Systemic proteome adaptions to 7-day complete caloric restriction in humans

Surviving long periods without food has shaped human evolution. In ancient and modern societies, prolonged fasting was/is practiced by billions of people globally for religious purposes, used to treat diseases such as epilepsy, and recently gained popularity as weight loss intervention, but we still have a very limited understanding of the systemic adaptions in humans to extreme caloric restriction of different durations. Here we show that a 7-day water-only fast leads to an average weight loss of 5.7 kg (±0.8 kg) among 12 volunteers (5 women, 7 men). We demonstrate nine distinct proteomic response profiles, with systemic changes evident only after 3 days of complete calorie restriction based on in-depth characterization of the temporal trajectories of ~3,000 plasma proteins measured before, daily during, and after fasting. The multi-organ response to complete caloric restriction shows distinct effects of fasting duration and weight loss and is remarkably conserved across volunteers with >1,000 significantly responding proteins. The fasting signature is strongly enriched for extracellular matrix proteins from various body sites, demonstrating profound non-metabolic adaptions, including extreme changes in the brain-specific extracellular matrix protein tenascin-R. Using proteogenomic approaches, we estimate the health consequences for 212 proteins that change during fasting across ~500 outcomes and identified putative beneficial (SWAP70 and rheumatoid arthritis or HYOU1 and heart disease), as well as adverse effects. Our results advance our understanding of prolonged fasting in humans beyond a merely energy-centric adaptions towards a systemic response that can inform targeted therapeutic modulation.

The Impact of an 8-Week Supplementation with Fermented and Non-Fermented Aronia Berry Pulp on Cardiovascular Risk Factors in Individuals with Type 2 Diabetes

Aronia berries contain antioxidants that may be health-promoting, e.g., demonstrated positive effects on hypertension and dyslipidaemia. There is a close link between cardiovascular diseases and hypertension and dyslipidaemia, and cardiovascular events are the leading cause of death among subjects with type 2 diabetes (T2D). Thus, we investigated the effect of an 8-week supplementation with fermented aronia extract (FAE), non-fermented aronia extract (AE), and placebo on cardiovascular risk factors. Snack bars were produced containing 34 g (37%) aronia extract, or 17 g (21%) wheat bran for placebo, as well as raisins and coconut oil. The study was randomized and blinded with a triple-crossover design. We examined the effects of aronia extracts on blood pressure, adiponectin, and high-sensitive C-reactive protein, and found no effects. After supplementation with placebo, there were significantly higher blood concentrations of total cholesterol, LDL-cholesterol, and HDL-cholesterol, with the placebo group showing significantly higher increases in total cholesterol and LDL-cholesterol than the AE group. Furthermore, we observed an increase in HDL-cholesterol in the FAE group and an increase in triglyceride in the AE group. Thus, we assume that the raisins may have increased the participants' cholesterol levels, with both AE and FAE having the potential to prevent this increase.

Aronia in the Type 2 Diabetes Treatment Regimen

Aronia melanocarpa berries are rich in antioxidants and possess a high antioxidant capacity. Aronia berries have shown potential in type 2 diabetes mellitus (T2DM) treatment, and previous studies indicate improvements in glycemia after supplementation. Unfortunately, the effectiveness of aronia berries is limited by the low bioavailability of aronia, which fermentation could potentially overcome. The objective of this study was to compare the effects of fermented or non-fermented aronia pulp with placebo in subjects with T2DM. This study was a triple-blinded, triple-crossover study with eight-week intervention periods with fermented aronia extract (FAE), non-fermented aronia extract (AE), and placebo. Extracts were incorporated in snack bars with 37% aronia (FAE or AE) or wheat bran (placebo) and 63% raisins and coconut oil. Pre- and post-treatment period, we did fasting blood samples, including hemoglobin A1c, fructosamine, insulin, glucose, glucagon-like peptide-1, glucose-dependent insulinotropic peptide (GIP) and glucagon, oral glucose tolerance tests, and anthropometric measurements. Of 36 randomized participants, 23 completed the trial. Aside from a higher increase in GIP after FAE supplementation compared to after placebo supplementation, aronia extracts had no effect. The increase in GIP levels after FAE supplementation may hold potential benefits, but the overall clinical impact remains unclear.

Use of Fermented Red Clover Isoflavones in the Treatment of Overactive Bladder in Postmenopausal Women: A Randomized, Double-Blinded, Placebo-Controlled Trial

Postmenopausal women are at risk of developing an overactive bladder (OAB). Conventional vaginal estrogen has shown promise for symptom relief. Isoflavones have proven effective as an alternative to estrogen treatment against menopause-related symptoms. However, its effect on OAB symptoms has not been studied. This study investigates if fermented red clover isoflavones reduce OAB symptoms in postmenopausal women. In this randomized, double-blinded, placebo-controlled trial, women were administered red clover extract (RCE) or a placebo twice daily for three months. Women filled out the International Consultation on Incontinence Questionnaire Overactive Bladder (ICIQ-OAB) and Urinary Incontinence Short Form (ICIQ-UI-SF), together with a fluid intake and voiding diary. A total of 33 women (16 in the RCE group and 17 in the placebo group) were included in the analysis. Baseline demographics and OAB characteristics were comparable across groups. Intake of RCE did not lead to significant relief in most urinary bladder symptom measures, although a significant reduction in the bother of urinary urgency (p = 0.033) and a tendency towards a decreased ICIQ-OAB score were observed (p = 0.056). In contrast, the placebo exhibited a significant decrease in the ICIQ-OAB score (p = 0.021) and in some diary outcomes. We found that an intake of isoflavones did not relieve OAB symptoms in postmenopausal women.

Similar performance after intake of carbohydrate plus whey protein and carbohydrate only in the early phase after non-exhaustive cycling

The aim of the present study was to compare performance five hours after a 90-min endurance training session when either carbohydrate only or carbohydrate with added whey hydrolysate or whey isolate was ingested during the first two hours of the recovery period.

METHODS

Thirteen highly trained competitive male cyclists completed three exercise and diet interventions (double-blinded, randomized, crossover design) separated by one week. The 90-min morning session (EX1) included a 60 min time-trial (TT₆₀ ). Immediately and one hour after exercise, participants ingested either 1) 1.2 g carbohydrate∙kg^-1 ∙h^-1 (CHO), 2) 0.8 g carbohydrate∙kg^-1 ∙h^-1 + 0.4 g isolate whey protein∙kg^-1 ∙h^-1 (ISO) or 3) 0.8 g carbohydrate∙kg^-1 ∙h^-1 + 0.4 g hydrolysate whey protein∙kg^-1 ∙h^-1 (HYD). Additional intakes were identical between interventions. After five hours of recovery, participants completed a time-trial performance (TT_P ) during which a specific amount of work was performed. Blood and urine were collected throughout the day.

RESULTS

TT_P did not differ significantly between dietary interventions (CHO: 43:54±1:36, ISO: 46:55±2:32, HYD: 44:31±2:01 min). Nitrogen balance during CHO was lower than ISO (p<0.0001) and HYD (p<0.0001), with no difference between ISO and HYD (p=0.317). In recovery, the area under the curve for blood glucose was higher in CHO compared to ISO and HYD. HR, VO₂ , RER, glucose, and lactate during EX2 were similar between interventions.

CONCLUSION

Performance did not differ after five hours of recovery whether carbohydrate only or isocaloric carbohydrate plus protein was ingested during the first two hours. Correspondingly, participants were not in negative nitrogen balance in any dietary intervention.

Effects of Aronia melanocarpa on Cardiometabolic Diseases: A Systematic Review of Quasi-Design Studies and Randomized Controlled Trials

OBJECTIVES: Aronia melanocarpa (Aronia) is a shrub with small berries, chokeberries. Chokeberries are claimed to possess health benefits due to a high content of polyphenols. Aronia is known to be extremely antioxidant; however, evidence for its health benefits is not established. This review gives an overview of the impact of Aronia on cardiometabolic risk factors and diseases. METHODS: Seventeen studies on cardiometabolic risk factors and diseases were identified through a systematic search on PubMed, Embase, and Cochrane. Inclusion criteria were studies with Aronia as intervention, performed in individuals with cardiometabolic disease or risk factors, e. g., type 2 diabetes (T2D), cardiovascular disease, hypertension, dyslipidaemia, impaired glucose tolerance, overweight, central obesity and smoking. Four of these studies were applicable for a quantitative analysis. RESULTS: Aronia did not influence body weight, circulating triglycerides, total cholesterol, high-density lipoprotein (HDL) cholesterol, or blood pressure. The quantitative analysis revealed a mean reduction in blood glucose of 0.44 mmol/l (P=0.0001) in the treatment group compared with the control group suggesting that Aronia treatment may have a beneficial impact on blood glucose. In addition, treatment durations of 6 weeks to 3 months tended to decrease low-density lipoprotein (LDL) cholesterol, while shorter treatment durations had no effect on LDL cholesterol. The quantitative analysis did not provide data on long-term effects of Aronia on lipids. CONCLUSIONS: More long-term high-quality randomized controlled studies are needed to clarify if dietary supplementation with Aronia has beneficial effects on cardiometabolic diseases.

Association of Low- and No-Calorie Sweetened Beverages as a Replacement for Sugar-Sweetened Beverages With Body Weight and Cardiometabolic Risk: A Systematic Review and Meta-analysis

Importance

There are concerns that low- and no-calorie sweetened beverages (LNCSBs) do not have established benefits, with major dietary guidelines recommending the use of water and not LNCSBs to replace sugar-sweetened beverages (SSBs). Whether LNCSB as a substitute can yield similar improvements in cardiometabolic risk factors vs water in their intended substitution for SSBs is unclear.

Objective

To assess the association of LNCSBs (using 3 prespecified substitutions of LNCSBs for SSBs, water for SSBs, and LNCSBs for water) with body weight and cardiometabolic risk factors in adults with and without diabetes.

Data Sources

Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception through December 26, 2021.

Study Selection

Randomized clinical trials (RCTs) with at least 2 weeks of interventions comparing LNCSBs, SSBs, and/or water were included.

