Oral insulin enhances intestinal regrowth following massive small bowel resection in rat

How Health Systems World-wide Fail Type 2 Diabetics

For over 50 years, health systems the world over have failed people with type 2 diabetes mellitus (T2DM). The WHO documents a quadrupling of people with diabetes in a 34-year period to 422 million in 2014, the overwhelming majority of whom were T2DM. This happened despite extensive scientific literature on the causes of, as well as proven treatments for, this disease. Using a health systems prism to review the extensive medical and nutritional T2DM published research, we identified three main shortcomings of health systems in T2DM: (i) failure in early detection; (ii) failure in understanding the actionable lifestyle drivers; and (iii) subsidizing the causes of the disease. Although small-scale success stories in T2DM control exist, the lack of documented evidence of any country-wide health system's successful attempt to address this epidemic is alarming. The immense and ever-growing health and economic burdens of T2DM should provide all the motivation needed for national and global efforts to counteract the political-economy constraints standing in the way of successful whole-of-system approaches to T2DM.

Galanin enhanced insulin-mediated intracellular signaling by regulating the stability of membrane-localized insulin/IR

Previous studies have shown that insulin has the important regulatory effect on the intestinal tract. However, until now, the biological properties of insulin on intestinal cell has not been revealed. Therefore, in the current research, we first studied the cell characteristics and signaling profiles of insulin in the intestinal cell model, and found that insulin can be internalized into the cytoplasm in a time-dependent manner. After internalization, insulin transported into different type of endosomes. More importantly, we explored the effect of galanin on insulin-mediated signaling pathways (galanin is a polypeptide composed of 29 amino acid residues, galanin is widely distributed in the central and peripheral nervous system and has a variety of biological activities), and found that galanin can increase insulin sensitivity by regulating insulin receptor (IR)-mediated signal transduction pathways. We further study the potential molecular mechanism by which galanin enhances insulin sensitivity, and found that galanin could increase the time of insulin acting on the cell membrane. Further experiments showed that galanin could stabilize the membrane-localized insulin/IR, which may be an important new potential mechanism by which galanin improves the biological activity of insulin. This study laid the foundation for exploring the relationship between galanin and insulin sensitivity.

Human Milk Hormone Intake in the First Month of Life and Physical Growth Outcomes in Preterm Infants

CONTEXT

Human milk contains hormones that regulate metabolism. Extrauterine growth restriction remains common among preterm infants, but the effect of ingesting milk hormones on preterm infant growth is poorly understood.

OBJECTIVE

To quantify associations of longitudinal exposure to leptin, adiponectin, and insulin in milk with physical growth of preterm infants.

DESIGN/METHODS

In 50 preterm neonates (median gestational age 29.4 weeks), we sampled maternal milk on day-of-life 7, 14, 21, and 28 and measured hormone levels in whole milk by ELISA. Milk leptin levels were available for a subset of 18 infants. We calculated milk hormone doses by multiplying the hormone level by the milk volume ingested on each day and estimated the area under the curve (AUC) to reflect longitudinal exposure. We analyzed associations of milk hormone exposure with growth outcomes in generalized estimated equations.

MAIN OUTCOME MEASURES

Weight gain velocity and z-scores in weight, length, head circumference, and body mass index at 36 weeks' postmenstrual age (PMA).

RESULTS

Higher leptin intake was associated with greater weight gain (2.17g/kg/day [95% CI, 1.31, 3.02]) and weight z-score at 36 weeks' PMA (0.30 [0.08, 0.53] higher z-score per tertile). Higher adiponectin intake was associated with greater length z-score (0.41 [0.13, 0.69]), however, this association was nullified after adjustment of protein and calorie intake. Higher adiponectin was associated with smaller head circumference z-score (-0.36 [-0.64, -0.07]). Insulin was not associated with growth outcomes.

CONCLUSIONS

Milk leptin and adiponectin exposures may affect growth of preterm infants. The long-term effects of milk hormones warrant further investigation.

