El tratamiento postnatal con melatonina modula la expresión de agentes prostanoides en pulmón de neonatos de oveja con hipertensión pulmonar / Melatonin modulates the expression of pulmonary prostanoids

Background: Living above 2,500 meters in hypobaric conditions induces pulmonary arterial hypertension of the neonate (PAHN), a syndrome whose main features are: pathological remodeling of the pulmonary vessels, abnormal vascular reactivity and increased oxidative stress. Melatonin could have pulmonary antioxidant, anti-remodeling and vasodilating properties for this condition. Aim: To determine the effect of melatonin at the transcript level of prostanoid pathways in the lung of neonatal lambs gestated and born under hypobaric hypoxia. Material and Methods: Vehicle (1.4% of ethanol, n = 6) or melatonin (1 mg * kg1, n = 5) were administered from the postnatal day 4 to 21 to lambs gestated and born at 3,600 meters above sea level. After one week of treatment completion, lung tissue was obtained, the transcript and protein levels of prostanoid synthases and receptors were assessed by RT-PCR and Western Blot. Results: Melatonin induced the expression of prostacyclin synthase transcript and increased protein expression of the prostacyclin receptor. In addition, the treatment decreased the expression of transcript and protein of cyclooxygenase-2, without changes in the expression of the prostanoid vasoconstrictor (thromboxane) pathway. Conclusions: Postnatal treatment with melatonin increases the expression of the prostacyclin-vasodilator pathway without changing the vasoconstrictor thromboxane pathway. Further, the decreased COX-2 induced by melatonin could be an index of lesser oxidative stress and inflammation in the lung.

El rol de la hipertensión pulmonar en la displasia broncopulmonar / The role of pulmonary hypertension on bronchopulmonary dysplasia

Resumen Hace 50 años Northway describió la Displasia Broncopulmonar (DBP), en nacidos de pretérmino expuestos a ventilación mecánica. Desde entonces, ha aumentado la sobrevida de ellos; sin embar go, ha aparecido una "nueva DBP" y la incidencia de esta no ha disminuido. Una de las caracte rísticas de esta patología es la remodelación vascular anómala, que en su expresión más severa se conoce como Hipertensión Pulmonar (HP); con una incidencia de 17%, que es proporcional a la severidad de la DBP (33% en DBP severa); y como un factor de mortalidad (hasta un 48% mortali dad a 2 años con HP por DBP). Debido a esto resulta importante conocer los métodos diagnósticos y alternativas terapéuticas, tema que se discute en esta revisión. Considerando la alta mortalidad de la asociación HP-DBP, adquiere importancia una estrategia de tamizaje en la población de riesgo. El gold standard para el diagnóstico de HP es el cateterismo cardíaco, sin embargo, el ecocardio-grama transtorácico es una herramienta útil para el tamizaje y diagnóstico de HP en pacientes dis-plásicos, con mediciones cuantitativas y cambios cualitativos en la evaluación diagnóstica. A nivel sanguíneo el péptido natriurético tipo B (BNP), ha mostrado ser útil en el seguimiento; en cuanto a imágenes, la tomografía computarizada se utiliza en casos severos. En cuanto a las terapias, se han propuesto el óxido nítrico inhalado como vasodilatador pulmonar, los inhibidores de la fosfodies-terasas -sildenafil-, los antagonistas de la endotelina -bosentán- y los análogos de prostaciclinas -iloprost-. Aún no se cuenta con evidencia de alta calidad para su uso, dosis y duración del trata miento, pero hay variadas experiencias clínicas. Además, es relevante el cuidado interdisciplinario, destacando optimizar la nutrición. El desafío es lograr una prevención efectiva de la DBP y de sus complicaciones. Un protocolo de tamizaje de HP debe asociarse a una estratificación de riesgo y directrices de tratamiento.