Data Extraction and Synthesis

Data were extracted and risk of bias was assessed by 2 independent reviewers. A network meta-analysis was performed with data expressed as mean difference (MD) or standardized mean difference (SMD) with 95% CIs. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) system was used to assess the certainty of the evidence.

Main Outcomes and Measures

The primary outcome was body weight. Secondary outcomes were other measures of adiposity, glycemic control, blood lipids, blood pressure, measures of nonalcoholic fatty liver disease, and uric acid.

Results

A total of 17 RCTs with 24 trial comparisons were included, involving 1733 adults (mean [SD] age, 33.1 [6.6] years; 1341 women [77.4%]) with overweight or obesity who were at risk for or had diabetes. Overall, LNCSBs were a substitute for SSBs in 12 RCTs (n = 601 participants), water was a substitute for SSBs in 3 RCTs (n = 429), and LNCSBs were a substitute for water in 9 RCTs (n = 974). Substitution of LNCSBs for SSBs was associated with reduced body weight (MD, -1.06 kg; 95% CI, -1.71 to -0.41 kg), body mass index (MD, -0.32; 95% CI, -0.58 to -0.07), percentage of body fat (MD, -0.60%; 95% CI, -1.03% to -0.18%), and intrahepatocellular lipid (SMD, -0.42; 95% CI, -0.70 to -0.14). Substituting water for SSBs was not associated with any outcome. There was also no association found between substituting LNCSBs for water with any outcome except glycated hemoglobin A1c (MD, 0.21%; 95% CI, 0.02% to 0.40%) and systolic blood pressure (MD, -2.63 mm Hg; 95% CI, -4.71 to -0.55 mm Hg). The certainty of the evidence was moderate (substitution of LNCSBs for SSBs) and low (substitutions of water for SSBs and LNCSBs for water) for body weight and was generally moderate for all other outcomes across all substitutions.

Conclusions and Relevance

This systematic review and meta-analysis found that using LNCSBs as an intended substitute for SSBs was associated with small improvements in body weight and cardiometabolic risk factors without evidence of harm and had a similar direction of benefit as water substitution. The evidence supports the use of LNCSBs as an alternative replacement strategy for SSBs over the moderate term in adults with overweight or obesity who are at risk for or have diabetes.

Effect of a Low-Carbohydrate High-Fat Diet and a Single Bout of Exercise on Glucose Tolerance, Lipid Profile and Endothelial Function in Normal Weight Young Healthy Females

Low-carbohydrate-high-fat (LCHF) diets are efficient for weight loss, and are also used by healthy people to maintain bodyweight. The main aim of this study was to investigate the effect of 3-week energy-balanced LCHF-diet, with >75 percentage energy (E%) from fat, on glucose tolerance and lipid profile in normal weight, young, healthy women. The second aim of the study was to investigate if a bout of exercise would prevent any negative effect of LCHF-diet on glucose tolerance. Seventeen females participated, age 23.5 ± 0.5 years; body mass index 21.0 ± 0.4 kg/m², with a mean dietary intake of 78 ± 1 E% fat, 19 ± 1 E% protein and 3 ± 0 E% carbohydrates. Measurements were performed at baseline and post-intervention. Fasting glucose decreased from 4.7 ± 0.1 to 4.4 mmol/L (p < 0.001) during the dietary intervention whereas fasting insulin was unaffected. Glucose area under the curve (AUC) and insulin AUC did not change during an OGTT after the intervention. Before the intervention, a bout of aerobic exercise reduced fasting glucose (4.4 ± 0.1 mmol/L, p < 0.001) and glucose AUC (739 ± 41 to 661 ± 25, p = 0.008) during OGTT the following morning. After the intervention, exercise did not reduce fasting glucose the following morning, and glucose AUC during an OGTT increased compared to the day before (789 ± 43 to 889 ± 40 mmol/L∙120min^–1, p = 0.001). AUC for insulin was unaffected. The dietary intervention increased total cholesterol (p < 0.001), low-density lipoprotein (p ≤ 0.001), high-density lipoprotein (p = 0.011), triglycerides (p = 0.035), and free fatty acids (p = 0.021). In conclusion, 3-week LCHF-diet reduced fasting glucose, while glucose tolerance was unaffected. A bout of exercise post-intervention did not decrease AUC glucose as it did at baseline. Total cholesterol increased, mainly due to increments in low-density lipoprotein. LCHF-diets should be further evaluated and carefully considered for healthy individuals.

Efficacy of Arabica Versus Robusta Coffee in Improving Weight, Insulin Resistance, and Liver Steatosis in a Rat Model of Type-2 Diabetes

The effects of chronic coffee exposure in models of type 2 diabetes mellitus (T2D) models is scarcely studied, and the efficacy of the main coffee species has never been compared. We tested the hypothesis that long-term consumption of arabica and robusta coffee may differentially delay and affect T2D development in Zucker diabetic fatty rats. Three study groups received either chow mixed with arabica or robusta instant coffee (1.8% w/w) or unsupplemented chow food for 10 weeks. Both coffee species reduced liver triglyceride content and area under the curve of fasting and postprandial insulin. At study end, plasma adiponectin, total cholesterol and high density lipoprotein levels were higher in the robust group compared with both arabica and control groups. The liver gene expression of Glucose-6-phosphatase, catalytic subunit (G6pc) and Mechanistic target of rapamycin (mTOR) in robusta and Cpt1a in both coffee groups was downregulated. In conclusion, long-term consumption of both coffee species reduced weight gain and liver steatosis and improved insulin sensitivity in a rat model of T2D. Robusta coffee was seemingly superior to arabica coffee with respect to effects on lipid profile, adiponectin level and hepatic gene expression.

GDF15 Provides an Endocrine Signal of Nutritional Stress in Mice and Humans

GDF15 is an established biomarker of cellular stress. The fact that it signals via a specific hindbrain receptor, GFRAL, and that mice lacking GDF15 manifest diet-induced obesity suggest that GDF15 may play a physiological role in energy balance. We performed experiments in humans, mice, and cells to determine if and how nutritional perturbations modify GDF15 expression. Circulating GDF15 levels manifest very modest changes in response to moderate caloric surpluses or deficits in mice or humans, differentiating it from classical intestinally derived satiety hormones and leptin. However, GDF15 levels do increase following sustained high-fat feeding or dietary amino acid imbalance in mice. We demonstrate that GDF15 expression is regulated by the integrated stress response and is induced in selected tissues in mice in these settings. Finally, we show that pharmacological GDF15 administration to mice can trigger conditioned taste aversion, suggesting that GDF15 may induce an aversive response to nutritional stress.

Protein intake in the early recovery period after exhaustive exercise improves performance the following day

The aim of the present study was to investigate the effect of protein and carbohydrate ingestion during early recovery from exhaustive exercise on performance after 18-h recovery. Eight elite cyclists (V̇o2max: 74.0 ± 1.6 ml·kg−1·min−1) completed two exercise and diet interventions in a double-blinded, randomized, crossover design. Participants cycled first at 73% of V̇o2max (W73%) followed by 1-min intervals at 90% of V̇o2max until exhaustion. During the first 2 h of recovery, participants ingested either 1.2 g carbohydrate·kg−1·h−1 (CHO) or 0.8 g carbohydrate + 0.4 g protein·kg−1·h−1 (CHO + PROT). The diet during the remaining recovery period was similar for both interventions and adjusted to body weight. After an 18-h recovery, cycling performance was assessed with a 10-s sprint test, 30 min of cycling at W73%, and a cycling time trial (TT). The TT was 8.5% faster (41:53 ± 1:51 vs. 45:26 ± 1:32 min; P < 0.03) after CHO + PROT compared with CHO. Mean power output during the sprints was 3.7% higher in CHO + PROT compared with CHO (1,063 ± 54 vs. 1,026 ± 53 W; P = 0.01). Nitrogen balance in the recovery period was negative in CHO and neutral in CHO + PROT (−82.4 ± 11.5 vs. 7.0 ± 15.4 mg/kg; P < 0.01). In conclusion, TT and sprint performances were improved 18 h after exhaustive cycling by CHO + PROT supplementation during the first 2 h of recovery compared with isoenergetic CHO supplementation. Our results indicate that intake of carbohydrate plus protein after exhaustive endurance exercise more rapidly converts the body from a catabolic to an anabolic state than carbohydrate alone, thus speeding recovery and improving subsequent cycling performance.

NEW & NOTEWORTHY Prolonged high intensity endurance exercise depends on glycogen utilization and high oxidative capacity. Still, exhaustion develops and effective recovery strategies are required to compete in multiday stage races. We show that coingestion of protein and carbohydrate during the first 2 h of recovery is superior to isoenergetic intake of carbohydrate to stimulate recovery, and improves both endurance time-trial and 10-s sprint performance the following day in elite cyclists.

The Physiological Effects of Dandelion (Taraxacum Officinale) in Type 2 Diabetes

The tremendous rise in the economic burden of type 2 diabetes (T2D) has prompted a search for alternative and less expensive medicines. Dandelion offers a compelling profile of bioactive components with potential anti-diabetic properties. The Taraxacum genus from the Asteraceae family is found in the temperate zone of the Northern hemisphere. It is available in several areas around the world. In many countries, it is used as food and in some countries as therapeutics for the control and treatment of T2D. The anti-diabetic properties of dandelion are attributed to bioactive chemical components; these include chicoric acid, taraxasterol (TS), chlorogenic acid, and sesquiterpene lactones. Studies have outlined the useful pharmacological profile of dandelion for the treatment of an array of diseases, although little attention has been paid to the effects of its bioactive components on T2D to date. This review recapitulates previous work on dandelion and its potential for the treatment and prevention of T2D, highlighting its anti-diabetic properties, the structures of its chemical components, and their potential mechanisms of action in T2D. Although initial research appears promising, data on the cellular impact of dandelion are limited, necessitating further work on clonal β-cell lines (INS-1E), α-cell lines, and human skeletal cell lines for better identification of the active components that could be of use in the control and treatment of T2D. In fact, extensive in-vitro, in-vivo, and clinical research is required to investigate further the pharmacological, physiological, and biochemical mechanisms underlying the effects of dandelion-derived compounds on T2D.

