Effects of Gender and Vitamin D on Vascular Reactivity of the Carotid Artery on a Testosterone-Induced PCOS Model.

The negative cardiovascular effects of polycystic ovary syndrome (PCOS) and vitamin D deficiency (VDD) have been discussed previously; however, the sex differences between PCOS females and males are not yet known. Our aim was to investigate the effect of PCOS and VDD in the carotid artery of male and female Wistar rats. Females were treated with transdermal testosterone (Androgel) for 8 weeks, which caused PCOS. VDD and vitamin D supplementation were accomplished via diet. The carotid arteries' contraction and relaxation were examined using myography. Receptor density was investigated using immunohistochemistry. In PCOS females, angiotensin receptor density, angiotensin II-induced contraction, androgen receptor optical density, and testosterone-induced relaxation increased. The increased contractile response may increase cardiovascular vulnerability in women with PCOS. As an effect of VDD, estrogen receptor density increased in all our groups, which probably compensated for the reduced relaxation caused by VDD. Testosterone-induced relaxation was decreased as a result of VDD in males and non-PCOS females, whereas this reduction was absent in PCOS females. Male sex is associated with increased contraction ability compared with non-PCOS and PCOS females. VDD and Androgel treatment show significant gender differences in their effects on carotid artery reactivity. Both VDD and PCOS result in a dysfunctional vascular response, which can contribute to cardiovascular diseases.

Role of CB1 Cannabinoid Receptors in Vascular Responses and Vascular Remodeling of the Aorta in Female Mice.

Both the endocannabinoid system (ECS) and estrogens have significant roles in cardiovascular control processes. Cannabinoid type 1 receptors (CB1Rs) mediate acute vasodilator and hypotensive effects, although their role in cardiovascular pathological conditions is still controversial. Estrogens exert cardiovascular protection in females. We aimed to study the impact of ECS on vascular functions. Experiments were performed on CB1R knockout (CB1R KO) and wild-type (WT) female mice. Plasma estrogen metabolite levels were determined. Abdominal aortas were isolated for myography and histology. Vascular effects of phenylephrine (Phe), angiotensin II, acetylcholine (Ach) and estradiol (E2) were obtained and repeated with inhibitors of nitric oxide synthase (NOS, Nω-nitro-L-arginine) and of cyclooxygenase (COX, indomethacin). Histological stainings (hematoxylin-eosin, resorcin-fuchsin) and immunostainings for endothelial NOS (eNOS), COX-2, estrogen receptors (ER-α, ER-ß) were performed. Conjugated E2 levels were higher in CB1R KO compared to WT mice. Vasorelaxation responses to Ach and E2 were increased in CB1R KO mice, attenuated by NOS-inhibition. COX-inhibition decreased Phe-contractions, while it increased Ach-relaxation in the WT group but not in the CB1R KO. Effects of indomethacin on E2-relaxation in CB1R KO became opposite to that observed in WT. Histology revealed lower intima/media thickness and COX-2 density, higher eNOS and lower ER-ß density in CB1R KO than in WT mice. CB1R KO female mice are characterized by increased vasorelaxation associated with increased utilization of endothelial NO and a decreased impact of constrictor prostanoids. Our results indicate that the absence or inhibition of CB1Rs may have beneficial vascular effects.

Sex differences in rat renal arterial responses following exercise training.

During aerobic exercise, hemodynamic alterations occur. Although blood flow in skeletal muscle arteries increases, it decreases in visceral vessels because of 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-wk-long intensive swimming program. Vascular function of isolated renal artery segments was examined by wire myography. Phenylephrine-induced contraction was lower in FSed than in 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 a 12-wk-long training, there are sex differences in renal arterial responses following exercise training. Swimming moderates renal artery vasoconstriction in male animals, whereas it depresses elastic fiber and smooth muscle actin density in females.NEW & NOTEWORTHY We provided the first detailed analysis of the adaptation of the renal artery after aerobic training in male and female rats. As a result of a 12-wk-long training program, the pharmacological responses of renal arteries changed only in male animals. In phenylephrine-induced contraction, cyclooxygenase-mediated vasoconstriction mechanisms lost their significance in female rats, whereas NO-dependent relaxation became a significant contraction reducing factor in both sexes. Early structural changes, such as reduced elastin and smooth muscle cell actin evolves in females.

Vitamin D Deficiency Reduces Vascular Reactivity of Coronary Arterioles in Male Rats.

