Plicní hypertenze je závažnou komplikací plicních i srdečních onemocnění. Základním stimulem pro vznik této hypertenze je hypoxie stěny periferních, prealveolárních plicních cév vyvolávající radikálové poškození a ztluštění jejich stěn a zvýšení jejich reaktivity na vazokonstrikční podněty. Omezení radikálového poškození je proto nadějnou cestou terapie hypoxické plicní hypertenze. Projekt je zaměřen na poznání změn produkce reaktivních sloučenin kyslíku a NO během chronické hypoxie, jejich podílu na vzniku a rozvoji hypoxické plicní hypertenze a zjištění způsobů jejich ovlivnění vhodných pro klinické využití. Při řešení projektu budeme používat experimentální metody vhodné pro laboratorní potkany, které jsou na našich pracovištích spolehlivě ověřeny. Experimenty budou prováděny jak "in vivo", tak "in vitro" na tkáňových kulturách a izolovaných buňkách.; Pulmonary hypertension is a major complication of respiratory and cardiovascular diseases. This hypertension is triggered by sustained hypoxia resulting in oxidant injury of the wall of peripheral, prealveolar pulmonary vessels, thickening of their walls and an increase in their reactivity to stimuli causing vasoconstriction. Limitation of oxidant injury could be therefore useful in treatment of HPH. Project is aimed at elucidation of mechanisms responsible for increased ROS and NO production during chronic hypoxia, a role of this increase in pathogenesis of HPH and possibility to interfere with this increase in clinically useful way. We plan to use an experimental approach using methods developed for experiments on rats and described in details in our previous publications. In vivo as well as in vitro experiments using cultured tissues and isolated cells are planned.

• MeSH
• hypoxie MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech MeSH
• onemocnění periferních cév MeSH
• oxid dusnatý analýza   MeSH
• oxidační stres MeSH
• plicní alveoly krevní zásobení   MeSH
• plicní hypertenze MeSH
• reaktivní formy kyslíku analýza   MeSH
• Check Tag
• krysa rodu rattus MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• angiologie
• pneumologie a ftizeologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu IGA MZ ČR

Exposure to hypoxia, leading to hypoxic pulmonary hypertension (HPH), is associated with activation of alveolar macrophages (AM). However, it remains unclear how AM participate in this process. There are studies which imply that the AM product monocyte chemoattractant protein-1 (MCP-1) plays an important role. Thus we tested: 1. if the selective elimination of AM attenuates HPH in rats, 2. the correlation of MCP-1 plasmatic concentrations with the presence and absence of AM during exposure to hypoxia, 3. the direct influence of hypoxia on MCP-1 production in isolated AM. We found that experimental depletion of AM attenuated the chronic hypoxia-induced increase in mean pulmonary arterial pressure, but did not affect the serum MCP-1 concentrations. Furthermore, the MCP-1 production by AM in vitro was unaffected by hypoxia. Thus we conclude that AM play a significant role in the mechanism of HPH, but MCP-1 release from these cells is most likely not involved in this process. The increase of MCP-1 accompanying the development of HPH probably originates from other sources than AM.

