Comparison of breast-feeding and formula feeding on intestinal and hepatic cholesterol metabolism in neonatal pigs

Neonatal Diet Impacts the Large Intestine Luminal Metabolome at Weaning and Post-Weaning in Piglets Fed Formula or Human Milk

The impact of human milk (HM) or dairy milk-based formula (MF) on the large intestine’s metabolome was not investigated. Two-day old male piglets were randomly assigned to HM or MF diet (n = 26/group), from postnatal day (PND) 2 through 21 and weaned to a solid diet until PND 51. Piglets were euthanized at PND 21 and PND 51, luminal contents of the cecum, proximal (PC) and distal colons (DC), and rectum were collected and subjected to metabolomics analysis. Data analyses were performed using Metaboanalyst. In comparison to MF, the HM diet resulted in higher levels of fatty acids in the lumen of the cecum, PC, DC, and rectum at PND 21. Glutamic acid was greater in the lumen of cecum, PC, and DC relative to the MF group at PND 21. Also, spermidine was higher in the DC and rectal contents of HM relative to MF at PND 21. MF diet resulted in greater abundances of amino acids in the cecal lumen relative to HM diet at PND 21. Additionally, several sugar metabolites were higher in various regions of the distal gut of MF fed piglets relative to HM group at PND 21. In contrast, at PND 51, in various regions there were higher levels of erythritol, maltotriose, isomaltose in HM versus MF fed piglets. This suggests a post weaning shift in sugar metabolism that is impacted by neonatal diet. The data also suggest that infant diet type and host-microbiota interactions likely influence the lower gut metabolome.

Breastfeeding in Infancy and Lipid Profile in Adolescence

OBJECTIVES

Breast milk has higher cholesterol than formula. Infants who are breastfed have different cholesterol synthesis and metabolism in infancy than infants who are formula fed. Little is known as to whether breastfeeding is associated with subsequent lipid profile, independent of adiposity. We assessed the association of breastfeeding in early infancy with lipid profile and adiposity at ∼17.5 years in a setting where exclusive breastfeeding is not associated with higher socioeconomic position.

METHODS

We used multivariable linear regression with multiple imputation and inverse probability weighting to examine the associations of contemporaneously reported feeding in the first 3 months of life (exclusive breastfeeding [7.5%], mixed feeding [40%], or always formula feeding [52%]) with lipids and adiposity at ∼17.5 years in 3261 participants in the Hong Kong Chinese birth cohort Children of 1997, adjusting for sex, birth weight, gestational weeks, parity, pregnancy characteristics, parents' highest education, mother's place of birth, and age at follow-up.

RESULTS

Exclusive breastfeeding, but not mixed feeding at 0 to 3 months, compared with formula feeding was associated with lower total cholesterol and low-density lipoprotein cholesterol but not with high-density lipoprotein cholesterol at ∼17.5 years. BMI and fat percentage measured by bioimpedance did not differ by type of infant feeding.

CONCLUSIONS

Exclusive breastfeeding in early infancy may promote a healthier lipid profile in late adolescence through mechanisms unrelated to adiposity, implicating its potential long-term benefits for cardiovascular health.

Evaluation of Dietary Bovine Milk Fat Globule Membrane Supplementation on Growth, Serum Cholesterol and Lipoproteins, and Neurodevelopment in the Young Pig

Introduction: Milk fat globule membrane (MFGM) is a protein- and phospholipid-rich membrane that surrounds the lipid droplet in milk. We have previously reported that a diet composed of a combination of prebiotics, bovine MFGM (bMFGM), and lactoferrin (bLf) supported brain development in young pigs. Due to the growing interest of its potential benefits in neurodevelopment, the present study focused on the effects of dietary bMFGM alone using the pig as a translational model. Methods: Male pigs were provided ad libitum access to milk replacer with added whey protein-lipid concentrate (source of bMFGM) at 0 (CONT), 2.5 (MFGM-2.5), or 5 (MFGM-5.0) g/L from postnatal day (PND) 2 to 31. Blood was collected from pigs at PND 15 and 31, and pigs underwent behavioral testing using the novel object recognition task starting at PND 25. At PND 31, magnetic resonance imaging was conducted and animals were subsequently euthanized for tissue collection. Results: No group differences in body weight gain or milk intake were observed. At PND 31, few group differences were detected in absolute and relative brain volumes, brain water diffusivity outcomes, or behavioral parameters using the novel object recognition task. Serum lipoprotein was higher in pigs receiving diets with added dietary bMFGM compared with the CONT group. Serum cholesterol and high-density lipoprotein significantly higher (all P < 0.05) in the MFGM-2.5 compared with the CONT group. However, cholesterol concentrations within the brain prefrontal cortex and hippocampus did not differ among dietary groups. Conclusion: In this pig model, dietary supplementation with bMFGM was well-tolerated and supported growth and dietary intake similar to the control formula. Added dietary bMFGM was associated with increased serum lipoprotein, but no group differences in early brain cholesterol concentrations, macrostructure, microstructure, or recognition memory pigs at 31 days of age. Further examination of longitudinal brain development and myelination in the pig, particularly at later ages/maturation, is warranted.