BACKGROUND: Vitamin D deficiency (VDD) may be considered an independent cardiovascular (CV) risk factor, and it is well known that CV risk is higher in males. Our goal was to investigate the pharmacological reactivity and receptor expression of intramural coronary artery segments of male rats in cases of different vitamin D supply. METHODS: Four-week-old male Wistar rats were divided into a control group (n = 11) with optimal vitamin D supply (300 IU/kgbw/day) and a VDD group (n = 11, <0.5 IU/kgbw/day). After 8 weeks of treatment, intramural coronary artery segments were microprepared, their pharmacological reactivity was examined by in vitro microangiometry, and their receptor expression was investigated by immunohistochemistry. RESULTS: Thromboxane A2 (TXA2)-agonist induced reduced vasoconstriction, testosterone (T) and 17-ß-estradiol (E2) relaxations were significantly decreased, a significant decrease in thromboxane receptor (TP) expression was shown, and the reduction in estrogen receptor-α (ERα) expression was on the border of significance in the VDD group. CONCLUSIONS: VD-deficient male coronary arteries showed deteriorated pharmacological reactivity to TXA2 and sexual steroids (E2, T). Insufficient vasoconstrictor capacity was accompanied by decreased TP receptor expression, and vasodilator impairments were mainly functional. The decrease in vasoconstrictor and vasodilator responses results in narrowed adaptational range of coronaries, causing inadequate coronary perfusion that might contribute to the increased CV risk in VDD.

Vitamin D Deficiency and Gender Alter Vasoconstrictor and Vasodilator Reactivity in Rat Carotid Artery.

The vitamin-D-sensitivity of the cardiovascular system may show gender differences. The prevalence of vitamin D (VD) deficiency (VDD) is high, and it alters cardiovascular function and increases the risk of stroke. Our aim was to investigate the vascular reactivity and histological changes of isolated carotid artery of female and male rats in response to different VD supplies. A total of 48 male and female Wistar rats were divided into four groups: female VD supplemented, female VDD, male VD supplemented, male VDD. The vascular function of isolated carotid artery segments was examined by wire myography. Both vitamin D deficiency and male gender resulted in increased phenylephrine-induced contraction. Acetylcholine-induced relaxation decreased in male rats independently from VD status. Inhibition of prostanoid signaling by indomethacin reduced contraction in females, but increased relaxation ability in male rats. Functional changes were accompanied by VDD and gender-specific histological alterations. Elastic fiber density was significantly decreased by VDD in female rats, but not in males. Smooth muscle actin and endothelial nitric oxide synthase levels were significantly lowered, but the thromboxane receptor was elevated in VDD males. Decreased nitrative stress was detected in both male groups independently from VD supply. The observed interactions between vitamin D deficiency and sex may play a role in the gender difference of cardiovascular risk.

Effects of Testosterone Deficiency and Angiotensin II-Induced Hypertension on the Biomechanics of Intramural Coronary Arteries.

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. Jósvai A, Török M, Mátrai M, et al. Effects of Testosterone Deficiency and Angiotensin II-Induced Hypertension on the Biomechanics of Intramural Coronary Arteries. J Sex Med 2020;17:2322-2330.

Geometric, elastic and contractile-relaxation changes in coronary arterioles induced by Vitamin D deficiency in normal and hyperandrogenic female rats.

Vitamin D (VitD) hypovitaminosis and androgen excess (AE) are both risk factors for cardiovascular diseases in fertile women. However, the possible early interaction between AE and VitD status is not clear. Our goal was to describe how VitD status influences early changes in the biomechanical reactivity of small coronary arterioles in adult female rats after transdermal testosterone treatment. Forty-six adolescent, 90-110-gram-weighed female Wistar rats were randomly grouped into 4 groups. Twenty-four animals received an optimal VitD-supplemented diet, from which 12 animals underwent transdermal testosterone treatment. Twenty-two animals received a VitD-deficient diet, from which 11 were treated with testosterone. At 8 weeks of treatment, invasive arterial blood pressure was registered after in vivo cannulation of carotid artery. Arteriolar end and side branches (200 µm diameter) of the left anterior descendent coronary artery (LAD) were obtained and examined with pressure arteriography in vitro. Similar segments were removed for histological examination. The inner and outer radii of the arterioles were measured using video-microscopy. Normal myogenic tone, maximal passive vasorelaxation and vasoconstriction of the arterioles were measured and statistically analyzed. The vessels' maximal smooth muscle relaxant potential, thromboxane-induced contraction capacity and normal myogenic tone were significantly influenced by actual VitD status. A lower relaxation capacity and increased wall thickness were observed in VitD-deficient groups, which could cause rigidity of the coronary arterioles and elevate cardiovascular risk. Supplementation of VitD could improve myogenic tone and relaxation and hold cardiovascular benefits.