European Society of Coloproctology consensus on the surgical management of intestinal failure in adults

Intestinal failure (IF) is a debilitating condition of inadequate nutrition due to an anatomical and/or physiological deficit of the intestine. Surgical management of patients with acute and chronic IF requires expertise to deal with technical challenges and make correct decisions. Dedicated IF units have expertise in patient selection, operative risk assessment and multidisciplinary support such as nutritional input and interventional radiology, which dramatically improve the morbidity and mortality of this complex condition and can beneficially affect the continuing dependence on parenteral nutritional support. Currently there is little guidance to bridge the gap between general surgeons and specialist IF surgeons. Fifteen European experts took part in a consensus process to develop guidance to support surgeons in the management of patients with IF. Based on a systematic literature review, statements were prepared for a modified Delphi process. The evidence for each statement was graded using Oxford Centre for Evidence-Based Medicine Levels of Evidence. The current paper contains the statements reflecting the position and practice of leading European experts in IF encompassing the general definition of IF surgery and organization of an IF unit, strategies to prevent IF, management of acute IF, management of wound, fistula and stoma, rehabilitation, intestinal and abdominal reconstruction, criteria for referral to a specialist unit and intestinal transplantation.

Chronic Exposure to Proline Causes Aminoacidotoxicity and Impaired Beta-Cell Function: Studies In Vitro

BACKGROUND

Pancreatic islet-cell dysfunction is a hallmark in the development of diabetes, but the reasons for the primary β-cell defect are still elusive. Elevated circulating proline levels have been found in subjects with insulin resistance, obesity, and type 2 diabetes. Therefore, we assessed β-cell function, gene expressions, and cell death after long-term exposure of pancreatic β-cells to excess proline in vitro.

METHODS

Isolated mouse islets and INS-1E cells were incubated with and without excess proline. After 72 h, we examined: (1) β-cell function, including basal insulin secretion (BIS) and glucose-stimulated insulin secretion (GSIS), (2) transcription factors related to insulin gene expression and enzymes involved in the tricarboxylic acid cycle and cholesterol biogenesis, (3) cellular triglycerides (TG) and cholesterol content, (4) the death of INS-1E cells and 3H thymidine incorporation, and (5) protein expression of INS-1E cells in response to proline by proteomics.

RESULTS

We found that high doses of proline increased BIS and decreased GSIS in both isolated mouse islets and INS-1E cells. MafA, insulin 1, and the cytochrome c oxidase subunit VIa polypeptide 2 mRNA expressions were all downregulated, indicating that proline impaired insulin gene transcription and mitochondrial oxidative phosphorylation. In contrast, mevalonate decarboxylase gene expression was upregulated, and simultaneously, cholesterol content in INS-1E cells was enhanced. Protein profiling of INS-1E cells revealed that cytosolic non-specific dipeptidase and α enolase were differentially expressed.

CONCLUSIONS

Our results indicate that proline-induced insulin transcription and mitochondrial oxidative phosphorylation impairment may contribute to the β-cell dysfunction observed in type 2 diabetes. Caution should be applied in interpreting the pathophysiological role of proline since very high proline concentrations were used in the experiments.

Intake of Protein Plus Carbohydrate during the First Two Hours after Exhaustive Cycling Improves Performance the following Day

Intake of protein immediately after exercise stimulates protein synthesis but improved recovery of performance is not consistently observed. The primary aim of the present study was to compare performance 18 h after exhaustive cycling in a randomized diet-controlled study (175 kJ·kg^-1 during 18 h) when subjects were supplemented with protein plus carbohydrate or carbohydrate only in a 2-h window starting immediately after exhaustive cycling. The second aim was to investigate the effect of no nutrition during the first 2 h and low total energy intake (113 kJ·kg^-1 during 18 h) on performance when protein intake was similar. Eight endurance-trained subjects cycled at 237±6 Watt (~72% VO_2max) until exhaustion (TTE) on three occasions, and supplemented with 1.2 g carbohydrate·kg^-1·h^-1 (CHO), 0.8 g carbohydrate + 0.4 g protein·kg^-1·h^-1 (CHO+PRO) or placebo without energy (PLA). Intake of CHO+PROT increased plasma glucose, insulin, and branch chained amino acids, whereas CHO only increased glucose and insulin. Eighteen hours later, subjects performed another TTE at 237±6 Watt. TTE was increased after intake of CHO+PROT compared to CHO (63.5±4.4 vs 49.8±5.4 min; p<0.05). PLA reduced TTE to 42.8±5.1 min (p<0.05 vs CHO). Nitrogen balance was positive in CHO+PROT, and negative in CHO and PLA. In conclusion, performance was higher 18 h after exhaustive cycling with intake of CHO+PROT compared to an isocaloric amount of carbohydrate during the first 2 h post exercise. Intake of a similar amount of protein but less carbohydrate during the 18 h recovery period reduced performance.

Caffeic acid, naringenin and quercetin enhance glucose-stimulated insulin secretion and glucose sensitivity in INS-1E cells

AIMS

Caffeic acid, naringenin and quercetin are naturally occurring phenolic compounds (PCs) present in many plants as secondary metabolites. The aim of this study was to investigate their effect on glucose-stimulated insulin secretion (GSIS) in INS-1E cells and to explore their effect on expression of genes involved in β-cell survival and function under normoglycaemic and glucotoxic conditions.

METHODS

For acute studies, INS-1E cells were grown in 11 mM glucose (72 h) and then incubated with the PCs (1 h) with 3.3/16.7 mM glucose; whereas, for chronic studies, the cells were grown in 11 mM glucose (72 h) with/without the PCs, and then incubated with 3.3/16.7 mM glucose (1 h); thereafter, GSIS was measured. For GSIS and gene expression studies (GES) under glucotoxic conditions, two sets of cells were grown in 11/25 mM glucose with/without the PCs (72 h): one was used for GES, using real time RT-PCR, and the other was exposed to 3.3/16.7 mM glucose, followed by measurement of GSIS.

RESULTS

The study demonstrated that the PCs can enhance GSIS under hyperglycaemic and glucotoxic conditions in INS-1E cells. Moreover, these compounds can differentially, yet distinctly change the expression profile of genes [Glut2 (glucose transporter 2), Gck (glucokinase), Ins1 (insulin 1), Ins2, Beta2 (neurogenic differentiation protein 1), Pdx1 (pancreatic and duodenal homeobox protein 1), Akt1 (RAC-α serine/threonine-protein kinase encoding gene), Akt2 (RAC-β serine/threonine-protein kinase encoding gene), Irs1 (insulin receptor substrate 1), Acc1 (acetyl CoA carboxylase 1), Bcl2 (β-cell lymphoma 2 protein), Bax (Bcl-2 associated X protein), Casp3 (Caspase 3), Hsp70 (heat shock protein 70), and Hsp90] involved in β-cell stress, survival and function.

CONCLUSION

The results indicate that the PCs tested enhance GSIS and glucose sensitivity in INS-1E cells. They also modulate gene expression profiles to improve β-cell survival and function during glucotoxicity.

Effects of whey proteins on glucose metabolism in normal Wistar rats and Zucker diabetic fatty (ZDF) rats

BACKGROUND

Beneficial effects of milk protein on glucose metabolism have been reported.

OBJECTIVES

We hypothesized that dietary supplementation with specific milk protein fractions could prevent diabetes and differentially alter tissue gene expression. Therefore, we studied the effects of supplementing the diet with whey isolate, whey hydrolysate, Α-lactalbumin, and casein proteins in Zucker Diabetic Fatty rats (ZDF) and normal Wistar rats. A chow diet was included as well.

METHODS

Six week old male ZDF (n = 60) and Wistar rats (n = 44) were used in a 13 week study. P-glucose, p-insulin, p-glucagon, HbA1c, total-cholesterol, HDL-cholesterol, and triglycerides were measured. An oral glucose tolerance test (OGTT) was performed. Liver, muscle, and adipose samples were used for RT-PCR. One-way ANOVA and multiple comparison tests were performed.

RESULTS

HbA1c increased during intervention, and was significantly lower for all milk protein fractions compared to chow in the ZDF rats (p < 0.05). At week 18, iAUCs during OGTT in the ZDF rats were similar for all milk protein-treated groups and significantly lower than in the chow fed group (p < 0.01). In the chow-fed group of ZDF rats, p-glucagon increased significantly compared to all milk protein fed animals. Total and HDL cholesterol were increased in the milk protein-treated ZDF rats compared with the control group. Expression of liver GYS2 and SREBP-2 were downregulated in the milk protein-fed ZDF groups compared with chow.

CONCLUSIONS

We conclude that milk protein fractions improve glycemic indices in diabetic rats. No major differences were seen between the milk protein fractions. However, the fractions had a differential impact on tissue gene expression, most pronounced in ZDF rats.

Polyphenol-rich bilberry ameliorates total cholesterol and LDL-cholesterol when implemented in the diet of Zucker diabetic fatty rats

BACKGROUND

Bilberries and blackcurrants are nutrient sources rich in bioactive components, including dietary fibers, polyphenols, and anthocyanins, which possess potent cardiovascular protective properties. Few studies investigating the cardio-protective effects of natural components have focused on whole bilberries or blackcurrants.

OBJECTIVE

The aim of this trial was to investigate whether a diet enriched with bilberries or blackcurrants has beneficial effects on glucose metabolism, lipid profile, blood pressure, and expression of genes related to glucose and lipid metabolism.

METHODS

Male Zucker Diabetic Fatty (ZDF) rats (n = 48) were randomly assigned to either a control, bilberry-enriched, blackcurrant-enriched, or fiber-enriched diet for 8 weeks ad libitum. Real-time quantitative PCR analysis was performed on liver, adipose, and muscle tissue. Berry polyphenol content was determined by HPLC and LC-MS analysis.

