) is to recognize patients at risk of further UTI-related problems. This study reports the clinical features of 19 pediatric patients with UTIs in whom associated hepatic and/or pulmonary nodules were incidentally diagnosed by the imaging tests performed for the UTI. Hepatic nodules in five patients were detected on ultrasound scans, and pulmonary nodules and both hepatic and pulmonary nodules were detected in 12 and two children by dimercaptosuccinic acid scintigraphy. The mean age of the patients was 24.5 months. Vesicoureteral reflux (VUR) was detected in nine of 17 patients (52.9%), acute pyelonephritis was identified in nine of 18 patients, and renal scarring was found in 57.1% patients with pyelonephritis. On follow-up, the hepatic and/or pulmonary nodules regressed in all patients. About 85.7% of patients experienced a recurrence of UTI within 1 year. In comparison with age- and sex-matched controls with UTIs without pulmonary or hepatic nodules, the presence of VUR and the recurrence of UTI within 1 year were higher in patients with UTIs and nodules (P<0.05). The hepatic and/or pulmonary nodules identified on the ultrasound scan and by dimercaptosuccinic acid scintigraphy may provide a valuable diagnostic marker for the proper management of patients with an UTI.

Aldosterone modulates cell proliferation and apoptosis in the neonatal rat heart

In the present study, we investigated whether and how the mineralocorticoid receptor antagonist spironolactone affects cardiac growth and development through apoptosis and cell proliferation in the neonatal rat heart. Newborn rat pups were treated with spironolactone (200 mg/kg/d) for 7 days. The cell proliferation was studied by PCNA immunostaining. The treatment with spironolactone decreased proliferating myocytes by 32% (P<0.05), and reduced myocytes apoptosis by 29% (P<0.05). Immunoblot and immunohistochemistry for the expression of p38, p53, clusterin, TGF-beta2, and extracellular signal-regulated kinase were performed. In the spironolactone group, p38, p53, clusterin, and TGF-beta2 protein expression was significantly decreased (P<0.05). These results indicate that aldosterone inhibition in the developing rat heart induces cardiac growth impairment by decreasing proliferation and apoptosis of myocytes.

Spironolactone, but not enalapril, potentiates hypoxia-inducible factor-1 alpha and Ets-1 expression in newborn rat kidney

Hypoxia is regarded as an important physiological factor that controls nephrogenesis. We investigated whether the renin-angiotensin-aldosterone system (RAAS) affects hypoxia-related target genes in developing kidneys. Newborn rat pups were treated with enalapril (30 mg/kg/d) or spironolactone (200 mg/kg/d) for 7 days. Tissue hypoxia was assessed by the uptake of a hypoxyprobe-1, pimonidazole (200 mg/kg), and the expression of hypoxia-responsive genes. In the enalapril group, hypoxia-inducible factor (HIF)-1alpha, HIF-2alpha, and Ets-1 protein expression were not changed, compared to the control group. In the spironolactone group, HIF-1alpha and Ets-1 protein expression were significantly increased by immunoblots and immunohistochemistry, whereas HIF-2alpha protein expression was not changed, compared to the control group. In the enalapril group, the immunoactivity of pimonidazole was not significantly different from that of the controls. However, in the spironolactone group, pimonidazole staining demonstrated that the cortex and medulla underwent severe hypoxia. In summary, our data showed that aldosterone inhibition in the developing kidney augmented the hypoxic responses, and up-regulated the expression of key mediators of hypoxia including HIF-1alpha and Ets-1. Angiotensin II inhibition did not affect hypoxia-related alterations in the developing kidney. The components of RAAS may differentially modulate renal hypoxia and its related target genes in the developing rat kidney.

Questionnaire survey on pediatric hypertension in Japan and Korea

BACKGROUND

Hypertension (HTN) is no longer viewed as an adult disease. The purpose of the present study was to understand how hypertensive children are evaluated and managed, by surveying pediatricians in Japan and South Korea.

METHODS

A questionnaire was mailed to 109 Japanese (JA) and 159 Korean (KO) pediatric cardiologists, pediatric nephrologists, and other pediatricians.

RESULTS

A total of 127 replies were received (response rate 47%). Most of respondents did not check blood pressure (BP) routinely in outpatient clinics (JA 77%, KO 88%). A mercury sphygmomanometer was the most commonly used method for BP measurements (JA 72%, KO 62%). BP treatment goals were usually set at the 95th percentile for age, gender, and height (JA 47%, KO 54%). More KO used a lower goal in children with primary HTN than JA. KO respondents preferred angiotensin-converting enzyme inhibitors (ACEI) as initial agents regardless of underlying diseases whereas JA respondents chose various medications, that is, calcium channel blockers, diuretics, and ACEI. For BP monitoring, self-monitoring was found to be most frequent in both countries (JA 80%, KO 57%). Ambulatory BP monitoring was not frequently utilized in both countries (JA 33% KO 34%).

