Disaccharidase activity in the intestinal tract of Wistar–Furth, diabetes-resistant and diabetes-prone BioBreeding rats

Bacillus coagulans GBI-30, 6086 (BC30) improves lactose digestion in rats exposed to a high-lactose meal

PURPOSE

Bacillus coagulans GBI-30, 6086 (BC30) was previously shown to improve nutrient digestibility and amino acid absorption from milk protein in vitro. However, the effect of supplementation with this probiotic on lactose digestibility has not yet been evaluated in vivo.

METHODS

Wistar female rats were exposed to an acute high-lactose diet (LD; 35% lactose) meal challenge after 7 days of administration of BC30 (LD-BC; n = 10) or vehicle (LD-C; n = 10). Rats treated with vehicle and exposed to control diet (CD; 35% corn starch) meal were used as controls (CD-C; n = 10). Carbohydrate oxidation (CH_OX) and lipid oxidation (L_OX) were monitored by indirect calorimetry before and after lactose challenge. After the challenge, rats were treated daily with vehicle or probiotic for an additional week and were fed with CD or LD ad libitum to determine the effects of BC30 administration in a lactose-induced diarrhoea and malnutrition model.

RESULTS

LD-C rats showed lower CH_OX levels than CD rats, while LD-BC rats showed similar CH_OX levels compared to CD rats during the lactose challenge, suggesting a better digestion of lactose in the rats supplemented with BC30. BC30 completely reversed the increase in the small intestine length of LD-C animals. LD-BC rats displayed increased intestinal mRNA Muc2 expression. No significant changes were observed due to BC30 administration in other parameters, such as serum calprotectin, intestinal MPO activity, intestinal A1AT and SGLT1 levels or intestinal mRNA levels of Claudin2 and Occludin.

CONCLUSION

Treatment with BC30 improved the digestibility of lactose in an acute lactose challenge and ameliorated some of the parameters associated with lactose-induced malnutrition.

Development of the Nonobese Diabetic Mouse and Contribution of Animal Models for Understanding Type 1 Diabetes

In 1974, the discovery of a mouse and a rat that spontaneously developed hyperglycemia led to the development of 2 autoimmune diabetes models: nonobese diabetic (NOD) mouse and Bio-Breeding rat. These models have contributed to our understanding of autoimmune diabetes, provided tools to dissect autoimmune islet damage, and facilitated development of early detection, prevention, and treatment of type 1 diabetes. The genetic characterization, monoclonal antibodies, and congenic strains have made NOD mice especially useful.Although the establishment of the inbred NOD mouse strain was documented by Makino et al (Jikken Dobutsu. 1980;29:1-13), this review will focus on the not-as-well-known history leading to the discovery of a glycosuric female mouse by Yoshihiro Tochino. This discovery was spearheaded by years of effort by Japanese scientists from different disciplines and dedicated animal care personnel and by the support of the Shionogi Pharmaceutical Company, Osaka, Japan. The history is based on the early literature, mostly written in Japanese, and personal communications especially with Dr Tochino, who was involved in diabetes animal model development and who contributed to the release of NOD mice to the international scientific community. This article also reviews the scientific contributions made by the Bio-Breeding rat to autoimmune diabetes.

A critical evaluation of statistical approaches to examining the role of growth trajectories in the developmental origins of health and disease

The developmental origins of health and disease hypothesis suggests that small birth size in conjunction with rapid compensatory childhood growth might yield a greater risk of developing chronic diseases in later life. For example, there is evidence that people who developed coronary heart disease and diabetes experienced different growth trajectories from those who did not develop these diseases. However, some of the methods used in these articles may have been flawed. We critically evaluate proposed approaches for identifying the growth trajectories distinctive to those developing later disease and identifying critical phases of growth during the early lifecourse. Among the approaches we examined (tracing the z-scores, lifecourse plots and models, lifecourse path analysis, conditional body size analysis, multilevel analysis, latent growth curve models and growth mixture models) conditional body size analysis, multilevel analysis, latent growth curve models and growth mixture models are least prone to collinearity problems caused by repeated measures. Multilevel analysis is more flexible when body size is not measured at the same age for all cohort members. Strengths and weaknesses of each approach are illustrated using real data. Demonstrating the influence of growth trajectories on later disease is complex and challenging; therefore, it is likely that a combination of approaches will be required to unravel the complexity in lifecourse research.