RESULTS

Bilberry enrichment reduced total (-21%, p = 0.0132) and LDL-cholesterol (-60%, p = 0.0229) levels, but increased HDL-cholesterol to a lesser extent than in controls. This may partly be due to the altered hepatic liver X receptor-α expression (-24%, p < 0.001). Neither bilberries nor blackcurrants influenced glucose metabolism or blood pressure. Nevertheless, transcriptional analysis implied a better conservation of hepatic and adipocyte insulin sensitivity by bilberry enrichment. Anthocyanins constituted 91% and 87% of total polyphenol content in bilberries and blackcurrants, respectively. However, total anthocyanin content (3441 mg/100 g) was 4-fold higher in bilberries than in blackcurrants (871 mg/100 g).

CONCLUSIONS

Bilberry consumption ameliorated total and LDL-cholesterol levels, but not HDL-cholesterol levels in ZDF rats. Neither bilberry nor blackcurrant enrichment delayed the development of diabetes or hypertension. Thus, in rats, bilberries may be valuable as a dietary preventive agent against hypercholesterolemia, probably by virtue of their high anthocyanin content.

Acute effects of continuous infusions of glucagon-like peptide (GLP)-1, GLP-2 and the combination (GLP-1+GLP-2) on intestinal absorption in short bowel syndrome (SBS) patients. A placebo-controlled study

BACKGROUND AND AIMS

The ileocolonic brake is impaired in short bowel syndrome (SBS) patients with distal bowel resections. An attenuated meal-stimulated hormone secretion may cause gastric hypersecretion, rapid gastric and intestinal transit and a poor adaptation. Attempting to restore this ileocolonic brake, this study evaluated the acute effects of continuous intravenous administration of glucagon-like peptide (GLP) 1 and 2, alone or in combination, on gastrointestinal function in SBS patients.

METHODS

SBS patients were admitted 4 times for identical 72-h balance studies, where infusions (1 pmol/kg/min) of GLP-1, placebo (saline), GLP-2 and GLP-1+2 (1 pmol/kg/min of each), were provided. Patients filled out a VAS questionnaire regarding subjective symptoms during treatments. Bone mineral content, body-weight and -composition were measured using DEXA scans. Blood glucose, insulin, pro insulin C-peptide and GLP concentrations were measured in relation to a standardized breakfast.

RESULTS

Nine SBS patients (5 women/4 men, aged 52±11) were enrolled and completed the study; 7 had end-jejunostomies, 2 had 50% of colon-in-continuity. All treatments significantly reduced the fecal wet weight, energy, nitrogen, sodium and potassium losses compared to placebo. However, only GLP-2 containing treatments increased absolute absorption of wet weight and sodium. Only GLP-1+2 improved the hydrational status evaluated by DEXA increases in the fat mass and calculated total body weight. GLP-1 and GLP-1+2 reduced the post-prandial blood glucose levels. A tendency of nausea and reduced appetite was seen in relation to GLP-1 treatment, but this was ameliorated by the co-administration of GLP-2.

CONCLUSION

GLP-1 decreased diarrhea and fecal excretions in SBS patients, but it seems less potent than GLP-2. The combination of GLP-1+2 numerically provided additive effects on intestinal absorption compared to either peptide given alone. Larger, long-term studies should further assess the potential of the glucagon-like peptides or analogs, alone or in combination, in the treatment of SBS patients.

Development and validation of the disease-specific Short Bowel Syndrome-Quality of Life (SBS-QoL™) scale

BACKGROUND & AIMS

Subjects with short bowel syndrome (SBS) have impaired quality of life (QoL). No disease-specific instrument has been available to measure treatment-induced changes in QoL over time. Therefore, the aim was to develop and validate an SBS-specific QoL scale.

METHODS

Classical test theory and Food and Drug Administration (FDA) guidance were applied for development and validation of the SBS-QoL™. Procedures included item generation and raw scale construction. Factor analysis, construct validity and internal consistency were assessed in a non-interventional observation, test re-test reliability and responsiveness in a randomised clinical study.

RESULTS

The SBS-QoL™ comprises 17 items including two subscales. Subjects assessed the scale as easy to handle and comprehensible. Good construct validity was shown by comparison with the Home Parenteral Nutrition-Quality Of Life questionnaire as an external scale, which yielded moderately high correlation (r ≥ 0.7). High internal consistency was demonstrated (Cronbach's alpha: 0.94). Also the test re-test reliability was high (r ≥ 0.95), indicating reliable reproducibility of results. The Responsiveness Index (1.84) indicated the ability of the scale to detect changes in QoL over time.

CONCLUSIONS

The SBS-QoL™ is an easy to handle and comprehensible SBS-specific subject-reported QoL scale. It is valid, reliable and sensitive with excellent psychometric characteristics to measure treatment-induced changes in QoL over time in subjects with SBS.

Impact of glucagon-like peptide-1 (7-36) amide, isosteviol and 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside on leucine-mediated α-cell dysfunction

AIM

To investigate the acute and chronic effects of l-leucine on pancreatic α-cell function in vitro. Furthermore, we wanted to explore if glucagon-like peptide-1 (GLP-1), isosteviol (ISV) and 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside (AICAR) counteract changes in α-cell function induced by chronic exposure to leucine.

METHODS

Isolated mice islets were incubated with 10 mM leucine for 2 or 72 h. We investigated glucagon and insulin secretion at 2 mM and 16.7 mM glucose. In addition, we cultured clonal α-TC1-6 cells with 5 mM leucine, 5 mM leucine plus GLP-1 (10(-6) M), or ISV (10(-6) M) or AICAR (10(-5) M) at high glucose for 72 h. We measured the glucagon secretion, cholesterol (CHO) and triglyceride (TG) content, cell proliferation as well as gene expression.

RESULTS

Ten millimolar of leucine for 2 h significantly stimulated glucagon and insulin secretion both at 2 and 16.7 mM glucose in mice islets. After 72 h incubation with 10 mM leucine the glucagon secretion was enhanced at both 2 and 16.7 mM glucose, whereas the glucose-stimulated insulin secretion (16.7 mM glucose) was inhibited. Chronic exposure to 5 mM leucine increased glucagon secretion, CHO and TG content, cell proliferation and Pcsk2 (p < 0.001), MafB (p < 0.05), Gcg (p < 0.001), Prkaa1 (p < 0.01), Hmgcr (p < 0.001), Srebf2 (p < 0.001), Acaca (p < 0.001), Mtor (p < 0.05) mRNA expression in clonal α-TC1-6 cells. While GLP-1 was cable of reducing glucagon hypersecretion and Pcsk2 (p < 0.05) mRNA expression. ISV and AICAR had no effect on leucine-induced glucagon hypersecretion.

CONCLUSIONS

Long-term exposure to leucine induces hypersecretion of glucagon secretion, that is, aminoacidotoxicity and influences some key genes of pancreatic α-cells. Interestingly, GLP-1 counteracts the leucine-induced α-cell dysfunction.

Randomised controlled trial of colostrum to improve intestinal function in patients with short bowel syndrome

BACKGROUND/OBJECTIVES

Colostrum is rich in immunoregulatory, antimicrobial and trophic components supporting intestinal development and function in newborns. We assessed whether bovine colostrum could enhance intestinal adaptation and function in adult short bowel syndrome (SBS) patients.

SUBJECTS/METHODS

Twelve SBS patients in this randomised cross-over study received 4 weeks oral supplement of bovine colostrum or an iso-energetic and iso-proteinaceous control (2.4 MJ/d, 500 ml/day) separated by a 4-week washout period. Patients were admitted four times for 72-h periods of fluid, electrolyte and nutrient balance studies. Meals, faeces and urine were weighed, and energy, macronutrient and electrolyte contents were analysed to calculate net nutrient uptake. Body composition was measured by dual-energy X-ray absorptiometry scans, and functional tests of handgrip strength and lung functions were performed. Eight patients completed the study and were included in the analysis.

RESULTS

Both supplements (colostrum and control) not only increased protein (0.96 ± 0.42 MJ/d, P=0.004 1.03 ± 0.44 MJ/d, P=0.003) and energy (1.46 ± 1.02 MJ/d, P=0.005, 1.76 ± 1.46 MJ/d, P=0.01) absorption but also absolute faecal wet weight excretions (231 ± 248 g/d, P=0.002, 319 ± 299 g/d, P=0.03), compared with baseline measurements. Both supplements improved handgrip strength (P=0.03) while only the control supplement increased lean body mass (1.12 ± 1.33 kg, P<0.049). Colostrum was not found to be superior to the control.

CONCLUSION

Intake of high-protein milk supplements increased net nutrient absorption for adult SBS patients, but at the expense of increased diarrhoea. Despite high contents of bioactive factors, colostrum did not significantly improve intestinal absorption, body composition or functional tests compared with the control.

Modern treatment of adult short bowel syndrome patients

By definition, intestinal failure prevails when oral compensation is no longer feasible and parenteral support is necessary to maintain nutritional equilibrium. In the past, conventional treatment has mainly focused on "making the most of what the short bowel syndrome patient still had" by optimizing remnant intestinal function through dietary interventions, antidiarrheals and antisecretory agents. However, modern treatment options are in the near horizon, and the increased understanding of the mediators for intestinal adaptation will lead to the expansion of the limited treatment armamentarium in short bowel syndrome patients with intestinal failure. The clinical meaningfulness and implications of the observed effects of growth hormone, glutamine, glucagon-like peptide 2 (GLP-2) and the dipeptidyl peptidase-4 degradation resistant analog, teduglutide, is presented in this review and balanced against treatment related adverse events and possible unfavourable effects of long-term, possibly lifelong, treatments.

Randomised placebo-controlled trial of teduglutide in reducing parenteral nutrition and/or intravenous fluid requirements in patients with short bowel syndrome

BACKGROUND AND AIMS

Teduglutide, a GLP-2 analogue, may restore intestinal structural and functional integrity by promoting repair and growth of the mucosa and reducing gastric emptying and secretion, thereby increasing fluid and nutrient absorption in patients with short bowel syndrome (SBS). This 24-week placebo-controlled study evaluated the ability of teduglutide to reduce parenteral support in patients with SBS with intestinal failure.

