title: Kidney Injury and Repair Biomarkers in Marathon Runners.
abstract: BACKGROUND
  Investigation into strenuous activity and kidney function has gained interest given increasing marathon participation.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Runners participating in the 2015 Hartford Marathon.
  
  
  METHODS
  Completing a marathon.
  
  
  RESULTS
  Acute kidney injury (AKI) as defined by AKI Network (AKIN) criteria. Stage 1 AKI was defined as 1.5- to 2-fold or 0.3-mg/dL increase in serum creatinine level within 48 hours of day 0 and stage 2 was defined as a more than 2- to 3-fold increase in creatinine level. Microscopy score was defined by the number of granular casts and renal tubular epithelial cells.
  
  
  METHODS
  Samples were collected 24 hours premarathon (day 0), immediately postmarathon (day 1), and 24 hours postmarathon (day 2). Measurements of serum creatinine, creatine kinase, and urine albumin were completed, as well as urine microscopy analysis. 6 injury urine biomarkers (IL-6, IL-8, IL-18, kidney injury molecule 1, neutrophil gelatinase-associated lipocalin, and tumor necrosis factor α) and 2 repair urine biomarkers (YKL-40 and monocyte chemoattractant protein 1) were measured.
  
  
  RESULTS
  22 marathon runners were included. Mean age was 44 years and 41% were men. 82% of runners developed an increase in creatinine level equivalent to AKIN-defined AKI stages 1 and 2. 73% had microscopy diagnoses of tubular injury. Serum creatinine, urine albumin, and injury and repair biomarker levels peaked on day 1 and were significantly elevated compared to day 0 and day 2. Serum creatine kinase levels continued to significantly increase from day 0 to day 2.
  
  
  CONCLUSIONS
  Small sample size and limited clinical data available at all time points.
  
  
  CONCLUSIONS
  Marathon runners developed AKI and urine sediment diagnostic of tubular injury. An increase in injury and repair biomarker levels suggests structural damage to renal tubules occurring after marathon. The results of our study should be validated in larger cohorts with longer follow-up of kidney function.
authors.affiliation: Program of Applied Translational Research, Department of Medicine, New Haven, CT; Section of Nephrology, Yale University School of Medicine, New Haven, CT.
authors.forename: Sherry G
authors.initials: SG
authors.lastname: Mansour
authors.affiliation: Program of Applied Translational Research, Department of Medicine, New Haven, CT.
authors.forename: Gagan
authors.initials: G
authors.lastname: Verma
authors.affiliation: Quinnipiac University, New Haven, CT.
authors.forename: Rachel W
authors.initials: RW
authors.lastname: Pata
authors.affiliation: Quinnipiac University, New Haven, CT.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Martin
authors.affiliation: Section of Nephrology, Yale University School of Medicine, New Haven, CT; Veterans Affairs Connecticut Healthcare System, New Haven, CT.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Perazella
authors.affiliation: Program of Applied Translational Research, Department of Medicine, New Haven, CT; Section of Nephrology, Yale University School of Medicine, New Haven, CT; Veterans Affairs Connecticut Healthcare System, New Haven, CT. Electronic address: chirag.parikh@yale.edu.
authors.forename: Chirag R
authors.initials: CR
authors.lastname: Parikh
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology / Q000209:etiology* / Q000652:urine; D000328:Adult; D015415:Biomarkers / Q000652:urine; D005260:Female; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012420:Running; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: Acute kidney injury (AKI); acute tubular injury; creatine kinase; injury biomarkers; marathon running; renal damage; repair biomarkers; serum creatinine; strenuous exercise; tubular injury; urine albumin; urine microscopy