The metabolic syndrome of fructose-fed rats: effects of long-chain polyunsaturated ω3 and ω6 fatty acids. V. Post-mortem findings

The present study deals with the possible effects of dietary ω3 and ω6 fatty acids upon the metabolic syndrome found in rats exposed for 8 weeks to a diet containing 64% (w/w) D-fructose instead of starch. Fructose-fed rats were found to display a modest increase in plasma albumin and protein concentration and more pronounced increases in plasma urea, creatinine, phospholipids, triglycerides and cholesterol concentrations, glycated hemoglobin concentration and liver contents of cholesterol, triglycerides and phospholipids. The plasma concentrations of HDL-cholesterol, calcium and iron were decreased, however, in the fructose-fed rats. In general, the partial substitution of sunflower oil by either safflower oil or salmon oil opposed the metabolic perturbations otherwise associated with the fructose-induced metabolic syndrome in the fructose-fed rats, with salmon oil demonstrating particular efficacy. Consideration is given to the possible biological determinants of these perturbations and their attenuation in rats exposed to safflower or salmon oil.

Enhanced post-natal growth is associated with elevated blood pressure in young Senegalese adults

BACKGROUND

Evidence suggests that intrauterine growth restriction followed by rapid post-natal growth is associated with high blood pressure. We assessed the effect of early size and post-natal growth on blood pressure in a population from West Africa, where fetal growth retardation and childhood malnutrition are common.

METHODS

A total of 1288 Senegalese subjects were followed from infancy to young adulthood (mean age 17.9 years). Adult systolic blood pressure (SBP) was regressed on infant and adult anthropometric characteristics.

RESULTS

In unadjusted analyses, infant size was positively associated with adult SBP (1.1 +/- 0.3; P = 0.001 for weight; 0.7 +/- 0.3; P = 0.04 for length). With adjustment for current size, the regression coefficients for infant size were reversed (-0.2 +/- 0.3; P = 0.51 for weight; -0.3 +/- 0.3; P = 0.35 for length). SBP increased by 4.1 and 2.9 mmHg for 1 standard deviation (SD) increase in current weight or height, respectively. No interaction between infant size and current size was found in the overall models (P = 0.11 for weight, P = 0.95 for height), but this term interacted with sex for weight effect. A negative interaction was found in males (-0.9 +/- 0.4; P = 0.02) but not in females (0.3 +/- 0.4; P = 0.46). The association of current weight with SBP was stronger in lighter weight male infants.

CONCLUSIONS

These findings support the hypothesis that subjects who were small in early life and experienced enhanced post-natal growth have higher levels of SBP, even in low-income settings.

Life course path analysis of birth weight, childhood growth, and adult systolic blood pressure

The inverse associations between birth weight and later adverse health outcomes and the positive associations between adult body size and poor health imply that increases in relative body size between birth and adulthood may be undesirable. In this paper, the authors describe life course path analysis, a method that can be used to jointly estimate associations between body sizes at different time points and associations of body sizes throughout life with health outcomes. Additionally, this method makes it possible to assess both the direct effect and the indirect effect mediated through later body size, and thereby the total effect, of size and changes in size on later outcomes. Using data on childhood body size and adult systolic blood pressure from a sample of 1,284 Danish men born between 1936 and 1970, the authors compared results from path analysis with results from 3 standard regression methods. Path analysis produced easily interpretable results, and compared with standard regression methods it produced a noteworthy gain in statistical power. The effect of change in relative body size on adult blood pressure was more pronounced after age 11 years than in earlier childhood. These results suggest that increases in body size prior to age 11 years are less harmful to adult blood pressure than increases occurring after this age.

Diabetes-prone BioBreeding rats do not have a normal immune response when weaned to a diet containing fermentable fibre

Diet is known to modulate the development of diabetes in diabetes-prone BioBreeding (BBdp) rats. The objective of the present study was to determine the effect of fermentable fibre (FF) on immune function in BBdp and diabetes-resistant BioBreeding (BBdr) rats after weaning. Weanling BBdp (thirty-six to thirty-eight per diet) and BBdr rats (thirty to thirty-two per diet) were fed a nutritionally complete, semi-purified, casein-based diet containing either cellulose (control diet, 8 % w/w) or FF (3·2 % cellulose+4·8 % w/w inulin). At 35 d, the small intestine was excised and lymphocytes isolated from spleen, mesenteric lymph nodes and Peyer's patches. Feeding FF to both BBdr and BBdp rats affected the production of anti-inflammatory cytokines (P=0·02). In BBdr rats, feeding FF compared with cellulose resulted in an increased small intestinal length (P=0·0031), higher proliferative (stimulation) index from both splenocytes (P=0·001) and mesenteric lymph nodes (P=0·04), and an increased proportion of CD8+ T-cells in the Peyer's patches (P=0·003). We did not observe an effect of diet on the number of IgA-bearing cells in the jejunum from BBdr rats. Feeding FF to BBdp rats did not affect the same parameters. BBdp rats had both a higher proportion of B-cells in the Peyer's patches (P=0·01) and a higher number of IgA+ cells in the jejunum (P=0·0036) when fed a diet containing FF, a response not observed in BBdr rats. We demonstrate that several aspects of the BBdp immune system respond differently than that of BBdr rats when challenged at weaning with FF.