METHODS

In 83 patients randomised to receive subcutaneous teduglutide 0.10 mg/kg/day (n = 32), 0.05 mg/kg/day (n = 35) or placebo (n = 16) once daily, parenteral fluids were reduced at 4-week intervals if intestinal fluid absorption (48 h urine volumes) increased ≥ 10%. Responders were subjects who demonstrated reductions of ≥ 20% in parenteral volumes from baseline at weeks 20 and 24. The primary efficacy end point, a graded response score (GRS), took into account higher levels and earlier onset of response, leading to longer duration of response. The intensity of the response was defined as a reduction from baseline in parenteral volume (from 20% to 100%), and the duration of the response was considered the response at weeks 16, 20 and 24. The results were tested according to a step-down procedure starting with the 0.10 mg/kg/day dose.

RESULTS

Using the GRS criteria, teduglutide in a dose of 0.10 mg/kg/day did not have a statistically significant effect compared with placebo (8/32 vs 1/16, p=0.16), while teduglutide in a dose of 0.05 mg/kg/day had a significant effect (16/35, p = 0.007). Since parenteral volume reductions were equal (353 ± 475 and 354 ± 334 ml/day), the trend towards higher baseline parenteral volume (1816 ± 1008 vs 1374 ± 639 ml/day, p=0.11) in the 0.10 mg/kg/day group compared with the 0.05 mg/kg/day group may have accounted for this discrepancy. Three teduglutide-treated patients were completely weaned off parenteral support. Serious adverse events were distributed similarly between active treatment groups and placebo. Villus height, plasma citrulline concentration and lean body mass were significantly increased with teduglutide compared with placebo.

CONCLUSIONS

Teduglutide was safe, well tolerated, intestinotrophic and suggested pro-absorptive effects facilitating reductions in parenteral support in patients with SBS with intestinal failure. ClinicalTrials.gov number NCT00172185.

Effects of elevated fatty acid and glucose concentrations on pancreatic islet function in vitro

AIMS/HYPOTHESIS

The aims of this study were to elucidate long-term effects of increased fatty acids and glucose concentrations on islet hormone secretion, triglyceride (TG) accumulation and fuel metabolism, and to determine the role of insulin on glucagon secretion.

METHODS

Isolated normal mouse islets were exposed to palmitate (0.6 mM) in the presence of high glucose (16.7 mM). After 48 h culture, glucagon secretion and content, insulin secretion and content, TG content and glucose oxidation were measured. The impact of etomoxir, an inhibitor of carnitine palmitoyl transferase-1, as well as of insulin, and alterations in gene expression were also investigated.

RESULTS

In the presence of palmitate, (i) high glucose caused no statistically significant suppression of glucagon while this was seen in the absence of palmitate; (ii) the insulin response to high glucose was impaired and (iii) an accumulation of TG and a decline in glucose oxidation were detected, whereas the glucagon content remained unchanged. However, etomoxir was capable of reducing glucagon secretion. Addition of exogenous insulin (10(-10)-10(-6) M) failed to restore alpha cell response to normal. Furthermore, 0.6 mM palmitate reduced the mRNA levels of acetyl-CoA carboxylase-1 and sterol regulatory element-binding protein-1c.

CONCLUSIONS/INTERPRETATION

In summary, high concentrations of palmitate and glucose cause a relative increase in glucagon secretion, a decline in insulin secretion, a loss of alpha cell sensitivity to glucose and an accumulation of TG. The inability of insulin to suppress glucagon may be because of insulin resistance of alpha cells.

Dose- and Glucose-Dependent Effects of Amino Acids on Insulin Secretion from Isolated Mouse Islets and Clonal INS-1E Beta-Cells

BACKGROUND

The influence of glucose and fatty acids on beta-cell function is well established whereas little is known about the role of amino acids (AAs).

METHODS

Islets isolated from NMRI mice were incubated overnight. After preincubation, isolated islets as well as clonal INS-1E beta-cells were incubated for 60 min in a modified Krebs Ringer buffer containing glucose and AAs.

RESULTS

At 16.7 mmol/l (mM) glucose, L-arginine, L-lysine, L-alanine, L-proline, L-leucine, and L-glutamine potentiated glucose-stimulated insulin secretion dose-dependently, while DL-homocysteine inhibited insulin secretion. Maximal insulin stimulation was obtained at 20 mM L-proline, L-lysine, L-alanine, L-arginine (islets: 2.5 to 6.7 fold increase; INS-1E cells: 1.6 to 2.2 fold increase). L-glutamine and L-leucine only increased glucose-stimulated (16.7 mM) insulin secretion (INS-1E cells: 1.5 and 1.3 fold, respectively) at an AA concentration of 20 mM. Homocysteine inhibited insulin secretion both at 5.6 mM and 16.7 mM glucose. At glucose levels ranging from 1.1 to 25 mM, the equimolar concentration of 10 mM, L-proline, L-lysine, L-arginine increased insulin secretion from mouse islets and INS-1E cells at all glucose levels applied, with a maximal effect obtained at 25 mM glucose. At a concentration of 10 mM, L-arginine and L-lysine had the highest insulinotropic potency among the AAs investigated.

CONCLUSION

L-arginine, L-lysine, L-alanine, L-proline, L-leucine and L-glutamine acutely stimulate insulin secretion from mouse islets and INS-1E cells in a dose- and glucose-dependent manner, whereas DL-homocysteine inhibits insulin release.

Rebaudioside A directly stimulates insulin secretion from pancreatic beta cells: a glucose-dependent action via inhibition of ATP-sensitive K-channels

Recently, we showed that rebaudioside A potently stimulates the insulin secretion from isolated mouse islets in a dose-, glucose- and Ca(2+)-dependent manner. Little is known about the mechanisms underlying the insulinotropic action of rebaudioside A. The aim of this study was to define the signalling system by which, rebaudioside A acts. Isolated mouse islets were used in the cAMP[(125)I] scintillation proximity assay to measure total cAMP level, and in a luminometric method to measure intracellular ATP and ADP concentrations. Conventional and permeabilized whole-cell configuration of the patch-clamp technique was used to verify the effect of rebaudioside A on ATP-sensitive K(+)-channels from dispersed single beta cells from isolated mouse islets. Insulin was measured by radioimmunoassay from insulinoma MIN6 cells. In the presence of 16.7 mM glucose, the addition of the maximally effective concentration of rebaudioside A (10(-9) M) increased the ATP/ADP ratio significantly, while it did not change the intracellular cAMP level. Rebaudioside A (10(-9) M) and stevioside (10(-6) M) reduced the ATP-sensitive potassium channel (K(ATP)) conductance in a glucose-dependent manner. Moreover, rebaudioside A stimulated the insulin secretion from MIN6 cells in a dose- and glucose-dependent manner. In conclusion, the insulinotropic effect of rebaudioside A is mediated via inhibition of ATP-sensitive K(+)-channels and requires the presence of high glucose. The inhibition of ATP-sensitive K(+)-channels is probably induced by changes in the ATP/ADP ratio. The results indicate that rebaudioside A may offer a distinct therapeutic advantage over sulphonylureas because of less risk of causing hypoglycaemia.

Isosteviol increases insulin sensitivity and changes gene expression of key insulin regulatory genes and transcription factors in islets of the diabetic KKAy mouse

AIMS

Isosteviol (ISV), a diterpene molecule, is an isomer of the backbone structure of a group of substances with recently proven antidiabetic capabilities in both man and rodents. The aim of this study was to investigate if ISV possesses beneficial effects on the metabolism in the diabetic KKAy mouse and to establish the long-term in vivo effects of ISV on the gene expression profile of key insulin regulatory genes in islets.

METHODS

Twenty KKAy mice, aged 5 weeks, were divided into two groups and treated for 9 weeks with either (i) standard chow diet (control) or (ii) chow + 20 mg/kg body weight of ISV. Blood samples were collected before and after intervention and were subsequently analysed. As a non-diabetic control group, 10 normal C57BL mice were fed with standard chow diet. Gene expression was determined in islets by quantitative real-time RT-PCR and Affymetrix microarray.

RESULTS

We demonstrated that long-term treatment with ISV improves glucose homeostasis, increases insulin sensitivity, lowers plasma triglycerides and lowers weight in the diabetic KKAy mice. Furthermore, ISV markedly changes the gene expression profile of key insulin regulatory genes GLUT2, Ins1, Ins2, Pdx1/Ipf1, Beta2/Neurod1, Pax6 and 11-beta-HSD-1 and beta-cell transcription factors Nkx2-2, Nkx6-1, C/EBPalpha and FoxA2 in isolated islets of the KKAy mice.

CONCLUSIONS

The results indicate that ISV improves glucose and insulin sensitivity as well as improving the lipid profile and upregulates the gene expression of key beta-cell genes, including insulin regulatory transcription factors.

Increased insulin sensitivity and changes in the expression profile of key insulin regulatory genes and beta cell transcription factors in diabetic KKAy-mice after feeding with a soy bean protein rich diet high in isoflavone content

High content isoflavone soy protein (SBP) (Abalon) has been found in animal studies to possess beneficial effects on a number of the characteristic features of the insulin resistance syndrome. The aim of this study was to investigate whether SBP exerts beneficial effects on metabolism in the diabetic KKAy-mouse. Furthermore, we investigated the long-term in vivo effect of SBP on the expression profile in islets of key insulin regulatory genes. Twenty KKAy-mice, aged 5 weeks, were divided into 2 groups and treated for 9 weeks with either (A) standard chow diet (control) or (B) chow + 50% SBP. Twenty normal C57BL-mice fed with standard chow diet served as nondiabetic controls (C). Blood samples were collected and analyzed before and after intervention. Gene expression was determined in islets by quantitative real-time RT-PCR and Affymetrix microarray. It was demonstrated that long-term treatment with SBP improves glucose homeostasis, increases insulin sensitivity, and lowers plasma triglycerides in diabetic KKAy-mice. SBP reduces fasting plasma glucose, insulin, triglycerides, and total cholesterol. Furthermore, SBP markedly changes the gene expression profile of key insulin regulatory genes GLUT2, GLUT3, Ins1, Ins2, IGF1, Beta2/Neurod1, cholecystokinin, and LDLr, and proliferative genes in islets isolated from KKAy-mice. After 9 weeks of treatment with SBP, plasma glucose and insulin homeostasis was normalized compared to start levels. The results indicate that SBP improves glucose and insulin sensitivity and up-regulates the expression of key insulin regulatory genes.