Axel AM, Safayi S, Elbrønd VS, Nielsen MO. Prenatal over- and undernutrition differentially program small intestinal growth, angiogenesis, absorptive capacity, and endocrine function in sheep

The aim was to test the hypothesis that prenatal under- and overnutrition in late gestation can program small intestinal (SI) growth, angiogenesis, and endocrine function to predispose for a hyperabsorptive state, thereby increasing the susceptibility to the adverse effects of an early postnatal obesogenic diet. Twin-pregnant ewes were exposed to adequate (NORM), LOW (50% of NORM), or HIGH (150% energy and 110% protein of NORM) diets through the last trimester (term ~147 days). From 3 days to 6 months of age, their lambs were fed either a moderate (CONV) or a high-carbohydrate high-fat (HCHF) diet. At 6 months of age, responses in plasma metabolites and insulin to refeeding after fasting were determined and then different segments of the SI were sampled at autopsy. Prenatal overnutrition impacts were most abundant in the duodenum where HIGH had increased villus amplification factor and lowered villi thickness with increased IRS-1 and reduced GH-R expressions. In jejunum, HIGH lambs had an increased expression of Lactate gene and amplified when exposed to HCHF postnatally. Specifically, in LOW, sensitivity to HCHF was affected in ileum. Thus, the mismatching LOW-HCHF nutrition increased expressions of angiogenic genes (VEGF, VEGF-R1, ANGPT1, RTK) and increased mucosa layer (tunica mucosa) thickness but reduced muscle layer (Tunica muscularis) thickness. The SI is a target of prenatal nutritional programming, where late gestation overnutrition increased and shifted digestive capacity for carbohydrates toward the jejunum, whereas late gestation undernutrition predisposed for ileal angiogenesis and carbohydrate and fat hyperabsorptive capacity upon subsequent exposure to postnatal obesogenic diet.

Effects of fenugreek (Trigonella foenum-graecumL.) seed extract supplementation in different energy density diets on growth performance, nutrient digestibility, blood characteristics, fecal microbiota, and fecal gas emission in growing pigs

This study evaluated the efficacy of fenugreek seed extract (FSE) in growing pigs. About 140 growing pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 23.70 ± 2.80 kg were used in a 6 wk trial. Treatments were (on as-fed basis) two levels of FSE (FSE0, 0 or FSE0.2, 2 g kg−1basal diet), and two levels of energy [low-energy diet (LED); 3160 or high-energy diet (HED); 3260 kcal kg−1metabolizable energy (ME)]. Pigs in HED and FSE0.2 diets had higher final BW, average daily gain, and gain:feed ratio (G:F) compared with in LED, and FSE0 diets, respectively (P < 0.05). Pigs fed the FSE0.2 and HED diets had higher energy (E) digestibility than the FSE0 and LED diets, respectively (P < 0.05). Pigs fed the FSE0.2 diet increased serum immunoglobulin G (IgG), and reduced total cholesterol (TC) concentration than the FSE0 diet (P < 0.05). Hydrogen sulfide (H2S) and ammonia (NH3) gas emission in FSE0.2 diet were lower than that in FSE0 group (P < 0.05). In conclusion, results indicated that dietary supplementation of FSE improved growth performance, digestibility, serum IgG, reduced serum TC, and noxious gas emission in growing pigs.

Effect of Oral Insulin on the Severity and Recovery of Methotrexate-Induced Gastrointestinal Mucositis in the Rat

OBJECTIVES

Gastrointestinal (GI) mucositis is an adverse-effect of chemo- and radiotherapy. Oral insulin has been suggested as possible intestinal growth factor and possible intervention for GI mucositis. We aimed to determine the effect of oral insulin on the severity and recovery of mucositis in a methotrexate (MTX)-induced GI mucositis rat model.

METHODS

Male Wistar rats (n = 24) received a single injection of 60 mg/kg MTX intravenously at day 0. From day -3 oral insulin was added to the drinking water. Group MTX received normal drinking water, group MTX+INS0.5 received 0.5 U/mL insulin, and group MTX+INS1 received 1 U/mL insulin in drinking water. The severity of mucositis was determined by intake, bodyweight, illness, and plasma citrulline. In the recovery phase, the function of the gut was tested with an oral glucose tolerance test, and villus and crypt length of the small intestine were measured.

RESULTS

MTX-induced mucositis in all 3 groups and oral insulin did not cause a change in the severity of mucositis, with comparable bodyweight, food intake, and water intake. Oral insulin did not alter the enterocyte mass, determined with plasma citrulline. The glucose level after bolus was higher in the MTX group than the MTX+INS1 group (P < 0.05). Histology was not significant different between all groups.

CONCLUSIONS

Oral insulin does not alter the severity or the acceleration of recovery of mucositis. Therefore, we conclude that it is not useful to further study oral insulin as possible intervention to prevent or treat chemotherapy-induced GI mucositis.

