Kidney Week

Abstract: TH-PO1044

Urinary Podocalyxin Protein Excretion Is an Early Biomarker in Age-Associated Kidney Disease

Session Information

• Glomerular Diseases: Epidemiology, Mechanisms, Complications, Outcomes
  November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

• Fukuda, Akihiro, Oita University, Yufu, Japan

Akihiro Fukuda,

• Kudo, Akiko, Oita University, Yufu, Japan

Akiko Kudo,

• Suzuki, Miho, Oita University, Yufu, Japan

Miho Suzuki,

• Aoki, Kohei, Oita University, Yufu, Japan

Kohei Aoki,

• Nakata, Takeshi, Oita University, Yufu, Japan

Takeshi Nakata,

• Kurosawa, Hiroyuki, Denka Seiken Co., Ltd, Gosen, Japan

Hiroyuki Kurosawa,

• Hara, Masanori, Niigata Wellness (Iwamuro Health Promotion Center), Niigata, Japan

Masanori Hara,

• Fukunaga, Naoya, Oita University, Yufu, Japan

Naoya Fukunaga,

• Shibata, Hirotaka, Oita University Faculty of Medicine, Yufu city, Japan

Hirotaka Shibata,

Background

Aging is the strongest known risk factor for end-stage kidney disease. Many factors including aging can cause podocyte injury. If the initiating injury causes a critical level of podocyte depletion, it can lead to glomerulosclerosis and progression. Age-associated reduction in podocyte density (increased glomerular volume per podocyte) is associated with podocyte hypertrophic stress and failure that leads to glomerulosclerosis in model systems and humans. Urinary podocyte excretion can be used to monitor glomerular disease activity and progression. This study investigated whether urinary podocyte protein excretion can be used for monitoring age-associated kidney diseases.

Methods

From June 2018 to March 2019, spot urine samples were collected from 261 healthy volunteers without diabetes, hypertension and albuminuria during medical checkups by age groups (20–29 years: n=48; 30–39 years: n=53; 40–49 years: n=59; 50–59 years: n=52; ≥60 years: n=49) We investigated the urinary supernatant (U-PCX) and sediment (Sed-PCX) podocalyxin protein levels by ELISA to reflect podocyte injury and podocyte detachment, respectively, and urinary albumin/creatinine ratio (U-ACR).

Results

There were no significantly differences in systolic blood pressure, fasting blood glucose, and body mass index among the groups. However, estimated glomerular filtration rate significantly decreased with age (20–29 years: 94±14.5 ml/min/1.73 m² vs ≥60 years: 74.5±14.1 ml/min/1.73 m², p<0.01)). U-PCX was significantly increased in the ≥60 years group (20–29 years: 94.4±57 vs. ≥60 years: 124.1±63.1 μg/g Cre, p<0.01). U-ACR was also significantly increased in the ≥60 years group (20–29 years: 5.2±4.2 vs. ≥60 years: 8.0±5.6 mg/gCre, p<0.01), but the levels were far lower than the microalbuminuria level. Meanwhile, Sed-PCX did not differ among the groups.

Conclusion

U-PCX, but not sed-PCX, was significantly increased the ≥60 years group without hypertension, diabetes, and microalbuminuria compared with other groups. These results suggest that age per se is a risk factor for podocyte injury and that U-PCX can be used for as an early (prior to overt albuminuria and podocyte detachment) biomarker in age-associated kidney disease.

Funding

• Government Support - Non-U.S.