Objective:To explore the value of MR elastography (MRE) and shear wave elastography (SWE) for staging liver fibrosis in a rabbit model.Methods:From March to November 2020, 200 healthy New Zealand white rabbits were randomly divided into control group ( n=40) and liver fibrosis group ( n=160) by random number table method. The volume ratio of CCl 4 and olive oil was 1∶1 to prepare 50% CCl 4 oil solution, and the experimental rabbits in the liver fibrosis group were subcutaneously injected with 50% CCl 4 olive oil solution. It was injected once a week at the dose of 0.1 ml/kg in the first to third weeks, once a week at the dose of 0.2 ml/kg in the 4th to 6th weeks. The dose of 0.1 ml/kg was injected twice a week from week 7 to 16. The control group were subcutaneously injected with an equal dose of normal saline. At the end of the 4th, 8th, 12th, and 16th week, 40 and 10 animals in the liver fibrosis group and the control group were randomly selected by random number table method for MRE and SWE, respectively, to obtain the liver elastic stiffness (LS), which were recorded as LS MRE and LS SWE. After the examination, the experimental rabbits were sacrificed and liver tissue of rabbits were taken for histopathological Scheuer staging, and they were divided into F0-F4 groups. One-way ANOVA was used to evaluate the differences of LS MRE and LS SWE in different stages of liver fibrosis. Spearman correlation was used to analyze the correlation between LS and pathological stages. The receiver operating characteristic curve was used to evaluate the efficacy of LS MRE and LS SWE in diagnosing liver fibrosis staging, and the area under the curve (AUC) was compared using the Z test. Results:Totally 162 rabbits were included, which covered F0 ( n=38), F1 ( n=33), F2 ( n=35), F3 ( n=31) and F4 ( n=25). Significant differences of LS MRE and LS SWE values were found among different stages of liver fibrosis ( F=295.29, 102.40, both P<0.001). LS MRE, LS SWE were both positively correlated with liver fibrosis stage ( r=0.93, 0.81, both P<0.001). The AUC of LS MRE for diagnosing liver fibrosis stages ≥F1, ≥F2, ≥F3, and ≥F4 were 0.955, 0.967, 0.996, and 0.980, respectively; the AUC of LS SWE were 0.856, 0.880, 0.974, and 0.953, respectively. The AUC of liver fibrosis stage ≥ F1, ≥ F2 for LS MRE value were greater than LS SWE value ( Z=2.93, 3.29, P=0.003, 0.001), and the AUC of ≥F3, ≥F4 had no significant differences ( Z=1.58, 1.68, P=0.115, 0.093). Conclusion:Both MRE and SWE can accurately predict the stage of liver fibrosis in experimental rabbits, and MRE is better than SWE in diagnosing early liver fibrosis.

Objective:To explore clinicopathological features and prognosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in children induced by antithyroid drugs.Methods:The clinicopathological features, treatment and prognosis of 3 children with AAV induced by antithyroid drugs in the Department of Pediatric Nephrology and Rheumatology of the First Affiliated Hospital of Sun Yat-sen University were analyzed retrospectively, and the literatures were reviewed.Results:(1) Among the 3 cases, there were 2 females and 1 male, whose ages were 12.6, 13.9 and 13.1 years old, respectively. All patients had medication history of propylthiouracil (PTU) and/or methimazole (MMI) before onset. Initial manifestation was pallor and renal involvements with nephrotic proteinuria, hematuria and renal function abnormality, while 2 of them had hypertension. Extrarenal manifestations were also presented: case 1 presented with rash, arthralgia and cardiac insufficiency; case 2 had brain involvement with repeated convulsions; case 3 presented with arthralgia and lung involvement. They were all tested positive for p-ANCA and MPO-ANCA. Initial renal histopathology of the 3 cases were consistent with ANCA-associated glomerulonephritis, which were classified into sclerosis, crescentic and mixed class respectively. After 8 months of treatments, repeated renal biopsy of case 3 had demonstrated progression to sclerosis class. Antithyroid drugs (PTU or MMI) were discontinued in 3 cases, and the children were all treated with corticosteroid combined with intravenous pulse cyclophosphamide therapy. Plasma exchange was performed in case 2 and case 3 due to rapidly progressive glomerulonephritis and disease recurrence (suspected pulmonary hemorrhage), respectively. Case 3 was treated with rituximab combined with mycophenolate mofetil after recurrence. The extrarenal symptoms relieved quickly after treatments in all cases. P-ANCA and MPO-ANCA became negative in case 1 and case 2 after 6 months of treatments but they were persistently positive in case 3. Three cases were followed up for 24 months, 10 months and 12 months, respectively: case 1 develop chronic kidney disease (CKD) stage 2 with normal urinalysis; case 2 develop CKD stage 5 and had sudden death at home at 10-month follow-up; case 3 develop CKD stage 4 with nephrotic proteinuria and microscopic hematuria. (2) There were totally 30 pediatric cases with AAV induced by PTU