Study Supports Renal Biomarker Candidate for Proliferative Lupus Nephritis Chronicity

In patients with proliferative lupus nephritis, renal neuraminidase 1 (NEU1) expression, a protein that has been linked to the pathogenesis of the disease, was associated with lupus nephritis chronicity and renal outcomes. This is according to a study published in Lupus Science & Medicine.¹

“This study provides supportive data to confirm the pathogenic role of NEU1 in proliferative lupus nephritis,” wrote Feng Yu, professor in the renal division of the department of medicine at Peking University First Hospital, Beijing. “New insights into the molecular mechanisms of lupus nephritis chronicity may shed promising therapeutic strategies.”

The renal pathological chronicity index (CI) has been shown to be an individual prognostic indicator of worse renal outcomes in patients with lupus nephritis. While several biomarkers that reflect chronicity have been studied, their sensitivities and specificities are limited. In this study, the researchers aimed to identify candidate biomarkers associated with renal pathological CI scores in patients with proliferative lupus nephritis.

In the study, the researchers compared the protein expression profiles, using renal biopsied specimens, from 10 patients with proliferative lupus nephritis and 6 healthy controls. The proteomic data was verified in a further 58 patients with proliferative lupus nephritis and 10 healthy controls by immunohistochemistry, and in 14 patients with proliferative lupus nephritis with urine samples to assess the urinary expression of the biomarker.

The results showed that the levels of 48 proteins were increased in the group with a CI ≥1 (the group of patients with renal chronicity) compared with those with a CI=0 and healthy controls (the group of patients/controls without renal chronicity).

NEU1 was “highly expressed in the kidney of patients with proliferative lupus nephritis and could co-localize with podocyte, mesangial cells, endothelial cells and tubule cells,” investigators wrote. This high expression was identified as an independent risk factor for renal prognosis (HR, 6.462 (95% CI 1.025 to 40.732), p=0.047).

NEU1 expression was correlated with serum creatinine value, estimated glomerular filtration rate and CI scores. Urinary NEU1 excretion in the patients with CI ≥1 was higher than in those with CI=0and was positively correlated with CI scores.

The authors cited the study’s small sample size as a limitation and suggested that the findings require further exploration.

Reference:

Mao Z, Tan Y, Yu F, et al Discovery of NEU1 as a candidate renal biomarker for proliferative lupus nephritis chronicity Lupus Science & Medicine 2021;8:e000569. doi: 10.1136/lupus-2021-000569