Angiotensin I converting enzyme activity in uranyl nitrate induced acute renal failure in rats

Polyphenolic fraction of Algerian propolis protects rat kidney against acute oxidative stress induced by doxorubicin

We evaluated the effects of propolis extract on renal oxidative stress induced by doxorubicin throughout an analytical and pharmacological study of the eastern Algerian propolis using thin layer chromatography, ultra-violet-high-performance liquid chromatography) and gas chromatography-mass spectrometry. The pharmacological study was carried out in vivo on Wistar rat pre-treated with propolis extract 100 mg/kg/day for seven days. Doxorubicin at 10 mg/kg of body weight was administered intravenously on Day 7. Serum creatinine concentration, scavenging effect of flavonoids, lipid peroxidation and glutathione concentration were measured. Chemical analysis allowed identification and quantification of the phenolic compounds including pinostrombin chalcone (38.91%), galangin (18.95%), naringenin (14.27%), tectochrysin (25.09%), methoxychrysin (1.14%) and a prenylated coumarin compound suberosin (1.65%). The total flavonoid concentration in the propolis extract was 370 mg (quercetin equivalents QE) /g dry weight (QE/g DWPE). Propolis extract restored the renal functions and reduced the toxic effect of doxorubicin. These data show a protective effect of Algerian propolis extract against doxorubicin-induced oxidative stress.

Losartan chemistry and its effects via AT1 mechanisms in the kidney

Besides the importance of the renin-angiotensin system (RAS) in the circulation and other organs, the local RAS in the kidney has attracted a great attention in research in last decades. The renal RAS plays an important role in the body fluid homeostasis and long-term cardiovascular regulation. All major components and key enzymes for the establishment of a local RAS as well as two important angiotensin II (Ang II) receptor subtypes, AT1 and AT2 receptors, have been confirmed in the kidney. In additional to renal contribution to the systemic RAS, the intrarenal RAS plays a critical role in the regulation of renal function as well as in the development of kidney disease. Notably, kidney AT1 receptors locating at different cells and compartments inside the kidney are important for normal renal physiological functions and abnormal pathophysiological processes. This mini-review focuses on: 1) the local renal RAS and its receptors, particularly the AT1 receptor and its mechanisms in physiological and pathophysiological processes; and 2) the chemistry of the selective AT1 receptor blocker, losartan, and the potential mechanisms for its actions in the renal RAS-mediated disease.

Angiotensin-converting enzyme in non-neoplastic kidney diseases

BACKGROUND

The angiotensin I-converting enzyme (ACE, CD143, kininase II) plays a critical role in controlling the level of vasoactive peptides such as angiotensins and kinins in the local circulations and tissue interstitium. Because recent work has documented a vessel-, organ-, and species-specific pattern of endothelial ACE expression in the vascular system, we have analyzed whether or not changes of this pattern occur in vessels, tubules, and interstitium of the human kidney that is affected by different non-neoplastic diseases.

METHODS

Using a set of well-characterized monoclonal antibodies (mAbs), ACE was assessed on renal tissue of 135 patients by immunohistochemistry, including an additional analysis at the ultrastructural level. A semiquantitative evaluation allowed the estimation and comparison of ACE content in different renal compartments. These data were compared with several clinical findings, diagnosis, therapeutic modalities, and histological features.

RESULTS

In contrast to the normal human kidney, where ACE is abundant in the brush border of the proximal tubule but is usually absent in endothelial cells of any vessel type, an endothelial neoexpression of ACE was observed in different diseases. In general, this neoexpression was associated with histological sites of interstitial fibrosis and showed some selectivity for glomerular endothelial cells in diabetes mellitus and chronic arterial hypertension. There was also a loss of epithelial ACE in the proximal tubule in certain pathological conditions, for example, in chronic fibroplastic processes, acute pyelonephritis, and different stages of acute renal failure.

CONCLUSIONS

Neoexpression of ACE by renal endothelial cells, as well as changes of the tubular ACE content, is a common finding in diseased human kidneys. As associated with certain tissue sites, clinical and/or morphological features, these changes may be involved in parenchymal remodeling and renal pathophysiology.