Expression Analysis of cPLA2 Alpha Interacting TIP60 in Diabetic KKAy and Non-Diabetic C57BL Wild-Type Mice: No Impact of Transient and Stable TIP60 Overexpression on Glucose-Stimulated Insulin Secretion in Pancreatic Beta-Cells

In the present study we investigate the expression levels of cytosolic phospholipase A2 alpha (cPLA2alpha) interacting histone acetyl transferase proteins TIP60alpha and TIP60beta in non-diabetic C57BL wild-type mice and obese type 2 diabetic KKAy model mice. The aim was to test our hypothesis that TIP60 plays a regulatory role in glucose-stimulated insulin secretion from pancreatic beta-cells.

MATERIAL AND METHODS

Ten obese diabetic KKAy mice and ten non-diabetic C57BL mice were fed a standard chow diet. After nine weeks, islet RNA was purified and used to measure TIP60 expression. We investigated the effect of TIP60alpha and TIP60beta on glucose-stimulated insulin secretion by transient and stable overexpression in the pancreatic mouse beta-cell line MIN6 and the rat beta-cell line INS-1E.

RESULTS

We found that non-diabetic C57BL mice and diabetic KKAy mice have the same level of both the alpha and beta splice forms of TIP60. Furthermore, we demonstrated that transient and stable expression of TIP60 in INS-1E cells affects neither glucose-stimulated insulin secretion, insulin output nor cell insulin content. Also susceptibility to developing gluco-toxicity was unaffected.

CONCLUSION

TIP60 over-expression does not affect glucose stimulated insulin secretion, insulin content or abnormal beta-cell function during glucotoxicity.

Can stevioside in combination with a soy-based dietary supplement be a new useful treatment of type 2 diabetes? An in vivo study in the diabetic goto-kakizaki rat

The diterpene glycoside stevioside (SVS) and soy bean protein isolate have both been shown to have beneficial effects in diabetes treatment. As they each show different benefits we investigated whether the combination of both substances shows an improvement in the treatment of diabetes in Goto-Kakizaki (GK) rats. Over the course of 4 wk, the rats were fed with the following four test diets (n = 12 per group): 1. Standard carbohydrate-rich laboratory diet (chow), 2. chow + SVS (0.03 g/kg BW/day), 3. 80% SPI + 20% chow and 4. 80% SPI + 20 % chow + SVS (0.03 g/kg BW/day). At the end of the course conscious rats underwent an intra-arterial glucose tolerance test (IAGTT) (2.0 g glucose/kg BW). Compared to normal chow diet, stevioside in combination with SPI shows the following beneficial effects in GK rats with mild type 2 diabetes: 1. a 56% reduction in plasma glucose (p < 0.001), 2. a 118% increase in first-phase insulin (p < 0.005), 3. a 20% reduction in glucagons (p < 0.05), 4. a 28% reduction in total cholesterol (p < 0.001), 5. a 13% reduction in FFA (p < 0.01), 6. a 49% reduction in TG (p < 0.001) and 7. a 11% reduction in the systolic blood pressure (p < 0.001). In conclusion, the combination of stevioside and SPI has synergistic positive effects on the characteristic features of the metabolic syndrome, i.e. hyperglycemia, hypertension and dyslipidemia.

Stevioside counteracts the alpha-cell hypersecretion caused by long-term palmitate exposure

Long-term exposure to fatty acids impairs beta-cell function in type 2 diabetes, but little is known about the chronic effects of fatty acids on alpha-cells. We therefore studied the prolonged impact of palmitate on alpha-cell function and on the expression of genes related to fuel metabolism. We also investigated whether the antihyperglycemic agent stevioside was able to counteract these effects of palmitate. Clonal alpha-TC1-6 cells were cultured with palmitate in the presence or absence of stevioside. After 72 h, we evaluated glucagon secretion, glucagon content, triglyceride (TG) content, and changes in gene expression. Glucagon secretion was dose-dependently increased after 72-h culture, with palmitate at concentrations >or=0.25 mM (P< 0.05). Palmitate (0.5 mM) enhanced TG content of alpha-cells by 73% (P< 0.01). Interestingly, stevioside (10(-8) and 10(-6) M) reduced palmitate-stimulated glucagon release by 22 and 45%, respectively (P< 0.01). There was no significant change in glucagon content after 72-h culture with palmitate and/or stevioside. Palmitate increased carnitine palmitoyltransferase I (CPT I) mRNA level, whereas stevioside enhanced CPT I, peroxisome proliferator-activated receptor-gamma, and stearoyl-CoA desaturase gene expressions in the presence of palmitate (P<0.05). In conclusion, long-term exposure to elevated fatty acids leads to a hypersecretion of glucagon and an accumulation of TG content in clonal alpha-TC1-6 cells. Stevioside was able to counteract the alpha-cell hypersecretion caused by palmitate and enhanced the expression of genes involved in fatty acid metabolism. This indicates that stevioside may be a promising antidiabetic agent in treatment of type 2 diabetes.

The short-term effect of fatty acids on glucagon secretion is influenced by their chain length, spatial configuration, and degree of unsaturation: studies in vitro

The influence of fatty acids on beta cell function has been well established whereas little is known about the role of fatty acids on alpha cell function. The aim of our study was to investigate the short-term effects of chain length, spatial configuration, and degree of unsaturation of fatty acids on glucagon secretion from isolated mouse islets and alpha tumor cell 1 clone 6 cells (alpha TC1-6 cells). Glucagon release was measured with different saturated and unsaturated fatty acids as well as cis and trans isomers of fatty acids at low and high glucose. Palmitate (0.1-0.5 mmol/L) immediately stimulated glucagon release in a dose-dependent manner from both isolated islets and alpha TC 1-6 cells. The longer chain length of saturated fatty acids, the higher glucagon responses were obtained. The average fold increase in glucagon to saturated fatty acids (0.3 mmol/L) compared to control was octanoate 1.5, laurate 2.0, myristate 2.9, palmitate 5.4, and stearate 6.2, respectively. Saturated fatty acids were more effective than unsaturated fatty acids in stimulating glucagon secretion. At an equimolar concentration, trans-fatty acids were more potent than their cis isomers. Fatty acids immediately stimulate glucagon secretion from isolated mouse islets pancreatic alpha cells. The chain length, spatial configuration, and degree of unsaturation of fatty acids influence the glucagonotropic effect.

Teduglutide (ALX-0600), a dipeptidyl peptidase IV resistant glucagon-like peptide 2 analogue, improves intestinal function in short bowel syndrome patients

BACKGROUND AND AIMS

Glucagon-like peptide 2 (GLP-2) may improve intestinal absorption in short bowel syndrome (SBS) patients with an end jejunostomy. Teduglutide (ALX-0600), a dipeptidyl peptidase IV resistant GLP-2 analogue, prolongs the intestinotrophic properties of GLP-2 in animal models. The safety and effect of teduglutide were investigated in SBS patients with and without a colon in continuity.

METHODS

Teduglutide was given subcutaneously for 21 days once or twice daily to 16 SBS patients in the per protocol investigational group, 10 with end jejunostomy (doses of 0.03 (n = 2), 0.10 (n = 5), or 0.15 (n = 3) mg/kg/day), one with <50% colon in continuity (dose 0.03 mg/kg/day), and five with > or = 50% colon in continuity (dose 0.10 mg/kg/day). Nutrient balance studies, D-xylose tests, and intestinal mucosa biopsies were performed at baseline, on the last three days of treatment, and after three weeks of follow up. Pre-study fasting native GLP-2 levels were determined for the five patients with > or = 50% colon in continuity.

RESULTS

Pooled across groups and compared with baseline, teduglutide increased absolute (+743 (477) g/day; p<0.001) and relative (+22 (16)%; p<0.001) wet weight absorption, urine weight (+555 (485) g/day; p<0.001), and urine sodium excretion (+53 (40) mmol/day; p<0.001). Teduglutide decreased faecal wet weight (-711 (734) g/day; p = 0.001) and faecal energy excretion (-808 (1453) kJ/day (-193 (347) kcal/day); p = 0.040). In SBS patients with end jejunostomy, teduglutide significantly increased villus height (+38 (45)%; p = 0.030), crypt depth (+22 (18)%; p = 0.010), and mitotic index (+115 (108)%; p = 0.010). Crypt depth and mitotic index did not change in colonic biopsies from SBS patients with colon in continuity. The most common side effects were enlargement of the stoma nipple and mild lower leg oedema. The improvements in intestinal absorption and decreases in faecal excretion noted after treatment had reversed after the drug free follow up period. A controlled study with a more robust design is ongoing in order to determine the optimal dosage of teduglutide for SBS patients to achieve the maximal effect and utility of this drug in clinical practice.

CONCLUSION

Teduglutide, at three dose levels for 21 days, was safe and well tolerated, intestinotrophic, and significantly increased intestinal wet weight absorption in SBS patients with an end jejunostomy or a colon in continuity.

