Response Of Smooth Muscle Research Articles

A Review of the Actions of Endogenous and Exogenous Vasoactive Substances during the Estrous Cycle and Pregnancy in Rats.

Simple SummaryThe vascular endothelium plays an essential role in regulating cardiovascular homeostasis by controlling the vascular tone. However, it is known that variations of sex hormones in the female during the reproductive cycle have a significant impact on the homeostasis of the female cardiovascular system. Therefore, this review shows an overview of how the vascular smooth muscle response is altered in the presence of some endogenous and exogenous substances with vasoactive actions during the estrous cycle and during pregnancy in rats. We performed a systematic review of the literature using the Web of Science, PubMed, and Scielo database through multiple combinations of terms. We selected only those terms that coincided with the objectives of this study. The result of the review shows that several studies have observed both vasoconstrictive and vasodilatory responses induced by vasoactive substances during the estrous cycle and in ovariectomized and pregnant rats. The understanding of these effects is essential to optimize and develop new treatments for some vascular pathologies.Vascular endothelium plays a key role in regulating cardiovascular homeostasis by controlling the vascular tone. Variations in sex hormones during the reproductive cycle of females affect the homeostasis of the cardiovascular system. Also, the evidence shows that estrogens show a cardioprotective effect. On this basis, this study describes some vascular responses induced by vasoactive substances during the estrous cycle in rats. We obtained the information available on this topic from the online databases that included scientific articles published in the Web of Science, PubMed, and Scielo. Many investigations have evaluated the vasoactive response of substances such as acetylcholine and norepinephrine during the estrous cycle. In this review, we specifically described the vascular response to vasoactive substances in rats during the estrous cycle, pregnancy, and in ovariectomized rats. In addition, we discussed the existence of different signaling pathways that modulate vascular function. The knowledge of these effects is relevant for the optimization and development of new treatments for some vascular pathologies.

Cryptostrobin and catechin isolated from Eugenia mattosii D. Legrand leaves induce endothelium-dependent and independent relaxation in spontaneously hypertensive rat aorta.

Considering the therapeutic potential of phenolic compounds, the purpose of the present study was to investigate the mechanisms involved in the relaxation induced by cryptostrobin and catechin, isolated from Eugenia mattosii D. Legrand leaves, in the aorta of spontaneously hypertensive rats (SHR). The thoracic aorta was isolated from SHR and kept in the organ bath system by recording contractile or relaxant responses. The addition of cumulative concentrations of cryptostrobin and catechin induced endothelium-dependent and-independent relaxation in aorta rings from SHR, as well as both compounds were effective in reducing phenylephrine-induced contraction. Pretreatment of aortic rings with Nω-nitro-l-arginine methylester (L-NAME, an inhibitor of nitric oxide synthase) or 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, an inhibitor of soluble guanylate cyclase), resulted in a significant change of relaxant effect induced by catechin, and a slight influence on cryptostrobin-induced relaxation. Muscarinic receptor and potassium channels are involved in catechin-induced relaxation as assessed using atropine (a muscarinic receptor antagonist), tetraethylammonium (a non-selective K+ channel blocker) and glibenclamide (an ATP-sensitive K+ channel blocker). Conversely, cryptostrobin, but not catechin, blunted the contraction induced by the addition of phenylephrine in a calcium-free solution. Besides that, cryptostrobin attenuated the contraction of rat aorta rings induced by internal Ca2+ release and external Ca2+ influx. These findings indicated that cryptostrobin and catechin alter vascular smooth muscle reactivity, and this effect may be involved, at least in part, by enhancing the endothelium NO/cGMP pathway and potassium channels activation. In addition, cryptostrobin reduced the phenylephrine, KCl and CaCl2-induced contractions in a calcium-free solution.

Responses of bladder smooth muscle to the stretch go through extracellular signal-regulated kinase (ERK)/p90 ribosomal S6 protein kinase (p90RSK)/Nuclear factor-κB (NF-κB) Pathway.

