ABSTRACT
The establishment of the gut microbiota immediately after birth is a dynamic process that may impact lifelong health. At this important developmental stage in early life, human milk oligosaccharides (HMOs) serve as specific substrates to shape the gut microbiota of the nursling. The well-orchestrated transition is important as an aberrant microbial composition and bacterial-derived metabolites are associated with colicky symptoms and atopic diseases in infants. Here, we study the trophic interactions between an HMO-degrader, Bifidobacterium infantis and the butyrogenic Anaerostipes caccae using carbohydrate substrates that are relevant in the early life period including lactose and total human milk carbohydrates. Mono- and co-cultures of these bacterial species were grown at pH 6.5 in anaerobic bioreactors supplemented with lactose or total human milk carbohydrates. A. caccae was not able to grow on these substrates except when grown in co-culture with B. infantis, leading to growth and concomitant butyrate production. Two levels of cross-feeding were observed, in which A. caccae utilised the liberated monosaccharides as well as lactate and acetate produced by B. infantis. This microbial cross-feeding points towards the key ecological role of bifidobacteria in providing substrates for other important species that will colonise the infant gut. The progressive shift of the gut microbiota composition that contributes to the gradual production of butyrate could be important for host-microbial crosstalk and gut maturation.
Subject(s)
Bifidobacterium longum subspecies infantis/metabolism , Clostridiales/metabolism , Lactose/metabolism , Milk, Human/metabolism , Oligosaccharides/metabolism , Bifidobacterium longum subspecies infantis/genetics , Bifidobacterium longum subspecies infantis/growth & development , Bioreactors/microbiology , Clostridiales/genetics , Clostridiales/growth & development , Coculture Techniques , Culture Media/metabolism , HumansABSTRACT
BACKGROUND: Hyperhaemolytic transfusion reaction (HHTR) has been well described in patients with sickle cell disease (SCD). It is characterised by a decrease in haemoglobin concentration to levels below those before transfusion and a fall in the absolute reticulocyte count. As red blood cells (RBC) alloantibodies are typically not detected in post-transfusion samples in acute forms of HHTR, we have previously proposed that both the transfused and autologous RBCs cells (HbSS/reticulocytes) are destroyed by activated macrophages. CASE REPORTS: We report a patient with SCD who presented with vaso-occlusive sickle cell crisis and developed a severe HHTR attributable to anti-Fy3. In addition to the usual supportive measures, the patient was treated with intravenous immunoglobulin (IVIG) and steroids. Serum ferritin levels were measured as an aspecific marker of macrophage activation. RESULTS: Steroids and IVIG were effective in managing HHTR. Ferritin levels were high at the time of haemolysis, (>10000 µg L(-1)) whereas recovery and cessation of haemolysis correlated with a decrease in ferritin levels. CONCLUSION: Serum ferritin values >10,000 µg L(-1) are considered pathognomic for conditions characterised by abnormal macrophage activation. In our case, serum ferritin levels correlate well with the disease activity and clinical response. This further supports our previous proposal that the activated macrophages play an important role in HHTR. Serum ferritin is a nonspecific marker of inflammation. A rapid specific bio-marker to measure the activity of macrophages in SCD in HHTR is desirable, and this area warrants further investigation.