• MeSH
• alveolární makrofágy sekrece   MeSH
• chemokin CCL2 krev   MeSH
• dichlormethylendifosfonát terapeutické užití   MeSH
• hypoxie komplikace   MeSH
• plicní hypertenze imunologie   prevence a kontrola   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Two mechanisms contribute in the development of pulmonary hypertension in pulmonary embolism (PE) - obstruction of pulmonary blood vessels and vasoconstriction. We hypothesize that hypoxia, increased shear stress and/or activation of gathered leukocytes in the PE may cause a release of reactive oxygen species (ROS). Therefore our aim was to determine the influence of the ROS scavenger Tempol on pulmonary hypertension and to describe NO synthase activity and production of NO oxidative products (NOx) after PE. In general anesthesia sephadex microspheres suspended in PSS were applied in right jugular vein as the pulmonary microembolism. Than we measured in isolated salt solution-perfused lungs the changes in perfusion pressure, activity of NO synthase and NOx plasma concentration in 7 groups of rats: C: control group (n=5), CN: C + sodium nitroprusside (SN) (n=5), EN: PE + SN (n=5), ETN: Tempol + PE + SN (n=5), CL: C + L-NAME (n=5), EL: PE + L-NAME (n=5), ETL: Tempol + PE + L-NAME (n=5). Tempol was applied intraperitoneally before PE. Animals that received Tempol (groups TN, TL) had significantly lower basal perfusion pressure than those which did not receive Tempol (EN, EL). Overall we measured a higher decrease of perfusion pressure than in the control group (C) after application of SN. Administration of L-NAME after PE (EL) increased the pressure more than in the control group (NL). NOx concentration was higher after PE. We found that preventive administration of Tempol decreases the increase in perfusion pressure after PE. PE increased NO release and concentration of NOx.

• MeSH
• aktivace enzymů účinky léků   fyziologie   MeSH
• cyklické N-oxidy farmakologie   terapeutické užití   MeSH
• krevní tlak účinky léků   fyziologie   MeSH
• krysa rodu rattus MeSH
• mikrocirkulace účinky léků   fyziologie   MeSH
• NG-nitroargininmethylester farmakologie   MeSH
• orgánové kultury - kultivační techniky MeSH
• plicní embolie farmakoterapie   metabolismus   MeSH
• plicní oběh účinky léků   fyziologie   MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku antagonisté a inhibitory   metabolismus   MeSH
• scavengery volných radikálů farmakologie   terapeutické užití   MeSH
• spinové značení MeSH
• synthasa oxidu dusnatého antagonisté a inhibitory   metabolismus   MeSH
• vazokonstrikce účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Lifesaving therapy for patients with end-stage lung disease is lung transplantation. However, there are not enough available donors. A relatively new method of transplantation from non-heart-beating donors (NHBDs) allows the treatment of the lung outside the body and could increase the number of suitable lungs. We have focused on hypercapnic ventilation, which has the possibility of reducing reactive oxygen species damage. We used four experimental and two control groups of adult rats. Each experimental group underwent the protocol of NHBD lung harvesting. The lungs were than perfused in an ex vivo model and we measured weight gain, arterial-venous difference in partial pressure of oxygen and perfusion pressure. We observed that hypercapnic ventilation during reperfusion reduces the development of pulmonary oedema and has a protective effect on the oxygen transport ability of the lungs after warm ischemia. The effect of CO2 on pulmonary oedema and on oxygen transport ability after warm ischemia could be of clinical importance for NHBD transplantation.

• MeSH
• hyperkapnie * MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech MeSH
• potkani Wistar MeSH
• reperfuzní poškození patofyziologie   prevence a kontrola   MeSH
• transplantace plic škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The present study was performed to evaluate the role of intrapulmonary activity of the two axes of the renin-angiotensin system (RAS): vasoconstrictor angiotensin-converting enzyme (ACE)/angiotensin II (ANG II)/ANG II type 1 receptor (AT₁) axis, and vasodilator ACE type 2 (ACE2)/angiotensin 1-7 (ANG 1-7)/Mas receptor axis, in the development of hypoxic pulmonary hypertension in Ren-2 transgenic rats (TGR). Transgene-negative Hannover Sprague-Dawley (HanSD) rats served as controls. Both TGR and HanSD rats responded to two weeks´ exposure to hypoxia with a significant increase in mean pulmonary arterial pressure (MPAP), however, the increase was much less pronounced in the former. The attenuation of hypoxic pulmonary hypertension in TGR as compared to HanSD rats was associated with inhibition of ACE gene expression and activity, inhibition of AT₁receptor gene expression and suppression of ANG II levels in lung tissue. Simultaneously, there was an increase in lung ACE2 gene expression and activity and, in particular, ANG 1-7 concentrations and Mas receptor gene expression. We propose that a combination of suppression of ACE/ANG II/AT₁receptor axis and activation of ACE2/ANG 1-7/Mas receptor axis of the RAS in the lung tissue is the main mechanism explaining attenuation of hypoxic pulmonary hypertension in TGR as compared with HanSD rats.

