Glomerular Circulation and Function

Urinary Cyclophilin A and serum Cystatin C as biomarkers for diabetic nephropathy in children with type 1 diabetes

BACKGROUND

Currently, microalbuminuria is the gold standard for detection and prediction of diabetic nephropathy (DN). However, microalbuminuria appears once significant kidney damage has actually occurred.

OBJECTIVES

We investigated the diagnostic role of urinary Cyclophilin-A (uCypA), uCypA/creatinine ratio (uCypA/Cr) and serum Cystatin-C (sCysC) as biomarkers for early detection of DN in children with type 1 diabetes mellitus (T1DM) of short duration (2-5 years) before microalbuminuria emerges.

METHODS

uCypA, uCypA/Cr, and sCysC levels were assessed in three age- and sex-matched groups; microalbuminuric diabetic group (n = 31), normoalbuminuric diabetic group (n = 29), and control group (n = 30). Glomerular filtration rate was estimated (eGFR) based on both serum creatinine (eGFR-Cr) and sCysC (eGFR-CysC).

RESULTS

Significantly higher sCysC and lower eGFR-CysC were detected in both diabetic groups compared to controls and in microalbuminuric compared to normoalbuminuric group. No detected significant difference in eGFR-Cr values across the studied groups. Both uCypA and uCypA/Cr were significantly elevated in microalbuminuric compared to both normoalbuminuric and control groups with no difference between normoalbuminuric and control groups. Prediction of microalbuminuria was conducted using sCysC with area under curve up to 0.980. Combined use of sCysC and uCypA had better diagnostic value than uCypA alone.

CONCLUSION

sCysC is a promising early biomarker for DN in childhood T1DM before albuminuria detection. eGFR-CysC is superior to eGFR-Cr in evaluating renal status in childhood T1DM. uCypA and uCypA/Cr were useful tools in predicting microalbuminuria, although not regarded as diagnostic biomarkers for early-stage DN in T1DM children by the current study.

Correlation between cystatin C-based formulas, Schwartz formula and urinary creatinine clearance for glomerular filtration rate estimation in children with kidney disease

INTRODUCTION

Assessment of glomerular filtration rate (GFR) is an important tool for monitoring renal function.

OBJECTIVES

Regarding to limitations in available methods, we intended to calculate GFR by cystatin C (Cys C) based formulas and determine correlation rate of them with current methods.

PATIENTS AND METHODS

We studied 72 children (38 boys and 34 girls) with renal disorders. The 24 hour urinary creatinine (Cr) clearance was the gold standard method. GFR was measured with Schwartz formula and Cys C-based formulas (Grubb, Hoek, Larsson and Simple). Then correlation rates of these formulas were determined.

RESULTS

Using Pearson correlation coefficient, a significant positive correlation between all formulas and the standard method was seen (R(2) for Schwartz, Hoek, Larsson, Grubb and Simple formula was 0.639, 0.722, 0.705, 0.712, 0.722, respectively) (P<0.001). Cys C-based formulas could predict the variance of standard method results with high power. These formulas had correlation with Schwarz formula by R(2) 0.62-0.65 (intermediate correlation). Using linear regression and constant (y-intercept), it revealed that Larsson, Hoek and Grubb formulas can estimate GFR amounts with no statistical difference compared with standard method; but Schwartz and Simple formulas overestimate GFR.

CONCLUSION

This study shows that Cys C-based formulas have strong relationship with 24 hour urinary Cr clearance. Hence, they can determine GFR in children with kidney injury, easier and with enough accuracy. It helps the physician to diagnosis of renal disease in early stages and improves the prognosis.

KNOW-Ped CKD (KoreaN cohort study for outcomes in patients with pediatric CKD): Design and methods

Background

The global prevalence of chronic kidney disease (CKD) is increasing. In children, CKD exhibits unique etiologies and can have serious impacts on children’s growth and development. Therefore, an aggressive approach to preventing the progression of CKD and its complications is imperative. To improve the understanding and management of Asian pediatric patients with CKD, we designed and launched KNOW-Ped CKD (KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease), a nationwide, prospective, and observational cohort study of pediatric CKD with funding from the Korean government.