CONCLUSION

The current assessment, management and differing trends in pediatric HTN in Japan and Korea have been identified in the present study. Pediatricians should be aware of the growing implications of HTN in children.

Albumin versus normal saline for dehydrated term infants with metabolic acidosis due to acute diarrhea

To compare the efficacy of albumin to normal saline (NS) for initial hydration therapy for dehydrated term infants with severe metabolic acidosis due to acute diarrhea.

STUDY DESIGN

We randomized 33 infants presenting with moderate-to-severe dehydration and metabolic acidosis (pH <7.25 or base excess (BE) <-15) into two groups, an albumin group (n=15) and a NS group (n=18). For initial hydration treatment, the albumin group received 5% albumin (10 ml kg(-1)), whereas the NS group received NS (10 ml kg(-1)).

RESULT

After 3 h of treatment, both groups improved. However, the magnitude of improvement in the pH, BE and HCO(3)(-) levels were not different in comparisons between these two groups. In addition, there were no differences either in the body weight and weight gain 4 days after treatment or in the length of hospital stay.

CONCLUSION

Albumin was not more effective than NS for initial hydration treatment of dehydrated term infants with metabolic acidosis due to acute diarrhea.

Endothelin A receptor blockade influences apoptosis and cellular proliferation in the developing rat kidney

Endothelin systems are believed to play important roles in the emergence and maintenance of functions of various organs during perinatal development, including the kidney. The present study was designed to investigate the roles of endothelin systems on physiologic renal growth and development. Newborn rat pups were treated with either Bristol-Myers Squibb-182874 (30 mg/kg/day), a selective endothelin A receptor (ET(A)R) antagonist, or vehicle for 7 days. To identify cellular changes, kidneys were examined for apoptotic cells by terminal deoxynucleotide transferase-mediated nick-end labeling stain and proliferating cell nuclear antigen (PCNA) by immunohistochemical (IHC) stain. To clarify the molecular control of these processes, immunoblots and reverse transcriptase-polymerase chain reaction for Clusterin, Bcl-2, Bcl-X(L), Bax, and p53 were performed. ETAR antagonist treatment resulted in reduced kidney weights, decreased PCNA-positive proliferating cells, and increased apoptotic cells. The protein expressions of renal Bcl-X(L) and Bax in the ETAR antagonist-treated group were significantly decreased, whereas the mRNA expressions of these genes were not changed. There were no significant differences in the expressions of Clusterin, Bcl-2, and p53. In conclusion, inhibition of endogenous endothelins impairs renal growth, in which decreased cellular proliferation, increased apoptosis and decreased expressions of renal Bcl-X(L) and Bax are possibly implicated.

Renin-Angiotensin system - considerations for hypertension and kidney

The kidneys play a fundamental role in the long-term control of arterial pressure by regulating sodium balance and extracellular fluid volume. The renin-angiotensin system (RAS) is at the center of the regulation of hypertension and progressive renal injury. It has gradually become clear that not only systemic RAS, but also intrarenal RAS has specific effects in the pathogenesis and progression of hypertension and renal damage. All of the RAS components are exhibited in the kidney and intrarenal angiotensin II (Ang II) is formed by multiple mechanisms. The demonstration of much enhanced levels of Ang II within specific renal compartments points out selective local regulation of Ang II in the kidney, showing that intrarenal Ang II levels are regulated in a way different from circulating Ang II. The importance of the RAS in involving proper nephrogenesis is also well known, and suppression of the RAS during fetal development may play a key role in mediating the structural and physiological changes observed in models of fetal programming of hypertension.

Genetic control of VEGF and TGF-beta1 gene polymorphisms in childhood urinary tract infection and vesicoureteral reflux

We investigated whether genetic polymorphisms of vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1), potential candidate genes in the pathogenesis of urinary tract infection (UTI) and vesicoureteral reflux (VUR), are associated with the susceptibility to UTI and VUR, and renal scarring. We recruited 89 controls and 86 UTI and 58 VUR children. The UTI group was subdivided into two groups according to renal scarring. Two polymorphisms of VEGF and three of TGF-beta1 genes were investigated by using PCR-restriction fragment length polymorphism analysis. In both UTI and VUR groups, there was an increase in frequency of the VEGF -460 CC (control, 4.3; UTI, 15.9; VUR, 17.8%; p < 0.05), TGF-beta1 -509 CC (control, 8.7; UTI, 34.6; VUR, 35.1%; p < 0.001), and TGF-beta1 -800 GG genotypes (control, 19.1; UTI, 40.5; VUR, 40.4%; p < 0.05). An increase in the TGF-beta1 +869 CC (scar-positive, 35.4; scar-negative, 10.3%; p < 0.05) and a decrease in the +869 TC genotype (scar-positive, 29.2; scar-negative, 55.2%; p < 0.05) were observed in the scar-positive subjects. There were no differences in +405 VEGF genotype frequencies. The VEGF T-460C and the TGF-beta1 C-509T, G-800A, and T869C polymorphisms could be genetic markers of the process of UTI and VUR.

