Cyclosporine A used in its treatment induces ischemia and the damage of the epithelial cells of renal tubules by the vasoconstriction of afferent arterioles
. In experimental tests and the culture of human tubular cells in vitro it has been demonstrated that ischemic injury increases the NGAL mRNA [8,22].
Kidney sections from control and hyperuricemic rats were stained with a-smooth muscle actin (aSMA), a marker for vascular smooth muscle cells (VSMC) to evaluate vascular hypertrophy at the levels of afferent arterioles and arcuate arteries.
Quantitative analysis using aSMA staining demonstrated that tempol also ameliorated the thickening of the afferent arterioles (Figure 7(b)).
The obstruction also increases pressure on the system, decreasing GFR and contributing to afferent arteriole constriction via tubuloglomerular feedback, which results in decreased glomerular capillary filtration pressure (Porth, 2007).
Atrial natiuretic peptide (ANP) vasodialates the afferent arteriole and constricts the efferent arteriole increasing GFR (Cheung et al., 2008).
Angiotensin II causes vasoconstriction, including of the afferent arterioles
, increasing glomerular hypertension and damage.
In addition, the decreased volume detected by the stretch receptors in the afferent arteriole leads to the release of renin into the systemic circulation resulting in the extrarenal production of AII.
The ARM, particularly the myogenic component, attempts to compensate by dilating the afferent arteriole, but this becomes dysfunctional when the MAP falls below about 70-80 mmHg.
This region of the distal tubule "touches" the cells of the afferent arteriole
, feeding the glomerular capillary associated with that nephron.
(27) has measured renal arteriolar diameter using a vascular cast technique and have found that the afferent arterioles
were constricted while the efferent arterioles were dilated in DOCA-salt hypertensive rats.
Iversen, "Angiotensin II-induced contraction is attenuated by nitric oxide in afferent arterioles
from the nonclipped kidney in 2K1C," American Journal of Physiology--Renal Physiology, vol.
But one key way hypertension hurts kidneys is by blunting the function of afferent arterioles
, tiny blood vessels that feed the filtering units.
Uncomplicated vascular immune complex deposits consist of a deposition of immunoglobulins and complement primarily in afferent arterioles
. The involved vessels show no evidence of injury and appear normal by light microscopy or contain subendothelial collections of eosinophilic material. The lupus microangiopathy is reported in 6% to 17% of renal biopsies and in 27% of autopsies on lupus patients.[21,23-27] Like uncomplicated deposits, this microangiopathy primarily involves afferent arterioles
, and large amounts of immunoglobulin and complement are found in arteriolar walls by immunofluorescence microscopy.