Cellular hypertrophy in mesenteric resistance vessels from renal hypertensive rats.

Abstract

SUMMARY To determine whether the increased thickness seen in media of mesenteric resistance vessels of Wistar-Kyoto rats made hypertensive by a Goldblatt procedure (one-kidney, one clip model) was due to hypertrophy or hyperplasia of smooth musde cells, the cellular dimensions of these vessels were estimated using a new, unbiased stereoJogkal method (the disector). Furthermore, to investigate whether the changes seen could be secondary to the increased blood pressure, morphometric measurements were also made in renal arcuate arteries, which, due to the constricting silver clip, probably had not been exposed to the increased pressure load. Vessels were mounted on a myograph, and their media thickness, lumen diameter, and maximum active wall tension response were measured. In the mesenteric vessels media thickness had increased by 58%, whereas no changes were seen In the renal vessels. Vessels were then fixed, and serial sections were made in the mesenteric vessels. The disector was used to calculate the numerical cell density in each vessel. By combining the myograph measurements and the estimated numerical cell density, the number of cells per segment unit length was calculated (renal hypertensive rats, IT is now well established that increased media thickness is associated with hypertension.1 In the spontaneously hypertensive rat (SHR), which is the most studied hypertensive model so far, the cellular basis for the observed medial hypertrophy seems to differ in various vascular beds.2 In the aorta 3 -4 and the superior mesenteric artery, 5 the increased media thickness is associated with hypertrophy, whereas the changes in smaller vessels are probably due to hyperplasia. -5 - 6 The changes in the conducting arteries are not seen prior to the elevation of the blood pressure, 7 and antihypertensive treatment 8 prevents the structural modifications of the vessels, suggesting that these changes are secondary to hypertension. In contrast, structural alterations in the small muscular arteries and arterioles are present at the prehypertensive and developing hypertensive phases, 7 and these changes

Absorption Spectroscopy for the Assessment of Small-Artery Structure

“…Since BP and R are themselves strongly correlated in this (correlation coefficient = 0.98 for 4 week group) and many other studies [21,23] their relationship to the observed spectral features is the most important result of this present study. Since these spectral features relate to the logistic function (equation (2)) which models the average spectral shape in the 350-550nm range, a connection is established between the presence of hypertension and the existence of differential absorption in the blue-green r e o n of the spectrum.…”

“…These effects are indeed implied by the significant correlation between R and the scaling factors for the 4-week group. In the less hypertropic 8-week group the number of correlation is reduced however significant correlations occur between b,, Al and BP, R. Since BP and R are themselves strongly correlated in this (correlation coefficient = 0.98 for 4 week group) and many other studies [21,23] their relationship to the observed spectral features is the most important result of this present study. Since these spectral features relate to the logistic function (equation (2)) which models the average spectral shape in the 350-550nm range, a connection is established between the presence of hypertension and the existence of differential absorption in the blue-green rgion of the spectrum.…”

“…Since the purpose of this study was to ascertain the usefulness of spectroscopy and not to investigate any aspect of this particular model of hypertension these results were extremely useful for the analysis of spectroscopic data. The second contributing factor, we believe is that the samples of hypertensive rats in this study, adapt relatively fast and efficiently to the elevated arterial pressure [21] as shown by the 8 week samples.…”

Structural changes in renal arterioles in Type I diabetic patients

“…Interestingly, in this context, in essential hypertension the arterioles respond, at least initially, with hypertrophy of the myomedial cells [5,23]. In this diabetic series, we rather saw degenerative changes and the disappearance of these cells.…”

Cardiovascular Influences of α 1b -Adrenergic Receptor Defect in Mice

“…In PHE-and vehicle-treated mice, a further evaluation of vascular smooth muscle cell morphology was performed through the dissector technique, as described previously. 8 …”