Kidney Veno-Muscular Characteristics and Kidney Disease Progression: A Native Kidney Biopsy Study

• Published in: Kidney medicine Vol. 5; no. 12; p. 100733
• Main Authors: Tsuji, Kenji, Nakanoh, Hiroyuki, Takahashi, Kensaku, Morita, Takafumi, Sang, Yizhen, Fukushima, Kazuhiko, Matsuoka-Uchiyama, Natsumi, Onishi, Yasuhiro, Uchida, Haruhito A., Kitamura, Shinji, Wada, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.12.2023; Elsevier
• Subjects: inflammation; interstitial fibrosis/tubular atrophy; kidney biopsy; kidney pathology; Original Research; Veno-muscular complex; veno-muscular complex; kidney biopsy; interstitial fibrosis/tubular atrophy; kidney pathology; inflammation
• ISSN: 2590-0595; 2590-0595
• DOI: 10.1016/j.xkme.2023.100733

Assessment of kidney biopsies provides crucial information for diagnosis and disease activity, as well as prognostic value. Kidney biopsy specimens occasionally contain veno-muscular complex (VMC), which consists of muscle tissues around the kidney venous system in the corticomedullary region. However, the role of VMC and the clinical significance of VMC variants is poorly understood. In the present study, we investigated VMC variants’ kidney prognostic values. Retrospective cohort study. Among 808 patients who underwent a kidney biopsy from 2011 to 2019, 246 patients whose kidney biopsy specimens contained VMC were enrolled. VMC variants; Inflammatory-VMC (an infiltration of ≥80 inflammatory cells/mm2-VMC area) and VMC hypertrophy (Hyper-VMC, a VMC average width ≥850 μm), and the interstitial fibrosis/tubular atrophy (IFTA) score. A decline in eGFR ≥40% from the baseline or commencement of kidney replacement therapy. Cox proportional hazards model. Among 246 patients with data on VMC, mean baseline eGFR was 56.0±25.6 ml/min per 1.73 m2; 80 had high inflammatory VMC and 62 had VMC hypertrophy. There were 51 kidney events over median follow-up of 2.5 years. We analyzed two VMC variants: Multivariable logistic regression analysis revealed that eGFR negatively correlated with the presence of both Inflammatory-VMC and Hyper-VMC. A Cox proportional hazards analysis revealed that Inflammatory-VMC (but not Hyper-VMC) was independently associated with the primary outcome after adjustments for known risk factors of progression, including proteinuria, eGFR and the interstitial fibrosis/tubular atrophy (IFTA) score (hazard ratio (HR) 1.97; 95% confidence interval, 1.00 to 3.91). Single-center study and small sample size. Assessment of Inflammatory-VMC provides additional kidney prognostic information to known indicators of kidney disease progression in patients who undergo kidney biopsy.