Abstract 50 years ago, Northway described Broncopulmonary Dysplasia (BPD) in preterm infants exposed to mechanical ventilation. Since then, their survival has increased, nevertheless a "new BPD" has appeared and its incidence has not diminished. One of the characteristics of this pathology is the the abnormal vascular remodeling, which in its most severe expression is known as Pulmonary Hyper tension (PH); with an incidence of 17% in patients with BPD, which is proportional to the severity of the disease (33% in severe BPD), and as mortality factor (up to 48% 2-year mortality in PH-BPD). Thereby, it is important to know the diagnostic methods and therapeutic alternatives, topics discus sed in this review. Considering the high mortality in BPD associated PH, screening strategies in at risk population become important. The gold standard is cardiac catheterization; however, transtho-rathic echocardiography is a useful tool for the screening and diagnosis of PH in displasic patients, using cuantitive measures and cualitative changes in the evaluation. Seric type-B natriuretic peptide has shown to be useful for follow-up; regarding images, CT scan is used in severe cases. In terms of therapy; inhaled Nitric Oxide as a pulmonary vasodilator, phosphodiesterase inhibitors -sildenafil-, endotelin antagonists -bosentan-, and prostacyclin analogues -iloprost-, have been proposed. Their use, dosis and treatment lenght still lack support of high quality evidence, but diverse clinical expe riences have been described. Interdisciplinary care is also important, highlighting to optimize nu trition. Therefore, the challenge is to effectively prevent BPD and its complications. A PH screening protocol should be associated with risk stratification and treatment guidelines.

Inactivated Pseudomonas aeruginosa inhibits hypoxia-induced pulmonary hypertension by preventing TGF-beta1/Smad signaling

Pseudomonas aeruginosa is one of the common colonizing bacteria of the human body and is an opportunistic pathogen frequently associated with respiratory infections. Inactivated P. aeruginosa (IPA) have a variety of biological effects against inflammation and allergy. Transforming growth factor-β (TGF-β) signaling plays a critical role in the regulation of cell growth, differentiation, and development in a wide range of biological systems. The present study was designed to investigate the effects of IPA on TGF-β/Smad signaling in vivo, using a hypoxia-induced pulmonary hypertension (PH) rat model. Sprague Dawley rats (n=40) were exposed to 10% oxygen for 21 days to induce PH. At the same time, IPA was administered intravenously from day 1 to day 14. Mean pulmonary artery pressure (mPAP) and the right ventricle (RV) to left ventricle plus the interventricular septum (LV+S) mass ratio were used to evaluate the development of PH. Vessel thickness and density were measured using immunohistochemistry. Primary arterial smooth muscle cells (PASMCs) were isolated and the proliferation of PASMCs was assayed by flow cytometry. The production of TGF-β1 in cultured supernatant of PASMCs was assayed by ELISA. The expression levels of α-smooth muscle actin (α-SMA), TGF-β1 and phospho-Smad 2/3 in PASMCs were assayed by western blot. Our data indicated that IPA attenuated PH, RV hypertrophy and pulmonary vascular remodeling in rats, which was probably mediated by restraining the hypoxia-induced overactive TGF-β1/Smad signaling. In conclusion, IPA is a promising protective treatment in PH due to the inhibiting effects on TGF-β1/Smad 2/3 signaling.

Contexto sociodemográfico de los homicidios en México D.F.: un análisis espacial / Sociodemographic context of homicide in Mexico City: a spatial analysis

OBJETIVO:Investigar el patrón de distribución espacial de la tasa de homicidios y su relación con las características sociodemográficas en las delegaciones de Benito Juárez, Coyoacán y Cuauhtémoc de la Ciudad de México en el año 2010. MÉTODOS: Estudio inferencial de corte transversal que usa métodos de análisis espacial para estudiar la asociación espacial de la tasa de homicidios y las características demográficas. La asociación espacial fue determinada a través del cociente de localización, análisis de regresión múltiple y el uso de la regresión geográficamente ponderada. RESULTADOS: Los homicidios muestran un patrón de localización heterogéneo con altas tasas en zonas con uso del suelo no residencial, con baja densidad de población y baja marginación. CONCLUSIONES: El uso de herramientas de análisis espacial son instrumentos poderosos para el diseño de políticas de seguridad pública preventiva y recreativa que busquen reducir la mortalidad por causas externas como homicidios.

OBJECTIVE:Investigate the spatial distribution pattern of the homicide rate and its relation to sociodemographic features in the Benito Juárez, Coyoacán, and Cuauhtémoc districts of Mexico City in 2010. METHODS: Inferential cross-sectional study that uses spatial analysis methods to study the spatial association of the homicide rate and demographic features. Spatial association was determined through the location quotient, multiple regression analysis, and the use of geographically weighted regression. RESULTS: Homicides show a heterogeneous location pattern with high rates in areas with non-residential land use, low population density, and low marginalization. CONCLUSIONS: Spatial analysis tools are powerful instruments for the design of prevention- and recreation-focused public safety policies that aim to reduce mortality from external causes such as homicides.