The present study was designed to study changes and its potential mechanisms in human bladder smooth muscle subjected to stretch. Bioinformatics analyses including differential expression analysis, overrepresentation enrichment analysis, principal component analysis, and weighted gene coexpression network analysis were used to analyze a microarray dataset (GSE47080) of partial bladder outlet obstruction (pBOO) in rat to find the potential changes of gene expressions. Bladder from pBOO model and human bladder smooth muscle cells (HBSMCs) subjected to sustained prolonged stretch were collected for Western blot analysis, real-time polymerase chain reaction, and fluorescence analysis to verify the changes of gene expressions and preliminarily study the potential role of signaling pathway regulation in treatment of pBOO. The bioinformatics analysis showed that chronic obstruction activated mitogen-activated protein kinase pathway and changed cytoskeleton structure in bladder smooth muscle. In in vivo experiments in mice, pBOO was verified by cystometry. Partial BOO activated the extracellular signal-regulated kinase (ERK)/p90 ribosomal S6 protein kinase (p90RSK)/nuclear factor-κB (NF-κB) signaling pathway in DM. The messenger RNA (mRNA) expressions of contractile phenotypic proteins increased after pBOO. In in vitro experiments of HBSMCs, mechanical stretch activated ERK/p90RSK/NF-κB in HBSMCs in a time-dependent manner. The mRNA expressions of α-smooth muscle actin and SM22 also increased and filamentous actin (F-actin) polymerization was enhanced as well. Inhibition of ERK/p90RSK/NF-κB pathway reversed mechanical stretch-induced changes of contractile phenotypic expression and F-action polymerization. Continuous stretch increases expressions of contractile phenotypic proteins and promotes the polymerization of F-actin. This process partially goes through ERK/p90RSK/NF-κB pathway.

Ventilasi dan Perfusi, serta Hubungan antara Ventilasi dan Perfusi

Lung is a place for gas exchange where ventilation and perfusion occurs. Ventilation is the first step where sequential process of inhalation and exhalation take place. Meanwhile perfusion as the other step facilitates the gas exchange and tissue supply need. Blood flows through the lungs are equals as the amount of cardiac output where the factors that control cardiac output are mainly peripheral factors, also control pulmonary blood flow. In general condition, pulmonary blood vessels act as a passive tube, which can be increased with the increasing pressure and narrowed the pressure drop. Oxygen absorption level from lungs into bloodstream is a critical determinant for functional capacity, and an important factor wheter in normal conditions (including exercise) or even in illness state. Lung diffusion capacity is influenced by several geometric and functional factors. Gravitation influence systematic gradient in ventilation and perfusion distribution. Ventilation and blood flow variations at horizontal level also occur due to intrinsic anatomic variations and vascular geometry, as well as the differences in airway and vascular smooth muscle response which modifies the distribution. The change of integrity intrapleural chamber, hydrostatic pressure and osmotic imbalance, malfunction of surfactants, other intrinsic weakness of the branching system in the form of a progressive airway, and all the things that could potentially damage the structure of the lung can cause ventilation and diffusion dysfunction.

Multi‐therapeutic action of chronic treatment with tadalafil in cardiovascular alterations and erectile function of rats with heart failure

