7.3.1. Obesity

Obesity and hypertension are chronic diseases that can ultimately lead to renal failure. Experimental models of these diseases have been used for long-term evaluation of the usefulness of urinary APs as renal injury biomarkers.

The obese Zucker rat is an animal model of human type II diabetes [130] characterized by obesity, dyslipidemia, insulin resistance, and kidney damage. Male obese (ZO) and lean (ZL) Zucker rats were studied for 6 months (age of 2–8 months) [131]. At the age of 8 months, ZO rats exhibited various renal lesions, including mild focal and segmental glomerulosclerosis and moderate tubulointerstitial damage. Urinary GluAp (APA) and AlaAp (APN) activities were measured monthly and were increased in ZO rats. Both APA and APN activities correlated with renal lesions and can be considered early diagnostic biomarkers of these lesions (Figure 6). AP activities also showed predictive correlations with the level of interstitial fibrosis in the kidney and with the amount of hydroxyproline accumulated in renal tissue at the age of 8 months. Hence, the early excretion of these markers also serves to evaluate the development of fibrosis in this experimental model.