Infant Formula Feeding Increases Hepatic Cholesterol 7α Hydroxylase (CYP7A1) Expression and Fecal Bile Acid Loss in Neonatal Piglets

Background

During the postnatal feeding period, formula-fed infants have higher cholesterol synthesis rates and lower circulating cholesterol concentrations than their breastfed counterparts. Although this disparity has been attributed to the uniformly low dietary cholesterol content of typical infant formulas, little is known of the underlying mechanisms associated with this altered cholesterol metabolism phenotype.

Objective

We aimed to determine the molecular etiology of diet-associated changes in early-life cholesterol metabolism with the use of a postnatal piglet feeding model.

Methods

Two-day-old male and female White-Dutch Landrace piglets were fed either sow milk (Sow group) or dairy-based (Milk group; Similac Advance powder) or soy-based (Soy group; Emfamil Prosobee Lipil powder) infant formulas until day 21. In addition to measuring serum cholesterol concentrations, hepatic and intestinal genes involved in enterohepatic circulation of cholesterol and bile acids were analyzed by real-time reverse-transcriptase polymerase chain reaction and Western blot. Bile acid concentrations were measured by liquid chromatography-mass spectrometry in serum, liver, and feces.

Results

Compared with the Sow group, hepatic cholesterol 7α hydroxylase (CYP7A1) protein expression was 3-fold higher in the Milk group (P < 0.05) and expression was 10-fold higher in the Soy group compared with the Milk group (P < 0.05). Likewise, fecal bile acid concentrations were 3-fold higher in the Soy group compared with the Milk group (P < 0.05). Intestinal mRNA expression of fibroblast factor 19 (Fgf19) was reduced in the Milk and Soy groups, corresponding to 54% and 67% decreases compared with the Sow group. In the Soy group, small heterodimer protein (SHP) protein expression was 30% lower compared with the Sow group (P < 0.05).

Conclusions

These results indicate that formula feeding leads to increased CYP7A1 protein expression and fecal bile acid loss in neonatal piglets, and this outcome is linked to reduced efficacy in inhibiting CYP7A1 expression through FGF19 and SHP transcriptional repression mechanisms.

Oral cyclosporine A in neonatal swines for transplantation studies

The purpose of this study is to define the optimal dose of oral cyclosporine A (CsA) microemulsion in newborn swine for transplantation studies and to describe its pharmacokinetics and acute renal effects in short-term administration. Thirteen neonatal pigs were randomized into four groups: one control and three groups with CsA administration at 4, 8 and 12 mg/kg/d for 15 days (D). Blood samples were collected on D 0, 2, 4, 9 and 14 to determine the changes of the CsA trough concentrations, the creatinine (Cr) and blood urea nitrogen (BUN) serum concentrations. On D 14, blood samples were collected every hour from 1 h to 10 h after CsA administration to determine the area under the curve (AUC). On D 15, kidneys were removed for histological analysis. We observed a stabilization of CsA trough concentrations from D 4 to D 14. On D 14, in the three treated groups, CsA trough concentrations were 687 ± 7, 1200 ± 77 and 2211 ± 1030 ng/ml, respectively; AUC (0-10 h) were 6721 ± 51 ng·h/ml in group 4 mg/kg/d, 13431 ± 988 ng·h/ml in group 8 mg/kg/d and 28264 ± 9430 ng·h/ml in group 12 mg/kg/d. Cr concentrations were not significantly different among the four groups; but compared to control group, BUN concentrations of the three treated groups increased significantly. CsA was well tolerated; neither acute, severe adverse event nor renal histological abnormality was observed. In conclusion, a 15-d course of oral CsA treatment ranged from 4 to 12 mg/kg/d is safe for newborn pigs, which need much lower CsA dose than adult pigs to reach comparable trough level and AUC. As immunosuppressive therapy in newborn pigs, we recommend a CsA dose of 4 mg/kg/d to achieve a trough blood concentration between 400 and 800 ng/ml.

Effects of early cholesterol intake on cholesterol biosynthesis and plasma lipids among infants until 18 months of age

BACKGROUND

The endogenous cholesterol fractional synthesis rate (FSR) is related inversely to infant dietary cholesterol at 4 months of age; however, it remains to be established whether this effect is permanent, possibly contributing to later hypercholesterolemia.

OBJECTIVE

To determine whether levels of dietary cholesterol in infancy induced changes in FSR and plasma lipid levels that persisted at 18 months.