Methods/design

From seven major centers, 450 patients <20 years of age with CKD stages I to V are recruited for the comprehensive assessment of clinical findings, structured follow-up, and bio-specimen collection. The primary endpoints include CKD progression, defined as a decline of estimated glomerular filtration rate by 50 %, and a requirement for renal replacement therapy or death. The secondary outcomes include the development of left ventricular hypertrophy or hypertension, impairment of growth, neuropsychological status, behavioral status, kidney growth, and quality of life.

Discussion

With this study, we expect to obtain more information on pediatric CKD, which can be translated to better management for the patients.

Trial registration

NCT02165878 (ClinicalTrials.gov), submitted on June 11, 2014.

Lifelike Vascular Reperfusion of a Thiel-Embalmed Pig Model and Evaluation as a Surgical Training Tool

BACKGROUND

Vascular reperfusion of Thiel cadavers can aid surgical and anatomical instruction. This study investigated whether ideal embalming circumstances provide lifelike vascular flow, enabling surgical practice and enhancing anatomical reality.

METHODS

Pressure-controlled pump-driven administration of blue embalming solution was assessed directly postmortem in a pig model (n = 4). Investigation of subsequent pump-driven vascular injection of red paraffinum perliquidum (PP) included assessment of flow parameters, intracorporeal distribution, anatomical alterations, and feasibility for surgical training. The microscopic distribution of PP was analyzed in pump-embalmed pig and gravity-embalmed human small intestines.

RESULTS

Embalming lasted 50-105 min, and maximum arterial pressure was 65 mm Hg. During embalming, the following consecutive alterations were observed: arterial filling, organ coloration, venous perfusion, and further tissue coloration during the next weeks. Most organs were adequately preserved. PP generated low arterial pressures (<30 mm Hg) and drained through the venous cannula. Generally, realistic reperfusion and preservation of original anatomy were observed, but leakage in the pleural, abdominal, and retroperitoneal cavities occurred, and computed tomography showed edematous spleen and liver. Reduction of arterial flow rates after venous drainage is a prerequisite to prevent anatomical deformation, allowing simulation of various surgeries. In pump-embalmed pig small intestines, PP flowed from artery to vein through the capillaries without extravasation. In contrast, arterioles were blocked in gravity-embalmed human tissues.

CONCLUSIONS

In a pig model, immediate postmortem pressure-controlled pump embalming generates ideal circumstances for (micro)vascular reperfusion with PP, permitting lifelike anatomy instruction and surgical training.

Laboratory blood tests useful in monitoring renal function in neonates

It is important to monitor renal function in the neonate, especially in premature infants where nephrogenesis is still in process upon birth. The kidneys are responsible for maintaining homeostasis in the extracellular environment by preventing overaccumulation of waste products and electrolytes. This review describes developmental physiology of the renal system as well as laboratory testing to monitor renal function and glomerular filtration in neonates. Drugs that may affect renal function in infants are also discussed.

Hydronephrosis: a view from the inside

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

Diagnosis and management of childhood polycystic kidney disease

A number of syndromic disorders have renal cysts as a component of their phenotypes. These disorders can generally be distinguished from autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) by imaging studies of their characteristic, predominantly non-renal associated abnormalities. Therefore, a major distinction in the differential diagnosis of enlarge echogenic kidneys is delineating ARPKD from ADPKD. ADPKD and ARPKD can be diagnosed by imaging the kidney with ultrasound, computed tomography, or magnetic resonance imaging (MRI), although ultrasound is still the method of choice for diagnosis in utero and in young children due to ease of use, cost, and safety. Differences in ultrasound characteristics, the presence or absence of associated extrarenal abnormalities, and the screening of the parents >40 years of age usually allow the clinician to make an accurate diagnosis. Early diagnosis of ADPKD and ARPKD affords the opportunity for maximal anticipatory care (i.e. blood pressure control) and in the not-too-distant future, the opportunity to benefit from new therapies currently being developed. If results are equivocal, genetic testing is available for both ARPKD and ADPKD. Specialized centers are now offering preimplantation genetic diagnosis and in vitro fertilization for parents who have previously had a child with ARPKD. For ADPKD patients, a number of therapeutic interventions are currently in clinical trial and may soon be available.