Differential sex-dependent susceptibility to diastolic dysfunction and arrhythmia in cardiomyocytes from obese diabetic HFpEF model.

AIM: Sex-differences in heart failure with preserved ejection fraction (HFpEF) are important, but key mechanisms involved are incompletely understood. While animal models can inform about sex-dependent cellular and molecular changes, many previous preclinical HFpEF models have failed to recapitulate sex-dependent characteristics of human HFpEF. We tested for sex-differences in HFpEF using a two-hit mouse model (leptin receptor-deficient db/db mice plus aldosterone infusion for 4 weeks; db/db+Aldo). METHODS AND RESULTS: We performed echocardiography, electrophysiology, intracellular Ca2+ imaging, and protein analysis. Female HFpEF mice exhibited more severe diastolic dysfunction in line with increased titin N2B isoform expression and PEVK element phosphorylation, and reduced troponin-I phosphorylation. Female HFpEF mice had lower BNP levels than males despite similar comorbidity burden (obesity, diabetes) and cardiac hypertrophy in both sexes. Male HFpEF mice were more susceptible to cardiac alternans. Male HFpEF cardiomyocytes (versus female) exhibited higher diastolic [Ca2+], slower Ca2+ transient decay, reduced L-type Ca2+ current, more pronounced enhancement of the late Na+ current, and increased short-term variability of action potential duration (APD). However, male and female HFpEF myocytes showed similar downregulation of inward rectifier and transient outward K+ currents, APD prolongation, and frequency of delayed afterdepolarizations. Inhibition of Ca2+/calmodulin-dependent protein kinase II (CaMKII) reversed all pathological APD changes in HFpEF in both sexes, and empagliflozin pretreatment mimicked these effects of CaMKII inhibition. Vericiguat had only slight benefits, and these effects were larger in HFpEF females. CONCLUSION: We conclude that the db/db+Aldo preclinical HFpEF murine model recapitulates key sex-specific mechanisms in HFpEF and provides mechanistic insights into impaired excitation-contraction coupling and sex-dependent differential arrhythmia susceptibility in HFpEF with potential therapeutic implications. In male HFpEF myocytes, altered Ca2+ handling and electrophysiology aligned with diastolic dysfunction and arrhythmias, while worse diastolic dysfunction in females may depend more on altered myofilaments properties.

Cardiac Protein Kinase D1 ablation alters the myocytes ß-adrenergic response.

ß-adrenergic (ß-AR) signaling is essential for the adaptation of the heart to exercise and stress. Chronic stress leads to the activation of Ca2+/calmodulin-dependent kinase II (CaMKII) and protein kinase D (PKD). Unlike CaMKII, the effects of PKD on excitation-contraction coupling (ECC) remain unclear. To elucidate the mechanisms of PKD-dependent ECC regulation, we used hearts from cardiac-specific PKD1 knockout (PKD1 cKO) mice and wild-type (WT) littermates. We measured calcium transients (CaT), Ca2+ sparks, contraction and L-type Ca2+ current in paced cardiomyocytes under acute ß-AR stimulation with isoproterenol (ISO; 100 nM). Sarcoplasmic reticulum (SR) Ca2+ load was assessed by rapid caffeine (10 mM) induced Ca2+ release. Expression and phosphorylation of ECC proteins phospholambam (PLB), troponin I (TnI), ryanodine receptor (RyR), sarcoendoplasmic reticulum Ca2+ ATPase (SERCA) were evaluated by western blotting. At baseline, CaT amplitude and decay tau, Ca2+ spark frequency, SR Ca2+ load, L-type Ca2+ current, contractility, and expression and phosphorylation of ECC protein were all similar in PKD1 cKO vs. WT. However, PKD1 cKO cardiomyocytes presented a diminished ISO response vs. WT with less increase in CaT amplitude, slower [Ca2+]i decline, lower Ca2+ spark rate and lower RyR phosphorylation, but with similar SR Ca2+ load, L-type Ca2+ current, contraction and phosphorylation of PLB and TnI. We infer that the presence of PKD1 allows full cardiomyocyte ß-adrenergic responsiveness by allowing optimal enhancement in SR Ca2+ uptake and RyR sensitivity, but not altering L-type Ca2+ current, TnI phosphorylation or contractile response. Further studies are necessary to elucidate the specific mechanisms by which PKD1 is regulating RyR sensitivity. We conclude that the presence of basal PKD1 activity in cardiac ventricular myocytes contributes to normal ß-adrenergic responses in Ca2+ handling.