Acute tubulointerstitial nephritis following ingestion of Chlorella tablets

Here, we report on a boy with acute tubulointerstitial nephritis (ATIN), who developed it following ingestion of Chlorella tablets as a food supplement. He was incidentally detected to have glucosuria, proteinuria, and leukocyturia during school mass screening. He had had a history of ingestion of Chlorella tablets for 3 months. Laboratory studies showed anemia, increased levels of creatinine, decreased glomerular filtration rate (GFR), hypokalemia, hypo-uricemia, hypophosphatemia, hypergammaglobulinemia, proteinuria, leukocyturia, and glucosuria. ATIN was diagnosed by renal biopsy. The patient's renal function improved after initiation of corticosteroid therapy and discontinuation of Chlorella for 6 months. Chlorella may be a causative allergen inducing tubulointerstitial injury in kidney.

AT1 antagonist modulates activin-like kinase 5 and TGF-beta receptor II in the developing kidney

Previous studies by our group have demonstrated that angiotensin-converting enzyme (ACE) inhibition in the developing kidney modulates transforming growth factor-beta receptors. Blocking of angiotensin II (ANG II) mainly through angiotensin II type 1 receptor (AT1) has been implicated in mediating this ACE inhibition. The present study was designed to investigate the effects of an AT1 antagonist, losartan, on transforming growth factor-beta1 (TGF-beta1), TGF-beta receptor I [TbetaRI, activin-like kinase (ALK)-1, ALK-5], TGF-beta receptor II (TbetaRII), and alpha-smooth muscle actin (alpha-SMA) expression in the developing kidney. Newborn rat pups were treated with losartan (30 mg/kg per day) or normal saline for 7 days. Kidneys were removed for immunohistochemistry, reverse transcription polymerase chain reaction (PCR), and Western blotting of TGF-beta1, ALK-1, ALK-5, TbetaRII, and alpha-SMA. Renal ALK-5 and TbetaRII protein expressions in the losartan-treated group were found to be significantly increased (P<0.05), whereas TGF-beta1, ALK-1, and alpha-SMA protein expressions were not changed by losartan treatment. The losartan-treated group also showed significantly increased mean tubular diameter and interstitial area of the kidney (P<0.05). These results suggest that AT1 inhibition in the developing kidney impairs renal growth and development and modulates the expression of ALK-5 and TbetaRII.

Genetic polymorphism of the renin-angiotensin system on the development of primary vesicoureteral reflux

BACKGROUND

The familial clustering of vesicoureteral reflux (VUR) has suggested a genetic basis. This study was designed to investigate the genetic polymorphism of the renin-angiotensin system (RAS) in Korean children.

METHODS

Genetic polymorphism of angiotensin-converting enzyme (ACE) and angiotensin II receptor genes was evaluated in 67 primary VUR patients and compared to 58 controls with no urological abnormalities. To detect the relation of the risk factors of primary VUR with the genetic polymorphism, the distribution of ACE, AT1 and AT2 genotypes after stratification by risk factors was also studied in the primary VUR patients.

RESULTS

The incidence of AT2 A-1332G transition was significantly lower in primary VUR patients (p = 0.047). Furthermore, in the case of combination of ACE and AT2 gene, a significantly lower incidence of primary VUR was seen with II genotype of ACE and A-1332G transition in the AT2 receptor gene (p = 0.003). Concerning the risk factors of primary VUR, there were no biologically significant results.

CONCLUSIONS

These findings indicate that a lower incidence of AT2 A-1332G transition is seen in primary VUR patients, at least in the Korean population. Also, in the case of combination of ACE and AT2 gene, the combination of ACE II genotype and AT2 A-1332G transition occurs infrequently in primary VUR.

