Rare renal proximal tubular dysfunctions in primary biliary cholangitis

Abstract

Introduction

Renal involvement of primary biliary cholangitis (PBC) usually presents as distal renal tubular acidosis. Proximal tubular (PT) dysfunctions in PBC were rarely reported with unclear clinicopathological characteristics and renal prognosis.

Methods

We identified 11 cases of PBC with PT dysfunctions (PBC-PT). Their medical document, kidney pathology, and follow-up data were retrospectively reviewed and analyzed.

Results

The 11 PBC-PT patients were mainly middle-aged (57.8 ± 5.2 years) females (81.8%). Most of them were asymptomatic PBC (7, 63.6%) with a high prevalence of elevated serum immunoglobulin M (IgM, 81.8%) and G (IgG, 54.5%) levels. In the kidney, they had a mean estimated glomerular filtration rate (eGFR) level of 46.54 ± 23.03 ml/min/1.73m², and 81.8% of them had eGFR below 60 ml/min/1.73m². They showed different degrees of PT dysfunctions, including hyperuricosuria, hypouricemia, normoglycemic glycosuria, generalized aminoaciduria, hyperphosphaturia, and hypophosphatemia. Their kidney pathology showed tubulointerstitial nephritis with lymphoplasmacytic infiltrates, brush border defects, and proximal tubulitis. After glucocorticoids treatment, the PT dysfunctions manifesting as hypophosphatemia, hypouricemia, and renal glycosuria all recovered, and the eGFR levels were improved from 43.24 ± 19.60 ml/min/1.73m² to 55.02 ± 21.14 ml/min/1.73m² (p = 0.028), accompanied by significant improvements of serum IgM levels (from 5.97 ± 4.55 g/L to 2.09 ± 1.48 g/L, p = 0.019).

Conclusions

The PT dysfunctions were rare in PBC patients, and glucocorticoids treatment could benefit the improvements of eGFR and tubular functions.

Keywords:

• primary biliary cholangitis
• proximal tubular dysfunctions
• glucocorticoids

Acknowledgements

We acknowledge a conference abstract named “Xiaoxiao Shi, Tianchen Guo, Yubing Wen, Xuemei Li, Limeng Chen*. Renal Proximal Tubular Dysfunctions in Primary Biliary Cholangitis. Kidney Week, American society of nephrology, 2022” as this manuscript was derived from it by the same research team.

Ethical approval and consent to participate

The study was performed in accordance with the Helsinki Declaration and approved by the local Ethic Committee of Peking Union Medical College Hospital (JS-2582). Informed written consent has been obtained from our patients as specified in the ICMJE recommendations.

Author contributions

Xiaoxiao Shi: conceptualization, methodology, investigation, formal analysis, writing—original draft preparation. Tianchen Guo: investigation, validation, formal analysis, writing—original draft preparation. Yubing Wen, Wei Ye, and Wenling Ye: methodology, data curation. Ke Zheng, Yan Qin, and Xuemei Li: resources, writing—reviewing and editing, supervision. Fengchun Zhang: resources, writing—reviewing and editing. Limeng Chen: conceptualization, resources, data curation, writing—reviewing and editing, project administration, and funding acquisition.

Disclosure statement

No conflicts of interest are relevant to this manuscript.

Data availability statement

The data underlying this article are available in the article and in its online supplementary material.

Additional information

Funding

This work was partially supported by grants from the National High Level Hospital Clinical Research Funding (2022-PUMCH-A-173 to S.X.; 2022-PUMCH-B-019, 2022-PUMCH-D-002 to C.L.); National Natural Scientific Foundation of China (82000663 to S.X.; 82170709, 81970607 to C.L.); National Key R&D Program of China (2022ZD0116003 to C.L.); CAMS Innovation Fund for Medical Sciences (CIFMS 2021-I2M-1-003 to C.L.); Capital’s Funds for Health Improvement and Research (CFH 2020-2-4018 to C.L.); Beijing Natural Science Foundation (L202035 to C.L.); the Capital Exemplary Research Wards Project (BCRW202001 to C.L.); The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.