RU2442982C1 - Method for diagnostics of renal parenchyma damage in children with vesicoureteric reflux - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: the method of diagnostics involves determination of vasculoendotelial factor in the patient urine and with its value above 140 pg/ml the damage of renal parenchyma is diagnosed.

EFFECT: method is non-invasive, more precise and simple compared with other renal parenchyma damage diagnostics methods.

1 dwg, 3 ex, 1 tbl

Description

The invention relates to pediatrics and can be used in urology and nephrology.

There is no doubt a significant success in understanding the mechanisms of formation of tubulointerstitial fibrosis, however, questions regarding the initiation and progression of renal parenchyma fibrosclerosis in children with vesicoureteral reflux (PMR) remain open. It is known that retrograde urine flow leads to renal parenchyma ischemia followed by activation of the renin-angiotensin system and damage to all nephron structures. Under conditions of local tissue hypoxia, a powerful release of the angiogenesis factor, vasculoendothelial growth factor (VEGF), occurs. This factor ensures the maintenance of organ function by improving blood flow in intact glomeruli.

The increasing interest of researchers is directed to the development and implementation of minimally invasive methods for diagnosing damage to the kidney parenchyma, since all available methods have a number of disadvantages, the main of which is invasiveness. In addition, the available arsenal of methods allows you to detect only gross damage to the renal parenchyma.

So, due to its relative safety, speed, cost-effectiveness, high accuracy, ultrasound (ultrasound) is widely used in children to identify the structure and size of the parenchyma and the collective kidney system [Becker A.M. Postnatal evaluation of infants with an abnormal antenatal renal sonogram / A.M. Becker // Current Opinion in Pediatrics. - 2009 .-- Vol.21. - P.207-213]. However, ultrasound can detect sclerotic changes in the kidneys when they are sufficiently pronounced [Gallo P., Schenone M., Giberti C. Ureteropelvic Junction Obstruction: Which Is the Best Treatment Today? / F. Gallo, M. Schenone, C. Giberti // J. Laparoendoscopic advanced surgical techniques. - 2009 .-- Vol.19 (5). - P.657-662].

Radioisotope diagnostic methods make it possible to determine the degree and volume of a functioning parenchyma by the integral capture index of a radiopharmaceutical [Khvorostov I.N., Zorky S.N., Smirnov I.E. Tactics for the treatment of vesicoureteral reflux in children // Bulletin of the Volgograd Scientific Center RAMS 4/2009; Fomin D.K. Diagnosis of obstructive uropathy in children by nuclear medicine methods: Abstract. dis. Doct. honey. sciences. - M., 2008. - 44 p.]. The disadvantages of this method are invasiveness, a high degree of radiation damage to other organs, as well as the high cost of using isotope equipment. In addition, anesthetics are required for children of a younger age group. All this limits the use of this method for the diagnosis of cicatricial changes in the kidney.

There is a method of ultrasound examination (ultrasound) of the kidneys in the color Doppler mapping mode, which allows you to determine the resistance index (IR) on the interlobar arteries, thereby indicating sclerotic changes in the parenchyma [Vrublevsky SG Diagnosis and treatment of children with expansion of the pyelocaliceal system // Questions of Practical Pediatrics. - 2008. - T.3. - Number 3. - p. 35-39; Kaminska A., Yamao Y. et al .. Evaluation of reflux kidney using renalresistive index / A. Kaminska, Y. Yamao et al., // J. Urol. - 2002 .-- Vol. 165 (6). - R 2010-2012]. The standard values of IR are 0.7 ± 0.02 (Pourcelot L. Application de l′examen Doppler a l′etude de la circulation peripherique.-Specia. ACD. Paris. - 1980. - P.125). So, as a result of their work, the authors concluded that the progression of chronic kidney diseases is accompanied by an increase in IR [Averchenko MV, Kovtun OP, Komarova S.Yu. Dopplerographic criteria for impaired renal blood flow in children with chronic diseases of the urinary system // Materials of the International School and Scientific and Practical Conference on Pediatric Nephrology "Actual Problems of Pediatric Nephrology." - Orenburg. - 2010. - S.362-363]. However, in recent years it has been shown that in patients with a severe degree of reflux nephropathy (PH), accompanied by a significant decrease in kidney size and the number of functioning parenchyma, there is a significant variety of resistive indicators of renal blood flow. The expected increase in IR in children with sclerotic changes in the renal parenchyma does not always occur. This phenomenon is associated with arteriovenous blood shunting at the juxtamedullary level, as a universal pathophysiological mechanism that is a means of pathological compensation for increased peripheral resistance, which determines the absence of a direct relationship between the degree of sclerosis of the renal parenchyma and peripheral resistance of arterial renal blood flow [Olkhova EB Ultrasound assessment of chronic pyelonephritis in children with vesicoureteral reflux / E. B. Olkhova, E. M. Krylova, I. I. Efremova // Nephrology and dialysis. - 2001. - No. 2. - S.299]. Thus, normal IR values do not prove the normal functional state of renal blood flow. These methods are subjective, depend on the qualifications of the specialist performing them, and do not provide information on the functional state of the kidneys. In addition, in patients with PMR, the speed characteristics of renal blood flow change significantly and are interpreted incorrectly, which does not allow reliable diagnosis of damage to the renal parenchyma.