IntroductionHeart failure (HF) is the common endpoint of several cardiovascular diseases. HF and ED share similar pathophysiological mechanisms that contribute to the progression of both disorders, with emphasis on endothelial dysfunction and reduced nitric oxide (NO) bioavailability. Drugs mimic the effect exerted by NO, such as tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor used in the ED treatment. Therefore, tadalafil may be a multi‐therapeutic agent in the treatment of cardiovascular alterations and erectile dysfunction associated with impaired of NO‐sGC‐cGMP signaling pathway? Thus, using the aortocaval fistula model (FAC) we investigated the contribution of tadalafil chronic treatment in the cardiac, vascular and erectile dysfunction of HF rats.MethodsHF was surgically induced through the FAC model, and after 8 weeks, these animals were submitted to cardiac function evaluation (echocardiogram) and subdivided into 3 groups: Sham, HF and HF/Tadalafil (5mg/day IP for more 4 weeks). Intracavernous pressure measurement (ICP) was used to evaluate erectile function in vivo. Response concentration curves were constructed to assess both vascular reactivity in response to phenylephrine (PE), acetylcholine and sodium nitroprusside (SNP), as well as the cavernosal muscle (CC) reactivity in response to PE and SNP. Electrical stimulation (EFS) were obtained to evaluate neurogenic contraction and nitrergic relaxation in CC rat.ResultsAfter 12 weeks, HF group presented both reduced of ejection and shortening fraction (p<0.05), as well present cardiac hypertrophy (P <0.05) when compared to the Sham group. Treatment with tadaladil restored the ejection and shortening fraction in the HF/Tadalafil (p<0.05), and reduced cardiac hypertrophy induced by HF. Moreover, HF animals presented an increase in the contractile vascular response mediated by PE when compared to Sham group (p<0.05), being this vascular hypercontractility restored by the tadalafil treatment (p<0.05). In addition, aorta of HF rats showed reduction of the ACh‐mediated relaxation (p<0.05) compared to the control, and this effect was restored by tadalafil treatment (p<0.05). Regarding erectile function, the data show that HF animals present a reduction of intracavernous pressure (p<0.05) compared to the Sham group, that was restored by tadalafil treatment (p<0.05). The contractile mechanism of CC, in response to PE and neurogenic electrical stimulation (p<0.05) were increased in HF rats, on the other side, the treatment with tadalafil improve the CC hypercontractility in these animals (p<0.05). In addition, tadalafil treatment also restored both SNP (p<0.05) and nitrergic (p<0.05) mediated relaxation in the CC of HF rats.ConclusionOur data show that the chronic treatment with tadalafil improved both vascular‐ and no‐vascular smooth muscle reactivity since exerting beneficial effects in the cardiovascular and erectile function in HF rats. Data suggesting that tadalafil acts is a multi‐therapeutic agent in HF rats.Support or Funding InformationFinancial suport: FAPESP: 2011/21095‐4 / CNPq: 423987/2016‐0This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Exercise training‐induced enhancement of coronary vasodilatory function is absent in rats lacking the transcription factor, Nrf2

Nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) is a transcription factor that is crucial in maintaining cellular redox homeostasis. Aerobic exercise training has been reported to enhance vasodilatory responses of coronary arterioles through signaling that involves reactive oxygen species. We hypothesized that deletion of Nrf2 would alter vasodilatory responses of coronary arterioles and limit exercise training‐induced adaptations of coronary vasodilatory function. We exercise trained wild type (WT) Sprague‐Dawley rats, and their littermates that were lacking the Nrf2 gene (Nrf2KO). Rats were either exercise trained (EX) on a motor‐driven treadmill 5 days/wk or remained sedentary (SED) in their cages for 10–12 weeks. A mixed moderate aerobic and high‐intensity interval training protocol was utilized. At the end of the training period, coronary arterioles were isolated and vasodilatory responses to intraluminal flow (pressure differences from 2–60 cm H2O) and the exogenous nitric oxide donor, Dea‐NONO‐ate (1×10−9–1×10−4M), were evaluated. Endothelium‐dependent vasodilation to intraluminal flow was not altered by either deletion of Nrf2 or by exercise training. In contrast, endotheliumin‐dependent vasodilation to Dea‐NONO‐ate, was reduced in coronary arterioles from Nrf2 rats as compared to arterioles from WT rats (WT vs Nrf2 KO; P=0.054). Exercise training increased responsiveness to Dea‐NONO‐ate in arterioles from WT rats (WT EX vs WT SED; P<0.05), but not in arterioles from Nrf2KO rats. These data suggest that deficiency of Nrf2 alters the function of vascular smooth muscle, but not the function of the vascular endothelium in coronary arterioles. Exercise training increases the vasodilatory responsiveness of coronary arteriolar smooth muscle to nitric oxide, but not in the absence of Nrf2, suggesting that mechanisms of redox homeostasis and nitric oxide signaling interact in the smooth muscle of coronary arterioles.Support or Funding InformationNIH R15AG055029This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Exercise training‐induced adaptations of vascular smooth muscle vasodilatory function are absent in muscle arterioles from rats lacking the nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) gene

Nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) is a transcription factor that is crucial in maintaining cellular redox homeostasis. Nrf2 protein increases with exercise training in skeletal muscle. Adaptations of the vasculature are often linked to changes in the metabolic profile of skeletal muscle. We hypothesized that deletion of Nrf2 would negate or reduce exercise training‐induced adaptations of arterioles from the soleus muscle. To test this hypothesis, we exercise trained wild type Sprague‐Dawley (WT) rats, and their littermates that were lacking the Nrf2 gene (Nrf2KO). Rats were either exercise trained (EX) on a motor‐driven treadmill 5 days/wk or remained sedentary (SED) in their cages for 10–12 weeks. A mixed moderate aerobic and high‐intensity interval training protocol was utilized. At the end of the training period, soleus muscle arterioles were isolated for assessment of vascular reactivity. Responsiveness to potassium chloride (KCl), phenylephrine, and the NO donor, Diethylamine‐NONO‐ate were evaluated. In resistance soleus muscle arterioles from WT rats, constriction to high concentrations of KCl (80–100 mM) was reduced (WT EX vs WT SED; P<0.05) by exercise training. In contrast, vasodilatory responsiveness to low concentrations of KCl (10–20 mM) was increased (WT EX vs WT SED; P<0.05) by exercise training in resistance arterioles from the soleus muscle of WT rats. Exercise training also increased vasodilatory responsiveness (WT EX vs WT SED; P=0.02) to DEA‐NONO‐ate in soleus muscle arterioles from WT rats. These exercise training‐induced adaptations were absent in soleus muscle arterioles from Nrf2KO rats. Vasoconstrictor responses to phenylephrine were not changed by exercise training in soleus muscle arterioles from WT rats, but tended to increase with exercise training in arterioles from Nrf2KO rats. These data suggest that exercise training enhances vasodilatory responsiveness of the vascular smooth muscle in soleus muscle arterioles from WT rats; however, exercise training‐induced enhancement of vasodilation in smooth muscle is absent in soleus muscle arterioles from Nrf2KO rats. This lack of vasodilatory adaptation may contribute to greater vasoconstrictor responses in arterioles from exercise‐trained Nrf2KO rats. Further experiments in denuded arterioles are needed to definitively determine whether these exercise training‐induced adaptations occur in the vascular smooth muscle or in the endothelium of soleus muscle arterioles from WT and Nrf2KO rats.Support or Funding InformationNIH Grant Number R15AG055029This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of PDE9 inhibitor BAY 73‐6691 in the contractile response of cavernosal and detrusor smooth muscle of sickle cell disease mice

IntroductionGenitourinary tract function is affected in sickle cell disease (SCD). Modulation of cyclic guanosine monophosphate (cGMP)‐dependent signalling is important for the contractile mechanism of detrusor (DSM) and corpus cavernosum (CC) smooth muscle and may characterize a therapeutic target for theses manifestations in the SCD. Phosphodiesterase‐9 (PDE9) specifically hydrolyzes cGMP, and was detected in CC and bladder urothelium. BAY 73‐6691, selective PDE9 inhibitor, has been used for understanding the role of cGMP signaling in the SCD. However, no previous studies have explored the selective PDE9 inhibition with BAY 73‐6691 in the DSM and CC in SCD.ObjectiveThe aim of this study was to investigate the effect of BAY 73‐6691 on the contractile response of CC and DSM of SCD mice.MethodsBerkeley transgenic sickle cell mice (SS) and C57BL/6 mice (control) were used. Cumulative concentration‐response curves to muscarinic receptor agonist carbachol (CCh; 0.01–100 μM), chloride potassium (KCl; 1–300 mM) and frequency‐response curves for electrical field stimulation (EFS; 1–32 Hz) were obtained in strips of DSM from both control and SS mice. In the CC, cumulative concentration‐response curves to α1‐adrenoceptor agonist phenylephrine (PE; 0.01–100 μM) and frequency‐response curves for electrical field stimulation (EFS; 1–32 Hz) were carried out in the absence and presence of BAY 73‐6691 (100 nM and 1 μM; 30 min).ResultsIn the evaluation of DSM, the SS mice presented an increased in the contractile response mediated by CCh (P<0.05), when compared to control mice. Surprisingly, BAY 73‐6691 increased the contraction mediated by CCh in DSM of SS mice (p<0.05), but did not alter the contraction response in the control mice. Contractile responses induced by KCl were increased in the SS mice (p<0.001) compared to control mice. However, no significant differences for BAY 73‐6671 incubation were found between control and SS group. EFS‐induced neurogenic contractions in the DSM of SS mice were 90% higher in the frequency of 32 Hz (p<0.01) compared to control. Pre‐incubation with BAY 73‐6671 no affect the neurogenic contraction in the control and SCD group. Cavernosal contractile to PE were higher in SS mice compared to control mice (P<0.01). Similarly to DSM, BAY 73‐6691 increased the contraction mediated by PE in CC of SS mice (p<0.05), but did not alter the contraction response in control mice. However, EFS‐induced neurogenic contractions in CC of SS mice were 49% lower in the frequency of 32 Hz (p<0.01) compared to the control. BAY 73‐6691 did not change the neurogenic contraction in both groups.ConclusionOur preliminary data shows that, BAY 73‐6691 promotes increase of contractile response in SS mice, acting in the muscarinic and adrenergic signaling pathway in the DSM and CC, respectively. Further experiments are needed to identify the exact mechanisms of drug‐induced alterations in the contraction of the DSM and CC in SCD.Support or Funding InformationFAPESPThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Genetic deletion of the DNA damage repair protein, ATM kinase, is not sufficient to induce vascular dysfunction in young mice

