Microbiota Composition of Breast Milk from Women of Different Ethnicity from the Manawatu-Wanganui Region of New Zealand

Human breastmilk components, the microbiota and immune modulatory proteins have vital roles in infant gut and immune development. In a population of breastfeeding women (n = 78) of different ethnicities (Asian, Māori and Pacific Island, New Zealand European) and their infants living in the Manawatu–Wanganui region of New Zealand, we examined the microbiota and immune modulatory proteins in the breast milk, and the fecal microbiota of mothers and infants. Breast milk and fecal samples were collected over a one-week period during the six to eight weeks postpartum. Breast milk microbiota differed between the ethnic groups. However, these differences had no influence on the infant’s gut microbiota composition. Based on the body mass index (BMI) classifications, the mother’s breast milk and fecal microbiota compositions were similar between normal, overweight and obese individuals, and their infant’s fecal microbiota composition also did not differ. The relative abundance of bacteria belonging to the Bacteroidetes phylum was higher in feces of infants born through vaginal delivery. However, the bacterial abundance of this phylum in the mother’s breast milk or feces was similar between women who delivered vaginally or by cesarean section. Several immune modulatory proteins including cytokines, growth factors, and immunoglobulin differed between the BMI and ethnicity groups. Transforming growth factor beta 1 and 2 (TGFβ1, TGFβ2) were present in higher concentrations in the milk from overweight mothers compared to those of normal weight. The TGFβ1 and soluble cluster of differentiation 14 (sCD14) concentrations were significantly higher in the breast milk from Māori and Pacific Island women compared with women from Asian and NZ European ethnicities. This study explores the relationship between ethnicity, body mass index, mode of baby delivery and the microbiota of infants and their mothers and their potential impact on infant health.

The effect of 'Zesy002' kiwifruit (Actinidia chinensis var. chinensis) on gut health function: a randomised cross-over clinical trial

Functional gastrointestinal disorders including constipation affect up to 14 % of the world's population. Treatment is difficult and challenging resulting in a need for alternative safe and effective therapies. The present study investigated whether daily consumption of three gold-fleshed kiwifruit could alleviate constipation and improve gastrointestinal discomfort in mildly constipated individuals with and without pain. A total of thirty-two participants were enrolled in a 16-week randomised, single-blind, crossover study. Participants received either three 'Zesy002' kiwifruit or 14·75 g Metamucil® (5 g dietary fibre/d (a positive control)) for 4 weeks each with a 4-week washout between treatments. A 2-week washout period was included at the beginning and end of the study. Daily bowel habit diaries were kept throughout the study. The primary outcome measure was differences in the number of complete spontaneous bowel movements (CSBM). Secondary outcome measures were bowel movement frequency and stool form as well as digestive symptoms and comfort. The number of CSBM per week was significantly greater during daily consumption of three kiwifruit compared with the baseline (6·3 v. 3·3; P < 0·05) and the Metamucil® treatment (6·3 v. 4·5; P < 0·05). Stool consistency was also improved, with kiwifruit producing softer stools and less straining (P < 0·05). Gastrointestinal discomfort was also improved compared with baseline for abdominal pain, constipation and indigestion (P < 0·05) during the kiwifruit intervention and constipation during the Metamucil® intervention (P < 0·05). This randomised controlled trial demonstrates that daily consumption of three gold-fleshed kiwifruit is associated with a significant increase of two CSBM per week and reduction in gastrointestinal discomfort in mildly constipated adults.

Kiwifruit-derived supplements increase stool frequency in healthy adults: a randomized, double-blind, placebo-controlled study

The worldwide growth in the incidence of gastrointestinal disorders has created an immediate need to identify safe and effective interventions. In this randomized, double-blind, placebo-controlled study, we examined the effects of Actazin and Gold, kiwifruit-derived nutritional ingredients, on stool frequency, stool form, and gastrointestinal comfort in healthy and functionally constipated (Rome III criteria for C3 functional constipation) individuals. Using a crossover design, all participants consumed all 4 dietary interventions (Placebo, Actazin low dose [Actazin-L] [600 mg/day], Actazin high dose [Actazin-H] [2400 mg/day], and Gold [2400 mg/day]). Each intervention was taken for 28 days followed by a 14-day washout period between interventions. Participants recorded their daily bowel movements and well-being parameters in daily questionnaires. In the healthy cohort (n = 19), the Actazin-H (P = .014) and Gold (P = .009) interventions significantly increased the mean daily bowel movements compared with the washout. No significant differences were observed in stool form as determined by use of the Bristol stool scale. In a subgroup analysis of responders in the healthy cohort, Actazin-L (P = .005), Actazin-H (P < .001), and Gold (P = .001) consumption significantly increased the number of daily bowel movements by greater than 1 bowel movement per week. In the functionally constipated cohort (n = 9), there were no significant differences between interventions for bowel movements and the Bristol stool scale values or in the subsequent subgroup analysis of responders. This study demonstrated that Actazin and Gold produced clinically meaningful increases in bowel movements in healthy individuals.