Dietary fenugreek seed extract improves performance and reduces fecal E. coli counts and fecal gas emission in lactating sows and suckling piglets

Hossain, M. M., Begum, M., Nyachoti, C. M., Hancock, J. D. and Kim, I. H. 2015. Dietary fenugreek seed extract improves performance and reduces fecal E. coli counts and fecal gas emission in lactating sows and suckling piglets. Can. J. Anim. Sci. 95: 561–568. This study evaluated the efficacy of fenugreek seed extract (FSE) in sows and suckling piglets. The trial was conducted with 78 multiparous sows and their litters in a 28-d feeding trial, and one of three diets: CON (control, basal diet); FSE1 (basal diet+0.1% FSE), and FSE2 (basal diet+0.2% FSE). Piglets suckling sows fed the FSE1 and FSE2 diets had higher average daily gain compared with those suckling sows fed the CON from week 2 to weaning (linear, P<0.05). At weaning, sows fed the FSE1 and FSE2 diets had higher immunoglobulin G and lower low-density lipoprotein–cholesterol concentrations compared with those fed the CON diet (linear, P<0.05). Sows fed the FSE2 diet linearly reduced total cholesterol concentrations at weaning (P<0.05). Piglets suckling sows fed the FSE2 diet had higher immunoglobulin G and red blood cell concentrations compared with those suckling sows fed the CON diet (linear, P<0.05). Sows fed the FSE2 diet had higher apparent total tract digestibility of N and gross energy and reduced fecal E. coli counts and ammonia gas emission compared with those fed the CON diet at weaning (linear, P<0.05). In conclusion, results indicate that feeding sows a diet supplemented with FSE in late gestation and lactation improved performance in sows and suckling piglets.

Both epidermal growth factor and insulin-like growth factor receptors are dispensable for structural intestinal adaptation

PURPOSE

Intestinal adaptation structurally represents increases in crypt depth and villus height in response to small bowel resection (SBR). Previously, we found that neither epidermal growth factor receptor (EGFR) nor insulin-like growth factor 1 receptor (IGF1R) function was individually required for normal adaptation. In this study, we sought to determine the effect of disrupting both EGFR and IGF1R expression on resection-induced adaptation.

METHODS

Intestinal-specific EGFR and IGF1R double knockout mice (EGFR/IGF1R-IKO) (n=6) and wild-type (WT) control mice (n=7) underwent 50% proximal SBR. On postoperative day (POD) 7, structural adaptation was scored by measuring crypt depth and villus height. Rates of crypt cell proliferation, apoptosis, and submucosal capillary density were also compared.

RESULTS

After 50% SBR, normal adaptation occurred in both WT and EGFR/IGF1R-IKO. Rates of proliferation and apoptosis were no different between the two groups. The angiogenic response was less in the EGFR/IGF1R-IKO compared to WT mice.

CONCLUSION

Disrupted expression of EGFR and IGF1R in the intestinal epithelial cells does not affect resection-induced structural adaptation but attenuates angiogenesis after SBR. These findings suggest that villus growth is driven by receptors and pathways that occur outside the epithelial cell component, while angiogenic responses may be influenced by epithelial-endothelial crosstalk.

Enriched Intestinal Stem Cell Seeding Improves the Architecture of Tissue-Engineered Intestine

OBJECTIVE

To develop a methodology to separate intestinal stem cell (ISC)-enriched crypts from differentiated epithelial cell (DEC)-containing villi to improve the morphology of tissue-engineered intestine (TEI).

METHODS

Small intestinal tissues from 5- to 7-day-old transgenic Lgr5-EGFP mice (with fluorescently labeled ISCs) were used to measure the height of villi and the depth of crypts. Based on the significant size difference between crypts and villi, a novel cell filtration system was developed. Filtration of mixed organoid units from full-thickness intestine of transgenic Lgr5-EGFP mice allowed determination of the percentage of ISCs in the different size-based filtration fractions obtained. In vivo, 5-7-day-old Lewis rat pups were used as cell donors to obtain purified crypts and villi, and the dams of the pups served as recipients. Flat and tubular polyglycolic acid (PGA) scaffolds were seeded with either ISC-enriched crypts or DEC-containing villi and implanted intra-abdominally on the anterior abdominal wall. After 1, 3, 7, 14, 21, and 28 days of in vivo incubation, explants were processed for histologic evaluation.