Vitamin D deficiency and androgen excess result eutrophic remodeling and reduced myogenic adaptation in small cerebral arterioles in female rats.

Vitamin D (vitD) insufficiency affects 1 billion people worldwide. Androgen excess (AE) occurs in 8% of fertile females. There are few data about the combined effect of vitD deficiency and AE on the early biomechanical changes of cerebral arterioles in fertile-aged female. Forty-six adolescent female Wistar rats (21-28 day-old, weighing 90-110 g) were grouped randomly in four groups: vitD supplemented groups with and without transdermal testosterone (T) treatment, as well as vitD deficient groups also with and without transdermal T (n = 11 or 12, in all cases). After 8 weeks of treatment, anterior cerebral arterioles (in vivo diameter of 90-130 µm) were obtained and cylindrical segments were examined by pressure arteriography. Myogenic tone, tangential stress and incremental elastic moduli were computed and statistically analyzed. Elastic density was studied on resorcin-fuchsin-stained histological section. VitD deficiency with T treatment resulted in significantly lower inner radii and higher wall thickness values with reduced tangential stress and increased elastic fiber density. VitD deficiency reduced myogenic tone at higher intraluminar pressures (>110 mmHg). Our conclusion is that plasma vitD level is an important factor in the control of myogenic tone in cerebral resistance arteries. AE and vitD deficiency acting parallel induce remodeling of their wall.

Remodeling of Wall Mechanics and the Myogenic Mechanism of Rat Intramural Coronary Arterioles in Response to a Short-Term Daily Exercise Program: Role of Endothelial Factors.

PURPOSE: Exercise elicits early adaptation of coronary vessels enabling the coronary circulation to respond adequately to higher flow demands. We hypothesized that short-term daily exercise induces biomechanical and functional remodeling of the coronary resistance arteries related to pressure. METHODS: Male rats were subjected to a progressively increasing 4-week treadmill exercise program (over 60 min/day, 1 mph in the final step). In vitro pressure-diameter measurements were performed on coronary segments (119 ± 5 µm in diameter at 50 mm Hg) with microarteriography. The magnitude of the myogenic response and contribution of endogenous nitric oxide and prostanoid production to the wall mechanics and pressure-diameter relationship were assessed. RESULTS: Arterioles isolated from exercised ani mals - compared to the sedentary group - had thicker walls, increased distensibility, and a decreased elastic modulus as a result of reduced wall stress in the low pressure range. The arterioles of exercised rats exhibited a more powerful myogenic response and less endogenous vasoconstrictor prostanoid modulation at higher pressures, while vasodilator nitric oxide modulation of diameter was augmented at low pressures (< 60 mm Hg). CONCLUSIONS: A short-term daily exercise program induces remodeling of rat intramural coronary arterioles, likely resulting in a greater range of coronary autoregulatory function (constrictor and dilator reserves) and more effective protection against great changes in intraluminal pressure, contributing thereby to the optimization of coronary blood flow during exercise.

Control of myogenic tone and agonist induced contraction of intramural coronary resistance arterioles by cannabinoid type 1 receptors and endocannabinoids.

It was tested whether intrinsic CB1R activation modifies myogenic and agonist induced contraction of intramural coronary resistance arteries of the rat. CB1R protein was detected by immuno-histochemistry and by Western blot, its mRNA by qRT-PCR in their wall. Microsurgically prepared cylindrical coronary segments (∼100-150µm) developed myogenic contraction (∼20% of relaxed luminal diameter), from which a substantial relaxation (∼15%) in response to WIN55212 (a specific agonist of the CB1Rs) has been found. CB1R-mediated relaxation was blocked by O2050 and AM251 (neutral antagonist and inverse agonist of the CB1R, respectively) and was partially blocked by the NO synthase blocker Nω-nitro-L-arginine. CB1R blockade enhanced myogenic tone and augmented AngII-induced vasoconstriction (from 17.8±1.2 to 29.1±2.9%, p<0.05). Inhibition of diacylglycerol lipase by tetrahydrolipstatin, (inhibitor of endogenous 2-AG production) also augmented coronary vasoconstriction. These observations prove that vascular endocannabinoids are significant negative modulators of the myogenic and agonist-induced tone of intramural coronary arterioles acting through CB1Rs.