• MeSH
• angiotensin I metabolismus   MeSH
• angiotensin II metabolismus   MeSH
• angiotensin konvertující enzym metabolismus   MeSH
• arteriální tlak MeSH
• hypoxie komplikace   enzymologie   patofyziologie   MeSH
• modely nemocí na zvířatech MeSH
• peptidové fragmenty metabolismus   MeSH
• plíce enzymologie   MeSH
• plicní hypertenze enzymologie   genetika   patofyziologie   prevence a kontrola   MeSH
• potkani Sprague-Dawley MeSH
• potkani transgenní MeSH
• protoonkogenní proteiny metabolismus   MeSH
• receptor angiotensinu typ 1 metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   MeSH
• renin-angiotensin systém * MeSH
• renin genetika   metabolismus   MeSH
• signální transdukce MeSH
• vazodilatace MeSH
• vazokonstrikce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Hypoxic pulmonary vasoconstriction (HPV) is a beneficial mechanism that diverts blood from hypoxic alveoli to better ventilated areas of the lung, but breathing hypoxic air causes the pulmonary circulation to become hypertensive. Responses to airway hypoxia are associated with depolarization of smooth muscle cells in the pulmonary arteries and reduced activity of K(+) channels. As Kv7 channels have been proposed to play a key role in regulating the smooth muscle membrane potential, we investigated their involvement in the development of HPV and hypoxia-induced pulmonary hypertension. Vascular effects of the selective Kv7 blocker, linopirdine, and Kv7 activator, flupirtine, were investigated in isolated, saline-perfused lungs from rats maintained for 3-5 days in an isobaric hypoxic chamber (FiO2 = 0.1) or room air. Linopirdine increased vascular resistance in lungs from normoxic, but not hypoxic rats. This effect was associated with reduced mRNA expression of the Kv7.4 channel α-subunit in hypoxic arteries, whereas Kv7.1 and Kv7.5 were unaffected. Flupirtine had no effect in normoxic lungs but reduced vascular resistance in hypoxic lungs. Moreover, oral dosing with flupirtine (30 mg/kg/day) prevented short-term in vivo hypoxia from increasing pulmonary vascular resistance and sensitizing the arteries to acute hypoxia. These findings suggest a protective role for Kv7.4 channels in the pulmonary circulation, limiting its reactivity to pressor agents and preventing hypoxia-induced pulmonary hypertension. They also provide further support for the therapeutic potential of Kv7 activators in pulmonary vascular disease.

• MeSH
• aminopyridiny farmakologie   MeSH
• analgetika farmakologie   MeSH
• arteria pulmonalis metabolismus   patologie   patofyziologie   MeSH
• blokátory draslíkových kanálů farmakologie   MeSH
• cévní rezistence účinky léků   MeSH
• draslíkové kanály KCNQ antagonisté a inhibitory   metabolismus   MeSH
• hladké svalstvo metabolismus   patologie   patofyziologie   MeSH
• hypoxie * metabolismus   patologie   patofyziologie   MeSH
• indoly farmakologie   MeSH
• krysa rodu rattus MeSH
• membránové potenciály účinky léků   MeSH
• plíce * krevní zásobení   metabolismus   patologie   patofyziologie   MeSH
• plicní hypertenze metabolismus   patologie   patofyziologie   MeSH
• plicní oběh * MeSH
• potkani Wistar MeSH
• pyridiny farmakologie   MeSH
• regulace genové exprese účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

