Antioxidant properties of breast milk in a novel in vitro digestion/enterocyte model.

OBJECTIVES: There is good evidence to suggest that human breast milk has antioxidant properties. Our primary goal was to investigate the antioxidant properties of human milk in a combined in vitro digestion/cell culture model that more closely replicates conditions in the gastrointestinal system of the preterm infant. MATERIALS AND METHODS: An in vitro digestion model was developed that incorporates both gastric and intestinal phases, based on reported luminal pH, digestive enzyme levels, and transit times observed in preterm infants. To mimic the human intestinal mucosa, 2 cell lines--Caco-2BBE and HT29-MTX--were cocultured on Matrigel, an artificial basement membrane substrate. Intracellular oxidative stress was measured with 2 broadly selective oxidant-sensitive dyes, and oxidative DNA damage was assessed by means of single-cell gel electrophoresis. RESULTS: Enterocyte differentiation and mucin secretion were observed by 14 seeding of cultures. Direct exposure to digested milk resulted in a loss of transepithelial electrical resistance; however, exogenous mucin mitigated this loss. Data suggested that both milk and digested milk alleviated oxidative stress in the coculture, and both reduced hydrogen peroxide-induced oxidative DNA damage, as demonstrated by the comet assay. CONCLUSIONS: Our results support the hypothesis that breast milk reduces oxidative stress in a cell culture model representative of the intestinal mucosa, and also confirmed the suitability of this combined in vitro digestion/cell culture system for investigating the physiologic effects of enteral nutrients such as breast milk, under conditions similar to those existing in the gastrointestinal system of the preterm infant.

Total spinal anesthesia for cardiac surgery: does it make a difference in patient outcomes?

BACKGROUND: Heart disease is a major cause of morbidity and mortality. While cardiac surgery is a viable treatment option, it is a potent physiological stressor. The surgical stress response may result in patient decompensation and negative patient outcomes. The goal of a novel anesthetic approach, which combines high spinal anesthesia with intrathecal morphine and general anesthesia (TSA), is to attenuate this stress response. PURPOSE: The primary purpose of this pilot study (n = 70) was to describe and compare the outcomes of TSA cardiac surgery with a matched control sample of patients who received the "standard general anesthetic" (GA). METHOD: A retrospective, descriptive, correlational design was used for a matched pair total sample of (n = 70). Following ethics approval, patient consents were obtained and chart review data collection was completed. FINDINGS: TSA patients were more likely to be extubated in the operating room (p < 0.0001) and also had significantly shorter overall duration of endotracheal intubation (p < 0.0008). During the initial 24 hours after surgery, the TSA group received significantly less morphine (p < 0.0001). The mean difference in postoperative hospital length of stay did not reach statistical significance. However, on average, the TSA group was discharged three days earlier than the GA group. CONCLUSION: This evidence highlights the clinical nursing relevance of the type of anesthesia on postoperative care and outcomes. The knowledge gained from these findings will help to enable the multidisciplinary critical care team to anticipate TSA patient outcomes and to facilitate the development of appropriate and effective evidence-based, patient-focused plans of care. This pilot study establishes sound rationale for subsequent larger prospective cohort research of the TSA patient population.

Microlipid-induced oxidative stress in human breastmilk: in vitro effects on intestinal epithelial cells.

OBJECTIVES: To (1) determine whether medium chain fatty acids (Microlipid) added to human breastmilk generates reactive oxygen species (ROS), and (2) measure the physiological effect(s) of Microlipid) (ML)-supplemented human breastmilk in an enterocyte cell culture bioassay. METHODS: ML was added to milk according to manufacturer's recommendations and total hydroperoxides measured at intervals with the FOX 2 and TBARS assays. Physiological effects of supplementation were measured using a human enterocyte cell line (Caco-2BBE) and/or a primary human fetal intestinal cell culture (FHS-74 Int). Endpoints included: intracellular oxidative stress, transepithelial electrical resistance (TEER), apoptosis, and interleukin (IL)-6 production. RESULTS: Immediately postsupplementation, ML did not significantly increase ROS, as determined by both the FOX 2 and TBARS assays. Further, storage of milk + ML at 4 degrees C prevented significant increases in total hydroperoxides. However, by 4 hours postsupplementation at room temperature, both assays revealed significantly higher hydroperoxide and lipid peroxide levels. ML-supplemented milk stored at room temperature for 4 hours had the following effects in cell culture bioassays: elevated oxidative stress, increased rates of apoptosis, decreased transmembrane electrical resistance (TEER) values and, in both cell culture assays, significantly increased secretion of IL-6. CONCLUSIONS: Based on our measurements of extracellular and intracellular ROS, milk supplemented with fresh ML does not induce significant oxidative stress. However, when stored for 4 hours at room temperature, ML induces significant levels of oxidative stress. Decreases in TEER and increases in apoptosis and IL-6 secretion are consistent with ML-induced oxidative stress. It therefore is likely that in clinical situations, if ML-supplemented milk is not administered quickly, the newborn may be placed at greater risk of oxidative stress.

Impact of iron and vitamin C-containing supplements on preterm human milk: in vitro.

Stress due to reactive oxygen species (ROS) may lead to neonatal diseases, such as necrotizing enterocolitis and respiratory distress. Enteral supplements for premature infants (PREM) added to human milk (HM) to increase nutrient content may induce lipid oxidation due to free radical formation via Fenton chemistry. We hypothesized that ferrous iron and vitamin C-containing supplements added to HM in vitro cause oxidation of milk fats, affect intracellular redox balance, and induce DNA damage. Lipid peroxidation in HM was measured by FOX-2 and TBARS assays; fatty acid composition of supplemented HM was measured by gas chromatography. Two cell culture bioassays were used for assessing either intracellular oxidative stress or DNA damage: the former involved Caco-2BBe cells, a secondary differentiated cell line, and the latter utilized FHS-74 Int cells, a primary fetal small intestinal culture. Lipid oxidation products of HM increased after the addition of iron alone, iron and vitamin C, or iron and a vitamin C-containing supplement (Trivisol, TVS). A reduced content of mono and polyunsaturated fatty acids in HM was also observed. Iron, not iron+vitamin C, but iron+TVS induced significant intracellular oxidative stress in FHS-74 Int cells. In contrast, iron, either alone or in combination with TVS or vitamin C, increased DNA damage in Caco-2BBE cells. Iron supplementation may increase oxidative stress in PREM infants and should be given separately from vitamin C-containing supplements.