The diterpene glycoside, rebaudioside A, does not improve glycemic control or affect blood pressure after eight weeks treatment in the Goto-Kakizaki rat

The plant, Stevia rebaudiana Bertoni (SrB), has been used for the treatment of diabetes in traditional medicine. Previously, we have demonstrated that long-term administration of the glycoside stevioside has insulinotropic, glucagonostatic, anti-hyperglycemic and blood pressure-lowering effects in type 2 diabetic animal models. The aim of this study was to elucidate if long-term administration of rebaudioside A, another glycoside isolated from the plant SrB, could improve glycemic control and lower blood pressure in an animal model of type 2 diabetes. We divided male Goto-Kakizaki (GK) rats into two groups which were fed a standard laboratory chow diet for eight weeks. The diet was supplemented with oral rebaudioside A (0.025 g/kg BW/day) in the experimental group. Blood glucose, weight, blood pressure and food intake were measured weekly. Animals were equipped with an intra-arterial catheter, and at week eight the conscious rats underwent an intra-arterial glucose tolerance test (IAGTT) (2.0 g/kg BW). During the IAGTT, the level of glucose, glucagon, and insulin responses did not differ significantly between the two groups. Fasting levels of glucose, glucagon, insulin or levels of blood lipids did not differ between the groups throughout the study period. We observed no effect on blood pressure or weight development. In conclusion, oral supplementation with rebaudioside A (0.025 g/kg BW/day) for eight weeks did not influence blood pressure or glycemic control in GK rats. Rebaudioside A failed to show the beneficial effects in diabetic animals previously demonstrated for stevioside.

Clinical significance of GLP-2 in short-bowel syndrome

Although long-term parenteral nutrition is lifesaving in patients with intestinal failure, it is expensive, severely impairs the quality of life in the short-bowel patients and is associated with serious complications such as catheter sepsis, venous occlusions and liver disease. Therefore, treatments that aim to minimize intestinal absorption, thereby eliminating or minimizing the need for parenteral support, are needed. As a result, glucagon-like peptide 2 (GLP-2) has received attention. In this review, the nature of short-bowel syndrome is described and the antisecretory, transit modulating and intestinotrophic effects of GLP-2 are presented. As illustrated in a pilot study, GLP-2 may prove to be important in the attempt to optimize remnant intestinal function thereby eliminating the need for parenteral support and improving quality of life in short-bowel patients with intestinal failure.

Antihyperglycemic effects of stevioside in type 2 diabetic subjects

Stevioside is present in the plant Stevia rebaudiana Bertoni (SrB). Extracts of SrB have been used for the treatment of diabetes in, for example, Brazil, although a positive effect on glucose metabolism has not been unequivocally demonstrated. We studied the acute effects of stevioside in type 2 diabetic patients. We hypothesize that supplementation with stevioside to a test meal causes a reduction in postprandial blood glucose. Twelve type 2 diabetic patients were included in an acute, paired cross-over study. A standard test meal was supplemented with either 1 g of stevioside or 1 g of maize starch (control). Blood samples were drawn at 30 minutes before and for 240 minutes after ingestion of the test meal. Compared to control, stevioside reduced the incremental area under the glucose response curve by 18% (P =.013). The insulinogenic index (AUC(i,insulin)/AUC(i,glucose)) was increased by approximately 40% by stevioside compared to control (P <.001). Stevioside tended to decrease glucagon levels, while it did not significantly alter the area under the insulin, glucagon-like peptide 1, and glucose-dependent insulinotropic polypeptide curves. In conclusion, stevioside reduces postprandial blood glucose levels in type 2 diabetic patients, indicating beneficial effects on the glucose metabolism. Stevioside may be advantageous in the treatment of type 2 diabetes.

Experimental approaches: dietary and hormone therapy

Patients who suffer from intestinal failure depend on parenteral support to maintain nutritional equilibrium. In this chapter, recommendations for evaluation the absorptive capacity of patients with intestinal failure are defined, and the evidence and magnitude of the effect of dietary and hormone therapy is given. Regarding dietary advice, the effects of employment of diets with various carbohydrate:fat ratios in short-bowel syndrome (SBS) patients with and without a preserved colon is presented. Focus has been placed on the use of growth hormone but also on the use of a novel intestinotrophic hormone, glucagon-like peptide 2, in the promotion of intestinal adaptation in SBS patients. Overall, the ultimate aim in the treatment of SBS patients is to optimize remnant intestinal function, thereby eliminating the need for parenteral support and improving quality of life in these patients.

Vitamin D status and measurements of markers of bone metabolism in patients with small intestinal resection

BACKGROUND AND AIMS

Vitamin D deficiency is common in patients with small intestinal resection and may lead to secondary hypersecretion of parathyroid hormone (PTH), which in turn may result in increased bone turnover rate and loss of bone mineral. The aims of this study were to investigate the prevalence of vitamin D deficiency, as assessed by low serum concentrations of 25-hydroxyvitamin D (25(OH)D) in patients with small intestinal resection and to explore the relation of 25(OH)D to PTH, markers of bone turnover rate, and bone mineral density (BMD) in these patients.

PATIENTS

Forty two patients with small intestinal resection, a faecal energy excretion of more than 2.0 MJ/day, and a mean length of the remaining small intestine of 199 cm were included. Diagnoses were Crohn's disease (n=35) and other (n=7).

METHODS

25(OH)D was analysed by radioimmunoassay and bone turnover rate was assessed by measurement of serum osteocalcin, serum alkaline phosphatase, urine pyridinoline, and urine deoxypyridinoline. BMD was measured by dual energy x ray absorptiometry.

RESULTS

Mean 25(OH)D concentration was 13.4 (SD 9.7) ng/ml, which was significantly below the reference mean of 26.4 (SD 13.2) ng/ml (p<0.001). Vitamin D deficiency (25(OH)D concentration </=8 ng/ml) was found in 38.1% of patients and was accompanied by raised concentrations of PTH and significantly increased markers of bone resorption (p<0.05). Low 25(OH)D concentrations correlated significantly with lower BMD z scores of the spine (r=0.38; p=0.02) and hip (r=0.33; p=0.04).

CONCLUSIONS

We found reduced 25(OH)D concentrations in patients with small intestinal resection, and showed that a deficient 25(OH)D concentration is associated with significantly increased markers of bone resorption and decreased BMD values.

Impact of dietary FA and energy restriction on plasma leptin and ob gene expression in mice

The aim of the present study was to elucidate whether the qualitative composition of dietary fat influences plasma leptin and adipose tissue ob gene expression differentially. Two high-fat diets and a diet rich in carbohydrate were each administered both ad libitum and with a 25% energy restriction. The high-fat diets contained 58 energy percent as either monounsaturated FA (MUFA) or saturated FA (SAFA), whereas the carbohydrate-rich diet (CH) contained 7 energy percent as fat. We aimed at obtaining the same final weight for the animals in the ad libitum group as in the energy-restricted groups. This goal was reached at the same time (days 22-24) for all groups except for the ad libitum animals fed on saturated fat (day 36). The plasma leptin concentrations on ad libitum CH and MUFA diets did not differ significantly (24.3 +/- 2.1 and 34.7 +/- 6.7 ng/mL, respectively) whereas the saturated fat diet caused a lower concentration (13.9 +/- 1.9 ng/mL; P < 0.05). Interestingly, no differences in plasma leptin levels between groups were seen in the energy-restricted groups (mean 8.0 +/- 1.0 ng/mL). The type of diet did not alter the ob gene expression in intraabdominal white adipose tissue; however, a lower expression level was found in the energy-restricted groups. The percentage of body fat in the three ad libitum fed groups did not differ (23 +/- 1%). Thus, short-term administration of a diet rich in SAFA suppresses circulating leptin levels without altering the adipose tissue ob gene expression. This indicates that saturated fat may alter protein handling by adipose tissue or the whole body clearance of leptin.

Antihyperglycemic and blood pressure-reducing effects of stevioside in the diabetic Goto-Kakizaki rat

Stevioside, a glycoside present in the leaves of the plant, Stevia rebaudiana Bertoni (SrB), has acute insulinotropic effects in vitro. Its potential antihyperglycemic and blood pressure-lowering effects were examined in a long-term study in the type 2 diabetic Goto-Kakizaki (GK) rat. Rats were fed 0.025 g x kg(-1) x d(-1) of stevioside (purity > 99.6%) for 6 weeks. An intra-arterial catheter was inserted into the rats after 5 weeks, and conscious rats were subjected to arterial glucose tolerance test (2.0 g x kg(-1)) during week 6. Stevioside had an antihyperglycemic effect (incremental area under the glucose response curve [IAUC]): 985 +/- 20 (stevioside) versus 1,575 +/- 21 (control) mmol/L x 180 minutes, (P <.05), it enhanced the first-phase insulin response (IAUC: 343 +/- 33 [stevioside] v 136 +/- 24 [control] microU/mL insulin x 30 minutes, P <.05) and concomitantly suppressed the glucagon levels (total AUC: 2,026 +/- 234 [stevioside] v 3,535 +/- 282 [control] pg/mL x 180 minutes, P <.05). In addition, stevioside caused a pronounced suppression of both the systolic (135 +/- 2 v 153 +/- 5 mm Hg; P <.001) and the diastolic blood pressure (74 +/- 1 v 83 +/- 1 mm Hg; P <.001). Bolus injections of stevioside (0.025 g x kg(-1)) did not induce hypoglycemia. Stevioside augmented the insulin content in the beta-cell line, INS-1. Stevioside may increase the insulin secretion, in part, by induction of genes involved in glycolysis. It may also improve the nutrient-sensing mechanisms, increase cytosolic long-chain fatty acyl-coenzyme A (CoA), and downregulate phosphodiesterase 1 (PDE1) estimated by the microarray gene chip technology. In conclusion, stevioside enjoys a dual positive effect by acting as an antihyperglycemic and a blood pressure-lowering substance; effects that may have therapeutic potential in the treatment of type 2 diabetes and the metabolic syndrome.

Short-term administration of glucagon-like peptide-2. Effects on bone mineral density and markers of bone turnover in short-bowel patients with no colon

BACKGROUND

Glucagon-like peptide 2 (GLP-2) is a newly discovered intestinotrophic hormone. We have recently reported that a 5-week GLP-2 treatment improved the intestinal absorptive capacity of short-bowel patients with no colon. Additionally, GLP-2 treatment was associated with changes in body composition that included a significant increase in total body bone mass. This article describes the effect of GLP-2 on spinal and hip bone mineral density (BMD) and biochemical markers of bone turnover in these patients.

