Abstract: The mammary gland and maternal milk are the product of millions of years of evolution that resul ted in an optimal composition that sustains the growth and development of newborns and infants. Maternal milk supports the growth, adaptation and survival of this immature organism. Recent studies have detected 1606 different proteins in human milk, most of them synthesized in the acini of the glandular tissue while others originate from distant organs such as the lymphoid tissue and the digestive tract. Maternal milk enzymes modify its proteins and liberate peptides with antimicrobial, antihypertensive or stimulatory activities. This proteolytic activity occurs at specific sites in peptide chains. To prevent the extemporaneous activation of these proteolytic enzymes, that would result in inflammatory processes, maternal milk also contains inhibitory peptides that together with the stimulatory peptides conform a complex regulatory system. Some enzymes in maternal milk main tain their activity in the gastrointestinal tract of infants and compensate for the decreased activity of digestive tract enzymes in newborns. Thus, the milk enterokynase stimulates the release of pancreatic proteases as it induces the liberation of cholecystokynin/pancreozymin. The bile salt-activated lipase of human milk is activated in the duodenum by the infants’ bile salts and partially compensates for the low levels of pancreatic lipase in newborns. These milk enzymes probably contribute to the nutrition of premature infants as they increase the availability of amino acids and peptides in their upper gastrointestinal tract; furthermore, as their intestinal epithelium is more permeable to peptides and partially digested protein this may help induce immune tolerance. The most relevant issues in the physiology and composition of the maternal milk are presented in this review.

Resumen: La glándula mamaria y la leche materna son el resultado de millones de años de una evolución que llevó a una composición óptima para el crecimiento y desarrollo de recién nacidos y lactantes; la leche materna favorece el crecimiento, la adaptación y la supervivencia de su organismo y de sus órganos inmaduros. Análisis recientes han demostrado en ella la presencia de 1606 proteínas que en su mayoría son sintetizadas en los acinos de la glándula mamaria aunque otras proteínas y péptidos provienen de órganos como el sistema linfático y el aparato digestivo. La composición de la leche materna incluye enzimas que modifican sus proteínas y originan péptidos antimicrobianos, antihipertensivos y estimuladores del metabolismo. Esta actividad proteolítica actúa en sitios específicos de las cadenas peptídicas de la proteína de la leche. La activación extemporánea de estos enzimas en los acinos es regulada por péptidos inhibidores y activadores que previenen procesos inflamatorios. Algunos enzimas de la leche actúan en el tubo digestivo de recién nacidos y lactantes y complemen tan la menor concentración y actividad de sus propios enzimas digestivos. Así, la enteroquinasa de la leche estimula la liberación de enzimas pancreáticos (mediada por el estímulo de la colecistoquinina-pancreozimina); la lipasa activada por las sales biliares complementa la baja producción de lipasa pancreática. Estas actividades probablemente facilitan la nutrición de los prematuros, cuyo tubo di gestivo es más permeable a las proteínas parcialmente hidrolizadas y cuyas actividades enzimáticas y factores defensivos locales no han alcanzado su plena madurez. Esto también puede estimular en ellos la tolerancia inmunológica. En este artículo se presentan los aspectos fisiológicos relevantes de la leche materna, y los avances en el conocimiento de su composición, para el cabal conocimiento del pediatra de esta importante materia.

Probiotics have been defined as live microorganisms which, when ingested in adequate numbers, confer health benefits to the host. They are currently consumed without any age restrictions and adverse effects such as sepsis, a marker of the risk of invasion of the bloodstream, are extremely infrequent. However, some health professionals express doubts about probiotics being truly innocuous. This review discusses the incidence of sepsis secondary to probiotics use, mainly lactobacilli and bifidobacteria, evaluated through molecular biology or classic culture techniques, showing that sepsis in large numbers of individuals along decennia is extremely low, of the order of 0,02% en some centers or as low as 1 case/million population in France. These data are important considering the use different species and strains of these microorganisms. Few studies which have reported other adverse effects but many of these have problems with their design that cast doubt about the validity of their results. On the contrary, it has been shown that probiotic microorganisms exert positive stimulatory effects on innate and acquired immunity, with decrease of the manifestations of atopy and eczema. These positive effects are further evidenced by the beneficial effects of many species of probiotics in preventing necrotizing enterocolitis in patients as functionally labile as premature-born babies.