Lower-limb veins are thicker and vascular reactivity is decreased in a rat PCOS model: concomitant vitamin D3 treatment partially prevents these changes.

Polycystic ovary syndrome (PCOS) causes vascular damage to arteries; however, there are no data for its effect on veins. Our aim was to clarify the effects of dihydrotestosterone (DHT)-induced PCOS both on venous biomechanics and on pharmacological reactivity in a rat model and to test the possible modulatory role of vitamin D3 (vitD). PCOS was induced in female Wistar rats by DHT treatment (83 µg/day, subcutaneous pellet). After 10 wk, the venous biomechanics, norepinephrine (NE)-induced contractility, and acetylcholine-induced relaxation were tested in saphenous veins from control animals and from animals treated with DHT or DHT with vitD using pressure angiography. Additionally, the expression levels of endothelial nitric oxide synthase (eNOS) and cyclooxygenase (COX-2) were measured using immunohistochemistry. Increased diameter, wall thickness, and distensibility as well as decreased vasoconstriction were detected after the DHT treatment. Concomitant vitD treatment lowered the mechanical load on the veins, reduced distensibility, and resulted in vessels that were more relaxed. Although there was no difference in the endothelial dilation tested using acetylcholine (ACh), the blocking effect of N(G)-nitro-l-arginine methyl ester (l-NAME) was lower and was accompanied by lower COX-2 expression in the endothelium after the DHT treatment. Supplementation with vitD prevented these alterations. eNOS expression did not differ among the three groups. We conclude that the hyperandrogenic state resulted in thicker vein walls. These veins showed early remodeling and altered vasorelaxant mechanisms similar to those of varicose veins. Alterations caused by the chronic DHT treatment were prevented partially by concomitant vitD administration.

Vicious Circle With Venous Hypertension, Irregular Flow, Pathological Venous Wall Remodeling, and Valve Destruction in Chronic Venous Disease: A Review.

Substantial advances occurred in phlebological practice in the last two decades. With the use of modern diagnostic equipment, the patients' venous hemodynamics can be examined in detail in everyday practice. Application of venous segments for arterial bypasses motivated studies on the effect of hemodynamic load on the venous wall. New animal models have been developed to study hemodynamic effects on the venous system. In vivo and in vitro studies revealed cellular phase transitions of venous endothelial, smooth muscle, and fibroblastic cells and changes in connective tissue composition, under hemodynamic load and at different locations of the chronically diseased venous system. This review is an attempt to integrate our knowledge from epidemiology, paleoanthropology and anthropology, clinical and experimental hemodynamic studies, histology, cell physiology, cell pathology, and molecular biology on the complex pathomechanism of this frequent disease. Our conclusion is that the disease is initiated by limited genetic adaptation of mankind not to bipedalism but to bipedalism in the unmoving standing or sitting position. In the course of the disease several pathologic vicious circles emerge, sustained venous hypertension inducing cellular phase transitions, chronic wall inflammation, apoptosis of cells, pathologic dilation, and valvular damage which, in turn, further aggravate the venous hypertension.

Angiotensin II induces vascular endocannabinoid release, which attenuates its vasoconstrictor effect via CB1 cannabinoid receptors.

In the vascular system angiotensin II (Ang II) causes vasoconstriction via the activation of type 1 angiotensin receptors. Earlier reports have shown that in cellular expression systems diacylglycerol produced during type 1 angiotensin receptor signaling can be converted to 2-arachidonoylglycerol, an important endocannabinoid. Because activation of CB(1) cannabinoid receptors (CB(1)R) induces vasodilation and reduces blood pressure, we have tested the hypothesis that Ang II-induced 2-arachidonoylglycerol release can modulate its vasoconstrictor action in vascular tissue. Rat and mouse skeletal muscle arterioles and mouse saphenous arteries were isolated, pressurized, and subjected to microangiometry. Vascular expression of CB(1)R was demonstrated using Western blot and RT-PCR. In accordance with the functional relevance of these receptors WIN55212, a CB(1)R agonist, caused vasodilation, which was absent in CB(1)R knock-out mice. Inhibition of CB(1)Rs using O2050, a neutral antagonist, enhanced the vasoconstrictor effect of Ang II in wild type but not in CB(1)R knock-out mice. Inverse agonists of CB(1)R (SR141716 and AM251) and inhibition of diacylglycerol lipase using tetrahydrolipstatin also augmented the Ang II-induced vasoconstriction, suggesting that endocannabinoid release modulates this process via CB(1)R activation. This effect was independent of nitric-oxide synthase activity and endothelial function. These data demonstrate that Ang II stimulates vascular endocannabinoid formation, which attenuates its vasoconstrictor effect, suggesting that endocannabinoid release from the vascular wall and CB(1)R activation reduces the vasoconstrictor and hypertensive effects of Ang II.

