Effect of different drug classes on reverse remodeling of intramural coronary arterioles in the spontaneously hypertensive rat

Perindopril Reduces Arterial Pressure and Does Not Inhibit Exercise-Induced Angiogenesis in Spontaneously Hypertensive Rats

ABSTRACT

Sympathetic activity, arteriolar structure, and angiogenesis are important mechanisms modulating hypertension and this study aimed to analyze the effects of perindopril treatment, associated or not with exercise training, on the mechanisms that control blood pressure (BP) in hypertensive rats. Spontaneously hypertensive rats (SHR) were allocated into 4 groups: 1/sedentary (S); 2/perindopril (P, 3.0 mg/kg/d); 3/trained (T); and 4/trained + perindopril (TP). Wistar rats were used as normotensive sedentary control group. SHR were assigned to undergo a treadmill training (T) or were kept sedentary. Heart rate, BP, sympathetic activity to the vessels (LF-SBP), and skeletal muscle and myocardial morphometric analyses were performed. BP was significantly lower after all 3 strategies, compared with S and was accompanied by lower LF-SBP (-76%, -53%, and -44%, for P, T, and TP, respectively). Arteriolar vessel wall cross-sectional area was lower after treatments (-56%, -52%, and -56%, for P, T, and TP, respectively), and only TP presented higher arteriolar lumen area. Capillary rarefaction was present in soleus muscle and myocardium in S group and both trained groups presented higher vessel density, although perindopril attenuated this increase in soleus muscle. Although myocyte diameter was not different between groups, myocardial collagen deposition area, higher in S group, was lower after 3 strategies. In conclusion, we may suggest that perindopril could be an option for the hypertensive people who practice exercise and need a specific pharmacological treatment to reach a better BP control, mainly because training-induced angiogenesis is an important response to facilitate blood flow perfusion and oxygen uptake and perindopril did not attenuate this response.

Identification of Aortic Proteins Involved in Arterial Stiffness in Spontaneously Hypertensive Rats Treated With Perindopril:A Proteomic Approach

Arterial stiffness, frequently associated with hypertension, is associated with disorganization of the vascular wall and has been recognized as an independent predictor of all-cause mortality. The identification of the molecular mechanisms involved in aortic stiffness would be an emerging target for hypertension therapeutic intervention. This study evaluated the effects of perindopril on pulse wave velocity (PWV) and on the differentially expressed proteins in aorta of spontaneously hypertensive rats (SHR), using a proteomic approach. SHR and Wistar rats were treated with perindopril (SHR_P) or water (SHRc and Wistar rats) for 8 weeks. At the end, SHR_C presented higher systolic blood pressure (SBP, +70%) and PWV (+31%) compared with Wistar rats. SHR_P had higher values of nitrite concentration and lower PWV compared with SHR_C. From 21 upregulated proteins in the aortic wall from SHR_C, most of them were involved with the actin cytoskeleton organization, like Tropomyosin and Cofilin-1. After perindopril treatment, there was an upregulation of the GDP dissociation inhibitors (GDIs), which normally inhibits the RhoA/Rho-kinase/cofilin-1 pathway and may contribute to decreased arterial stiffening. In conclusion, the results of the present study revealed that treatment with perindopril reduced SBP and PWV in SHR. In addition, the proteomic analysis in aorta suggested, for the first time, that the RhoA/Rho-kinase/Cofilin-1 pathway may be inhibited by perindopril-induced upregulation of GDIs or increases in NO bioavailability in SHR. Therefore, we may propose that activation of GDIs or inhibition of RhoA/Rho-kinase pathway could be a possible strategy to treat arterial stiffness.

Blood pressure normalization via pharmacotherapy improves cutaneous microvascular function through NO-dependent and NO-independent mechanisms

Hypertension is associated with endothelial dysfunction and vascular remodeling.

OBJECTIVE

To assess effects of antihypertensive pharmacotherapy on eNOS- and iNOS-dependent mechanisms and maximal vasodilator capacity in the cutaneous microvasculature.

METHODS

Intradermal microdialysis fibers were placed in 15 normotensive (SBP 111±2 mm Hg), 12 unmedicated hypertensive (SBP 142±2 mm Hg), and 12 medicated hypertensive (SBP 120±2 mm Hg) subjects. Treatments were control, iNOS-inhibited (1400w), and NOS-inhibited (l-NAME). Red cell flux, measured during local heating (42°C) and ACh dose-response protocols, was normalized to CVC (flux MAP^-1 ) and a percentage of maximal vasodilation (%CVC_max ).

RESULTS

Compared to normotensives, ACh-mediated vasodilation was attenuated in the hypertensive (P<.001), but not in medicated subjects (P=.83). NOS inhibition attenuated ACh-mediated vasodilation in normotensives compared to hypertensive (P<.001) and medicated (P<.001) subjects. With iNOS inhibition, there was no difference in ACh-mediated vasodilation between groups. Compared to the normotensives, local heat-induced vasodilation was attenuated in the hypertensives (P<.001), but iNOS inhibition augmented vasodilation in the hypertensives so this attenuation was abolished (P=.31). Compared to normotensives, maximal vasodilator capacity was reduced in the hypertensive (P=.014) and medicated subjects (P=.004).

CONCLUSIONS

In the cutaneous microvasculature, antihypertensive pharmacotherapy improved endothelial function through NO-dependent and NO-independent mechanisms, but did not improve maximal vasodilator capacity.

Microvessels of the heart: Formation, regeneration, and dysfunction

This issue of microcirculation focusses on the special topic of "microvessels of the heart" and contains five state-of-the-art reviews and one expert article that reflect current efforts to address the major gaps in our understanding of these key microvessels. In the adult heart, most attention until recently (especially among the clinical cardiology community) has been given to the main coronary arteries, which are the culprit vessels in patients with coronary artery disease, including its most serious manifestation, acute MI. However, due to major advances in efficiently reopening the acutely blocked coronary arteries, MI is no longer the killer disease it once was. In contrast, there are few treatment options for patients who develop microvascular obstruction during acute MI. Indeed, we have a very poor understanding of this disease, or even how heart vessels are initially formed in development. This is surprising in light of the essential nature of the cardiac microvessels for efficient cardiac function throughout life. The articles in this issue are from six keynote speakers at the 66th annual meeting of the BMS at Newcastle University and review our understanding of these key vessels from initial development to their role in adult heart disease.