RESULTS

Small intestine from transgenic Lgr5-EGFP mice contained villi with an average height of 134.89±41.91 μm and crypts with an average depth of 49.59±8.95 μm. After filtration, we found that the 100-200 μm fractions contained relatively pure villi in which DECs were located, whereas the 25-70 μm range fractions contained concentrated crypts in which ISCs were located. In vivo, flat PGA scaffolds implanted with purified crypts formed well-developed mucosa by day 14 postimplantation, whereas flat scaffolds seeded with villi were replaced with fibrous tissue. Tubular scaffolds seeded with the crypt fraction developed a well-formed mucosal layer on the interior surface, with 80.9% circumferential mucosal engraftment and an average villous height of 478±65 μm, which was very close to native intestine (512±98 μm), whereas tubular scaffolds seeded with the villous fraction only had 21.7% circumferential mucosal engraftment and an average villous height of 243±78 μm.

CONCLUSION

The novel filtration system described can effectively and efficiently isolate ISC-containing crypts. TEI produced from ISC-containing crypts has an improved morphology that is similar to native intestine.

Insulin-like growth factor 2 and its enterocyte receptor are not required for adaptation in response to massive small bowel resection

PURPOSE

Enhanced structural features of resection-induced intestinal adaptation have been demonstrated following the administration of multiple different growth factors and peptides. Among these, the insulin-like growth factor (IGF) system has been considered to be significant. In this study, we employ mutant mouse strains to directly test the contribution of IGF2 and its enterocyte receptor (IGF1R) toward the adaptation response to massive small bowel resection (SBR).

METHODS

IGF2-knockout (IGF2-KO) (n=8) and intestine specific IGF1R-knockout mice (IGF1R-IKO) (n=9) and their wild type (WT) littermates (n=5, n=7, respectively) underwent 50% proximal SBR. At post-operative day 7, structural adaptation was measured as crypt depth and villus height. Rates of enterocyte proliferation and apoptosis were also recorded.

RESULTS

The successful deletion of IGF2 and IGF1R expression in the enterocytes was confirmed by RT-PCR and Western blot, respectively. Normal adaptation occurred in both IGF2-KO and IGF1R-IKO mice after 50% SBR. Post-operative rates of proliferation and apoptosis in both IGF2-KO and IGF1R-IKO mice were no different than their respective controls.

CONCLUSION

IGF2 and functional IGF1R signaling in enterocytes are both dispensable for resection-induced adaptation responses. The mechanism for IGF-stimulation of intestinal adaptation may involve other ligands or cellular compartments within the intestine.

Time- and segment-related changes of postresected intestine: a 4-dimensional model of intestinal adaptation

OBJECTIVES

The aim of the present study was to investigate the segment- and time-related changes in rat short bowel syndrome and construct a 4-dimensional (4D) geometrical model of intestinal adaptation.

METHODS

Sprague-Dawley rats were divided into 3 groups: 2-day, 7-day, and 15-day postresection groups in which 75% of the jejunoileum was removed. Histological and morphometrical parameters in the remaining proximal to distal intestinal segments, from the jejunum to the distal colon, were comparatively evaluated in the groups. The data were used to construct a 4D geometric model in which villi were considered as cylinders, and their surface area was expressed as cylinder lateral area.

RESULTS

Major adaptive changes were observed in the ileum consisting of an increase in both the diameter of base and the height of villi. A parallel reduction in their number/mm was observed. The resulting ileal architecture was characterized by a limited number of large villi. An opposite pattern was observed in the jejunum whose postresection structure consisted of an increased number of villi. No changes were observed in the colon. Postresection restructuring was early and faster in the ileum than in the jejunum resulting in an increase in absorptive area of 81.5% and 22.5% in the ileum and jejunum, respectively.

CONCLUSIONS

Postresection adaptation is intestinal segment-specific because all of the major changes occur in the ileum rather than in the jejunum. Sparing ileal segments during resection may improve the outcome of patients undergoing extensive intestinal resection. Our 4D model can be used to test interventions aimed at optimizing postresection intestinal adaptation.

Endogenous growth hormone and insulin after interposition of a reversed jejunal segment in short bowel syndrome. An experimental study on pigs

BACKGROUND

Interposition of a reversed jejunal loop in short bowel sydrome has previously been investigated in human along with animal models and seemed able to facilitate intestinal adaptation. However, it is unclear if growth hormone and insulin, well known for their implication in short bowel pathophysiology, intervene on this effect.

