THE IMPACT OF TC-99M DMSA SCINTIGRAPHY ON DNA DAMAGE AND OXIDATIVE STRESS IN CHILDREN

Background: Tc-99m DMSA scintigraphy is a commonly used imaging modality in the pediatric population. The radiopharmaceuticals which have the effects of ionizing are used in this method. This study aimed to investigate the impact of the Tc-99m DMSA scan on renal oxidative stress and mononuclear leukocyte DNA damage. Methods: Twenty-seven patients who performed Tc-99m DMSA scintigraphy were included in this study. Three ml heparinized blood samples were taken just before, during, and after a week from the scintigraphy. Mononuclear leukocyte(MNL) DNA damage, total antioxidant status (TAS), and total oxidant status(TOS) were measured in blood samples. The oxidative stress index (OSI) was calculated. The spot urine samples were taken from each patient before and within three days after performing the scintigraphy. TAS/Creatinine(TAS/Cr), TOS/Creatinin(TOS/Cr), and N-acetyl-glucosaminidase/creatinine(NAG/Cr) levels were measured in urine samples. OSI was calculated. Results: There was no statistically significant difference in the values of TAS, TOS and OSI studied in serum samples between controls and study group(p=0.105, p=0.913, and p=0.721, respectively). There was no statistically significant difference in the levels of TAS/Cr, TOS/Cr, NAG/Cr, and OSI which were studied in urine samples before and after scintigraphy scan(p=0.381, p=0.543, p=0.129 and p=0.08 respectively). The levels of DNA damage were increased only after the performance of the scintigraphy scan and decreased a week later(p<0.05). Conclusions: The effect of Tc-99m DMSA scintigraphy is insufficient to create oxidative damage, but it can cause DNA damage via the direct impact of ionizing radiation which can be repaired again in a short time. Keywords: Tc-99m DMSA, DNA damage; reactive oxygen species; renal tubular injury; children

Interrater Reliability of 99mTc-DMSA Scintigraphy Performed as Planar Scan vs. SPECT/Low Dose CT for Diagnosing Renal Scarring in Children

99mTc-dimercaptosuccinic acid (DMSA) scintigraphy is currently the method of choice for assessing renal scarring in children, but it is not established whether conducting the scan as a single photon emission tomography combined with low-dose CT (SPECT/ldCT) scan provides additional diagnostic benefits when compared to conventional planar scintigraphy. In the present study, we evaluated the interrater reliability of DMSA SPECT/ldCT vs. planar DMSA scintigraphy for diagnosing renal scarring. Methods: Two nuclear medicine physicians blinded to patient data retrospectively analysed all paediatric 99mTc-DMSA scintigraphes that were conducted in our department for the assessment of post pyelonephritis renal scarring between 2011 and 2016. All scintigraphies included both a planar scan and SPECT/ldCT, and were performed on either a Phillips Precedence 16 slice CT or a Siemens Symbia 16 slice CT. The readers were blinded to each other’s readings and to patient data, and assessed all scans dichotomously for evidence of renal scarring. For each scan, the readers further noted if they were confident in their interpretation. Results: A total of 46 pairs of planar SPECT/ldCT DMSA scans were included. The readers were unconfident about their interpretation of 40% of the planar scans and 5% of the SPECT/ldCT scans. The interrater agreement rate was 72% for planar scans and 91% for SPECT/ldCT, and the corresponding Cohen’s kappa values were 0.38 and 0.79. Conclusion: DMSA SPECT/ldCT is associated with higher reader confidence and interrater reliability than conventional planar DMSA scintigraphy for the assessment of post pyelonephritis renal scarring in children.

P0305DIAGNOSTIC VALUE OF TGF-B-1 AND ANG II EXCRERION IN URINE IN CHILDREN WITH VESICOURETERAL REFLUX DEPENDING ON THE THERAPEUTIC APPROACH

Background and Aims to determine the diagnostic value of profibrogenic cytokines of transforming growth factor (TGF-β1) and angiotensin II (AngII) in urine to detect the severity of tubulointerstitial fibrosis in children with vesicoureteral reflux (VUR) depending on the therapeutic approach. Method 117 patients aged 3 to 16 years (mean age 10.2 ± 4.5, 70.1% of girls) with VUR were examined. The control group consisted of 20 healthy children. All children underwent a complete nephrological examination. The levels of TGF-β1 and AngII were determined in morning urine using the ELISA method and counted for urine creatinine. To identify the severity of the lesion of the renal parenchyma, a static DMSA scintigraphy was performed. Results depending on the therapeutic approach, the children were divided into 2 groups: 1 gr. - children on conservative treatment (63.2%), 2 gr. - children, after surgical correction of VUR (36.8%). In each group, 3 subgroups were identified depending on the development of tubulo-interstitial fibrosis according to DMSA: A subgr. - without signs of sclerosis (15.4%), B subgr. - 1-2 foci (44.74%) and C subgr - &gt; 3-4 foci of sclerosis (40.1%). All patients with VUR had a high urinary excretion of TGF-β1/Cr and AngII/Cr when compared with the control group (p&lt;0.05). Regardless of the therapeutic approach, in subgroups A (without foci of sclerosis) and B (1-2 foci of sclerosis), patients had a statistically significantly lower level of excretion of these cytokines when compared with patients from subgroup C (p &lt;0.05). No significant difference was found in the urinary excretion of TGF-β1/Cr and AngII/Cr depending on the therapeutic approach. Conclusion we established a reliable dependence of the excretion of TGF-β1/Cr and AngII /Cr in the urine on the severity of tubulo-interstitial fibrosis according to DMSA scintigraphy in children with VUR. At the same time, we did not note the dependence of the excretion of TGF-β1/Cr and AngII/Cr in the urine on the method of the therapeutic approach. Therefore, the study of the excretion of TGF-β1/Cr and AngII/Cr in the urine as non-invasive markers can be used as a criterion for the progression of nephropathy in VUR, regardless of treatment methods.

The Screening of Renoprotective Agents by 99mTc-DMSA: A Review of Preclinical Studies

Background: Nephrotoxicity is a prevalent consequence of cancer treatment using radiotherapy and chemotherapy or their combination. There are two methods; histological and biochemical, to assess the kidney damage caused by toxic agents in animal studies. Although these methods are used for the try-out of renoprotective factors, these methods are invasive and time-consuming, and also, lack the necessary sensitivity for primary diagnosis. Quantitative renal 99mTc-DMSA scintigraphy is a noninvasive, precise and sensitive radionuclide technique which is used to assess the extent of kidney damage, so that the extent of injury to the kidney will be indicated by the renal uptake rate of 99mTc-DMSA in the kidney. In addition, this scintigraphy evaluates the effect of the toxic agents by quantifying the alterations in the biodistribution of the radiopharmaceutical. Conclusion: In this review, the recent findings about the renoprotective agents were evaluated and screened with respect to the use of 99mTc-DMSA , which is preclinically and clinically used for animal cases and cancer patients under the treatment by radiotherapy and chemotherapy.