Ambient black carbon reaches the kidneys

Leen Rasking; Priyanka Koshy; Eva Bongaerts; Hannelore Bové; Marcel Ameloot; Michelle Plusquin; Katrien De Vusser; Tim S Nawrot

doi:10.1016/j.envint.2023.107997

Ambient black carbon reaches the kidneys

Environ Int. 2023 Jul:177:107997. doi: 10.1016/j.envint.2023.107997. Epub 2023 May 30.

Authors

Leen Rasking¹, Priyanka Koshy², Eva Bongaerts¹, Hannelore Bové³, Marcel Ameloot⁴, Michelle Plusquin¹, Katrien De Vusser⁵, Tim S Nawrot⁶

Affiliations

¹ Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
² Department of Pathology, University Hospitals Leuven, Leuven, Belgium.
³ Department of Sciences, Hasselt University, Diepenbeek, Belgium.
⁴ Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.
⁵ Nephrology and Kidney Transplantation, University Hospital Leuven, Leuven, Belgium; Department of Microbiology and Immunology, Leuven University, Leuven, Belgium.
⁶ Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium; Department of Public Health and Primary Care, Environment and Health Unit, Leuven University, Leuven, Belgium. Electronic address: tim.nawrot@uhasselt.be.

PMID: 37269720
DOI: 10.1016/j.envint.2023.107997

Abstract

Background: Ultrafine particles, including black carbon (BC), can reach the systemic circulation and therefore may distribute to distant organs upon inhalation. The kidneys may be particularly vulnerable to the adverse effects of BC exposure due to their filtration function.

Objectives: We hypothesized that BC particles reach the kidneys via the systemic circulation, where the particles may reside in structural components of kidney tissue and impair kidney function.

Methods: In kidney biopsies from 25 transplant patients, we visualized BC particles using white light generation under femtosecond-pulsed illumination. The presence of urinary kidney injury molecule-1 (KIM-1) and cystatin c (CysC) were evaluated with ELISA. We assessed the association between internal and external exposure matrices and urinary biomarkers using Pearson correlation and linear regression models.

Results: BC particles could be identified in all biopsy samples with a geometric mean (5th, 95th percentile) of 1.80 × 10³ (3.65 × 10², 7.50 × 10³) particles/mm³ kidney tissue, predominantly observed in the interstitium (100 %) and tubules (80 %), followed by the blood vessels and capillaries (40 %), and the glomerulus (24 %). Independent from covariates and potential confounders, we found that each 10 % higher tissue BC load resulted in 8.24 % (p = 0.03) higher urinary KIM-1. In addition, residential proximity to a major road was inversely associated with urinary CysC (+10 % distance: -4.68 %; p = 0.01) and KIM-1 (+10 % distance: -3.99 %; p < 0.01). Other urinary biomarkers, e.g., the estimated glomerular filtration rate or creatinine clearance showed no significant associations.

Discussion and conclusion: Our findings that BC particles accumulate near different structural components of the kidney represent a potential mechanism explaining the detrimental effects of particle air pollution exposure on kidney function. Furthermore, urinary KIM-1 and CysC show potential as air pollution-induced kidney injury biomarkers for taking a first step in addressing the adverse effects BC might exert on kidney function.

Keywords: Air pollution; Black carbon; Fine particulate matter; Kidney function; Kidney transplantation; Kidneys.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / adverse effects
Air Pollutants* / analysis
Air Pollution* / analysis
Biomarkers
Carbon / adverse effects
Carbon / analysis
Humans
Kidney / chemistry
Particulate Matter / adverse effects
Particulate Matter / analysis
Soot* / adverse effects
Soot* / analysis

Substances

Air Pollutants
Biomarkers
Carbon
Particulate Matter
Soot