Microbial Perspectives in Very Low Birth Weight Infants Expressing High Calprotectin Levels
Abstract:
Aims: Pathologic Gastrointestinal (GI) disorders, e.g. Necrotizing Enterocolitis (NEC), represent significant morbidity and mortality in pre-mature infants. Infants with NEC have been described with higher levels of Calprotectin, a marker of mucosal inflammation, than in healthy infants. It has also been reported that microbiota plays a major role in intestinal inflammation observed in different functional GI disorders such as IBD & IBS. The aim of our study was to investigate the role of the microbiota on elevated Calprotectin level in very low birth weight infants.
Methods: Stool samples were collected daily from 5 very low birth weight infants (<1500g) from their 3rd to 60th day of life or until discharged from the hospital. Samples were stored at -20 C until been processed. Calprotectin levels were measured in stool using a standardized ELISA assay (PhiCal). In parallel, bacterial DNA was extracted and then amplified by PCR. PCR amplification of 16S rDNA gene sequences in combination with Denaturing Gradient Gel Electrophoresis (PCR/DGGE) was used to assess the composition of fecal microbiota.
Results: The dynamic of bacterial diversification was time and infant dependant. For example, infant #0003 showed an increase of the bacterial diversity of microbiota profiles composed with a 5 different groups of bacteria at 18th Day
of life and with more than 19 different bacterial groups at 60th Day of life. Calprotectin levels were higher in subjects with severe GI disorders (475 versus 190 μg/g stool). Unfortunately, we were not able to identify specific bacteria or microbial profiles correlated with high Calprotectin levels. Interestingly in all of the subjects, the detection of new bacterial colonizers in infant stools was correlated with temporal elevated Calprotectin levels.
Methods: Stool samples were collected daily from 5 very low birth weight infants (<1500g) from their 3rd to 60th day of life or until discharged from the hospital. Samples were stored at -20 C until been processed. Calprotectin levels were measured in stool using a standardized ELISA assay (PhiCal). In parallel, bacterial DNA was extracted and then amplified by PCR. PCR amplification of 16S rDNA gene sequences in combination with Denaturing Gradient Gel Electrophoresis (PCR/DGGE) was used to assess the composition of fecal microbiota.
Results: The dynamic of bacterial diversification was time and infant dependant. For example, infant #0003 showed an increase of the bacterial diversity of microbiota profiles composed with a 5 different groups of bacteria at 18th Day
of life and with more than 19 different bacterial groups at 60th Day of life. Calprotectin levels were higher in subjects with severe GI disorders (475 versus 190 μg/g stool). Unfortunately, we were not able to identify specific bacteria or microbial profiles correlated with high Calprotectin levels. Interestingly in all of the subjects, the detection of new bacterial colonizers in infant stools was correlated with temporal elevated Calprotectin levels.
Conclusions: Intestinal colonization by bacteria in very low birth weight infants leads to a strong host-bacteria cross talk resulting in measurable modulation of fecal Calprotectin expression.
