Unveiling the Features of Mercury-Associated Minimal Change Disease: Comparison with Primary Minimal Change Disease

Ai-Bo Qin; Xiao-Juan Yu; Su-Xia Wang; Fu-de Zhou; Ming-Hui Zhao

doi:10.1159/000510877

Unveiling the Features of Mercury-Associated Minimal Change Disease: Comparison with Primary Minimal Change Disease

Kidney Dis (Basel). 2021 Mar;7(2):156-165. doi: 10.1159/000510877. Epub 2020 Sep 29.

Authors

Ai-Bo Qin^{1

2

3

4

5}, Xiao-Juan Yu^{1

2

3

4

5}, Su-Xia Wang^{1

2

3

4

5

6}, Fu-de Zhou^{1

2

3

4

5}, Ming-Hui Zhao^{1

2

3

4

5

7}

Affiliations

¹ Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.
² Institute of Nephrology, Peking University, Beijing, China.
³ Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.
⁴ Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China.
⁵ Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China.
⁶ Electron Microscopy Laboratory, Pathological Center, Peking University First Hospital, Beijing, China.
⁷ Peking-Tsinghua Center for Life Sciences, Beijing, China.

Abstract

Introduction: Long-term exposure to mercury can cause minimal change disease. However, the current understanding of mercury-associated minimal change disease (M-MCD) is inadequate. To improve the understanding of M-MCD, this study retrospectively analyzed the clinicopathological, ultrastructural, and prognostic features of M-MCD, in comparison with primary minimal change disease (P-MCD).

Methods: We retrospectively analyzed the clinicopathological data of 21 M-MCD patients and 21 P-MCD patients. Electron micrographs of glomerular capillaries were taken, and the foot process width (FPW) was measured. A receiver operating characteristics (ROC) curve analysis was performed to determine the optimum cutoff value of FPW that can differentiate the M-MCD from P-MCD.

Results: M-MCD patients presented similar clinical and routine pathological characteristics with P-MCD patients but had lower levels of FPW (935.0 [interquartile range (IQR) 853.7-1,176.7] nm vs. 1,403.2 [IQR 1,089.2-1,841.8] nm, p = 0.002). ROC curve analysis showed that FPW value below 1,385 nm might help to differentiate M-MCD from P-MCD (area under the curve of 0.787, sensitivity of 94.7%, and specificity of 52.4%). For patients with M-MCD, 77.8% achieved complete remission after mercury detoxification monotherapy. Patients with M-MCD had a lower relapse rate than patients with P-MCD (0 vs. 47.1%, p = 0.003). In addition, there was no significant difference in remission time between M-MCD patients treated with mercury detoxification monotherapy and those initially treated with immunosuppressive therapy (2.0 [IQR 1.0-6.0] months vs. 2.0 [IQR 1.5-2.5] months, p = 0.606).

Conclusions: M-MCD patients showed similar clinicopathological features with P-MCD patients, but with less severe foot process effacement, suggesting different pathogenesis of these 2 disease entities. The treatment of mercury detoxification was highly effective for patients with M-MCD and can be considered as a primary choice in clinical practice.

Keywords: Cosmetics; Foot process effacement; Mercury; Minimal change disease; Nephrotic syndrome.