From Living in Saltwater to a Scarcity of Salt and Water, and Then an Overabundance of Salt-The Biological Roller Coaster to Which the Renin-Angiotensin System Has Had to Adapt: An Editorial.

Angiotensin II (Ang II) is a hormone with much more complex actions than is typical for other agonists with heterotrimeric G protein-coupled receptors (GPCRs) [...].

Role of the Endocannabinoid System in Metabolic Control Processes and in the Pathogenesis of Metabolic Syndrome: An Update.

Metabolic syndrome is a complex disease state, which appears mostly as a consequence of an unhealthy, sedentary lifestyle. Metabolic complications include insulin resistance (IR), diabetes, dyslipidemia, hypertension, and atherosclerosis, impairing life standards and reducing life expectancy. The endocannabinoid system (ECS) has an important role in signalization processes, not only in the central nervous system, but also in the peripheral tissues. Several physiological functions are affected, and overexpression or downregulation contributes to several diseases. A better understanding of the functions of cannabinoid (CB) receptors may propose potential therapeutic effects by influencing receptor signaling and enzymes involved in downstream pathways. In this review, we summarize recent information regarding the roles of the ECS and the CB1 receptor signaling in the physiology and pathophysiology of energy and metabolic homeostasis, in the development of obesity by enhancing food intake, upregulating energy balance and fat accumulation, increasing lipogenesis and glucose production, and impairing insulin sensitivity and secretion. By analyzing the roles of the ECS in physiological and pathophysiological mechanisms, we introduce some recently identified signaling pathways in the mechanism of the pathogenesis of metabolic syndrome. Our review emphasizes that the presence of such recently identified ECS signaling steps raises new therapeutic potential in the treatment of complex metabolic diseases such as diabetes, insulin resistance, obesity, and hypertension.

Impact of Sex and Exercise on Femoral Artery Function: More Favorable Adaptation in Male Rats.

Blood flow increases in arteries of the skeletal muscles involved in active work. Our aim was to investigate the gender differences as a result of adaptation to sport in the femoral arteries. Vascular reactivity and histology of animals were compared following a 12-week swimming training. Animals were divided into sedentary male (MS), trained male (MTr), sedentary female (FS), and trained female (FTr) groups. Isolated femoral artery rings were examined by wire myography. Contraction induced by phenylephrine (Phe) did not differ between the four groups. The contractile ability in the presence of indomethacin (INDO) was decreased in both sedentary groups. However, we found a specific cyclooxygenase-2 (COX-2) role only in FS rats. After exercise training, we observed increased vasoconstriction in both sexes, when nitro-L-arginine methyl ester (L-NAME) was present. The COX-dependent vasoconstriction effect disappeared in MTr animals, and the COX-2-dependent vasoconstriction effect disappeared in FTr ones. Relaxation was reduced significantly, when L-NAME was present in MTr animals compared to in FTr rats. The training was associated with greater endothelial nitric oxide synthase (eNOS) protein expression in males, but not in females. The present study proves that there are gender differences regarding adaptation mechanisms of musculocutaneous arteries to sports training. In males, relaxation reserve capacity was markedly elevated compared to in females.

Pharmacological reactivity of resistance vessels in a rat PCOS model - vascular effects of parallel vitamin D3 treatment.

The aim of this study was to clarify the effects of dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS) on pharmacological reactivity of a resistance vessel in a rat model and the possible modulatory role of 1,25-(OH)2-cholecalciferol (vitamin D3). The PCOS model was induced in adolescent female Wistar rats by a 10-week DHT treatment. Norepinephrine induced contractility and acetylcholine relaxation were tested in arterioles by pressure arteriography in control as well as DHT- and DHT plus vitamin D3-treated (DHT+D3) animals. Decreased vasoconstriction and dilatation were detected after DHT treatment. Concomitant vitamin D3 treatment increased the contractile response and resulted in more relaxed vessels. Endothelial dilation tested with acetylcholine was lower after DHT treatment, this effect was not depend on vitamin D3 supplementation. In conclusion, hyperandrogenic state resulted in reduced endothelium- and smooth muscle-dependent vasorelaxation and constriction with a complete loss of nitric oxide (NO)-dependent relaxation compared with controls. These alterations caused by chronic DHT treatment were partially reversed by concomitant vitamin D3 administration.