Ataxia telangiectasia mutated (ATM) kinase orchestrates the cellular response to double stranded DNA breaks, phosphorylating and activating downstream targets that lead to cell cycle arrest or apoptosis, as well as by recruiting the machinery necessary for DNA repair. In the vasculature, ATM may play a critical role in maintaining genomic stability, thereby preserving vascular function, as aberrant DNA repair has been implicated in vascular dysfunction. Here, we evaluated several measures of vascular function in ATM knockout (ATM −/−) and wildtype (ATM +/+) mice (4–6 mo, n=7–9/group). Aortic pulse wave velocity, a measure of large artery stiffness, was similar between groups (P>0.05). Furthermore, using an automated capture and analysis system we assessed markers of microvascular perfusion and glycocalyx properties. Perfused microvascular density, a measure of the number of perfused microvessels in a given area, and red blood cell (RBC) fraction, a marker of the heterogeneity of RBCs between microvessel segments, were not significantly different between groups (P>0.05). Likewise, perfused boundary region, a measure of endothelial glycocalyx barrier function, was not significantly different between ATM −/− and ATM +/+ controls (P>0.05). Furthermore, we examined endothelium‐dependent dilation and nitric oxide (NO) bioavailability in mesenteric arteries by measuring vasodilation to acetylcholine (ACh) in the absence and presence of the nitric oxide synthase inhibitor, L‐NAME. Maximal vasodilation to ACh did not differ between groups (P>0.05). Likewise, the contribution of NO to maximal vasodilation was similar between ATM −/− and ATM +/+ mice (P>0.05). Next, we assessed smooth muscle responsiveness to NO by measuring vasodilation to the NO donor, sodium nitroprusside (SNP). Maximal vasodilation to SNP did not differ between groups (P>0.05). Lastly, we evaluated the passive mechanical properties of isolated mesenteric arteries and found no differences in vessel lumen diameter in response to increasing pressure between ATM −/− and ATM +/+ mice (P>0.05). In conclusion, these findings suggest that removal of a major kinase involved with double stranded DNA damage signaling does not affect vascular function in young mice. This could be due to several reasons. First, young mice may have not accumulated sufficient DNA damage and mutagenesis to induce dysfunction or second, signaling downstream from DNA damage may drive vascular dysfunction. Thus, future studies are warranted that examine the role of ATM kinase in vascular function in response to conditions that augment DNA damage.Support or Funding InformationFunding Information: Funded in part by awards from the NIH, R01 AG048366, R01 AG050238, K02 AG045339 and K99 AT010017, and by US Department of Veterans Affairs 1I01BX002151.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Paying the Toll for Inflammation

Paying the Toll for Inflammation

Study on in Vivo Pial Vessels Alterations and Activity of Isolated Vascular Smooth Muscles in Abdominal Hypertension Rats.

Intra-abdominal hypertension is known as a factor affecting cerebral haemodynamics. Sustainably elevated abdominal pressure may disturb the balance of intracranial/blood pressure ratio, eventually developing perfusion pressure to drop. The aim of this study is to investigate the influence of artificially elevated intra-abdominal pressure upon brain pial vessels condition and contractile reactivity of isolated rat arteria carotis communis and vena jugularis to norepinephrine and serotonin. The abdominal pressure of rats anaesthetized with xylazine 10 mg/kg and ketamine 100 mg/kg was increased up to 25 mm Hg by insufflation of air through venflon cannula and maintained for period of 1 to 3 hours. Craniotomy of left parietal area was carried out by micro drill. Open scull and cranial window techniques were applied. Outer diameters of superficial pial vessels were measured by USB digital microcamera (magnification up to 400x). Contractile reactivity of smooth muscle preparations from arteria carotis communis and vena jugularis of euthanized abdominal-hypertensive (AH) rats was registered isometrically. Increased smooth muscle reactivity of a. carotis communis from AH rats to serotonin (10-8-10-4 mol/l) but not to norepinephrine compared to controls was registered. The changes tended to be higher in long lasting (3 hours) exposure of AH rats. Increase in outer diameter of pial vessels during maintenance of abdominal hypertension in both open scull and cranial window techniques was found. The increased intra-abdominal pressure causes dilatation of small superficial cerebral blood vessels and increases the smooth muscle reactivity of isolated arteria carotis communis to 5-HT.