Los probióticos son microorganismos vivos que cuando son administrados en cantidades adecuadas confieren beneficios a la salud del huésped. Su empleo es muy amplio en todas las edades, y los episodios adversos asociados con ellos, incluyendo casos de sepsis, que hagan suponer un riesgo real y manifiesto de invasión del torrente sanguíneo o algún tipo de contagio son muy infrecuentes. Sin embargo, algunos profesionales de la salud manifiestan dudas respecto de su inocuidad. Esta revisión revela que la incidencia de sepsis por probióticos, principalmente lactobacilos y bifidobacterias, evaluada en casuísticas numerosas a lo largo de decenios usando métodos de biología molecular o cultivos, es muy baja: del orden de 0,021% en algunas estadísticas y podría llegar hasta 1 caso/1.000.000 de habitantes. Estos datos son importantes teniendo en cuenta el empleo masivo de diversas especies y cepas, sin restricciones de ninguna especie y en todas las edades. Algunos estudios que comunican otros efectos adversos tienen problemas de diseño que ponen en duda su validez. Por el contrario, se ha demostrado que los probióticos ejercen efectos positivos estimulando la inmunidad innata y adquirida, en el tratamiento de la atopia y eccema y en la prevención de la enterocolitis necrosante en sujetos tan vulnerables como los prematuros.

La obesidad está asociada con una inflamación de bajo grado que contribuye al desarrollo de la insulino-resistencia y de la diabetes. El objetivo de este estudio fue evaluar las concentraciones plasmáticas de ácidos grasos saturados (AGS), monoinsaturados (AGMI) y poliinsaturados (AGPI) en sujetos obesos asintomáticos y determinar el ratio ácido araquidónico/ácido eicosapentanoico [ARA/EPA] como un posible marcador de inflamación, con su eventual asociación con los niveles de proteína C reactiva ultrasensible (PCRus). Se reclutaron 14 sujetos obesos (34,4 ± 11.1 años; índice de masa corporal: 36,0 ± 4,5 kg/m2) y 12 normopeso (30,6 ± 7.8 años; índice de masa corporal: 23,6 ± 2,4 kg/m2); las concentraciones plasmáticas de ácidos grasos fueron determinados por cromatografía de gases. Los niveles de PCRus fueron más elevadas en los sujetos obesos (p=0,01) y correlacionaron con el contenido de grasa corporal. Los porcentajes relativos de AGS, AGMI, AGPI no se vieron afectados en los sujetos obesos, pero sus concentraciones plasmáticas se incrementaron en comparación con el grupo control. Sin embargo, no se observaron diferencias en las concentraciones de PUFAs de cadena larga (DHA, EPA y ARA) ni en el ratio ARA/EPA en los sujetos obesos. Estas observaciones no apoyan el uso del ratio ARA/EPA como un marcador de inflamación de bajo grado evaluada por PCRus en este grupo de sujetos obesos asintomáticos.

Obesity is associated with a low grade inflammation which contributes to the development of insulin resistance and diabetes. The aim of this study was to assess the total saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs) in plasma from asymptomatic obese subjects and to determine the arachidonic/eicosapentanoic acid ratio [ARA/EPA] as a marker of inflammation, and its eventual association with ultrasensitive CRP. Fourteen obese (34.4 ± 11.1y.; BMI: 36.0 ± 4,5 kg/m2) and 12 normal-weight (30.6 ± 7.8y.; BMI: 23,6± 2,4 kg/m2) subjects were recruited and their plasma fatty acids were determined by gas chromatography. usCRP was higher in the obese subjects (p=0,01) and correlates with their body fat content. The percentages of SFAs, MUFAs, PUFAs were not affected in the obese subjects but their concentrations were increased, compared with the control group. However, no differences in the long chain PUFAs (DHA and EPA) concentrations or in the plasmatic ARA/EPA ratio were observed in these subjects. These observations do not support a relation between the ARA/EPA ratio and the presence of low grade inflammation evaluated by plasma usCRP in this group of asymptomatic obese subjects.

