Background Andropause and hypertension also increase the risk of coronary artery damage. Aim To investigate the effect of testosterone deficiency and hypertension on intramural coronary vessels. Methods 4 groups of 8-week-old Sprague-Dawley rats were studied: control male (Co, n=10), orchidectomized male (OCT, n=13), angiotensin (AII) hypertensive male (AII, n=10), and AII hypertensive and OCT (AII + OCT, n=8). Surgical orchidectomy was performed, and an osmotic minipump was inserted for chronic angiotensin II infusion (100 ng/min/kg). After 4 weeks, spontaneous tone and biomechanical properties of the intramural coronary resistance artery were investigated in vitro, by pressure microarteriography. Outcomes Morphology and biomechanics of the intramural coronaries were evaluated: the outer diameter, wall thickness–to–lumen diameter ratio, and tangential wall stress in the contracted and relaxed states. Results The outer diameter was reduced in OCT and AII + OCT groups (on 50 mmHg 315 ± 20 Co; 237 ± 21 OCT; 291 ± 16 AII, and 166 ± 12 μm AII + OCT). The increased wall thickness–to–lumen diameter ratio resulted in lower tangential wall stress in AII + OCT rats (on 50 mmHg 19 ± 2 Co; 24 ± OCT; 26 ± 5 AII, and 9 ± 1 kPa AII + OCT). Spontaneous tone was increased in the hypertensive rats (AII and AII + OCT groups) (on 50 mmHg 7.7 ± 1.8 Co; 6.1 ± 1.4 OCT; 14.5 ± 3.0 AII, and 17.4 ± 4.1 % AII + OCT). Clinical Implications Andropause alone can be considered as a cardiovascular risk factor that will further exacerbate vascular damage in hypertension. Strengths & Limitations A limitation of our study is that it was performed on relatively young rats, and the conclusions might not apply to coronary remodelling in older animals with slower adaptation processes. Conclusions Testosterone deficiency and hypertension damage the mechanical adaptation of the vessel wall additively: double noxa caused inward eutrophic remodeling and increased tone.

Background: Biomechanical remodeling of coronary resistance arteries in physiological left ventricular hypertrophy has not yet been analyzed, and the possible sex differences are unknown. Methods: Wistar rats were divided into four groups: male and female sedentary controls (MSe and FSe) and male and female animals undergoing a 12-week intensive swim training program (MEx and FEx). On the last day, the in vitro contractility, endothelium-dependent dilatation, and biomechanical properties of the intramural coronary resistance arteries were investigated by pressure microarteriography. Elastica and collagen remodeling were studied in histological sections. Results: A similar outer radius and reduced inner radius resulted in an elevated wall to lumen ratio in the MEx and FEx animals compared to that in the sedentary controls. The wall elastic moduli increased in the MEx and FEx rats. Spontaneous and TxA 2 agonist-induced tone was increased in the FEx animals, whereas endothelium-dependent relaxation became more effective in MEx rats. Arteries of FEx rats had stronger contraction, while arteries of MEx animals had improved dilation. Conclusions: According to our results, the coronary arterioles adapted to an elevated load during long-term exercise, and this adaptation depended on sex. It is important to emphasize that in addition to differences, we also found many similarities between the sexes in the adaptive response to exercise. The observed sport adaptation in the coronary resistance arteries of rats may contribute to a better understanding of the physiological and pathological function of these arteries in active and retired athletes of different sexes.

Background We aimed to identify sex differences in the network properties and to recognize the geometric alteration effects of long-term swim training in a rat model of exercise-induced left ventricular (LV) hypertrophy. Methods Thirty-eight Wistar rats were divided into four groups: male sedentary, female sedentary, male exercised and female exercised. After training sessions, LV morphology and function were checked by echocardiography. The geometry of the left coronary artery system was analysed on pressure-perfused, microsurgically prepared resistance artery networks using in situ video microscopy. All segments over > 80 μm in diameter were studied using divided 50-μm-long cylindrical ring units of the networks. Oxidative-nitrative (O-N) stress markers, adenosine A2A and estrogen receptor (ER) were investigated by immunohistochemistry. Results The LV mass index, ejection fraction and fractional shortening significantly increased in exercised animals. We found substantial sex differences in the coronary network in the control groups and in the swim-trained animals. Ring frequency spectra were significantly different between male and female animals in both the sedentary and trained groups. The thickness of the wall was higher in males as a result of training. There were elevations in the populations of 200- and 400-μm vessel units in males; the thinner ones developed farther and the thicker ones closer to the orifice. In females, a new population of 200- to 250-μm vessels appeared unusually close to the orifice. Conclusions Physical activity and LV hypertrophy were accompanied by a remodelling of coronary resistance artery network geometry that was different in both sexes.

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During aerobic exercise, hemodynamic alterations occure; while blood flow in skeletal muscle arteries increases, it decreases in visceral vessels due to mesenterial vasoconstriction. However, maintaining renal blood flow during intensive sport is also a priority. Our aim was to investigate the changes of vascular reactivity and histology of isolated renal artery of male and female rats in response to swim-training. Wistar rats were distributed into four groups: male sedentary (MSed), male trained (MTr), female sedentary (FSed), and female trained (FTr). Trained animals underwent a 12-week-long intensive swimming program. Vascular function of isolated renal artery segments was examined by wire myography. Phenylephrine-induced contraction was lower in FSed compared to MSed animals, and it was decreased by training in male but not in female animals. Inhibition of cyclooxygenases by indomethacin reduced contraction in both sedentary groups, and in MTr but not in FTr animals. Inhibition of nitric oxide production increased contraction in both trained groups. Acetylcholine induced relaxation was similar in all experimental groups showing predominant NO-dependency. Elastin and smooth muscle cell actin density was reduced in female rats after aerobic training. This study shows that, as a result of 12-weeks-long training, there are sex differences in renal arterial responses following exercise training. Swimming moderates renal artery vasoconstriction in male animals, while it depresses elastic fiber and smooth muscle actin density in females.