To test whether macrophages can play any role in hypoxic pulmonary vasoconstriction, we tested the in vitro response of rings from small pulmonary arteries to the activation of macrophages by FMLP, a substance stimulating predominantly membrane-bound NADPH oxidase. A small vessel myograph was used to measure the responses of rings from small pulmonary arteries (300-400 microm) isolated from rat lungs. Rings from 5 rats were placed into both chambers of the myograph. The vessels were stabilized for 40 min and then normalized by automatic stretching to a wall tension equivalent to the intravascular pressure 30 mm Hg. At the start of each experiment, vessels were exposed to 80 mM K+ to obtain maximal contractile response, which was used to normalize subsequent contractile responses. 2x10(6) viable macrophages, obtained by peritoneal lavage, were added into one chamber, then 5 microM FMLP was administrated to both chambers and the tension measurement was started. The hydrogen peroxide concentration produced by stimulated macrophages was measured luminometrically. The concentrations of H2O2 in specimens from chambers containing activated macrophages rose from 3.5+/-1.5 nM to 110+/-28 nM within 25 min of stimulation, while FMLP itself didn't increase the H2O2 concentration from the baseline value (4.5+/-3 nM) in samples from control chambers. After FMLP administration, the tension of the vessel rings in the presence of macrophages reached 0.23+/-0.07 of maximal contractile response, it did not change in controls. The addition of ROS scavenger 4-hydroxy-TEMPO blocked the contractile response to the activation of macrophages. We conclude that the activation of macrophages stimulates the contraction of small pulmonary arteries and that this contraction is probably mediated by reactive oxygen species.

• MeSH
• arteria pulmonalis metabolismus   MeSH
• krysa rodu rattus MeSH
• orgánové kultury - kultivační techniky MeSH
• peritoneální makrofágy metabolismus   MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• vazokonstrikce fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthases (NOS). Oxidative stress oxidises BH4 to dihydrobioptein (BH2), resulting in the uncoupling of the two enzymatic domains of NOS and the production of superoxide rather than NO (NOS uncoupling). Oxidative stress is known to be increased in the early stage of chronic hypoxia. This study investigated the participation of NOS uncoupling in the early phase of hypoxia-induced pulmonary hypertension in rats. Rats were exposed to 10% O(2) for 4 days. We investigated the effect of BH4 in vitro on isolated rat lungs and isolated rat peripheral pulmonary blood vessels and in vivo on exhaled NO concentration in exhaled air. BH4 attenuated hypoxic pulmonary vasoconstriction in isolated lungs and its effect was reversed by l-NAME (NOS inhibitor). The main finding of the study is that the effect of BH4 was smaller in rats exposed to 4 days of hypoxia than in normoxic controls. The finding was similar in isolated pulmonary blood vessels. BH4 increased exhaled NO in both normoxic and hypoxic rats. This increase was blunted by l-NIL (specific iNOS inhibitor) and therefore attributable to iNOS. We conclude that BH4 increased NO production in both normoxic and hypoxic rats. The increase was, however, smaller in hypoxic lungs than in controls. We assume that the smaller increase in NO production in hypoxic lungs is due to the decreased BH4/BH2 ratio in chronic hypoxia and NOS uncoupling resulting from this condition.