Posición prona: efecto sobre el intercambio gaseoso y en la capacidad funcional para el ejercicio en pacientes con hipertensión pulmonar / Prone position: effect on gas exchange and functional capacity for exercise in patients with pulmonary hypertension

El objetivo del estudio fue evaluar el intercambio gaseoso y el comportamiento funcional cardiorrespiratorio en pacientes con hipertensión pulmonar (HTP) antes, durante y después del cambio de posición a decúbito prono. Treinta pacientes con HTP y alteraciones en el intercambio gaseoso fueron incluidos en el estudio. Las variables de intercambio gaseoso se evaluaron en decúbito supino para obtener los valores basales y en decúbito prono a los 30, 120 y 240 min. Así mismo, se sometieron al test marcha 6 minutos (6MWT) previo y posterior a 30 días de sueño nocturno en prono. Después de cuatro horas, todos los pacientes presentaron un incremento de la PaO2 y en la saturación arterial de oxígeno (SaO2), con disminución en los cortocircuitos intrapulmonares, mejorando el intercambio gaseoso y por consiguiente de la demanda fisiológica impuesta por el ejercicio en pacientes con HTP.

The objective of this investigation was to evaluate gas exchange and cardiopulmonary functional behavior in patients with pulmonary hypertension (PH) before, during and after the change to a prone position. Thirty patients with PH and alterations in gas exchange were included in the study. Gas exchange measurements were performed in four stages: at the baseline supine position and after 30, 120 and 240 minutes in prone position. Also, the patients were evaluated by the six minutes walking test (6MWT) after 30 days in prone position during night’s sleep. After four hours in prone position, all patients showed an increase of PaO2 and arterial saturation of oxygen (SaO2), with a decrease of intrapulmonary shunts, improving the gas exchange and therefore the physiological demand imposed by exercise in patients with PH.

Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT1 receptor (AT1-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO2 = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT1-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT1-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT1-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT1-R staining, but C animals showed weak iNOS and AT1-R staining. Macrophages of L and P animals showed moderate and weak AT2-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT1-R blockade. We suggest that AT1-R blockade might act through AT2-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

Interpretation and Use of Natriuretic Peptides in Non-Congestive Heart Failure Settings

Natriuretic peptides (NPs) have been found to be useful markers in differentiating acute dyspneic patients presenting to the emergency department (ED) and emerged as potent prognostic markers for patients with congestive heart failure (CHF). The best-established and widely used clinical application of BNP and NT-proBNP testing is for the emergent diagnosis of CHF in patients presenting with acute dyspnea. Nevertheless, elevated NPs levels can be found in many circumstances involving left ventricular (LV) dysfunction or hypertrophy; right ventricular (RV) dysfunction secondary to pulmonary diseases; cardiac inflammatory or infectious diseases; endocrinology diseases and high output status without decreased LV ejection fraction. Even in the absence of significant clinical evidence of volume overload or LV dysfunction, markedly elevated NP levels can be found in patients with multiple comorbidities with a certain degree of prognostic value. Potential clinical applications of NPs are expanded accompanied by emerging reports regarding screening the presence of secondary cardiac dysfunction; monitoring the therapeutic responses, risk stratifications and providing prognostic values in many settings. Clinicians need to have expanded knowledge regarding the interpretation of elevated NPs levels and potential clinical applications of NPs. Clinicians should recognize that currently the only reasonable application for routine practice is limited to differentiation of acute dyspnea, rule-out-diagnostic-tests, monitoring of therapeutic responses and prognosis of acute or decompensated CHF. The rationales as well the potential applications of NPs in these settings are discussed in this review article.

Inhibition of expression of hypoxia-inducible factor-1alpha mRNA by nitric oxide in hypoxic pulmonary hypertension rats / 华中科技大学学报（医学）（英德文版）