Variability in measurements of blood glucose response to foods in human subjects is not reduced after a standard breakfast

Measurements of blood glucose response to food are highly variable. We determined whether within-individual variability in data for blood glucose responses were reduced if individuals consumed a standard meal 2 hours before testing and investigated the effect of serving size. Blood glucose responses to muesli and macaroni cheese were determined in 13 individuals by taking 2 fasting capillary blood samples. Food was then consumed, and capillary blood samples were taken every 15 minutes for the first hour and every 30 minutes for the second hour. The incremental area under the blood glucose response curve was determined, and glycemic glucose equivalents (GGEs) were calculated. The GGE values were not significantly different whether the muesli and macaroni cheese were fed fasting or after a standard breakfast (29.2 vs 34.5 g for muesli and 11.0 vs 14.6 g for macaroni cheese). Within-individual coefficients of variation were not significantly different whether the food was consumed fasting or after a standard breakfast (24.9% and 32.5% for muesli and 38.1% and 59.4% for macaroni cheese). Differences in GGE between measured and estimated half serving size for macaroni cheese were 0.8 g (P = .6) and for muesli, 3 g (P = .2); for the double serving size for macaroni cheese, 1.7 g (P = .7); and for muesli, 6.7 g (P = .06). The GGE values for foods and variability in blood glucose response within individuals were not significantly different whether individuals fasted or consumed a standard breakfast before testing. However, blood glucose levels tended to differ significantly after consumption of the double serving size of muesli compared with other serving sizes.

Considerable temporal variability in glucose reference curves in humans for a year period

Glycemic glucose equivalent (GGE) is a measure of the blood glucose response to a defined portion of food. Their calculation requires the measurement of a standard glucose-response curve, with beverages containing 0, 12.5, 25, 50, and 75 g of glucose measured twice each. This study was designed to determine the stability of an individual's glucose-response curve measured every 3 months for a year and of their GGE estimates for 10 foods for that period. The blood glucose response to beverages containing 0, 12.5, 25, 50, and 75 g glucose and to 10 foods was measured for 16 healthy individuals. Capillary blood samples were collected fasting, then every 15 minutes for 1 hour, and every 30 minutes for at least 2 hours. The slopes and intercepts of the 4 glucose curves and the GGE of the 10 foods calculated using the available curves for each food was compared. The results showed considerable temporal variability in the slope (intraindividual coefficient of variation (CV) = 30%) and intercept (intraindividual CV = 40%) of the glucose curves. However, if GGE values were categorized into 3 groups (low GGE, < or = 10; medium GGE, 10.01-19.99; and high GGE, > or = 20), all but one food was consistently classified in the same category across the 4 glucose curves. In conclusion, it appears that if the exact GGE value is required, glucose curves should be repeated at least once every 3 months, but if foods are classed into general GGE categories, it may be possible to use the same glucose curve for a longer period.

Immunomodulation of cultured vascular endothelial cells by serial cell passage

Endothelial cell seeding has been successful in reducing the thrombogenecity of prosthetic vascular grafts in animal models, but results from clinical trials have been largely disappointing. These poor results have been associated with poor graft coverage in immediate seeding trials, and failure of cell culture in staged procedures. These problems could be largely overcome by utilising a bank of allogeneic endothelial cells, providing an ever ready supply. However, one potential pitfall with this technique would be the possibility of a rejection response following transplantation.

AIM

To study the effects of prolonged tissue culture, on the ability of endothelial cells to generate an immune response.

METHODS AND RESULTS

The immunogenecity of human umbilical vein endothelial cells was measured using the mixed lymphocyte endothelial reaction. It was demonstrated that prolonged tissue culture significantly reduced the immunogenecity of the cells, from a mean of 7261 cpm (S.E. +/- 243, n = 3) for cells of subculture 3, to 5478 cpm (+/- 156, p = 0.04) for cells of subculture 7 (p = 0.04, Wilcoxon paired rank test), but did not significantly impair morphology or antithrombotic function.