CME Accreditation Page

Meconium aspiration syndrome (MAS) is a major cause of respiratory insufficiency in the term and post-term newborns. There are several pathomechanisms participating in this disorder, particularly the airway obstruction, surfactant dysfunction, inflammation, lung edema, pulmonary vasoconstriction and bronchoconstriction. Inflammatory changes resulting from meconium aspiration cause severe impairment of lung parenchyma and surfactant, and influence the reactivity of both vascular and airway smooth muscle. Therefore, anti-inflammatory drugs may be of benefit in the management of MAS. This article reviews the pharmacological actions and side effects of various anti-inflammatory drugs used up to now in the experimental models of MAS and in the treatment of newborns with meconium aspiration.

Sustained exercise hyperemia during prolonged adenosine infusion in humans.

The contribution of Adenosine (ADO) to exercise hyperemia remains controversial and it is unknown whether ADO can evoke the prolonged vasodilation seen during exercise bouts. Therefore, we tested hypotheses in the human forearm during 3 h of intra‐arterial high dose ADO infusion: (1) skeletal muscle blood flow would wane over time; (2) exercise hyperemic responses during ADO administration would be unaffected compared to baseline. Using sodium nitroprusside (SNP), we tested parallel hypotheses regarding nitric oxide (NO) in a separate group of participants. Seventeen young healthy participants (ADO: n = 9; SNP: n = 8) performed multiple rhythmic handgrip exercise bouts (20% of maximum), two during saline and five during 3 h of continuous drug infusion. Five minutes of ADO infusion resulted in a ~5‐fold increase in forearm vascular conductance (FVC; 4.8 ± 0.6 vs. 24.2 ± 3.2 mL/min/100 mmHg, P < 0.05). SNP caused a ~4‐fold increase (4.4 ± 0.6 vs. 16.6 ± 2 mL/min/100 mmHg, P < 0.05). FVC did not wane over time with ADO (24.2 ± 3.2 and 22 ± 1.2 mL/min/100 mmHg [P > 0.05]) or SNP (16.6 ± 2 and 14.1 ± 2.4 mL/min/100 mmHg [P > 0.05]) at 5 versus 150 min. Superimposed exercise during ADO or SNP infusions evoked marked and consistent additional dilation over the course of the infusions. Our findings demonstrate that in humans there is no reduction in endothelial or vascular smooth muscle responsiveness to the exogenous vasodilatory metabolites ADO and NO. Additionally, even in the presence of an exogenous vasodilator, superimposed exercise can cause significant hyperemia.

Double deletion of calponin 1 and calponin 2 in mice decreases systemic blood pressure with blunted length-tension response of aortic smooth muscle

Calponin is a family of actin filament-associated regulatory proteins. Among its three isoforms, calponin 1 is smooth muscle specific and calponin 2 is expressed in smooth muscle and certain non-muscle cells. Previous studies showed that calponin 1 knockout mice had detectable changes in the contractility of urogenital smooth muscle whereas other smooth muscles were less affected. To investigate the possibility that calponins 1 and 2 have overlapping functions in smooth muscle, we examined the effect of double knockout of calponin 1 and calponin 2 genes (Cnn1 and Cnn2) on smooth muscle functions. The results showed for the first time that calponin 1 and calponin 2 double knockout in mice does not cause lethality. The double knockout mice showed decreased systemic blood pressure, decreased force development and blunted length tension response in endothelial-removed aortic rings. A compensatory increase of calponin 1 was found in smooth muscle of Cnn2−/− mice but not vice versa. Cnn1−/− and Cnn2−/− double knockout aortic smooth muscle exhibits faster relaxation than that of wild type control. Double deletion or co-suppression of calponin 1 and calponin 2 in vascular smooth muscle to blunt myogenic response may present a novel approach to develop new treatment for hypertension.