FINDINGS

Porcine models were randomly allocated to two cohorts: (1) short bowel (SB) group (n = 8) and (2) short bowel reverse jejunal segment (SB-RS) group (n = 8). Amongst other parameters serum growth hormone and insulin were measured at baseline, as well as on postoperative day 30 and 60.

CONCLUSION

Both endogenous hormones failed to demonstrate significant difference in respect to potential direct effect to mechanisms of enhanced intestinal adaptation in reversed group.

Oral insulin stimulates intestinal epithelial cell turnover following massive small bowel resection in a rat and a cell culture model

PURPOSE

We have recently reported that oral insulin (OI) stimulates intestinal adaptation after bowel resection and that OI enhances enterocyte turnover in correlation with insulin receptor expression along the villus-crypt axis. The purpose of the present study was to evaluate the effect of OI on intestinal epithelial cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS) and in a cell culture model.

METHODS

Caco-2 cells were incubated with increasing concentrations of insulin. Cell proliferation and apoptosis were determined by FACS cytometry. Cell viability was investigated using the Alamar Blue technique. Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the third postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real time PCR was used to determine the level of bax and bcl-2 mRNA and western blotting was used to determine bax, bcl-2, p-ERK and AKT protein levels. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant.

RESULTS

Treatment of Caco-2 cells with insulin resulted in a significant increase in cell proliferation (twofold increase after 24 h and 37% increase after 48 h) and cell viability (in a dose-dependent manner), but did not change cell apoptosis. In a rat model of SBS, treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Elevated cell proliferation rate in insulin treated rats was accompanied by elevated AKT and p-ERK protein levels. Decreased cell apoptosis in SBS-INS rats corresponded with a decreased bax/bcl-2 ratio.

CONCLUSIONS

Oral insulin stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat model of SBS and a cell culture model.

Effect of oral insulin on diabetes-induced intestinal mucosal growth in rats

BACKGROUND

To evaluate the intestinal response to the induction of diabetes and to oral insulin (OI) administration in a rat.

METHODS

Male Sprague-Dawley rats were divided into four experimental groups: control rats, CONTR-INS rats that were treated with OI given in drinking water for 7 days, diabetic rats that were injected with one dose of streptozotocin, and diabetic rats treated with OI. Intestinal structural changes, enterocyte proliferation and enterocyte apoptosis, bax and bcl-2 mRNA and protein levels, insulin receptor expression and ERK protein levels were determined at sacrifice. A one-way ANOVA for comparison, followed by Tukey's test for pair-wise comparison, were used for statistical analysis.

RESULTS

Induction of diabetes resulted in a significant increase in bowel and mucosal weight (P < 0.05), mucosal protein (P < 0.05), villus height and crypt depth in jejunum and ileum (P < 0.05), and mucosal DNA in ileum (P < 0.05) (vs. control animals). Diabetes also enhances ERK-induced cell proliferation (P < 0.05) and concomitant bax/bcl-2 induced cell apoptosis (P < 0.05). Treatment of diabetic rats with OI resulted in a significant decrease in jejunal protein content (P < 0.05), jejunal and ileal villus height (P < 0.05), and jejunal crypt depth (P < 0.05), as well as an inhibition of ERK-related cell proliferation in ileum (P < 0.05). Expression of insulin receptor was down-regulated following OI administration in both control and diabetic animals.

CONCLUSIONS

Experimental STZ-induced diabetes causes intestinal mucosal growth and enhances enterocyte turnover in a rat model. OI administration diminishes diabetes-accelerated cell turnover and diabetes-induced mucosal hyperplasia.

Oral insulin stimulates intestinal epithelial cell turnover in correlation with insulin-receptor expression along the villus-crypt axis in a rat model of short bowel syndrome

PURPOSE

It has been reported that oral insulin (OI) has a trophic effect on intestinal mucosa. In the present study, we evaluated the effect of OI on enterocyte turnover and correlated it with insulin-receptor expression along the villus-crypt axis in a rat model of short bowel syndrome (SBS).

METHODS

Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the fourth postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real-time PCR was used to determine the level of insulin receptor-beta (IRB) mRNA. Insulin-receptor expression along the villus-crypt axis (villus tips, lateral villi and crypts) was assessed by immunohistochemistry. The effect of OI on cell turnover for each compartment was evaluated in correlation with the receptor expression. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant.