According to the literature, no information was found on the assessment of angiogenesis for the diagnosis of damage to the renal parenchyma in children with MTCT. There is no information on the quantification of VEGF in healthy children.

The objective of the invention is to develop a non-invasive, accurate, simple and most sensitive method for diagnosing damage to the renal parenchyma in children with MTCT.

As a result of our study, for the first time a quantitative determination of VEGF in urine was performed in practically healthy children without pathology from the urinary system and children with MTCT. VEGF has been found to be directly related to damage to the renal parenchyma in children.

VEGF - a factor involved in the regulation of physiological processes such as angiogenesis and lymphogenesis, is synthesized by podocytes, endothelial cells. It ensures the preservation of intact glomerular capillaries due to endothelial proliferation and has no effect on hypertrophic glomeruli. The role of the factor in maintaining peritubular blood flow was also identified. Its vasodilating effect is due to the activation, primarily of endothelial NO synthase [Gu J.W., Manning R.D. Jr., Young E. et al. Vascular endothelial growth factor receptor inhibitor enhances dietary salf-induced hypertension in Sprague-Dawley rats / J.W. Gu, R. D. Manning, E. Jr., Young et al. // Am. J.Physiol. Regul. Integr. Comp. Physiol. - 2009 .-- Vol.297 (1). - P.-142-148].

Our study is based on the analysis of the level of VEGF urinary excretion in 20 practically healthy children who have no pathology from the urinary system, as well as in 63 children with MTCT. The average age of all children was 2.6 ± 2.5 years.

To diagnose renal parenchyma damage, all patients underwent VEGF enzyme-linked immunosorbent assay using Bender Medsistems test systems (Austria) using an enzyme-linked immunosorbent analyzer Stat Fax 2010 (Stat Fax USA). Urine sampling was performed prior to treatment. Urine samples were centrifuged at 5000 vol. min for 15 minutes, and the supernatant was frozen and stored at a temperature of 18 degrees Celsius until analysis. Similarly, urine samples of practically healthy children were frozen.

Statistical analysis of the results of examination and treatment of patients was carried out using the Statistica 9.0 for Windows application package by StatSoft-Russia Corporation (2009).

After analyzing the results of the study, we first determined the quantitative characteristics of VEGF in urine in healthy children, which were as follows: M = 63.24 pg / ml, SD = 28.79. Values ranged from 25 to 140 pg / ml.

We examined 63 children with varying degrees of reflux. All patients underwent a comprehensive clinical laboratory and X-ray examination. An ultrasound scan of the kidneys and bladder was considered the screening method for diagnosing the pathology of the urinary system. For detection of reflux, cystourethrography was used. To assess the morphofunctional state of the kidneys, excretory urography was used. In children from the age of four, the method of dynamic nephroscintigraphy with the determination of glomerular filtration rate was used to assess renal function. All patients underwent assessment of renal blood flow using ultrasound of the kidneys in color Doppler mapping.

It should be noted that in 49% of patients with reflux, there were no signs of damage to the renal parenchyma according to the standard examination complex. As a rule, these children were examined in connection with a history of pyelonephritis attacks.

All patients, depending on the degree of MTCT, were divided into three groups: group 1 included 20 patients with II degree of reflux; group 2 included 23 patients with III degree of reflux; Group 3 consisted of 20 patients with IV degree of reflux. The data of our study are given in the table.