Saponins of Dioscorea Nipponicae Inhibits IL-17A-Induced Changes in Biomechanical Behaviors of In Vitro Cultured Human Airway Smooth Muscle Cells.

Airway hyperresponsiveness (AHR) is one of the main pathologic features of bronchial asthma, which is largely attributable to enhanced contractile response of asthmatic airway smooth muscle. Although β2 adrenergic receptor agonists are commonly used to relax airway smooth muscle for treating AHR, there are side effects such as desensitization of long-term use. Therefore, it is desirable to develop alternative relaxant for airway smooth muscle, preferably based on natural products. One potential candidate is the inexpensive and widely available natural herb saponins of Dioscorea nipponicae (SDN), which has recently been reported to suppress the level of inflammatory factor IL-17A in ovalbumin-induced mice, thereby alleviating the inflammation symptoms of asthma. Here, we evaluated the biomechanical effect of SDN on IL-17A-mediated changes of cultured human airway smooth muscle cells (HASMCs) in vitro. The stiffness and traction force of the cells were measured by optical magnetic twisting cytometry (OMTC), and Fourier transform traction microscopy (FTTM), respectively. The cell proliferation was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetry, the cell migration was measured by cell scratch test, and the changes of cell cytoskeleton were assessed by laser confocal microscopy. We found that the stiffness and traction force of HASMCs were enhanced along with the increases of IL-17A concentration and exposure time, and SDN treatment dose-dependently reduced these IL-17A-induced changes in cell mechanical properties. Furthermore, SDN alleviated IL-17A-mediated effects on HASMCs proliferation, migration, and cytoskeleton remodeling. These results demonstrate that SDN could potentially be a novel drug candidate as bronchodilator for treating asthma-associated AHR.

The Effects of Paracetamol and Ibuprofen on Smooth Muscle Response of the Bronchospasm: an in Vitro Study

The Effects of Paracetamol and Ibuprofen on Smooth Muscle Response of the Bronchospasm: an in Vitro Study

Hypoxia-inducible factors-α as a regulator for forkhead box protein M1 in pulmonary artery hypertension

Hypoxia is defined as decreased levels of oxygen in the cells, which are caused by vascular and pulmonary diseases. The catalysts of hypoxia in the physiological role are important in all living cells, whereas its metabolic dysfunction is related to many diseases. Hypoxia-inducible factors (HIFs) activity should be controlled by providing HIF modules. Forkhead box protein M1 (FOXM1) plays a crucial role in the maintenance and differentiation of airways epithelial cell lining, especially during embryonic life, where it is essential in the formation and proliferation of pulmonary vessels. FOXM1 is overexpressed in the pulmonary artery smooth muscle in response to hypoxia through the elements that are present in the promoters of FOXM1; therefore, it was used to diagnose patients with pulmonary artery hypertension.

Dividing neutrophils in subsets reveals a significant role for activated neutrophils in the development of airway hyperreactivity.

Previous research has emphasized the importance of eosinophils in allergic asthma, while paying less attention to neutrophils. The known functionality of neutrophils in the inflammatory process has recently changed and knowledge about subsets of neutrophils, as characterized by their expression of CD16 and CD62L, has surfaced. Their specific roles in asthma are still unknown. To study the functional differences between subsets of neutrophils by characterizing the impact of individual subsets on airway smooth muscle reactivity. The direct effect of neutrophils on airway hyperresponsiveness was assessed by co-culturing different subsets of neutrophils (produced by LPS invitro stimulation) with human isolated small airways or murine tracheae with subsequent evaluation of smooth muscle reactivity to bradykinin in myographs. Supernatants and tissue were saved for ELISA and immunohistochemistry. The CD16high CD62Ldim neutrophils were found to enhance the response to bradykinin in both human isolated small airways and murine tracheae. No such effects were obtained for the other subsets. The response is due to an upregulation of bradykinin receptor 2 through release of TNFα from the neutrophil. The present study introduces a new concept regarding the role of neutrophils and defines a novel direct link between a specific activated neutrophil subset and airway smooth muscle, establishing neutrophils as important players in the development of asthmatic airway hyperactivity.