METHODS

A prospective clinical trial was conducted with 47 infants, from their first week of life until 18 months of age, who received human milk (HM) until weaned (n = 15) or were randomized to receive modified cow's milk formula (MCF) with added cholesterol (n = 15) or cow's milk formula (CF) (n = 17) for 12 months. Cholesterol contents of HM, MCF, and CF were 120, 80, and 40 mg/L, respectively. FSR and plasma lipid levels were measured at 4 and 18 months.

RESULTS

At 4 months, total cholesterol and low-density lipoprotein cholesterol levels were higher for infants fed HM and MCF, compared with CF. High-density lipoprotein cholesterol levels were higher in the MCF group than in the HM and CF groups. FSR in the HM group (0.034 +/- 0.005 pools per day) was lower than that in the CF group (0.052 +/- 0.005 pools per day). There was no difference between the HM and MCF (0.047 +/- 0.005 pools per day) groups or between the MCF and CF groups. At 18 months, there were no differences in FSRs or plasma lipid profiles between the groups.

CONCLUSION

Although cholesterol intake before weaning affects FSRs and plasma lipid profiles at 4 months, these differences do not persist after weaning to an unrestricted diet at 18 months. This provides additional evidence that there is no imprinting of FSR in infancy with differing dietary levels of cholesterol.

Dietary phospholipid alters biliary lipid composition in formula-fed piglets

Plasma cholesterol, arachidonic acid (AA, 20:4n-6), and docosahexaenoic acid (DHA, 22:6n-3) are higher in breast-fed infants than in infants fed formula without cholesterol, AA, or DHA. This study investigated differences in plasma, hepatic, and bile lipids and phospholipid fatty acids, and expression of hepatic proteins involved in sterol metabolism that result from feeding formula with cholesterol with egg phospholipid to provide AA and DHA. For this study, three groups of piglets were evaluated: piglets fed formula with 0.65 mmol/L cholesterol, the same formula with 0.8% AA and 0.2% DHA from egg phospholipid, and piglets fed sow milk. Piglets fed the formula with phospholipid AA and DHA had higher plasma high density lipoprotein, but not apoprotein (apo) B cholesterol or triglyceride; higher bile acid and phospholipid concentrations in bile; and higher liver and bile phospholipid AA and DHA than piglets fed formula without AA and DHA (P < 0.05). Hydroxy methylglutaryl (HMG)-CoA reductase and 7-alpha-hydroxylase, the rate-limiting enzymes of cholesterol and bile acid synthesis, respectively, and low density lipoprotein receptor mRNA levels were not different between piglets fed formula without and with phospholipid AA and DHA, but HMG-CoA reductase and 7alpha-hydroxylase mRNA were higher, and plasma apo B containing lipoprotein cholesterol was lower in all piglets fed formula than in piglets fed milk. These studies show that supplementing formula with AA and DHA from egg phospholipid alters bile metabolism by increasing the bile AA and DHA, and bile acid and phospholipid.

Effect of feeding diets of varying fatty acid composition on apolipoprotein expression in newborn swine

The purpose of this study was to determine the effect of chronic (1 wk) feeding of dietary triacylglycerol (TG) of varying fatty acid composition on small intestinal and hepatic apolipoprotein expression, as well as serum lipid and apolipoprotein concentrations, in newborn swine. Two-day-old female swine were fed one of three diets by gavage with the following lipid composition: medium-chain TG (MCT; MCT oil), intermediate-chain saturated TG (ICST; coconut oil), and long-chain polyunsaturated TG (LCPUT; safflower oil) at 753 kJ . kg-1 . day-1 with 51% of energy from fat. After 1 wk, serum lipids and apolipoprotein concentrations were measured, and jejunal apolipoprotein B (apo B) and apo A-I mass and apo B, apo A-I, apo A-IV, and apo C-III synthesis were measured. Liver was processed for determination of apo B and apo A-I mass and apo B, apo A-I, apo C-III, and beta-actin mRNA abundance by slot blot hybridization. Compared with the MCT and LCPUT groups, the ICST group had higher total serum cholesterol, TG, high-density lipoprotein (HDL)-cholesterol, and apo A-I concentrations. There were no differences among the three groups for intestinal apolipoprotein mass or synthesis. In liver, apo A-I mass was highest in the ICST group. Liver apo A-I and apo C-III mRNA abundance was highest in the ICST group. Among all three groups, hepatic apo A-I mass correlated significantly with plasma HDL-cholesterol concentrations, and serum TG concentrations correlated with hepatic apo C-III mRNA abundance. In conclusion, we found that in the newborn piglet, chronic feeding of ICST increases serum total cholesterol, TG, HDL-cholesterol, and apo A-I concentrations and hepatic expression of apo A-I and apo C-III mRNA, compared with feeding of MCT or LCPUT. We speculate that increased hepatic apo A-I expression may contribute to the higher serum HDL and apo A-I concentrations in the ICST animals. Increased hepatic expression of apo C-III with ICST feeding may contribute to the higher serum TG concentrations by apo C-III-mediated inhibition of the catabolism of triacylglycerol-rich lipoproteins.