Diabetes and Excess Aldosterone Promote Heart Failure With Preserved Ejection Fraction.

Background The pathobiology of heart failure with preserved ejection fraction (HFpEF) is still poorly understood, and effective therapies remain limited. Diabetes and mineralocorticoid excess are common and important pathophysiological factors that may synergistically promote HFpEF. The authors aimed to develop a novel animal model of HFpEF that recapitulates key aspects of the complex human phenotype with multiorgan impairments. Methods and Results The authors created a novel HFpEF model combining leptin receptor-deficient db/db mice with a 4-week period of aldosterone infusion. The HFpEF phenotype was assessed using morphometry, echocardiography, Ca2+ handling, and electrophysiology. The sodium-glucose cotransporter-2 inhibitor empagliflozin was then tested for reversing the arrhythmogenic cardiomyocyte phenotype. Continuous aldosterone infusion for 4 weeks in db/db mice induced marked diastolic dysfunction with preserved ejection fraction, cardiac hypertrophy, high levels of B-type natriuretic peptide, and significant extracardiac comorbidities (including severe obesity, diabetes with marked hyperglycemia, pulmonary edema, and vascular dysfunction). Aldosterone or db/db alone induced only a mild diastolic dysfunction without congestion. At the cellular level, cardiomyocyte hypertrophy, prolonged Ca2+ transient decay, and arrhythmogenic action potential remodeling (prolongation, increased short-term variability, delayed afterdepolarizations), and enhanced late Na+ current were observed in aldosterone-treated db/db mice. All of these arrhythmogenic changes were reversed by empagliflozin pretreatment of HFpEF cardiomyocytes. Conclusions The authors conclude that the db/db+aldosterone model may represent a distinct clinical subgroup of HFpEF that has marked hyperglycemia, obesity, and increased arrhythmia risk. This novel HFpEF model can be useful in future therapeutic testing and should provide unique opportunities to better understand disease pathobiology.

Nitrosylation of cardiac CaMKII at Cys290 mediates mechanical afterload-induced increases in Ca2+ transient and Ca2+ sparks.

Cardiac mechanical afterload induces an intrinsic autoregulatory increase in myocyte Ca2+ dynamics and contractility to enhance contraction (known as the Anrep effect or slow force response). Our prior work has implicated both nitric oxide (NO) produced by NO synthase 1 (NOS1) and calcium/calmodulin-dependent protein kinase II (CaMKII) activity as required mediators of this form of mechano-chemo-transduction. To test whether a single S-nitrosylation site on CaMKIIδ (Cys290) mediates enhanced sarcoplasmic reticulum Ca2+ leak and afterload-induced increases in sarcoplasmic reticulum (SR) Ca2+ uptake and release, we created a novel CRISPR-based CaMKIIδ knock-in (KI) mouse with a Cys to Ala mutation at C290. These CaMKIIδ-C290A-KI mice exhibited normal cardiac morphometry and function, as well as basal myocyte Ca2+ transients (CaTs) and ß-adrenergic responses. However, the NO donor S-nitrosoglutathione caused an acute increased Ca2+ spark frequency in wild-type (WT) myocytes that was absent in the CaMKIIδ-C290A-KI myocytes. Using our cell-in-gel system to exert multiaxial three-dimensional mechanical afterload on myocytes during contraction, we found that WT myocytes exhibited an afterload-induced increase in Ca2+ sparks and Ca2+ transient amplitude and rate of decline. These afterload-induced effects were prevented in both cardiac-specific CaMKIIδ knockout and point mutant CaMKIIδ-C290A-KI myocytes. We conclude that CaMKIIδ activation by S-nitrosylation at the C290 site is essential in mediating the intrinsic afterload-induced enhancement of myocyte SR Ca2+ uptake, release and Ca2+ transient amplitude (the Anrep effect). The data also indicate that NOS1 activation is upstream of S-nitrosylation at C290 of CaMKII, and that this molecular mechano-chemo-transduction pathway is beneficial in allowing the heart to increase contractility to limit the reduction in stroke volume when aortic pressure (afterload) is elevated. KEY POINTS: A novel CRISPR-based CaMKIIδ knock-in mouse was created in which kinase activation by S-nitrosylation at Cys290 (C290A) is prevented. How afterload affects Ca2+ signalling was measured in cardiac myocytes that were embedded in a hydrogel that imposes a three-dimensional afterload. This mechanical afterload induced an increase in Ca2+ transient amplitude and decay in wild-type myocytes, but not in cardiac-specific CaMKIIδ knockout or C290A knock-in myocytes. The CaMKIIδ-C290 S-nitrosylation site is essential for the afterload-induced enhancement of Ca2+ transient amplitude and Ca2+ sparks.

Acetogeninas, alternativa en el tratamiento de cáncer en caninos / Acetogenins, alternative cancer treatment in dogs / Acetogeninas, alternativa no tratamento de câncer em caninos

Resumen El cáncer es una enfermedad que implica la alteración de procesos celulares, como metabolismo celular, activación o silenciamiento de genes y crecimiento descontrolado. Es una las principales causas de muerte en humanos, así como en animales de compañía, por lo cual cada vez es más importante la búsqueda y desarrollo de medicamentos. Algunos de los medicamentos que se producen para tratar el cáncer, provienen de plantas, como el taxol y la vincristina. La necesidad de ampliar el uso de productos naturales para tratar esta enfermedad, no solo en humanos sino en animales de compañía como caninos, abre las puertas a la búsqueda de actividad biológica de plantas que son usadas popularmente por presentar algún efecto con la enfermedad. Este es el caso de la guanábana (Annona muricata), de la cual se han extraído metabolitos secundarios (acetogeninas) que presentan in vitro mayor toxicidad en líneas celulares cancerígenas comparadas con líneas celulares normales. El fin de esta revisión fue realizar una aproximación de los usos de estos metabolitos en cáncer, para ello fue hecha una búsqueda en PubMed con diferentes palabras claves y se concluyó, que las acetogeninas comprenden una fuente potencial para el desarrollo de medicamentos contra el cáncer.

Abstract Cancer is a disease that alter cellular processes, like cell metabolism, activation and deactivation of genes and uncontrolled growth. It is one of the main causes of death in humans, as well as in companion animals, which is why it is increasingly important to seek and develop medicines for the treatment. Some of the drugs that are produced to treat cancer come from plants, such as taxol and vincristine. The necessity to expand the use of natural products to treat this disease, not only in humans but also in companion animals such as dogs, opens the doors to seek biological activity of plants that are commonly used because they present some effect over the disease. This is the case of soursop (Annona muricata), from which secondary metabolites (acetogenins) have been extracted and have presented in vitro greater toxicity in cancer cell lines compared to normal cell lines. Therefore, this review was carried out in order to make an approximation of the uses of these metabolites in cancer, for which a search was carried out in PubMed with different key words and it was concluded that acetogenins comprise a potential source for the development of medicines against cancer.

Resumo O câncer é uma doença que envolve a alteração de processos celulares, como o metabolismo celular, ativação ou silenciamento de genes e o crescimento descontrolado. É uma das principais causas de morte em humanos, assim como em animais de companhia, para os quais a busca e o desenvolvimento de medicamentos são cada vez mais importantes. Algumas das drogas que são produzidas para tratar o câncer são derivadas de plantas, como o taxol e a vincristina. A necessidade de ampliar o uso de produtos naturais para tratar esta doença, não somente em humanos, mas em animais de companhia, como cães, abre as portas para a busca da atividade biológica de plantas que são popularmente usadas para causar algum efeito na doença. Este é o caso da graviola (Annona muricata), da qual se extraíram os metabólitos secundários (acetogeninas), que apresentam maior toxicidade in vitro nas linhagens de células cancerígenas do que nas linhagens normais. O objetivo desta revisão foi fazer uma aproximação dos usos desses metabólitos no câncer, para os quais foi feita uma pesquisa em PubMed com palavras-chave diferentes e concluiu-se que as acetogeninas constituem uma fonte potencial para o desenvolvimento de drogas anti-câncer.

Parámetros electrocardiográficos en caballos de raza Criollo Colombiano, pacientes de un establecimiento veterinario de Antioquia, Colombia / Electrocardiographic parameters in Colombian Creole horses, patients in a veterinary establishment in Antioquia, Colombia / Parâmetros eletrocardiográficos em cavalos de raça Criollo Colombiano, pacientes de um estabelecimento veterinário de Antioquia, Colômbia

Las alteraciones cardiacas en los equinos no se manifiestan de una manera habitual como en otros animales; sin embargo, hay afecciones que requieren ser diagnosticadas correctamente para evaluar el desempeño atlético. Son varios los estudios publicados respecto a la utilización de métodos diagnósticos complementarios en cardiología equina, como el electrocardiograma (ECG). A pesar de ello aún no se tienen datos de referencia para el caso del caballo Criollo Colombiano (CCC). El objetivo de este estudio fue describir los trazados electrocardiográficos de 57 CCC pacientes de la Clínica Veterinaria Lasallista, con alta previa y sin alteraciones clínicas evidentes. Los ECG fueron hechos en sistema base-ápex y los animales fueron divididos en grupos de edad. Para el análisis de los datos se hizo estadística descriptiva, análisis de varianza de una vía y coeficientes de correlación. De cada grupo se obtuvieron rangos de amplitud y duración de las diferentes ondas, intervalos y segmentos. Solo se evidenció diferencia estadísticamente significativa de la duración de la onda P e intervalo PR entre grupos de edad. Existieron correlaciones de algunos de los parámetros del ECG con el peso, la edad y la frecuencia cardiaca. Con este trabajo se hace un aporte importante para aquellas ocasiones en que sea necesario recurrir al electrocardiograma para validar la información obtenida en el examen clínico o cuando se sospeche de una cardiopatía en CCC, principalmente, en el caso de arritmias.

Cardiac disorders in horses are not generally manifested as in other animals; however, there are conditions that need to be properly diagnosed to assess athletic performance. There are several studies on the use of complementary diagnostic methods, such as an electrocardiogram (ECG), in equine cardiology. Despite this, there are no baseline data for the case of Colombian Creole horses (CCH). This study aimed to describe the electrocardiographic tracings of 57 CCH patients at the Clínica Veterinaria Lasallista, with prior discharge and no obvious clinical abnormalities. ECGs were performed on animals divided into age groups. For data analysis, descriptive statistics, one-way analysis of variance, and correlation coefficients were used. From each group, ranges of the amplitude and duration of various waves, intervals and segments were obtained. The only statistically significant difference was evidenced in the duration of the P-wave and the PR interval between age groups. Some of the ECG parameters had correlations with weight, age, and heart rate. This study makes an important contribution for those occasions when it is necessary to use electrocardiograms to validate the information obtained in clinical examination or in case of a suspected heart disease in CCHs, mainly, in case of arrhythmias.

As alterações cardíacas nos equinos não se manifestam de uma maneira habitual como em outros animais; contudo, há afecções que requerem ser diagnosticadas corretamente para avaliar o desempenho atlético. São vários os estudos publicados sobre a utilização de métodos diagnósticos complementares em cardiologia equina, como o eletrocardiograma (ECG). Apesar disso ainda não se têm dados de referência para o caso do cavalo Criollo Colombiano (CCC). O objetivo deste estudo foi descrever os traços eletrocardiográficos de 57 CCC pacientes da Clínica Veterinária Lassalista, com alta prévia e sem alterações clínicas evidentes. Os ECG foram fatos em sistema base-ápex e os animais foram divididos em grupos de idade. Para a análise dos dados fez-se estatística descritiva, análise de variação de uma via e coeficientes de correlação. De cada grupo se obtiveram rangos de amplitude e duração das diferentes ondas, intervalos e segmentos. Solo se evidenciou diferença estatisticamente significativa da duração da onda P e intervalo PR entre grupos de idade. Existiram correlações de alguns dos parâmetros do ECG com o peso, a idade e a frequência cardíaca. Com este trabalho se contribui significativamente para aquelas ocasiões em que seja necessário recorrer ao eletrocardiograma para validar a informação obtida no exame clínico ou quando haja suspeita de uma cardiopatia em CCC, principalmente, no caso de arritmias.

Estudio cuantitativo de algunas medidas ecocardiográficas en caballos Criollo Colombiano / Quantitative study of some echocardiography measures in Colombian Creole horses / Estudo quantitativo de algumas medidas ecocardiográficas em cavalos Criollo Colombiano

La ecocardiografía es considerada una de las herramientas de mayor valor diagnóstico en la evaluación de la anatomía y la función cardiaca, pues permite visualizar de forma no invasiva aspectos como el grosor de las válvulas cardiacas y el espesor del tabique interventricular, además de la posibilidad de medir las dimensiones de las cavidades del corazón. El objetivo de este trabajo fue determinar algunas características cuantitativas de ecocardiografías hechas en 60 equinos raza Caballo Criollo Colombiano (CCC) de cualquier sexo, edad y peso. Las ecocardiografías fueron hechas en modo M, a partir de imágenes bidimensionales, en el plano tres, cuarto espacio intercostal de la ventana paraesternal derecha. Fueron evaluados los siguientes parámetros: DVId (diámetro del ventrículo izquierdo en diástole), DVIs (diámetro del ventrículo izquierdo en sístole), SIVd (tabique interventricular en diástole), SVIs (tabique interventricular en sístole), PPd (pared posterior del ventrículo izquierdo en diástole), PPs (pared posterior del ventrículo izquierdo en sístole), FE (fracción de eyección), FA (fracción de acortamiento) y MVI (masa del ventrículo izquierdo). Para el análisis de los datos se hicieron grupos según la edad. Dependiendo de la distribución de los datos, se analizaron la media y la desviación estándar, y la mediana y los percentiles (software SPSS 21.0). Con este trabajo se hace un aporte importante para aquellas ocasiones en que sea necesario recurrir a la ecocardiografía para validar la información obtenida en el examen clínico o cuando se sospeche de una cardiopatía en CCC.

Echocardiography is considered a tool of great diagnostic value in the evaluation of cardiac anatomy and function, as it allows to non-invasively visualize aspects such as heart valve thickness and interventricular septum thickness, in addition to the possibility of measuring the dimensions of the heart chambers. This study aimed to determine some quantitative characteristics of echocardiograms taken in 60 Colombian Creole horses (CCH) of any sex, age, and weight. Images were obtained by two-dimensionally-guided M-mode echo-cardiography, in plane three, fourth intercostal space on the right parasternal area. The following parameters were evaluated: LVDd (left ventricular diameter in diastole), LVDs (left ventricular diameter in systole), IVSd (interventricular septum in diastole), ISVs (interventricular septum in systole), LVPWd (left ventricular posterior wall in diastole), LVPWs (left ventricular posterior wall in systole), EF (ejection fraction), FS (fractional shortening), and LVM (left ventricular mass). For data analysis, age groups were formed. Depending on data distribution, the study analyzed: mean and standard deviation, and median and percentiles (SPSS 21.0 software). This work makes an important contribution for those occasions when it is necessary to use echocardiography to validate the information obtained in clinical examination or in case of suspected heart disease in CCHs.

A ecocardiografia é considerada uma das ferramentas de maior valor diagnóstico na avaliação da anatomia e a função cardíaca, pois permite visualizar de forma não invasiva aspectos como a grossura das válvulas cardíacas e a espessura do tabique interventricular, além da possibilidade de medir as dimensões das cavidades do coração. O objetivo deste trabalho foi determinar algumas características quantitativas de eco cardiografias realizadas em 60 cavalos Criollo Colombiano (CCC) de qualquer sexo, idade e peso. As ecocardiografias foram realizadas em modo M guiado a partir de imagens bidimensionais, no plano três, quarto espaço intercostal paraesternal direito. Foram avaliados os seguintes parâmetros: DVId (diâmetro do ventrículo esquerdo em diástole), DVIs (diâmetro do ventrículo esquerdo em sístole), SIVd (septo interventricular em diástole), SVIs (septo interventricular em sístole), PPd (parede posterior do ventrículo esquerdo em diástole), PPs (parede posterior do ventrículo esquerdo em sístole), FE (fração de ejecção), FA (fração de encurtamento) e MVI (massa do ventrículo esquerdo). Para a análise dos dados se formaram grupos de acordo à idade. Dependendo da distribuição dos dados, se analisaram: média e desvio padrão, e mediana e percentis (software SPSS 21.0). Com este trabalho se faz uma importante contribuição para aquelas ocasiões em que seja necessário recorrer à ecocardiografia para validar a informação obtida no exame clínico ou quando haja suspeita de uma cardiopatia em CCC.

Dilation of a Proximal Esophageal Stricture by Endoscopically and Radiologically Guided Balloon in a Falabella Foal / Dilatación de estenosis esofágica proximal con balón guiado por endoscopia y radiografía en potro falabella / Dilatação de estenose esofágica proximal com balão guiado por endoscopia e radiografia em potro falabella

Esophageal strictures or stenosis are generally triggered by necrosis, as a result of the pressure caused by esophageal impactions that generate ulceration and erosion of the esophageal mucosa, as well as due to lesions caused by the oral administration of corrosive agents, cervical trauma and congenital strictures. Esophageal dilation procedures have been used for the treatment of strictures in humans and small animals but are rarely used in horses, given the number of sessions required for successful treatment and the limited information published on the subject. The objective of this work was to determine the effectiveness of esophageal dilation with an endoscopically and radiologically guided balloon in a Falabella foal with an esophageal stricture caused by an obstruction. The result was successful after five sessions of dilation when the patient tolerated solid food, and no complications were found after six months of observation.

Las estenosis esofágicas son causadas, generalmente, por necrosis, consecuencia de la presión ejercida por impacciones esofágicas que erosionan y ulceran la mucosa esofágica, además de las lesiones causadas por la ingestión oral de agentes corrosivos, el trauma cervical y las estenosis congénitas. Los procedimientos de dilataciones esofágicas se han utilizado en pequeños animales y en humanos para el tratamiento de estenosis; pero son escasamente utilizados en caballos, debido a la cantidad de sesiones que se requieren para obtener el éxito y a la escasa información publicada al respecto. El objetivo de este trabajo fue determinar la efectividad de la dilatación esofágica con balón guiado por endoscopia y radiografía en un potro falabella con estenosis esofágica mural, producto de una obstrucción. El resultado fue exitoso, pues el animal, después de cinco sesiones seguidas de dilataciones, toleró la vía oral para alimentos sólidos y así fue sometido a observación durante seis meses, sin complicaciones evidentes.

As estenoses esofágicas são causadas, geralmente, por necrose, consequência da pressão exercida por impactações esofágicas que corroem e ulceram a mucosa esofágica, além das lesões causadas pela ingestão oral de agentes corrosivos, o trauma cervical e as estenoses congênitas. Os procedimentos de dilatações esofágicas Têm sido utilizados em pequenos animais e em humanos para o tratamento de estenose; mas são escassamente utilizados em cavalos, devido à quantidade de sessões requeridas para obter o êxito e à escassa informação publicada com respeito a isso. O objetivo deste trabalho foi determinar a efetividade da dilatação esofágica com balão guiado por endoscopia e radiografia em um potro falabella com estenose esofágica mural, produto de uma obstrução. O resultado foi exitoso, pois o animal, depois de cinco sessões seguidas de dilatações, tolerou a via oral para alimentos sólidos e assim foi submetido à observação durante seis meses, sem complicações evidentes.

Presencia de obstrucción recurrente de las vías aéreas en un grupo de caballos criollos colombianos con signología respiratoria / Presence of Recurrent Airway Obstruction in a Group of Colombian Native Horses with Respiratory Symptoms / Presença de obstrução recorrente das vias aéreas em um grupo de cavalos criollos colombianos com signologia respiratória

El objetivo de este estudio es determinar la presencia de obstrucción recurrente de las vías aéreas (ORVA) mediante un lavado broncoalveolar (LBA) en un grupo de veinte equinos criollos colombianos con signología respiratoria. A cada animal se le realizó un examen clínico para corroborar la alteración respiratoria y poder realizar posteriormente el LBA. Los resultados obtenidos muestran que un 65% de los animales del estudio resultó positivo a ORVA, teniendo como base la clínica y los resultados del LBA, y que del total de animales positivos un 61,5% presentó esta afección en forma severa. También se encontró una asociación entre la cantidad de neutrófilos en relación con la coloración del líquido del LBA y una relación inversa entre la citología celular de macrófagos y neutrófilos. Se concluye que el caballo criollo colombiano, al igual que otras razas equinas, presenta ORVA, en algunos casos de forma severa, relacionados con factores predisponentes como alojamiento y estabulación.

The purpose of this study was to determine the presence of recurrent airway obstruction (RAO) through bronchoalveolar lavage (BAL) in a group of twenty Colombian native horses with respiratory symptoms. Each animal underwent a clinical examination in order to corroborate the respiratory disturbance and later perform the BAL. The results obtained showed that 65% of the animals under study tested positive for RAO, based on the clinical and BAL results, and that, among the total number of animals that tested positive, 61.5% suffered a severe form of such condition. We also found an association between the number of neutrophils and the color of the BAL fluid, and an inverse relationship between cell cytology of macrophages and neutrophils. It is concluded that the Colombian native horse, like other horse breeds, suffers from RAO, sometimes severely, related to predisposing factors such as accommodation and stabling.

O objetivo deste estudo foi determinar a presença de obstrução recorrente das vias aéreas (ORVA) mediante um lavado bronco alveolar (LBA) em um grupo de vinte equinos criollos colombianos com signologia respiratória. Com cada animal foi realizado um exame clínico para corroborar a alteração respiratória e poder realizar posteriormente o LBA. Os resultados obtidos mostram que o 65% dos animais do estudo teve um resultado positivo a ORVA, tendo como base a clínica e os resultados do LBA e que do total de animais positivos 61,5% apresentou esta afecção em forma severa. Também se encontrou uma associação entre a quantidade de neutrófilos em relação com a coloração do líquido do LBA e uma relação inversa entre a citologia celular de macrófagos e neutrófilos. Conclui-se que o cavalo criollo colombiano, igualmente a outras raças equinas, apresenta ORVA, e em alguns casos de forma severa, relacionados com fatores predisponentes como alojamento e estabulação.