CONCLUSION

This study provides evidence that prolonged tissue culture provides morphologically and functionally intact, immunomodified endothelial cells which may potentially be used in seeding prosthetic vascular grafts.

Attachment, replication and thrombogenicity of genetically modified endothelial cells

Endothelial cell seeding of prosthetic surfaces has been proposed as a technique to improve the patency of vascular grafts following arterial reconstruction. The introduction of specific recombinant DNA into seeded endothelial cells may enhance the anti-thrombogenic nature of the endothelial-blood interface with a consequent reduction in graft thrombosis. However, the successful use of genetically modified endothelial cells in the seeding process relies on the cells retaining normal function in terms of cellular replication, attachment and secretion of anti-thrombotic mediators. Successful genetic manipulation of human endothelial cells has been accomplished by viral and chemical methods.

AIM

To study the functional characteristics of electrontransfected endothelial cells.

METHODS AND RESULTS

Endothelial cells were electro-transfected with the test plasmid pTCF at a transfection efficiency of 10% utilising a single electric pulse with an electric field of 1000 volts/cm and a time constant of 12.8ms. The functional status of transfected endothelial cells was then compared with a control endothelial cell population. There were no significant differences in replication (p = 0.76), attachment (p = 0.43), basal (p = 0.89) or stimulated (p = 0.11) prostacyclin release between transfected cells as compared with control endothelial cells.

CONCLUSIONS

Genetically modified cells are functionally normal, and may be used in endothelial cell seeding of prosthetic vascular surfaces.

Optimisation of gene transfer into vascular endothelial cells using electroporation

OBJECTIVES

We have examined the conditions required to obtain optimum transfection efficiencies for human umbilical vein endothelial cells by transduction with a plasmid conferring neomycin resistance.

MATERIALS AND METHODS

Preliminary studies examined the effects of electric discharges using the Biorad Gene Pulser on endothelial cells. Post-electroporation, there was a significant decrease in cell survival with increasing voltages (100-400 volts; p = 0.03), capacitances [125-960 microFarads (microF); p = 0.02], number of electric pulses (1-2; p = 0.03) and decreasing cell concentrations (p = 0.01). The optimal cell concentration was 3 x 10(6) cells/ml. Transfection studies utilised the neomycin resistance expressing plasmid, pTCF; transfectants were selected with the neomycin analogue G-148.

RESULTS

Electro-transfection was optimised with increasing voltages (p = 0.02) and capacitances (p = 0.01) using a single pulse. Optimal transfection was obtained using 400 volts with a capacitance of 960 microF using a single pulse; the median transfection efficiency was 10%. Transduced endothelial cells stably expressed the plasmid for 12 days and at least two cell passages.

CONCLUSIONS

The results indicate that endothelial cells can be efficiently transduced by electroporation to stably express an introduced gene. This may have important implications in vascular surgery.

Effect of pulsatile shear stress on endothelial attachment to native vascular surfaces

An in vitro model of vascular damage was used to investigate the ability of seeded endothelial cells to resist shear stresses generated in a perfusion circuit. At perfusion rates of 100 ml/min the maximum shear stress reached 16.5 dyn/cm2. At this level the rate of cell detachment from the damaged vascular surface was 88 per cent per h for the first 20 min of flow but gradually decreased to 5 per cent per h after 90 min. These findings suggest that endothelial cells may be retained on damaged vascular surfaces in conditions that approximate to arterial flow.

The effect of transluminal endothelial seeding on myointimal hyperplasia following angioplasty

Myointimal hyperplasia develops as a generalised response to vascular injury, and may cause stenoses in 40% of all peripheral arterial reconstructions. Disruption of the endothelial monolayer is a prerequisite for the development of intimal hyperplasia, and may be the initiating event in this process. This study examined the hypothesis that restenosis following balloon angioplasty may be reduced by rapid restoration of the endothelial monolayer, achieved by endothelial seeding. Bilateral iliac angioplasties were performed in 11 rabbits. A double balloon catheter was used to seed one angioplasty site with autogenous endothelial cells; the contralateral site was sham seeded with culture medium and acted as a control. Arterial patency rates, the degree of intimal hyperplasia (IH/IEL), and the extent of endothelialisation were quantified at 1 (n = 5) and 3 (n = 6) weeks following balloon dilatation. The results suggest that transluminal endothelial seeding may be a therapeutically applicable technique as it decreases myointimal hyperplasia, and increases patency following angioplasty. This study also illustrates the protective effect of the vascular endothelium following arterial injury, and indicates that intensive efforts should be made to preserve the endothelium during vascular reconstruction.

