Kidney Week

Abstract: SA-PO799

Bariatric Surgery Reduces Elevated Urinary Mitochondrial DNA Copy Number in Non-Diabetic Obese Patients

Session Information

• CKD: Epidemiology, Risk Factors, Prevention - III
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 1901 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

• Lee, Haekyung, Soonchunhyang University Hospital, Seoul, Korea (the Republic of)

Haekyung Lee,

• Kim, Hyoungnae, Soonchunhyang University Hospital, Seoul, Korea (the Republic of)

Hyoungnae Kim,

• Park, Moo Yong, Soonchunhyang University Hospital, Seoul, Korea (the Republic of)

Moo Yong Park,

• Noh, Hyunjin, Soonchunhyang University Hospital, Seoul, Korea (the Republic of)

Hyunjin Noh,

• Kwon, Soon hyo, Soonchunhyang University Hospital, Seoul, Korea (the Republic of)

Soon hyo Kwon,

Background

Obesity is an independent risk factor for chronic kidney disease (CKD). However, the mechanisms responsible for renal injury have not been totally elucidated. Mitochondrial damage is considered to have implications for renal injury, and urinary mitochondrial DNA (mtDNA) is a marker of mitochondrial damage. We hypothesized that urinary mtDNA copy number in non-diabetic obese patients would be higher than in healthy volunteers, and bariatric surgery could reverse elevated urinary mtDNA copy number.

Methods

We prospectively recruited age-sex matched healthy controls and non-diabetic obese patients who were going to undergo bariatric surgery (n = 22 each; male=8, female=14) at a single center in Korea. We quantified the urinary absolute copy number of the mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND-1) gene in healthy volunteers by quantitative polymerase chain reaction. In obese patients, mtND-1 copy number was measured before bariatric surgery and six months after bariatric surgery.

Results

Age (35.2 ± 9.6 years vs 32.2 ± 10.0 years) and eGFR (108.1 ± 11.7 mL/min vs 109.7 ± 24.0 mL/min) in both groups were not significantly different. 24 hour urinary albumin was higher in the obese group (2.7 ± 3.0 mg/day vs 52.9± 163.6 mg/day, P<0.001). In the obese group, BMI decreased from 41.0 ± 5.7 to 36.0 ± 7.2 (P=0.002) six months after bariatric surgery. Urinary mtND-1 copy number in the obese group was higher in healthy controls (P=0.001) (fig 1). In obese patients with high urinary mtND-1 copy number, bariatric surgery reduced urinary mtND-1 copy number (P=0.006).

Conclusion

Obesity is associated with elevated urinary mtND-1 copy number. Bariatric surgery reduces urinary mtDNA in obese patients with especially high mtDNA copy number. This suggests bariatric surgery would improve mitochondrial damage in kidney cells.

Urinary ND-1/nDNA copy number in healthy volunteers and obese patients

Funding

• Government Support - Non-U.S.