Se analizó la biodiversidad de especies de Lactobacillus en muestras de calostro de 116 madres chilenas mediante PCR y secuenciación del rDNA 16S. Se aislaron lactobacilos en 55,3% de las muestras, con concentraciones de 3,33 ± 0,55 (log UFC / ml). Las especies predominantes fueron L. plantarum (64%), L. fermentum (16%) y L. pentosus (9%). 28% de las cepas aisladas fueron resistentes a pH gástrico y a las sales biliares, lo que sugiere que podrían ser utilizados como probióticos.

The biodiversity of Lactobacillus spp. in colostrum samples from 116 Chilean mothers was analyzed by PCR and 16S rDNA sequencing. Lactobacilli were isolated in 55.3% of the samples, with concentrations of 3.33 ± 0.55 (log CFU/ml). The predominant species were L. plantarum (64%), L. fermentum (16%) and L. pentosus (9%). 28% of the isolated strains were resistant to gastric pH and bile salts, suggesting that they could be used as probiotics.

Um modelo preditivo previamente calculado para o risco de saúde selecionou crianças que sofriam de 4 a 5 vezes mais de doenças do que seus pares não selecionados. Resultados preliminares sugeriram que esse risco referia-se a sintomas neuróticos maternos. Para avaliar esta hipótese, 52 mães, cuja criança tinha um escore preditivo positivo (grupo 1) e 52 nas quais este escore era negativo (grupo 2), foram avaliados por meio do Questionário de Saúde Geral de Goldberg (GHQ-30). Um total de 41,9% e 20,5% das mães do grupo 1 e 2, respectivamente, tiveram escores acima de 11 pontos no GHQ-30, o qual ficou estabelecido como o ponto de corte. Conclui-se que entre famílias pobres da cidade de Santiago, mães de crianças com alto risco de diarréia persistente tiveram freqüência aumentada de sistemas neuróticos deficitários. Novos programas visando esse tipo de crianças deveriam incluir apoio psicológico para suas mães.

A previously calculated predictive model for health risk selects infants who suffer 4-5 times more morbidity than their unselected peers. Preliminary results suggested that this risk is related to maternal neurotic symptomatology. To evaluate this hypothesis, 52 consecutive mothers whose infants had a positive predictive score (Group 1) and 52 in whom this was negative (Group 2) were evaluated by means of Goldberg's General Health Questionnaire (GHQ - 30). A total of 41.9% and 20.5% of the mothers in Groups 1 and 2, respectively, scored above 11 points in GHQ-30, established as the cut off point. It is concluded that among poor urban families in Santiago mothers of infants with high risk of persistent diarrhoea have increased frequency of detectable neurotic symptoms. New programs aimed at this type of infant should include psychological support for their mothers.

Um modelo preditivo previamente calculado para o risco de saúde selecionou crianças que sofriam de 4 a 5 vezes mais de doenças do que seus pares não selecionados. Resultados preliminares sugeriram que esse risco referia-se a sintomas neuróticos maternos. Para avaliar esta hipótese, 52 mães, cuja criança tinha um escore preditivo positivo (grupo 1) e 52 nas quais este escore era negativo (grupo 2), foram avaliados por meio do Questionário de Saúde Geral de Goldberg (GHQ-30). Um total de 41,9% e 20,5% das mães do grupo 1 e 2, respectivamente, tiveram escores acima de 11 pontos no GHQ-30, o qual ficou estabelecido como o ponto de corte. Conclui-se que entre famílias pobres da cidade de Santiago, mães de crianças com alto risco de diarréia persistente tiveram freqüência aumentada de sistemas neuróticos deficitários. Novos programas visando esse tipo de crianças deveriam incluir apoio psicológico para suas mães.

A previously calculated predictive model for health risk selects infants who suffer 4-5 times more morbidity than their unselected peers. Preliminary results suggested that this risk is related to maternal neurotic symptomatology. To evaluate this hypothesis, 52 consecutive mothers whose infants had a positive predictive score (Group 1) and 52 in whom this was negative (Group 2) were evaluated by means of Goldberg's General Health Questionnaire (GHQ - 30). A total of 41.9% and 20.5% of the mothers in Groups 1 and 2, respectively, scored above 11 points in GHQ-30, established as the cut off point. It is concluded that among poor urban families in Santiago mothers of infants with high risk of persistent diarrhoea have increased frequency of detectable neurotic symptoms. New programs aimed at this type of infant should include psychological support for their mothers.