Adherence and renal biopsy feasibility in the Renin Angiotensin-System Study (RASS) primary prevention diabetes trial

N-Acetyl-seryl-aspartyl-lysyl-proline is a potential biomarker of renal function in normoalbuminuric diabetic patients with eGFR ≥ 30 ml/min/1.73 m2

BACKGROUND

A biomarker, by which we can predict alterations of renal function in normoalbuminuric diabetic patients, is not available. Here, we report that endogenous anti-fibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) represents a potential biomarker to predict alterations in eGFR in normoalbuminuric diabetic patients.

METHODS

We analyzed 21 normoalbuminuric diabetic patients with eGFR ≥ 30 ml/min/1.73 m² and measured AcSDKP levels in first morning void urine. We divided patients into two groups based on the median values: low or high urinary AcSDKP groups (uAcSDKP/Cr^low or uAcSDKP/Cr^high). At baseline, no significant differences in sex, age, HbA1c, BMI, serum creatinine levels, etc., were observed between the two groups.

RESULTS

During ~ 4 years, the alteration in eGFR [ΔeGFR^op (ΔeGFR observational periods)] was significantly stable in uAcSDKP/Cr^high group compared with uAcSDKP/Cr^low group over time (P = 0.003, χ² = 8.58). We also evaluated urine kidney injury molecule-1 (uKim-1) levels and found that ΔeGFR^op was also stable in low uKim-1 group compared with high uKim-1 group over time (P = 0.004, χ² = 8.38). Patients who fulfilled the criteria for both uAcSDKP/Cr^high and uKim-1^low exhibited stable ΔeGFR^op (P < 0.001, χ² = 30.4) when compared to the remaining patients. Plasma AcSDKP (P = 0.015, χ² = 5.94) and urine β2-microglobulin (P = 0.038, χ² = 4.31) also display weak but significant predictor of ΔeGFR^op as well.

CONCLUSION

AcSDKP represents a potentially useful biomarker to predict alterations in the renal function of patients with diabetes presenting normoalbuminuria.

Expanding the Role for Kidney Biopsies in Acute Kidney Injury

Acute kidney injury (AKI) is a highly heterogeneous, common, and potentially devastating condition associated with markedly increased hospital length of stay, cost, mortality, and morbidity. Expanding the role for kidney biopsies in AKI may offer fresh insights into disease heterogeneity, molecular mechanisms, and therapeutic targets. A number of challenges face investigators and clinicians considering research biopsies in AKI: ensuring patient safety, ensuring the ethical conduct of research studies, and maximizing the scientific yield of the kidney tissue obtained. The societal benefits of research that lead to novel strategies for preventing and treating AKI would be enormous. Rethinking our current approach to the role of kidney biopsy for AKI diagnosis and research may be a major step toward the promise of personalized medicine in nephrology.