Postoperative Compensatory Changes and Blood Flow Parameter of the Preserved Kidney in Elderly Living Related Donors Evaluated by Doppler Ultrasonography

Solitary Functioning Kidneys Attenuate Renal Hemodynamics Responses to Angiotensin II in Male But Not in Female Rats

Backgrounds

People with solitary functioning kidneys (SFK) are prone to renal failure with time. Accordingly, local renin angiotensin system (RAS) and renal functions in subjects with SFK may act differently compared to normal condition. This study was designed to determine the renal hemodynamics responses to angiotensin II (Ang. II) in SFK male and female rats.

Methods

Fifty to sixty-day-old male and female Wistar rats were subjected to unilateral renal artery obstruction, and 28 days later basal renal hemodynamic responses to Ang. II were examined in SFK groups compared to sham groups.

Results

The findings indicated lower renal vascular resistance (RVR) and renal blood flow (RBF) responses to Ang. II in male SFK compared to sham group. Such observation was not seen in female animals.

Conclusions

An increase in renal metabolism due to hyperfunction, especially in SFK male rats, may cause a decrease in RVR. Moreover, the lower RBF response to Ang. II may be related to alteration to Ang. II receptors in the remnant kidneys in SFK rats.

Current evidence on the use of anti-RAAS agents in congenital or acquired solitary kidney

RATIONAL

The inhibition of renin-angiotensin-aldosterone system (RAAS) is a major strategy for slowing the progression of chronic kidney disease (CKD). The utility of anti-RAAS agents in patients with congenital or acquired solitary kidney is still controversial.

OBJECTIVE

A systematic literature review was conducted.

MAIN FINDINGS

The conclusions of the few available studies on the topic are homogeneously in agreement with a long-term reno-protective activity of anti-RAAS drugs in patients with solitary kidney, especially if patients are hypertensive or proteinuric. However, angiotensin 2 (ANG2) levels permit a functional adaptation to a reduced renal mass in adults and is crucial for sustaining complete kidney development and maturation in children. A hormonal interference on ANG2 levels has been supposed in women. Consequently, at least in children and women, the use of ARBs appears more appropriate. Principle conclusions: Available data on this topic are limited; however, by their overall assessment, it would appear that anti-RAAS drugs might also be reno-protective in patients with solitary kidney. The use of ARBs, especially in children and in women, seems to be more appropriate. However, more experimental data would be strictly necessary to confirm this hypothesis.