Involvement of transient receptor potential melastatin 4 channels in the resting membrane potential setting and cholinergic contractile responses in mouse detrusor and ileal smooth muscles.

Here, we investigated the effects of 9-hydroxyphenanthrene (9-phenanthrol), a potent and selective transient receptor potential melastatin 4 (TRPM4) channel blocker, on the resting membrane potential and cholinergic contractile responses to elucidate the functional role of TRPM4 channels in the contractile activities of mouse detrusor and ileal longitudinal smooth muscles. We observed that, 9-phenanthrol (3–30 µM) did not significantly inhibit high K+-induced contractions in both preparations; however, 9-phenanthrol (10 µM) strongly inhibited cholinergic contractions evoked by electrical field stimulation in detrusor preparations compared to inhibitions in ileal preparations. 9-Phenanthrol (10 µM) significantly inhibited the muscarinic agonist, carbachol-induced contractile responses and slowed the maximum upstroke velocities of the contraction in detrusor preparations. However, the agent (10 µM) did not inhibit the contractions due to intracellular Ca2+ release evoked by carbachol, suggesting that the inhibitory effect of 9-phenanthrol may primarily be due to the inhibition of the membrane depolarization process incurred by TRPM4 channels. On the other hand, 9-phenanthrol (10 µM) did not affect carbachol-induced contractile responses in ileal preparations. Further, 9-phenanthrol (10 µM) significantly hyperpolarized the resting membrane potential and decreased the basal tone in both detrusor and ileal muscle preparations. Taken together, our results suggest that TRPM4 channels are constitutively active and are involved in setting of the resting membrane potential, thereby regulating the basal tone in detrusor and ileal smooth muscles. Thus, TRPM4 channels play a significant role in cholinergic signaling in detrusor, but not ileal, smooth muscles.

Evaluation of pharmacological correction of L-name-induced endothelial dysfunction, platelet aggregation and venous tone with diosmin Detralex 1000 mg

Introduction. Chronic venous diseases are one of the urgent problems of modern medicine. Recent studies have shown high significance of endothelial dysfunction (ED) and oxidative stress in their pathogenesis. For the correction of the occurring changes, drugs of the flavonoid group, particularly diosmin and hesperidin, are currently used. Numerous studies have confirmed a vast range of biological effects of diosmin; however, there are only sporadic data on its endothelium protective effects.&#x0D; Materials and methods. The study was performed in 70 white mature male rats of Wistar line, weighing 180-220 g. ED simulation was performed using non-selective blocker of NO-synthase N-nitro-L-arginine methyl ester (L-NAME). Functional vascular tests and biochemical markers were used to determine a degree of correction of functional disorders. An anti-inflammatory effect of Detralex 1000 mg was estimated in 10 mature albino rabbits weighing 2800 - 3200 g by using o-xylene. The study of the venotonic property of the drug was carried out in the experiment in an isolated segment of the rats’ portal vein with Ca2+ solutions at a concentration of 0.08-1.75 mcM. The histologic specimens were prepared in accordance with the generally accepted methods.&#x0D; Results and discussion. The administration of the test drug did not lead to a statistically significant decrease in blood pressure in the conditions of L-NAME-induced ED. However, there was a dose-dependent statistically significant decrease in the coefficient of ED (CED), which indicates a positive endothelium protective effect. Course administration of Detralex 1000 mg leads to a significant dose-dependent correction of platelet aggregation disorders, which is manifested in the extended aggregation time. The results of studying an anti-inflammatory activity of the drug showed a decrease in the size of spots caused by the application of o-xylene, and the extention of the time interval before their onset. Studying a Ca2+-mediated smooth muscle response showed that the vein contractile force reaches its maximum at a higher dosage of the drug with a lower concentration of Ca2+. In the morphological study of the stomach wall, small and large intestine of the intact rats and rats receiving a course of Detralex 1000 mg, there were no inflammatory changes in the mucosa of the comparison group.&#x0D; Conclusions. The study found that Detralex 1000 mg significantly reduces the ED coefficient and slows platelet aggregation against the background of L-NAME-induced ED; the efficacy is dose-dependent. Detralex 1000 mg dose-dependently reduces vascular permeability disorders caused by the application of o-xylene. The test drug has a Ca2+-mediated mechanism of increasing the contractile activity of the venous wall. It was found that the course administration of the drug per os has no local irritative effect.