A single-center，case-control study was conducted at Ruijin Hospital north district, Shanghai Jiaotong University School of Medicine. We recruited 128 patients of CKD with a certain etiology of glomerulonephritis or diabetic nephrology administered during January 2017 and January 2018 in the department of nephrology. Healthy controls were recruited from adults who underwent physical examinations during a health check-up at our hospital and excluded those with kidney disease according to medical history, urinary routine, renal function and urinary ultrasound. Subjects occupationally exposed to pesticides were excluded. The study was approved by the Institutional Ethics Committee for Human Research (IEC-HR) of Ruijin hospital.
Clinical information of patients from CKD group was collected, including: (1) demographic data: gender, age, weight, height, and body mass index (BMI)；(2) complications: hypertension, diabetes, etc. (3) laboratory results: 24-hour urinary protein, plasma albumin, serum creatinine, serum uric acid, estimated glomerular filtration rate, total cholesterol, total triglyceride, hemoglobin； (4) Renal histopathology were collected if the patients had undergone a renal biopsy. The information of gender, age, fasting blood sugar, glycosylated hemoglobin, total cholesterol, total triglyceride, and blood pesticide were collected in healthy controls.
Blood Samples collection and pesticides detection
Venous blood samples (5mL) were drawn after overnight fasting and collected in sterile EDTAcontaining vials. After sampling, 3 mL of blood was sent to the laboratory center of this hospital and 2 ml of whole blood was used for pesticide extraction. Analyses of pesticides were performed using gas chromatography coupled to high-resolution mass spectrometry (GC/HRMS) system.
We tested 26 types of pesticides or metabolites including: α-Hexachlorocyclohexane, β-Hexachlorocyclohexane, Lindane, δ-Hexachlorocyclohexane, Fenitrothion, beta-Endosulfan, p,p'-DDE, buprofezin, alpha-endosulfan, p,p'-DDD, p,p'-DDT, o,p'-DDT, bifenthrin, fenpropathrin, cyhalothrin-1, cyhalothrin-2, cis-permethrin, trans-permethrin, cypermethrin-1, cypermethrin-2, cypermethrin-3, cypermethrin-4, flucythrinate-1, flucythrinate-2, Deltamethrin-1, Deltamethrin-2.
Grading of renal tubulointerstitial lesions
Renal tubulointerstitial lesions were graded according to the degree of inflammatory cell infiltration, tubular atrophy and interstitial fibrosis:
Level 0 (No): Normal, no changes in renal tubules, no or very few inflammatory cells in the interstitium, no fibrosis.
Level 1 (Light): Renal tubular epithelial cells showed mild atrophy, degeneration, focal distribution, a small amount of inflammatory cell infiltration, small focus of fibrosis, lesion range was less than 25%.
Level 2（Medium）: Renal tubular epithelial cells showed moderate atrophy, degeneration and moderate inflammatory cell infiltration, fibrosis, lesions range was 26-50%.
Level 3（Heavy）: Renal tubular epithelial cells showed severe atrophy, degeneration, necrosis, patchy distribution, a large number of inflammatory cells infiltration and fibrosis, the lesion range was more than 50%.
Statistical analysis was carried out using SPSS software version 17.0. Normally distributed data were expressed as mean ± SD and non-normal distributed data were expressed by median and interquartile range. Differences between groups were evaluated using the Mann–Whitney U test (where the data were not distributed normally) or Student t test/ANOVA for normally distributed data. The comparison of rates between groups was carried out by chi-square test. Association of p, p’-DDE with eGFR and 24-hour urinary protein were tested using Spearmen’s correlation analysis. binary logistic regression analysis was used to calculate the risk of CKD.