• MeSH
• biopteriny analogy a deriváty   metabolismus   MeSH
• hypoxie metabolismus   patofyziologie   MeSH
• krysa rodu rattus MeSH
• oxid dusnatý biosyntéza   MeSH
• plíce metabolismus   patofyziologie   MeSH
• plicní hypertenze metabolismus   patofyziologie   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chronic hypoxia induces an increased production of nitric oxide (NO) in pulmonary prealveolar arterioles. Bioavailability of the NO in the pulmonary vessels correlates with concentration of L-arginine as well as activity of phosphodiesterase-5 enzyme (PDE-5). We tested a hypothesis whether a combination of L-arginine and PDE-5 inhibitor sildenafil has an additive effect in reduction of the hypoxic pulmonary hypertension (HPH) in rats. Animals were exposed to chronic normobaric hypoxia for 3 weeks. In the AH group, rats were administered L-arginine during chronic hypoxic exposure. In the SH group, rats were administered sildenafil during chronic hypoxic exposure. In the SAH group, rats were treated by the combination of L-arginine as well as sildenafil during exposure to chronic hypoxia. Mean PAP, structural remodeling of peripheral pulmonary arterioles (%DL) and RV/LV+S ratio was significantly decreased in the SAH group compared to hypoxic controls even decreased compared to the AH and the SH groups in first two measured parameters. Plasmatic concentration of cGMP and NOx were significantly lower in the SAH group compared to hypoxic controls. We demonstrate that NO synthase substrate L-arginine and phosphodiesterase-5 inhibitor sildenafil administered in combination are more potent in attenuation of the HPH compared to a treatment by substances given alone.

• MeSH
• arginin aplikace a dávkování   MeSH
• hypoxie komplikace   farmakoterapie   patofyziologie   MeSH
• kombinovaná farmakoterapie MeSH
• krevní tlak účinky léků   MeSH
• krysa rodu rattus MeSH
• piperaziny aplikace a dávkování   MeSH
• plicní hypertenze farmakoterapie   etiologie   patofyziologie   MeSH
• potkani Wistar MeSH
• puriny aplikace a dávkování   MeSH
• sulfony aplikace a dávkování   MeSH
• synergismus léků MeSH
• vazodilatancia aplikace a dávkování   MeSH
• výměna plynů v plicích účinky léků   MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chronic hypoxia causes oxidative injury of pulmonary vessels and attenuates their reactivity to different stimuli. When combined with hypercapnia, biochemical markers of this injury are reduced but the effect of concomitant hypoxia and hypercapnia on vascular reactivity is not fully understood. This study was therefore designed to test whether hypercapnia can prevent also the hypoxia-induced loss of reactivity of pulmonary vessels. The reactivity of vessels from rats exposed either to hypoxia or hypoxia combined with hypercapnia was tested using a small vessel myograph (M 500A, Linton, Norfolk, GB). The second and third intrapulmonary branches of pulmonary arteries were isolated under a dissecting microscope from lungs of 8 control rats (group N), 6 rats exposed to hypoxia for 5 days (isobaric, 10 % O(2), group H) and 7 rats exposed to hypoxia combined with hypercapnia for 5 days (10 % O(2), 5 % CO(2), group H+CO(2)). The transmural pressure was set by automatic normalization to 30 mm Hg. The vessel size did not vary among the groups. After stabilization we challenged the vessels twice with KCl (80 mM) and once with PGF(2alpha) (0.1 mM). There were no significant differences in KCl induced contractions among the groups. The responses to PGF(2alpha) were expressed as a ratio to the maximal tension obtained by the exposure to 80 mM KCl. Contractions induced by PGF(2alpha) were markedly reduced in group H (0.07+/-0.02) and in group H+CO(2) (0.26+/-0.03) in comparison with group N (0.83+/-0.07). The vessels of group H responded to PGF(2alpha) less than those of group H+CO(2). However we observed the attenuated reactivity also in group H+CO(2) in comparison with N. Hypercapnia therefore partially blunted the hypoxia-induced loss of reactivity in pulmonary arteries. This finding supports the hypothesis that hypercapnia significantly alters the nature of lung injury induced by chronic hypoxia.

• MeSH
• arteria pulmonalis účinky léků   patofyziologie   MeSH
• časové faktory MeSH
• chronická nemoc MeSH
• hyperkapnie patofyziologie   MeSH
• hypoxie patofyziologie   MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech MeSH
• potkani Wistar MeSH
• vazokonstrikce * účinky léků   MeSH
• vazokonstriktory farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH