Mannose-binding lectin gene polymorphism and its effect on short term outcomes in preterm infants / Polimorfismo do gene da lectina ligante de manose e seu efeito em desfechos de curto prazo em bebês prematuros

Abstract Objective: Mannose-binding lectin, which belongs to the collectin family, is an acute-phase reactant that activates the complement system. This study aimed to investigate the effect of MBL2 gene polymorphism on short-term outcomes in preterm infants. Method: Infants of <37 gestational weeks who were admitted to the neonatal intensive care unit during a two-year period were enrolled in this prospective study. The neonates were categorized into two groups according to their MBL2 genotypes. Normal MBL2 genotype was defined as MBL2 wild-type (AA genotype), whereas mutant MBL2 genotype was defined as MBL2 variant-type (AO/OO genotype). The relationship between MBL2 genotype and short-term morbidity and mortality was evaluated. Results: During the two-year study period, 116 preterm infants were enrolled in this study. In MBL2 variant-type, mannose-binding lectin levels were significantly lower and incidences of mannose-binding lectin deficiency (MBL level < 700 ng/mL) were higher (p < 0.001). In this group, the prevalence of respiratory distress syndrome and mortality was significantly higher (p < 0.001, p = 0.03 respectively). In the MBL2 wild-type group, the prevalence of necrotizing enterocolitis (NEC) was higher (p = 0.01). Logistic regression analyses revealed that MBL2 variant-type had a significant effect on respiratory distress syndrome development (odds ratio, 5.1; 95% confidence interval, 2.2-11.9; p < 0.001). Conclusions: MBL2 variant-type and mannose-binding lectin deficiency are important risk factors for respiratory distress syndrome development in preterm infants. Additionally, there is an association between MBL2 wild-type and NEC. Further studies on this subject are needed.

Resumo Objetivo: A lectina ligante de manose (MBL, do inglês mannose-binding lectin), que pertence à família das colectinas, é um reagente de fase aguda que ativa o sistema complemento. Este estudo teve como objetivo investigar o efeito do polimorfismo do gene MBL2 em desfechos de curto prazo em prematuros. Método: Este estudo prospectivo incluiu crianças com menos de 37 semanas de gestação admitidas na unidade de terapia intensiva neonatal durante dois anos. Os neonatos foram categorizados em dois grupos de acordo com os genótipos do MBL2. O genótipo normal do gene MBL2 foi definido como MBL2 do tipo selvagem (genótipo AA), enquanto o genótipo mutante do gene MBL2 foi definido como o gene variante (genótipo AO/OO). Foi avaliada a relação entre o genótipo MBL2 e a morbidade e mortalidade em curto prazo. Resultados: Durante o período de dois anos, 116 bebês prematuros foram incluídos neste estudo. Os níveis de lectina ligante de manose foram significativamente menores nos variantes do MBL2 e as incidências de deficiência de lectina ligante de manose (nível de MBL < 700 ng/mL) foram maiores (p < 0,001). Nesse grupo, a prevalência de síndrome do desconforto respiratório (SDR) e a mortalidade foram significativamente maiores (p < 0,001, p = 0,03, respectivamente). No grupo MBL2 do tipo selvagem, a prevalência de enterocolite necrosante foi maior (p = 0,01). Análises de regressão logística revelaram que os genes variantes do MBL2 apresentaram um efeito significativo no desenvolvimento da síndrome do desconforto respiratório (odds ratio, 5,1; intervalo de confiança de 95%, 2,2-11,9; p < 0,001). Conclusões: As variantes do MBL2 e a deficiência de lectina ligante de manose são importantes fatores de risco para o desenvolvimento da síndrome do desconforto respiratório em neonatos prematuros. Além disso, existe uma associação entre MBL2 do tipo selvagem e a enterocolite necrosante. Mais estudos são necessários sobre esse assunto.

Enfermedad por coronavirus (COVID-19) en terapia intensiva: informe de un caso / Coronavirus disease (covid-19) in critical care: a case report

Una de las características de la afección pulmonar por enfermedad por coronavirus (COVID-19) es la disociación entre la gravedad de la hipoxemia y el mantenimiento de una mecánica respiratoria relativamente conservada. En este contexto se ha establecido una teoría en relación con dos fenotipos de pacientes con síndrome de distrés respiratorio del adulto (SDRA): un fenotipo Low, caracterizado por baja elastancia y baja reclutabilidad, y un fenotipo High, con características de alta elastancia y alta reclutabilidad. Presentamos el caso de un paciente que cursó internación en la Unidad de Terapia Intensiva de Adultos de nuestro hospital, con clínica, mecánica ventilatoria y patrón tomográfico compatible con el fenotipo Low de SDRA por COVID-19. (AU)

Dissociation between severity of hypoxemia and relative preserved respiratory mechanics is a characteristic observed in lung impairment due to coronavirus disease (COVID-19). Patients with COVID-19 that present adult respiratory distress syndrome (ARDS) are identified for one of two phenotypes according to a theory recently established. The Low phenotype is distinguished by low elastance and low recruitability; and the High phenotype, by high elastance and high recruitability. The case describes a patient admitted in the adult Intensive Care Unit of Hospital Italiano de Buenos Aires with observed symptoms, ventilatory mechanics and tomographic pattern that are compatible with Low phenotype of ARDS due to COVID-19. (AU)

Déficit congénito de proteína de surfactante: caso clínico / Deficiency of surfactant protein: Case report

Introducción: El déficit congénito de surfactante es una entidad de diagnóstico inhabitual en recién nacidos. Se reporta un caso clínico de déficit de proteína B del surfactante, se revisa el estudio, tratamiento y diagnóstico diferencial de los déficit de proteínas del surfactante y enfermedad crónica intersticial de la infancia. Caso clínico: Recién nacido de término que cursa dificultad respiratoria, con velamiento pulmonar recurrente y respuesta transitoria a administración de surfactante. El estudio inmunohistoquímico y genético confirmaron diagnóstico de déficit de proteína B de surfactante. Conclusiones: La enfermedad pulmonar congénita requiere un alto índice de sospecha. El déficit de proteína B de surfactante genera un cuadro clínico progresivo y mortal en la mayoría de los casos, al igual que el déficit de transportador ATP binding cassette, sub-family A member 3 (ABCA3). El déficit de proteína C es insidioso y puede presentarse con un patrón radiológico pulmonar intersticial. Debido a la similitud en el patrón histológico, el estudio genético permite una mayor certeza en el pronóstico y la posibilidad de entregar un adecuado consejo genético.

Introduction: Congenital surfactant deficiency is a condition infrequently diagnosed in newborns. A clinical case is presented of surfactant protein B deficiency. A review is performed on the study, treatment and differential diagnosis of surfactant protein deficiencies and infant chronic interstitial lung disease. Case report: The case is presented of a term newborn that developed respiratory distress, recurrent pulmonary opacification, and a transient response to the administration of surfactant. Immunohistochemical and genetic studies confirmed the diagnosis of surfactant protein B deficiency. Conclusions: Pulmonary congenital anomalies require a high index of suspicion. Surfactant protein B deficiency is clinically progressive and fatal in the majority of the cases, similar to that of ATP binding cassette subfamily A member 3 (ABCA3) deficiency. Protein C deficiency is insidious and may present with a radiological pulmonary interstitial pattern. Due to the similarity in the histological pattern, genetic studies help to achieve greater certainty in the prognosis and the possibility of providing adequate genetic counselling.

Predisposición genética y síndrome de distrés respiratorio agudo pediátrico: nuevas herramientas de estudio genético / Genetic predisposition and Pediatric Acute Respiratory Distress Syndrome: New tools for genetic study

El síndrome de distrés respiratorio agudo (SDRA) es la forma más grave de falla respiratoria. Teóricamente, cualquier noxa pulmonar aguda puede resultar en un SDRA, pero solo un pequeño porcentaje de individuos desarrolla la enfermedad. Sobre este fundamento, factores genéticos han sido implicados en el riesgo de desarrollar SDRA. Basado en la fisiopatología de esta enfermedad, múltiples genes candidatos han sido evaluados como potenciales modificadores, tanto en pacientes como en modelos animales de SDRA. Datos experimentales y estudios clínicos recientes sugieren que variantes de genes implicados en procesos clave de daño tisular, celular y molecular pulmonar pueden influir en la predisposición y el pronóstico del SDRA. Sin embargo, la patogénesis del SDRA pediátrico es compleja y, en consecuencia, es posible anticipar que muchos genes pueden contribuir a ella. Variantes genéticas, tales como polimorfismos de nucleótido simple y variantes del número de copias, están probablemente asociadas con la predisposición al SDRA en niños con lesión pulmonar primaria. El estudio de asociación del genoma completo (GWAS, del inglés Genome-Wide Association Study) puede examinar estas variantes sin sesgos y ayudar a identificar nuevos genes fundamentales y vías patogénicas clave para futuros análisis. Esta aproximación también puede tener implicancias clínicas diagnósticas y terapéuticas, como predecir el riesgo del paciente o desarrollar un enfoque terapéutico personalizado para este grave síndrome.

Acute respiratory distress syndrome (ARDS) is the most severe form of respiratory failure. Theoretically, any acute lung condition can lead to ARDS, but only a small percentage of individuals actually develop the disease. On this basis, genetic factors have been implicated in the risk of developing ARDS. Based on the pathophysiology of this disease, many candidate genes have been evaluated as potential modifiers in patient, as well as in animal models, of ARDS. Recent experimental data and clinical studies suggest that variations of genes involved in key processes of tissue, cellular and molecular lung damage may influence susceptibility and prognosis of ARDS. However, the pathogenesis of pediatric ARDS is complex, and therefore, it can be expected that many genes might contribute. Genetic variations such as single nucleotide polymorphisms and copy-number variations are likely associated with susceptibility to ARDS in children with primary lung injury. Genome-wide association (GWA) studies can objectively examine these variations, and help identify important new genes and pathogenetic pathways for future analysis. This approach might also have diagnostic and therapeutic implications, such as predicting patient risk or developing a personalized therapeutic approach to this serious syndrome.

Surfactant protein B gene polymorphism in preterm babies with respiratory distress syndrome

The etiology of respiratory distress syndrome (RDS) is multifactorial and multigenic. Studies have suggested that polymorphisms and mutations in the surfactant protein B (SP-B) gene are associated with the pathogenesis of RDS. The objectives of this study were to determine and compare the frequencies of SP-B gene polymorphisms in preterm babies with and without RDS. We studied 151 neonates: 79 preterm babies without RDS and 72 preterm newborns with RDS. The following four SP-B gene polymorphisms were analyzed: A/C at -18, C/T at 1580, A/G at 9306, and G/C at nucleotide 8714. The polymorphisms were detected by PCR amplification of genomic DNA and genotyping. The genotypes were determined using PCR-based converted restriction fragment length polymorphisms. The control group consisted of 42 (53 percent) girls and 37 (47 percent) boys. Weight ranged from 1170 to 3260 g and mean gestational age (GA) was 33.9 weeks (range: 29 to 35 weeks and 6 days). The RDS group consisted of 31 (43 percent) girls and 41 (57 percent) boys. Weight ranged from 614 to 2410 g and mean GA was 32 weeks (range: 26 to 35 weeks). The logistic regression model showed that GA was the variable that most contributed to the occurrence of RDS. The AG genotype of the A/G polymorphism at position 9306 of the SP-B gene was a protective factor in this population (OR = 0.1681; 95 percentCI = 0.0426-0.6629). We did not detect differences in the frequencies of the other polymorphisms between the two groups of newborns.

Factores de riesgo para diabetes gestacional en población obstétrica / Risk factors for gestacional diabetes in obstetric popullation

La diabetes mellitus gestacional (DMG) se define como una intolerancia a los carbohidratos de severidad variable, que comienza o que es detectada por primera vez durante el embarazo.Su prevalencia es del 7% según la población estudiada y la prueba de diagnóstico utilizada. En Colombia los datos son inferiores a los descritos en la literatura con reportes que van desde 0,34% a 2,03%. Los hispanos son considerados población de alto riesgo para diabetes gestacional, estosdatos son disímiles de lo reportado en la literatura internacional y sería pertinente preguntarse si esta población considerada como de alto riesgo corresponde únicamente a los hispanos que viven en Estados Unidos ó Europa. No existen estudios propios que determinen cuáles son los factores de riesgo para nuestra población obstétrica. Conociendo la controversia sobre la realización del tamizaje, es importante identificar a través de la revisión de la evidencia los factores de riesgo para diabetes gestacional.

Gestational Diabetes Mellitus (GDM) is defined as carbohydrate intolerance of variable severity with onset or first recognition during pregnancy. it’s the literature reports prevalence of 7%, rate which varies according to the population studied and the diagnostic test utilized. In Colombia the scant data available, shows prevalencerates that are lower ranging from 0,34 % to 2,03 %. In the United States the population identified as Hispanicis considered to be at high risk for GDM. These data are different to the international literature and would be then pertinent to ask if ethnicity as a risk factor and as described before, corresponds only to the Hispanicpoulations that live in the United States or Europe. There aren´t studies available that determine which are therisk factors for our obstetric population. Due to the controversy currently existing in the literatureabout the tests that should be used or not for screening for GDM, it is important to review the current evidence available.

Comparison of surfactant protein B polymorphisms of healthy term newborns with preterm newborns having respiratory distress syndrome

Polymorphisms and mutations in the surfactant protein B (SP-B) gene have been associated with the pathogenesis of respiratory distress syndrome (RDS). The objective of the present study was to compare the frequencies of SP-B gene polymorphisms between preterm babies with RDS and healthy term newborns. We studied 50 preterm babies with RDS (inclusion criteria - newborns with RDS and gestational age between 28 and 33 weeks and 6 days), and 100 healthy term newborns. Four SP-B gene polymorphisms were analyzed: A/C at nucleotide -18, C/T at nucleotide 1580, A/G at nucleotide 9306, and G/C at nucleotide 8714, by PCR amplification of genomic DNA and genotyping by cRFLP. The healthy newborns comprised 42 female and 58 male neonates; 39 were white and 61 non-white. The RDS group comprised 21 female and 29 male preterm neonates; 28 were white and 22 non-white. Weight ranged from 640 to 2080 g (mean: 1273 g); mean gestational age was 31 weeks and 2 days (range: 28-33 weeks and 6 days). When white children were analyzed separately, a statistically significant difference in the G/C polymorphism at 8714 was observed between groups (P = 0.028). All other genotype frequencies were similar for both groups when sex and race were analyzed together. Analysis of the SP-B polymorphism G/C at nucleotide 8714 showed that among white neonates the GG genotype was found only in the RDS group at a frequency of 17 percent and the GC genotype was more frequently found in healthy term newborns. These data demonstrate an association of GG genotype with RDS.

The importance of surfactant on the development of neonatal pulmonary diseases

Pulmonary surfactant is a substance composed of a lipoprotein complex that is essential to pulmonary function. Pulmonary surfactant proteins play an important role in the structure, function, and metabolism of surfactant; 4 specific surfactant proteins have been identified: surfactant proteins-A, surfactant proteins-B, surfactant proteins-C, and surfactant proteins-D. Clinical, epidemiological, and biochemical evidence suggests that the etiology of respiratory distress syndrome is multifactorial with a significant genetic component. There are reports about polymorphisms and mutations on the surfactant protein genes, especially surfactant proteins-B, that may be associated with respiratory distress syndrome, acute respiratory distress syndrome, and congenital alveolar proteinosis. Individual differences regarding respiratory distress syndrome and acute respiratory distress syndrome as well as patient response to therapy might reflect phenotypic diversity due to genetic variation, in part. The study of the differences between the allelic variants of the surfactant protein genes can contribute to the understanding of individual susceptibility to the development of several pulmonary diseases. The identification of the polymorphisms and mutations that are indeed important for the pathogenesis of the diseases related to surfactant protein dysfunction, leading to the possibility of genotyping individuals at increased risk, constitutes a new research field. In the future, findings in these endeavors may enable more effective genetic counseling as well as the development of prophylactic and therapeutic strategies that would provide a real impact on the management of newborns with respiratory distress syndrome and other pulmonary diseases.

O surfactante pulmonar é uma substância composta por um complexo lipoprotéico essencial para a função pulmonar normal. As proteínas do surfactante têm importante papel na estrutura, função e metabolismo do surfactante. São descritas quatro proteínas específicas denominadas surfactante pulmonar-A, surfactante pulmonar-B, surfactante pulmonar-C e surfactante pulmonar-D. Evidências clínicas, epidemiológicas e bioquímicas sugerem que a etiologia da síndrome do desconforto respiratório é multifatorial com um componente genético significativo. Existem na literatura algumas descrições sobre a presença de polimorfismos e mutações em genes dos componentes do surfactante, particularmente no gene da surfactante pulmonar-B, os quais parecem estar associados à síndrome do desconforto respiratório, síndrome da angustia respiratória aguda e proteinose alveolar congênita. Diferenças individuais relacionadas à síndrome do desconforto respiratórioe síndrome da angustia respiratória aguda e à resposta dos pacientes ao tratamento podem refletir diversidade fenotípica, devido, parcialmente, à variação genética. O estudo das diferenças entre as variantes alélicas dos genes das proteínas do surfactante pode ajudar na compreensão das variabilidades individuais na susceptibilidade ao desenvolvimento de várias doenças pulmonares. A determinação de quais polimorfismos e mutações são, de fato, importantes na patogênese das doenças relacionadas à disfunção das proteínas do surfactante e a possibilidade da realização da genotipagem em indivíduos de alto risco constitui um novo campo de pesquisa, que pode permitir, futuramente, um aconselhamento genético mais efetivo, resultando no desenvolvimento de estratégias profiláticas e terapêuticas que representem um impacto real no manejo dos recém-nascidos portadores da síndrome do desconforto respiratório e outras patologias pulmonares.