In order to study the effect of nitric oxide (NO) on the expression of hypoxia-inducible factor-1 alpha (HIF-1alpha) mRNA in hypoxic pulmonary hypertension (HPH) rats, 30 healthy male Wistar rats were randomly divided into normoxic control group, chronic hypoxic group and hypoxia plus L-arginine (L-Arg) group. The animal model of HPH was developed. The mean pulmonary arterial pressure (mPAP) was measured by inserting a microcatheter into the pulmonary artery. The HIF-1alpha mRNA expression levels were detected by in situ hybridization (ISH) and semiquantitative RT-PCR. It was found that after 14 days hypoxia, the mPAP in normoxic control group (17.6 +/- 2.7 mmHg, 1 mmHg=0.133 kPa) was significantly lower than that in chronic hypoxic group (35.8 +/- 6.1 mmHg, t=0.2918, P<0.05) and mPAP in chronic hypoxic group was higher than that in hypoxia plus L-arginine group (24.4 +/- 3.8 mmHg, t=0.2563, P<0.05). ISH showed that the expression of HIF-1alpha mRNA in the intraacinar pulmonary arteriolae (IAPA) in normoxic control group (0.1076 +/- 0.0205) was markedly weaker than that in chronic hypoxic group (0.3317 +/- 0.0683, t=3.125, P<0.05) and that in chronic hypoxic group was stronger than that in hypoxia plus L-arginine group (0.1928 +/- 0.0381, t=2.844, P<0.05). RT-PCR showed that the content of HIF-1alpha mRNA in chronic hypoxic group (2.5395 +/- 0.6449) was 2.16 times and 1.75 times higher than that in normoxic control group (1.1781 +/- 0.3628) and hypoxia plus L-arginine group (1.4511 +/- 0.3981), respectively. It is concluded that NO can reduce the mPAP by the inhibition of the expression of HIF-1alpha mRNA, which may be one of the mechanisms through which NO affects the pathogenesis of HPH.

The role of endogenous carbon monoxide in the hypoxic vascular remodeling of rat model of hypoxic pulmonary hypertension / 华中科技大学学报（医学）（英德文版）

We investigated the expression of heme oxygenase-1 (HO-1) gene and production of endogenous carbon monoxide (CO) in the rat lung tissue at different time points of chronic hypoxic pulmonary hypertension and the effect of hemin on the expression of HO-1 gene and pulmonary hypertension. A rat model of hypoxic pulmonary hypertension was recreated by exposure to intermittent normobaric hypoxic environment (10% O2). Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to determine the level of HO-1 mRNA in the rat lung tissue and double wave length spectrophotometry was used to evaluate the quantity of COHb in arterial blood. Cardiac catheterization was employed to measure the right ventricular systolic pressure (RVSP) and HE staining was performed in dissected lung tissue to observe the pathological changes of the intra-acinar pulmonary arteries (IAPA). It was found that (1) There was a low level of HO-1 mRNA in normal rat lung tissue, but the level of HO-1 mRNA increased by 2-4 times in the lung tissue of hypoxic rats (P<0.01). The quantity of COHb was 2-3 times those of control group (P<0.01 or P<0.05). These were accompanied by the increased of RVSP and the thickened IAPA; (2) Hemin could keep the HO-1 mRNA and COHb in the hypoxic rat lung tissue at a high level, and partially suppressed the increase of rat RVSP, thereby ameliorating the pathological changes of IAPA. In conclusion, the upregulation of the expression of HO-1 gene and production of CO in the rat lung of hypoxic pulmonary hypertension plays a role of inhibition in the development of hypoxic pulmonary hypertension. Hemin has a therapeutic effect on hypoxic pulmonary hypertension.

Oxido nítrico inhalado en cirugía de válvula mitral en pacientes con hipertensión arterial pulmonar: (estudio preliminar) / Nitric oxide in mitral valve replacement in patients with pulmonary arterial hypertension: (preliminary report)

El óxido nítrico, es considerado actualmente como una de las terapéuticas alternativas para la hipertensión arterial pulmonar ya sea primaria o secundaria tanto en pacientes adultos como en pacientes pediátricos. Se llevó a cabo un estudio prospectivo en el cual se incluyeron pacientes portadores de valvulopatía mitral e hipertensión arterial pulmonar. Se administró óxido nítrico inhalado a la dosis de 40 ppm y FiO2 mayor a 75 por ciento a través de la máquina de anestesia. Estos pacientes fueron sujetos a cambio valvular mitral (ya sea mecánica o biológica) y se valoraron parámetros hemodinámicos (presiones pulmonares, sistémicas, gasto cardiaco y otras derivadas de la colocación de catéter de flotación pulmonar), valorando la disminución de la presión arterial pulmonar. Una vez terminada la cirugía se suspendió la administración de dicho gas y se tomaron muestras sanguíneas de metahemoglobina. Los resultados revelaron que el óxido nítrico a la dosis de 40 ppm fue capaz de reducir las resistencias vasculares pulmonares en 17 por ciento, se encuentra libre de efectos deletéreos cardiovasculares y no presenta niveles tóxicos de metahemoglobina