Indicator Group 1 (n = 20) Group 2 (n = 23) Group 3 (n = 20) M SD M SD P * -level M SD P * -level p ** - level VEGF, pg / mL 449.45 199.04 848.69 586.94 0.05 3880.17 2563,74 0.002 0.002

As can be seen from the table, the VEGF indices in the urine of patients with reflux, including those with its low degrees, were significantly higher than the upper limit of the norm (140 pg / ml), which is logical, since in the anamnesis of these children repeated exacerbations of pyelonephritis were noted leading to damage to the renal parenchyma, which was not diagnosed by the results of standard examination methods.

Thus, the increase in VEGF in urine in patients with MTCT indicates the important role of blood flow remodeling and the development of local tissue hypoxia in the mechanisms of sclerotic processes potentiation in renal parenchyma during reflux.

Clinical examples:

1. Zavatskaya Milan, 1 year 7 months, was admitted to the pediatric urology department with a diagnosis of Congenital malformation of the urinary system. Left-sided vesicoureteral reflux of the II degree. Chronic obstructive pyelonephritis, inactive phase. From the anamnesis: twice during the year. exacerbations of pyelonephritis. Inflammatory changes in the blood and urine are absent.

The level of urinary excretion of a marker of angiogenesis: VEGF - 439.6 pg / ml. When performing mixed cystourethrography revealed bilateral passive and active reflux on the left sides of the II degree. According to the ultrasound of the kidneys and bladder, the size of the kidney on the left is 62 × 29 mm, the parenchyma is 10 mm, the dimensions of the pelvis are 3.9 × 4.1 mm; on the right, the size of the kidney is 61 × 28 mm, the parenchyma is 10 mm, the dimensions of the pelvis are 3.3 × 3.5 mm. According to the Doppler study of the vessels of the kidneys, there are no hemodynamically significant disorders. IR at the level of the main stovol, segmental and arc arteries on the left was within normal limits and was equal to 0.65; 0.68; 0.64, respectively (which is the norm). According to excretory urography, the removal of contrast is timely on both sides.

Despite the absence of signs of damage to the renal parenchyma according to the standard complex examination of a patient with MTCT, an increase in the level of VEGF was noted, which reflects damage to the renal parenchyma even with a small degree of reflux.

2. Bogacheva Alena, 2 months old, was admitted to the pediatric urology department with a diagnosis of Congenital malformation of the urinary system. Left-sided active and passive vesicoureteral reflux of the III degree. Chronic obstructive pyelonephritis, active phase. Condition after nephrectomy on the right due to multicystosis. Initial clinical and laboratory data: OAK: erythrocytes -3.5 × 10 ¹² / l, hemoglobin - 123 g / l, hematocrit - 34.1, white blood cells 9.1 × 10 ⁹ / l, stab-core - 1%, segmented - 32 %, eosinophils - 7%, lymphocytes - 56%, monocytes - 4%, platelets - 265 × l0%, LII = 0.07, INN = 0.03, LI = 1.6, IIR = 15.75; biochemical analysis of blood: total protein - 60 g / l, urea 3.3 mmol / l, creatinine - 40.8 μmol / l; OAM: reaction - slightly acidic, density = 1005, red blood cells 0 in the field of view, white blood cells 10 in the field of view, protein - 0.09 g / l. The level of urinary excretion of markerangiogenesis: VEGF - 750 pg / ml. When performing mixed cystourethrography, bilateral passive and active reflux on the left of the III degree was revealed. According to the ultrasound of the kidneys and bladder, the size of the kidney on the left is 52 × 30 mm, the parenchyma is 7.8 mm, the size of the pelvis is 12.8 × 13.8 mm; on the right is not visualized. According to the Doppler study of the blood vessels of the kidney, there are no hemodynamically significant disorders. IR at the level of the main stovol, segmental and arc arteries on the left was within normal limits and was equal to 0.67; 0.66; 0.61, respectively (which corresponds to normal values). According to excretory urography, the removal of contrast is slowed down on the left.