Dietary triacylglycerols with palmitic acid (16:0) in the 2-position increase 16:0 in the 2-position of plasma and chylomicron triacylglycerols, but reduce phospholipid arachidonic and docosahexaenoic acids, and alter cholesteryl ester metabolism in formula-Fed piglets

Milk triacylglycerols have an unusual fatty acid distribution, with palmitic acid (16:0) esterified predominately at the center (sn-2) position. Other dietary triacylglycerols contain 16:0 predominantly at the sn-1,3 positions. This study was designed to evaluate the effect of formula triacylglycerol fatty acid distribution on the composition and distribution of plasma lipoprotein fatty acids in piglets fed formula containing synthesized triacylglycerols or palm olein oil with about 32 or 4.2% 16:0, respectively, in fatty acids at the sn-2 position, with comparison to piglets fed sow's milk. Feeding formula with 16:0 at the triglyceride sn-2 position or sow's milk resulted in higher chylomicron triacylglycerol sn-2 16:0 than when palm olein was fed. This suggests that dietary triacylglycerol sn-2 position fatty acids are conserved during digestion, absorption and reassembly to chylomicron triacylglycerols. The increased chylomicron triacylglycerol sn-2 position 16:0 in piglets fed synthesized triacylglycerols was accompanied by lower chylomicron triacylglycerol arachidonic and docosahexaenoic acid than in piglets fed formula with palm olein, suggesting an interaction between dietary triacylglycerol saturated fatty acid distribution and (n-6) and (n-3) fatty acid transport.

Cholesterol and fatty acid metabolism in piglets fed sow milk or infant formula with or without addition of cholesterol

Several studies have reported that plasma cholesterol and phospholipid (PL) levels of arachidonic acid (20:4n-6) are lower and PL levels of linoleic acid (18:2n-6) are higher in infants fed formula than in infants fed human milk. Plasma cholesterol level and possibly the dietary intake of cholesterol could be related to plasma PLn-6 fatty acid metabolism because plasma PL 18:2n-6 is used for esterification of plasma free cholesterol. Whether the low cholesterol content of infant formula as compared with human milk is related to the difference in plasma n-6 fatty acid levels between infants fed human milk and infants fed formula is not known. This study determined the effect of feeding formula with 0.05 mmol cholesterol/L, formula with 1.09 mmol cholesterol/L, or sow milk with 0.34 mmol cholesterol/L on plasma, liver, and bile lipid fatty acid levels and liver low-density lipoprotein (LDL) receptor mass in piglets. Liver microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity and plasma lathosterol were assayed as indices of liver and body cholesterol synthesis, respectively. Formula with or without cholesterol added, or sow milk, was fed from birth to 18 days of age. Providing cholesterol in the formula did not correct the significantly lower plasma cholesterol or plasma and liver PL 20:4n-6 levels associated with formula feeding. The liver total cholesterol and cholesteryl esters (CE), biliary bile acid, and PL concentrations were significantly higher and the liver HMG CoA reductase activity and plasma lathosterol:cholesterol ratio were significantly lower in piglets fed the formula with cholesterol than in piglets fed the formula without cholesterol added.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of developmental changes and early nutrition on cholesterol metabolism in infancy: a review

Plasma cholesterol levels usually range between 50 and 100 mg/dl at birth, with the cholesterol approximately equally distributed between low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Plasma cholesterol increases rapidly over the first days after birth, predominantly due to an increase in cholesterol with LDL, irrespective of whether the infant is breast fed or fed with infant formulas. With continued feeding, plasma cholesterol becomes progressively, and significantly, higher in infants who are breast fed compared to those fed low-cholesterol, polyunsaturated fatty acid-rich infant formula. Studies in the developing young of other species have suggested that up-regulation of cholesterol synthesis, or turnover and excretion, at stages when these pathways are acquiring functional maturity may have lasting effects on cholesterol metabolism. The information available, however, indicates the diet-related differences in plasma cholesterol of the more mature human newborn are temporal in nature and probably not of significance to adult cardiovascular disease. Infants born early in the third trimester of gestation, however, are at risk for marked elevations in plasma cholesterol, with stimulation of endogenous cholesterol biosynthesis, as a result of the intravenous nutrition required to sustain life. Whether this has long-term consequences for this group of infants is unknown. There is presently no reason to advocate diet modification to alter the plasma cholesterol of normal infants under the age of 2 years.