RESULTS

Treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Insulin-receptor expression in crypts significantly increased in SBS rats (vs. Sham rats) and was accompanied by a significant increase in enterocyte proliferation following OI administration. A significant increase in insulin-receptor expression at the tip of the villous and in the lateral villous in SBS rats (vs. Sham) was accompanied by decreased cell apoptosis in these compartments following treatment with OI.

CONCLUSIONS

In a rat model of SBS, OI enhances enterocyte turnover and stimulates intestinal adaptation. The stimulating effect of insulin on enterocyte turnover correlates with insulin-receptor expression along the villus-crypt axis.

Oral insulin supplementation in paediatric short bowel disease: a pilot observational study

BACKGROUND AND AIM

Insulin is present in human milk, and oral insulin supplementation causes a dramatic adaptive gut growth in a rat model of short bowel syndrome (SBS). We conducted an open-label pilot observational study to examine whether oral insulin supplementation to paediatric patients with SBS decreases the need for parenteral nutrition (PN).

METHODS

Between April 2004 and March 2006, 10 premature infants and children were recruited from 8 paediatric gastroenterology centres in Israel, Croatia, and Germany. Enrolled subjects received 1 unit of insulin (Actrapid, Novonordisk, Denmark)/kg body weight per dose x 4/day (every 6 hours) for 28 days. We monitored glucose blood levels, weight, enteral and parenteral intake of calories, carbohydrates, and lipids. In addition, blood levels of albumin, ALT, AST, GGT, ALP, total cholesterol, triglycerides, and anti-insulin antibodies were recorded.

RESULTS

On average, enteral intake increased from 45.6% +/- 30.6% to 58.9% +/- 28.2% (not statistically significant), and ALT blood levels decreased from 194 +/- 128 U to 136 +/- 79 U (not statistically significant). Two (2/10) infants were weaned off PN. None of the children developed insulin antibodies.

CONCLUSIONS

Oral insulin supplementation in paediatric SBS is not associated with short-term side effects. Although clinical improvement was observed in a subset of children, whether these effects are due to insulin administration is uncertain. The efficacy of oral insulin remains to be determined in a double-blind manner using a preparation that is resistant to degradation in the stomach.

Oral insulin enhances cell proliferation and decreases enterocyte apoptosis during methotrexate-induced mucositis in the rat

OBJECTIVE

Oral insulin (INS) has been shown to protect intestinal epithelial cells from injury caused by ischemia-reperfusion and endotoxemia. In the present study, we tested whether oral insulin can protect gut epithelial cells from methotrexate (MTX)-induced intestinal damage.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were divided into 3 experimental groups. Control rats were treated with normal saline given intraperitoneally (CONTR), MTX rats were treated with a single dose (20 microg/kg) of MTX given intraperitoneally, and MTX-INS rats were treated with oral insulin given in drinking water (1 U/mL) 72 hours after IP injection of a single dose of MTX (similar to MTX rats). Three days after either MTX or saline injection, rats were killed. Intestinal mucosal damage (Park injury score), mucosal structural changes, enterocyte proliferation, and enterocyte apoptosis were measured. Reverse transcription polymerase chain reaction was used to determine the level of bax and bcl-2 mRNA expression.

RESULTS

MTX-INS rats demonstrated a greater jejunal and ileal mucosal weight, ileal mucosal DNA, greater jejunal villus height, greater jejunal and ileal crypt depth, greater enterocyte proliferation index in ileum, and lower enterocyte apoptosis in ileum than did MTX-nontreated animals. Treatment with insulin did not change the injury score grade in comparison with MTX animals. A significant decrease in cell apoptosis was observed in MTX-INS rats (vs MTX) and also a decrease in a bax mRNA expression and decrease in a bax/bcl-2 ratio.

CONCLUSIONS

In a rat model of MTX-induced mucositis, oral insulin supplementation does not prevent mucosal injury but improves intestinal recovery and enhances enterocyte survival.