and MMI, including 27 reported cases in the literature and 3 cases in this study. Symptoms of AAV appeared in children after an average administration of (37.5±4.0) months of PTU (range from one month to 96 months and 8 months of MMI alone). Kidney (28 cases, 93.3%) and lung (12 cases, 40.0%) were commonly involved, while brain (2 cases, 6.7%) was rarely involved. The pathological changes of kidney were crescent nephritis (5/23) and necrotizing pauci-immune complex nephritis (11/23). The total remission rate was 93.3% (28/30) after antithyroid drugs withdrawal and treatment with corticosteroids and immunosuppressive therapy, however, there were still severe cases with progression to CKD stage 5, and death. (3) Thirty cases were divided into complete response group ( n=19) and incomplete response group ( n=11) according to the treatment response. Compared with complete response group, the proportions of massive proteinuria (8/11 vs 5/19), fibrinoid necrosis (7/9 vs 4/14), deposition of immune complex in renal tissues (6/9 vs 2/14) and administration of immunosuppressants (10/11 vs 5/19), and degree of tubular atrophy (0/1/2/3 grade, 2/4/2/1 vs 9/5/0/0) in incomplete response group were higher (all P<0.05). Conclusions:PTU and MMI can both induce AAV in children, and AAV may occur after short-term course of administration. Kidney and lung are commonly involved while brain involvement is rarely seen. Timely withdrawal of antithyroid drugs and proper treatments with corticosteroids and immunosuppressants can result in high remission rate, though there are still some severe cases. Nephrotic-range proteinuria, renal fibrinoid necrosis, immune-complex deposition and tubular atrophy may be the risk factors of AAV for poor prognosis.

Objective:To perform a prospective cohort study to identify individual susceptibility of glucocorticoid (GC) -associated osteonecrosis of the femoral head (GA-ONFH) and their clinical and genetic risk factors. Methods:The present prospective cohort study enrolled patients who received their first GC therapy between July 2015 and January 2018 at Zhongshan Hospital. All patients did not receive any GC treatment before enrollment. Further, they planned to start GC treatment with the dose (equivalent prednisone) of ≥30 mg/d, lasted ≥3 weeks, or pulse dose ≥200 mg/d, lasted ≥3 d. Blood samples were collected before GC treatment to evaluate bone metabolism and its released factors. Hip MRI was performed at the 1st, 3rd, 6th, 12th and 24th month to diagnose GA-ONFH. All patients were followed-up for ≥2 years. The endpoint was regarded as diagnosis of GA-ONFH or completion of 2 years follow-up. Lasso regression was performed to determine which clinical features were associated with GA-ONFH. A nested case-control sub-cohort (A, n=12) was established prospectively based on the main cohort by 1∶1 matching. Whole exome sequencing was performed to screen differential and functional candidate single nucleotide polymorphisms and insertion-deletions (SNP/InDels). Another sub-cohort (B, n=50) was constructed retrospectively in patients with GA-ONFH and non-ONFH patients received standard high dose GC treatment for more than two years. The candidate SNP/InDels were verified by Sanger sequencing based on the patients from sub-cohort B. Results:A total of 96 patients were enrolled of which 88 of them (32 males and 56 females, mean age 42.30 years) completed follow-up. Eight cases (9.1%) were diagnosed with GA-ONFH. The median time from the start of GC therapy to the diagnosis of ONFH was 53.00(34.00,13.50) days. The baseline characteristics, such as age, sex and body mass index, indicated no significant difference between the ONFH group and the non-ONFH group. The cumulative GC dose of the ONFH patients in the first month was higher than that of non-ONFH [32.74(29.55, 47.05) mg/kg vs. 24.00(21.10, 29.45) mg/kg, Z=-2.410, P=0.016]. However, there was no significant difference of patients who underwent pulse therapy (37.5% vs. 10.0%, adjusted χ 2=2.829, P=0.093). The ratio of serum apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) in patients with ONFH was higher than that in non-ONFH group before GC use [0.95(0.80, 1.50) vs. 0.70(0.60, 0.80), Z=-2.875, P=0.000]. Due to the multicollinearity, Lasso regression model was performed to reduce overfitting. All variables were included in the model. The results suggested that higher ApoB/ApoA1 ratio, lower serum β-c-terminal telopeptide (β-CTX) and higher cumulative GC dose in the first month were the top three risk factors of GA-ONFH. This model had an accuracy of 0.982 in internal validation. Seven differential candidate SNP/InDels were found by whole exome sequencing of sub-cohort A. We further verified these SNP/InDels in sub-cohort B. The patients with COLEC12 mutation (rs2305027, G1816A) were at risk of GA-ONFH ( OR=6.00, 95% CI: 1.17, 30.73). Conclusion:Higher first-month GC dose, lower serum β-CTX level before treatment, higher ApoB/ApoA1 ratio and COLEC12 mutation (rs2305027, G1816A) could increase the risk of GA-ONFH.