Platelet deposition after angioplasty is abolished by restoration of the endothelial cell monolayer

PURPOSE

Percutaneous transluminal angioplasty of an atheromatous plaque causes endothelial desquamation and intimal dissection with the consequent formation of a thrombogenic flow surface. In this study we investigated the hypothesis that platelet deposition after balloon angioplasty may be decreased by rapid restoration of the endothelial cell monolayer, achieved by transluminally seeding angioplasty sites with endothelial cells.

METHODS

Bilateral external iliac angioplasty was performed in eight New Zealand white rabbits. One angioplasty site was isolated from the circulation and incubated with a supraconfluent endothelial cell suspension with a double balloon catheter; the contralateral angioplasty site was sham seeded with culture medium. The deposition of autologous indium 111-labeled platelets on the angioplasty sites was quantified 30 minutes after restoration of flow and was referenced to an undamaged segment of aorta that acted as a negative control.

RESULTS

Platelet deposition on the nonseeded angioplasty site (13.1 x 10(4) platelets/mm2) was significantly higher than on nondilated segments (3.4 x 10(4) platelets/mm2; p = 0.014). Restorationof endothelial cell coverage by endothelial seeding significantly reduced platelet deposition on dilated arterial segments to levels not significantly higher than in controls (3.6 x 10(4) platelets/mm2; p = 0.014).

CONCLUSIONS

These results illustrate that rapid reendothelialization of angioplasty sites decreases subsequent platelet deposition and may reduce the rate of acute arterial reocclusion complicating endovascular techniques.

A method to transluminally seed angioplasty sites with endothelial cells using a double balloon catheter

Acute arterial reocclusion and late restenosis following angioplasty may be partially caused by loss of the endothelial cell monolayer during balloon dilatation. Rapid restoration of the endothelial cell monolayer by endothelial cell transplantation has the potential to increase the antithrombotic nature of the angioplasty site and also to prevent myointimal hyperplasia which is the cause of late restenosis. We have investigated a method to transluminally deliver endothelial cells to angioplasty sites using a double balloon catheter with a central instillation port. Inflation of the balloons allows a segment of artery to be isolated from the circulation which may then be incubated with infused endothelial cells. The external iliac arteries of New Zealand white rabbits were dilated for 30 s at 8 atm pressure using a 3 mm balloon angioplasty catheter. Indium-111 labelled allogeneic rabbit endothelial cells were seeded onto the angioplasty site and retained in contact with the vascular surface for 30 min by continued inflation of the isolation balloons. After 30 min, the balloons were deflated and flow restored. Percentage cell retention was calculated by determining the gamma activity of the seeded angioplasty site, and referencing this to the contralateral sham seeded site. Results are expressed as a median with 95% confidence intervals and suggest that endothelial cells may be successfully delivered and retained on damaged vascular surfaces [table: see text].

Effect of seeding time and density on endothelial cell attachment to damaged vascular surfaces

An in vitro model to facilitate the study of endothelial cell seeding of damaged vascular surfaces has been developed. This may have applications in the study of endothelial seeding of angioplasty and endarterectomy sites. Using this model, the optimum endothelial seeding time for attachment to damaged vascular surfaces should not exceed 30 min and, to achieve confluent cell attachment, a seeding density > 5 x 10(5) cells/cm2 should be used.

Endothelial cell seeding of damaged native vascular surfaces: prostacyclin production

Endothelial cell seeding has been successful in reducing the thrombogenicity of prosthetic vascular grafts in animal and clinical studies. The reduction in thrombogenicity may be attributed to the intrinsic properties of endothelial cells themselves, and their ability to produce anti-thrombogenic mediators such as prostacyclin, and endothelium-derived relaxing factor. Endothelial seeding of damaged vascular surfaces produced during percutaneous transluminal angioplasty and endarterectomy is an attractive possibility due to the excellent attachment characteristics of the sub-endothelial tissue exposed during these procedures. The ability of endothelial seeded damaged vascular surfaces to produce prostacyclin was measured in an in vitro model of vascular injury. Endothelial-seeded damaged surfaces produced significantly higher prostacyclin release than did vessels damaged by balloon dilatation (265.5 pg cm-2 min-1 and 87.5 pg cm-2 min-1 respectively). This study provides evidence that endothelial seeding of damaged native vascular surfaces is technically feasible and that seeding may reduce the thrombogenicity of vascular surfaces following balloon dilatation.