Oral insulin up-regulates Toll-like receptor 4 expression and enhances intestinal recovery following lipopolysaccharide-induced gut injury in a rat

In the present study, we evaluated the protective effect of oral insulin (OI) on intestinal mucosa following lipopolysaccharide-induced intestinal damage in a rat. Male Sprague-Dawley rats were divided into three experimental groups: Sham rats, LPS-rats that were treated with lipopolysaccharide (LPS), and LPS-INS rats that were treated with OI given in drinking water 72 h before and following injection of LPS. Intestinal structural changes, enterocyte proliferation, enterocyte apoptosis, and mucosal expression of Toll-like receptor 4 (TLR4) were determined 24 h after the last LPS injection. LPS-INS animals showed a significantly greater bowel and mucosal weight in jejunum and ileum, mucosal DNA and protein in jejunum and ileum, villus height in ileum, crypt depth in jejunum and ileum, cell proliferation rates in jejunum, and significantly lower apoptotic index in ileum compared to LPS- animals. LPS rats demonstrated 50% increase in TLR4 expression in jejunum compared to sham animals. Treatment with OI resulted in a three-fold increase in TLR4 expression in jejunum, compared to LPS animals. In conclusion, OI improves intestinal recovery after LPS endotoxemia in a rat.

Trophic Effect of Bee Pollen on Small Intestine in Broiler Chickens

In this study, the effects of bee pollen on the development of digestive organs were evaluated in broiler chickens. A total of 144 1-day-old AA broiler chickens were randomly and equally divided into two groups, assigned as the control group and the pollen group, respectively. The control group was fed with a basic diet, while the pollen group was fed with a basic diet supplemented with 1.5% bee pollen over a period of 6 weeks. At the end of each week, the digestive organs were obtained for comparison from 12 broilers randomly selected from each group. The results demonstrated that compared to the control group, the small intestine villi from the duodenum, jejunum, and ileum were longer and thicker in the pollen group. This difference was more significant during early development, especially through the first 2 weeks. Bee pollen increased the length of the villi by 37.1% and 29.4% in the duodenum, 28.1% and 33.7% in the jejunum, and 18.6% and 16.2% in the ileum in week 1 and 2, respectively. Furthermore, the small intestinal glands were developed at a higher density in the pollen group, and the depth of the glands was significantly increased by bee pollen in the first 2 weeks. These findings suggest that bee pollen could promote the early development of the digestive system and therefore is a potentially beneficial food supplement for certain conditions, such as short bowel syndrome.

Two-hit rat model of short bowel syndrome and sepsis: independent of total parenteral nutrition, short bowel syndrome is proinflammatory and injurious to the liver

INTRODUCTION

Infants with short bowel syndrome (SBS) are at a high risk for infectious complications and liver failure. We hypothesized that SBS, independent of total parenteral nutrition, is a proinflammatory state that is magnified by sepsis.

METHODS

Sprague-Dawley rats were divided into 2 groups: sham laparotomy (SH, n = 10) or 75% small bowel resection (n = 10). After 14 days, each group underwent a second sham laparotomy (SH/SH and SBS/SH) or cecal ligation and puncture, followed 16 hours later by cecal excision and peritoneal washout (SH/sepsis and SBS/sepsis). Animals were killed 56 hours later.

RESULTS

The SBS rats had higher serum levels of interleukin (IL) 6 vs SH (355 +/- 99 vs 104 +/- 71 pg/mL, P < .05). Liver injury scores were higher in SBS/sepsis compared with SBS/SH animals (3.7 +/- 0.7 vs 1.9 +/- 0.3, P < .05). Hepatic messenger RNA levels of IL-6 (12.8-fold change [FC]) and tumor necrosis factor alpha (5.65 FC) were elevated in SBS vs SH rats; and IL-6 (114 FC), tumor necrosis factor alpha (3.87 FC), and Toll-like receptor 4 (7.65 FC) were increased in SBS/sepsis compared with SH/sepsis animals.

CONCLUSION

Our results suggest that SBS, independent of total parenteral nutrition, is a proinflammatory state and that sepsis induces an exaggerated proinflammatory cytokine response that may play an important role in liver damage and may be mediated by Toll-like receptor 4.

Gastrointestinal tract as a target organ for orally administered insulin

The intestine is not considered to be a classic target tissue for insulin. Recent in vitro and in vivo experiments suggest that intestinal as well as systemic effects are observed following oral administration of insulin. Local effects include enhancement of intestinal growth, cell maturation, enzyme expression, gut adaptation after intestinal resection and reduction of intestinal permeability. Systemic effects, at least in animal models, include favorable effects on blood glucose and lipid profile and on the prevention of autoimmunity and attenuating the atherosclerotic process.