Despite a significant degree of reflux, no changes in the ultrasound of the kidneys with a Doppler study of the vessels of the kidneys were recorded. Only according to excretory urography there is a slowdown in the evacuation function of the kidney, which may indicate damage to the renal parenchyma. The level of VEGF in the urine was significantly increased compared with its indicators in the urine of practically healthy children, which indicates severe damage to the renal parenchyma and is also confirmed by excretory urography, which has several disadvantages, the main of which is invasiveness.

3. Amons Natalia, 5 years 5 months, was admitted to the children's urology department with a diagnosis of Congenital malformation of the urinary system. Doubling the left kidney. Bubble-ureter reflux of the fourth degree in the lower segment on the left. Condition after endoscopic correction of reflux to the lower segment of the left kidney with a biostable drug. Chronic obstructive pyelonephritis in remission. Initial clinical and laboratory data: OAK: erythrocytes - 3.95 × 10 ¹² / l, hemoglobin - 112 g / l, hematocrit - 32.6, leukocytes 4.1 × 10 ⁹ / l, stab - 2%, segmented - 39 %, eosinophils - 1%, lymphocytes - 53%, monocytes - 2%, platelets - 232 × 10 ⁹ / L, LII = 0.38, INN = 0.05, LI = 1.3, IIR = 10.8; biochemical analysis of blood: total protein - 72.3 g / l, albumin-globulin coefficient - 0.95; OAM: the reaction is acidic, density = 1015, red blood cells 0 in the field of view, white blood cells 0-1 in the field of view, the protein is negative. The level of urinary excretion of a marker of angiogenesis: VEGF - 2219 pg / ml. When performing mixed cystourethrography, passive and active reflux to the lower segment of the left double kidney of the fourth degree was revealed. According to the ultrasound of the kidneys and bladder, the size of the kidney on the left is 102 mm × 43.0 mm, the parenchyma is 12.1 mm, the dimensions of the upper pelvis before the mycysis are 6.9 mm × 9.1 mm, and after it is 4.0 mm / 3.4 mm ; the sizes of the lower pelvis before the micration - 8.1 mm × 10.9 mm, after - 7.7 mm × 10.6 mm; on the right, the size of the kidney is 76 mm × 29.7 mm, the parenchyma is 11.3 mm, the dimensions of the pelvis are 5.1 mm × 4.1 mm. According to the Doppler study of the vessels of the kidneys, there are no hemodynamically significant disorders. IR at the level of the main stovol, segmental and arc arteries on the left was within normal limits and was 0.64; 0.7; 0.6, respectively. According to dynamic nephroscintigraphy, the removal of the radiopharmaceutical is slowed down on the left.

It can be seen from the above example that no changes in the ultrasound of the kidneys with a dopplerographic study of the vessels of the kidneys were recorded. Only according to dynamic nephroscintigraphy, there is a slowdown in the removal of the radiopharmaceutical, which indicates damage to the renal parenchyma. The VEGF level was 2219 pg / ml, which is significantly higher than the upper limit of this factor in the urine of practically healthy children (140 pg / ml) and indicates significant damage to the renal parenchyma, which is also confirmed by nephroscintigraphy, which has a number of significant drawbacks, the main of which is high, degree of radiation exposure and invasiveness.

Thus, as can be seen from the description of the method and the above examples, the proposed method is non-invasive, simple, accurate and more sensitive in the diagnosis of damage to the renal parenchyma. For the first time, VEGF values for practically healthy children, ranging from 25 to 140 pg / ml, were given and it was proved that values in the VEGF urine above 140 pg / ml indicate damage to the renal parenchyma. Our data allow us to detect changes in the renal parenchyma in children with MTCT in the early stages of the formation of nephrosclerosis, while standard examination methods only detect gross damage to the renal parenchyma, objectively evaluate the treatment, improve treatment outcomes for children with reflux and prevent the formation of renal failure in early childhood, and clarification of the mechanisms of initiation of nephrosclerosis will provide an opportunity to discover new directions and prospects in the treatment of patients with congenital and anatomical and functional urinary tract disorders. The data obtained can be included in the algorithm for examining patients with MTCT for early diagnosis of renal parenchyma damage using a non-invasive, accurate, simple and more sensitive method, which is extremely important for pediatric practice.

Claims (1)

A method for diagnosing damage to the renal parenchyma in children with vesicoureteral reflux, which consists in determining vasculoendothelial factor in the urine of patients and diagnosing damage to the renal parenchyma with its value above 140 pg / ml.