ACE inhibition modulates transforming growth factor-beta receptors in the young rat

The renin-angiotensin system plays an important role in renal growth and development. Exposure of the neonate to angiotensin converting enzyme (ACE) inhibitors increases mortality and results in growth retardation and abnormal renal development. It has been demonstrated that ACE inhibition in the developing kidney reduces the renal expression of growth factors, which may account for renal growth impairment. This study was designed to investigate the relationship between renal growth impairment and the expression of transforming growth factor-beta1 (TGF-beta1), TGF-beta receptor I [TbetaRI, activin-like kinase (ALK)-1 and ALK-5], and TGF-beta receptor II (TbetaRII). Newborn rat pups were treated with enalapril (30 mg/kg per day) or vehicle for 7 days, and kidneys were removed for Western blotting of TGF-beta1, ALK-1, ALK-5, and TbetaRII, and for RT-PCR of ALK-5 and TbetaRII. TGF-beta1, ALK-1, ALK-5, and TbetaRII were also detected by immunohistochemistry. Enalapril treatment resulted in an increased mortality (30.4%) by day 7, and reduced body weight and kidney weight ( P<0.05 versus vehicle). Enalapril decreased renal TGF-beta1, ALK-1, and ALK-5 protein expression ( P<0.05). Also, enalapril decreased ALK-5 mRNA expression ( P<0.05). TbetaRII expression was not changed by enalapril treatment. These results indicate that ACE inhibition in the developing kidney decreases TGF-beta1, ALK-1, and ALK-5 expression, which may account for renal growth impairment. TbetaRII may not be modulated by ACE inhibition in the developing kidney.

Immunohistochemical characterization of cellular infiltrate in nasal polyp from aspirin-sensitive asthmatic patients

BACKGROUND

The immunopathologic mechanism of nasal polyp in aspirin-sensitive asthma remains to be further defined.

OBJECTIVE

To characterize the features of the inflammatory cellular infiltrate in the nasal polyp tissue from aspirin-sensitive asthmatic patients.

METHODS

We have taken nasal polyp tissue during nasal polyp resection from 13 aspirin-sensitive asthma, 6 allergic, and 12 non-allergic subjects. Immunohistochemistry was employed to stain and enumerate the individual inflammatory cell types using monoclonal antibodies against tryptase (AA1) to identify mast cells, against secreted forms of eosinophil cationic protein (EG2), to identify activated eosinophils, against neutrophil elastase (NE) for neutrophils and against T cell surface markers (CD3) to identify total T cells.

RESULTS

There were no significant differences in AA1 + cells among three groups (P>.05). EG2 + cells tended to be higher in ASA-sensitive asthmatic patients than in allergic and non-allergic subjects, but no statistical significance was observed. NE+ cells were found in most subjects of the three groups and their numbers were significantly higher in allergic subjects than in aspirin-sensitive asthma (P<.05). Some patients had CD3+ cells with no statistical significance among the three groups. Significant correlation was found in numbers between NE+ cell and AA1+ cell (r=.44, P=.01), and between NE+ cell and EG2+ cell (r=.40, P=.02).

CONCLUSION

These findings suggested that major effector cells such as mast cells and eosinophils might be placed in the center of the inflammatory response of nasal polyps, regardless of their association with aspirin sensitivity.

Neutrophil infiltration and release of IL-8 in airway mucosa from subjects with grain dust-induced occupational asthma

BACKGROUND

The immuno-pathological mechanism for occupational asthma induced by grain dust (GD) remains to be clarified. There have been few reports suggesting the involvement of neutrophils inducing bronchoconstriction after inhalation of GD.

OBJECTIVE

To further understand the role of neutrophil in the pathogenesis of GD-induced asthma.

MATERIALS AND METHODS

We studied the phenotype of leucocytes of the bronchial mucosa in patients with GD-induced asthma. Bronchial biopsy specimens were obtained by fibreoptic bronchoscopy from six subjects with GD-induced asthma. Six allergic asthma patients sensitive to house dust mite were enrolled as controls. Bronchial biopsy specimens were examined by immunohistochemistry with a panel of monoclonal antibodies to tryptase-containing mast cell (AA1), activated eosinophil (EG2), pan T-lymphocyte (CD3) and neutrophil elastase (NE). Induced sputum was collected before and after the GD-bronchoprovocation test. The IL-8 level in the sputum was measured using ELISA.

RESULTS

There was a significant increase in the number of AA1+ and NE+ cells in bronchial mucosa of GD-induced asthma, compared with those of allergic asthma (P=0.01, P=0.01, respectively). No significant differences were observed in the number of EG2+ and CD3+ cells (P = 0.13, P=0.15, respectively). IL-8 was abundant in the sputum of all GD-induced asthma patients and significantly increased after the bronchial challenges compared with the baseline value (P = 0.03).

CONCLUSION

These findings support the view that neutrophil recruitment together with mast cells may contribute to the bronchoconstriction induced by GD. A possible involvement of IL-8 was suggested.