Wheat protein-induced proinflammatory T helper 1 bias in mesenteric lymph nodes of young diabetes-prone rats

AIMS/HYPOTHESIS

Type 1 diabetes is the result of an inflammatory T helper 1 (Th1) lymphocyte-mediated beta cell destructive process. The majority of diabetes-prone BioBreeding (BBdp) rats fed wheat protein-based diets, such as NTP-2000, develop type 1 diabetes and display a mild coeliac-like enteropathy. Mesenteric lymph nodes (MLNs), which drain the gut, are the major inductive site where dietary antigens are recognised in the gut-associated lymphoid tissue (GALT). We hypothesised that this compartment could be a site of abnormal wheat protein-induced Th1 cell activation.

METHODS

MLN cells were isolated from BBdp and BB control (BBc) rats that were fed NTP-2000 or a hydrolysed casein (HC)-based diet at ages that pre-date classic insulitis. The inflammatory status, phenotype and proliferation of these cells in response to wheat protein were determined.

RESULTS

The expression ratio of T-bet : Gata3, master transcription factors for Th1 and Th2 cytokines, was increased in the MLN from NTP-2000-fed BBdp rats compared with that from BBc rats, mainly due to decreased Gata3 expression. CD3(+)CD4(+)IFN-gamma(+) T cells were more prevalent in the MLN of wheat-fed BBdp rats, but remained at control levels in BBdp rats fed a diabetes-retardant HC diet. BBdp MLN cells proliferated in response to wheat protein antigens in a specific, dose-dependent manner, and >93% of cells were CD3(+)CD4(+) T cells. This proliferation was associated with a low proportion of CD4(+)CD25(+) T cells and a high proportion of dendritic cells in the MLN of BBdp rats.

CONCLUSIONS/INTERPRETATION

Before insulitis is established, the MLNs of wheat-fed BBdp rats contain an unusually high proportion of Th1 cells that proliferate specifically in response to wheat protein antigens.

Changes in intestinal morphology and permeability in the biobreeding rat before the onset of type 1 diabetes

OBJECTIVE

Type 1 diabetes is an autoimmune disorder that occurs in genetically susceptible individuals. It has been hypothesized that the disease could be triggered by environmental agents that gain entry into the body through small intestinal absorption. Increased intestinal permeability has been reported both in spontaneous animal models of type 1 diabetes and human type 1 diabetes. In these studies, we examined both the physical and functional permeability characteristics of the small intestine in diabetes-prone and control rats.

METHODS

In a series of studies, BioBreeding diabetes-prone(n = 31), BioBreeding diabetes-resistant (n = 20) and control Wistar (n = 25) rats were examined at intervals from 21 to 125 days of age.

RESULTS

The percentage of goblet cells and the mucosal crypt depth were significantly greater in BioBreeding diabetes-prone than BioBreeding diabetes-resistant rats (P < 0.001 and P = 0.01, respectively). BioBreeding diabetes-prone and BioBreeding diabetes-resistant rats expressed less of the tight junction protein claudin (P < 0.05) and exhibited greater intestinal permeability (P < 0.001) than did Wistar rats. Intestinal permeability measured both in vivo and ex vivo decreased in all rat strains as age increased (P < 0.001).

CONCLUSIONS

In a genetically susceptible rodent model of diabetes, early increased intestinal permeability might allow unregulated passage of environmental antigens that could potentially trigger the autoimmune response leading to type 1 diabetes.

Gut permeability and intestinal mucins, invertase, and peroxidase in control and diabetes-prone BB rats fed either a protective or a diabetogenic diet

This study deals with the enteropathy recently identified in diabetes-prone BB rats (BBdp). Diabetes-resistant BB rats (BBc) and BBdp rats were fed from days 32-39 onward either a protective diabetes-retardant hydrolyzed casein diet (HC) or a plant-based diabetogenic (NTP) diet. The NTP diet decreased body weight and plasma insulin in BBc and BBdp rats. The BBdp rats displayed low intestinal invertase and increased intestinal peroxidase activity. In the BBdp rats fed the HC diet, the mucin content 30-35 cm below the pylorus was higher and the gut permeability lower than in the other three rat groups. There was a significant inverse correlation between gut permeability and the insulinogenic index in the BBdp rats fed the HC or NTP diet. Thus, in BBdp rats, the HC diet somehow prevents the increase in gut permeability and the decrease in the insulinogenic index otherwise found in some of these diabetes-prone animals.