The effect of hydrogen sulfide on the contractility of cerebral arterioles. A pilot study.

BACKGROUND AND AIMS: Endogenous gaseous substances, such as NO and CO have been found to be effective vasodilators earlier. H2S has been identified as an additional one, however, for that substance both vasodilatory and vasoconstrictor responses have been described in different vascular territories. Our aim was to examine the effect of hydrogen sulfide on the tone of cerebral arterioles and some aspects of its mechanism. METHODS: The work was performed on excised rat anterior cerebral artery segments in vitro (diameter range 150-250 µm), using a pressure myograph system. We used NaHS as exogenous H2S donor, propargylglycine (PAG) to abolish the endogenous synthesis of hydrogen sulfide and 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) to examine the potential role of Cl-/HCO3 - exchanger in the effects of H2S. The time course of the events after application of exogenous H2S was also evaluated. RESULTS: Our findings revealed that in these pathologically important vessels (1) endogenously produced H2S is not a vasodilator, but a moderate vasoconstrictor; (2) H2S has a biphasic effect: low concentrations are moderate vasoconstrictors, while at higher concentrations the initial contraction is followed by dilatation; (3) that vasodilation is prevented by DIDS (4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid disodium, an inhibitor of the Cl-/HCO3 - exchanger). CONCLUSION: These studies confirm that H2S should be taken into consideration as a modulator of cerebral arteriolar tone in mammals.

Vitamin-D Deficiency and Supplementation Altered the Network of the Coronary Arteries in a Rodent Model-In Situ Video Microscopic Technique.

The aim of our study was to identify whether vitamin-D deficiency (VDD) can alter the geometry of the coronary-resistance-artery system. Male Wistar rats were divided into vitamin-D-deficient (VD-, n = 10) and vitamin-D-supplemented (VD+, n = 8) groups. After eight weeks, branches and segments of the left-anterior-descending-coronary-artery (LAD) network were analyzed by a video-microscopy technique. Segments were divided into 50 µm-long cylindrical ring units. VDD did not increase the number of morphological abnormalities. The number of segments did not differ between the groups (VD-: 210 and VD+: 224; pooled data of 8 networks). A larger lumen area of branches was found in VD+ group, while 1-4-order branches were lengthier in the VD- group. VD- rats had less rich coronary-resistance-artery networks in terms of 50 µm-long units. (VD-: 6365 vs. VD+: 6602; pooled data of 8 networks). VD+ animals were richer in the 100-350 µm outer diameter range, and VD- animals were richer in the 400-550 µm-diameter units. In VD- rats, 150-200 and 300 µm units were almost missing at higher flow distances from the orifice. Serum vitamin-D alterations caused by dietary changes can affect the geometry of the coronary-artery network, which may contribute to vitamin-D-dependent changes in cardiovascular mortality.

Accurate Quantitative Histomorphometric-Mathematical Image Analysis Methodology of Rodent Testicular Tissue and Its Possible Future Research Perspectives in Andrology and Reproductive Medicine.

Infertility is increasing worldwide; male factors can be identified in nearly half of all infertile couples. Histopathologic evaluation of testicular tissue can provide valuable information about infertility; however, several different evaluation methods and semi-quantitative score systems exist. Our goal was to describe a new, accurate and easy-to-use quantitative computer-based histomorphometric-mathematical image analysis methodology for the analysis of testicular tissue. On digitized, original hematoxylin-eosin (HE)-stained slides (scanned by slide-scanner), quantitatively describable characteristics such as area, perimeter and diameter of testis cross-sections and of individual tubules were measured with the help of continuous magnification. Immunohistochemically (IHC)-stained slides were digitized with a microscope-coupled camera, and IHC-staining intensity measurements on digitized images were also taken. Suggested methods are presented with mathematical equations, step-by-step detailed characterization and representative images are given. Our novel quantitative histomorphometric-mathematical image analysis method can improve the reproducibility, objectivity, quality and comparability of andrological-reproductive medicine research by recognizing even the mild impairments of the testicular structure expressed numerically, which might not be detected with the present semi-quantitative score systems. The technique is apt to be subjected to further automation with machine learning and artificial intelligence and can be named 'Computer-Assisted or -Aided Testis Histology' (CATHI).