METHODS

In an open-labelled pilot study, eight short-bowel patients (3M, 5F; mean age 49 years) with small-bowel resection and no colon received 400 microg s.c. of GLP-2 twice daily for 5 weeks. Four received home parenteral nutrition (mean length of residual jejunum 83 cm) and 4 did not (mean length of ileum resected 106 cm). The outcome measures were the mean percent change from baseline in spinal and hip BMD measured by dual-energy X-ray absorptiometry, changes in four biochemical markers of bone-turnover, PTH, 25-hydroxy vitamin-D, and the intestinal absorption of calcium.

RESULTS

Mean +/- s(x) (SEM) percent changes in spinal and hip BMD were 1.1+/-0.4% (P < 0.05) and 1.9+/-0.8% (P = 0.06), respectively. The intestinal calcium absorption increased by 2.7% (P = 0.87). Serum ionized calcium increased in 5/8 patients with a concomitant decrease in serum PTH values. Three of the four markers of bone turnover decreased.

CONCLUSION

A 5-week GLP-2 administration significantly increased spinal BMD in short-bowel patients with no colon. The mechanism by which GLP-2 affects bone metabolism remains unclear, but may be related to an increased mineralization of bone resulting from an improved intestinal calcium absorption.

Stevioside induces antihyperglycaemic, insulinotropic and glucagonostatic effects in vivo: studies in the diabetic Goto-Kakizaki (GK) rats

Extracts of leaves from the plant Stevia rebaudiana Bertoni have been used in the traditional treatment of diabetes in Paraguay and Brazil. Recently, we demonstrated a direct insulinotropic effect in isolated mouse islets and the clonal beta cell line INS-1 of the glycoside stevioside that is present in large quantity in these leaves. Type 2 diabetes is a chronic metabolic disorder that results from defects in both insulin and glucagon secretion as well as insulin action. In the present study we wanted to unravel if stevioside in vivo exerts an antihyperglycaemic effect in a nonobese animal model of type 2 diabetes. An i.v. glucose tolerance test (IVGT) was carried out with and without stevioside in the type 2 diabetic Goto-Kakizaki (GK) rat, as well as in the normal Wistar rat. Stevioside (0.2 g/kg BW) and D-glucose (2.0 g/kg BW) were administered as i.v. bolus injections in anaesthetized rats. Stevioside significantly suppressed the glucose response to the IVGT in GK rats (incremental area under the curve (IAUC): 648 +/- 50 (stevioside) vs 958 +/- 85 mM x 120 min (control); P < 0.05) and concomitantly increased the insulin response (IAUC: 51116 +/- 10967 (stevioside) vs 21548 +/- 3101 microU x 120 min (control); P < 0.05). Interestingly, the glucagon level was suppressed by stevioside during the IVGT, (total area under the curve (TAUC): 5720 +/- 922 (stevioside) vs 8713 +/- 901 pg/ml x 120 min (control); P < 0.05). In the normal Wistar rat stevioside enhanced insulin levels above basal during the IVGT (IAUC: 79913 +/- 3107 (stevioside) vs 17347 +/- 2882 microU x 120 min (control); P < 0.001), however, without altering the blood glucose response (IAUC: 416 +/- 43 (stevioside) vs 417 +/- 47 mM x 120 min (control)) or the glucagon levels (TAUC: 5493 +/- 527 (stevioside) vs 5033 +/- 264 pg/ml x 120 min (control)). In conclusion, stevioside exerts antihyperglycaemic, insulinotropic, and glucagonostatic actions in the type 2 diabetic GK rat, and may have the potential of becoming a new antidiabetic drug for use in type 2 diabetes.

Glucagon-like peptide 2 improves nutrient absorption and nutritional status in short-bowel patients with no colon

BACKGROUND & AIMS

Glucagon-like peptide 2 (GLP-2) is intestinotrophic, antisecretory, and transit-modulating in rodents, and it is mainly secreted from the intestinal mucosa of the terminal ileum and colon after food ingestion. We assessed the effect of GLP-2 on the gastrointestinal function in patients without a terminal ileum and colon who have functional short-bowel syndrome with severe malabsorption of wet weight (>1.5 kg/day) and energy (>2.3 MJ/day) and no postprandial secretion of GLP-2.

METHODS

Balance studies were performed before and after treatment with GLP-2, 400 microg subcutaneously twice a day for 35 days, in 8 patients (4-17 years from last bowel resection; 6 with Crohn's disease). Four patients received home parenteral nutrition (mean residual jejunum, 83 cm), and 4 did not (mean ileum resection, 106 cm). Biopsy specimens were taken from jejunal/ileal stomas, transit was measured by scintigraphy, and body composition was measured by dual-energy x-ray absorptiometry.

RESULTS

Treatment with GLP-2 improved the intestinal absorption of energy 3.5% +/- 4.0% (mean +/- SD) from 49.9% to 53.4% (P = 0.04), wet weight 11% +/- 12% from 25% to 36% (P = 0.04), and nitrogen 4.7% +/- 5.4% from 47.4% to 52.1% (P = 0.04). Body weight increased 1.2 +/- 1.0 kg (P = 0.01), lean body mass increased 2.9 +/- 1.9 kg (P = 0.004), fat mass decreased 1.8 +/- 1.3 kg (P = 0.007), and 24-hour urine creatinine excretion increased (P = 0.02). The time to 50% gastric emptying of solids increased 30 +/- 16 minutes from 89 to 119 minutes (P < 0.05). Small bowel transit time was not changed. Crypt depth and villus height were increased in 5 and 6 patients, respectively.

CONCLUSIONS

Treatment with GLP-2 improves intestinal absorption and nutritional status in short-bowel patients with impaired postprandial GLP-2 secretion in whom the terminal ileum and the colon have been resected.

Intestinal growth adaptation and glucagon-like peptide 2 in rats with ileal--jejunal transposition or small bowel resection

Glucagon-like peptide 2 (GLP-2), produced by enteroendocrine L-cells, regulates intestinal growth. This study investigates circulating and intestinal GLP-2 levels in conditions with altered L-cell exposure to nutrients. Rats were allocated to the following experimental groups: ileal-jejunal transposition, resection of the proximal or distal half of the small intestine, and appropriate sham-operated controls. After two weeks, ileal-jejunal transposition led to pronounced growth of the transposed segment and also of the remaining intestinal segments. Plasma GLP-2 levels increased twofold, whereas GLP-2 levels in the intestinal segments were unchanged. In resected rats with reduced intestinal capacity, adaptive small bowel growth was more pronounced following proximal resection than distal small bowel resection. Circulating GLP-2 levels increased threefold in proximally resected animals, and twofold in the distally resected group. Tissue GLP-2 levels were unchanged in resected rats. The data indicate that transposition of a distal part of the small intestine, and thereby exposure of L cells to a more nutrient-rich chyme, leads to intestinal growth. The adaptive intestinal growth is associated with increased plasma levels of GLP-2, and GLP-2 seems to act in an endocrine as well as a paracrine manner.

Effect of high-dose growth hormone and glutamine on body composition, urine creatinine excretion, fatty acid absorption, and essential fatty acids status in short bowel patients: a randomized, double-blind, crossover, placebo-controlled study

BACKGROUND

Positive effects of high dose growth hormone and glutamine (GH + GLN) on body composition in short bowel patients have been described. Lack of effects on intestinal absorption found in some studies has been ascribed to concomitant essential fatty acid (EFA) deficiency. This study describes changes in body weight (BW) and composition, 24-h urine creatinine excretion, intestinal fatty acid absorption (total, saturated, unsaturated and EFA), and EFA status in relation to treatment with GH + GLN in 8 short bowel patients.

METHODS

A double-blind, crossover study between placebo and growth hormone (mean, 0.12 mg/kg/day) plus oral (mean, 28 g/day) and parenteral glutamine (mean, 5.2 g/day) for 28 days. Body composition was measured by dual-energy absorptiometry (DEXA) scans. Intestinal fatty acid absorption was evaluated in balance studies, and EFAs were measured in plasma phospholipids by gas liquid chromatography.

RESULTS

Active treatment did not increase BW, lean body mass (LBM), fat mass (FM) and bone mass significantly compared with placebo treatment, but BW increased 1.03 kg (1.7%, P < 0.05), LBM 2.93 kg (8.7%, P < 0.001) and FM decreased 2.41 kg (10.6%, P < 0.001) in comparison with baseline. Twenty-four-hour urine creatinine excretion did not differ between study periods. No changes in intestinal absorption of fatty acids were seen, and no changes in EFAs measured in plasma phospholipids were observed. Only 1 of 8 patients, who did not receive parenteral lipids, had a Holman index above 0.2, indicative of EFA deficiency. All developed peripheral oedema.

CONCLUSIONS

Combined high dose growth hormone and glutamine administered for 4 weeks, did not improve absorption of fatty acids or EFA status in short bowel patients. No changes in BW or composition were seen when comparing treatment to placebo periods. The increase in LBM measured by DEXA scan, comparing treatment and baseline periods, was not accompanied by an increase in the 24-h urinary creatinine excretion and is suspected to be associated with an accumulation in extracellular fluids.

Potential targets for glucagon-like peptide 2 (GLP-2) in the rat: distribution and binding of i.v. injected (125)I-GLP-2

Glucagon-like peptide 2 (GLP-2) is a 33-amino acid (1-33) intestinotrophic peptide. In this study, the distribution and binding of i.v. injected radiolabeled GLP-2 (1-33) were investigated in rats using autoradiography in order to target possible binding sites. The major part of (125)I-GLP-2 (1-33) was distributed to kidneys, liver, and the gastrointestinal tract. In the small intestine, a high density of grains was localized in the epithelium with a predominance in the luminal part of the villus. The saturability of (125)I-GLP-2 (1-33) was investigated by administration of excess amounts of non-radioactive GLP-2 (1-33) or the primary metabolite of GLP-2 degradation, GLP-2 (3-33). In the small intestine, (125)I-GLP-2 was displaced both by non-radioactive GLP-2 (1-33) and (3-33), suggesting that the uptake of GLP-2 (1-33) in the small intestine is receptor-specific and that the metabolite GLP-2 (3-33) may interact with the GLP-2 receptor.

Elevated plasma glucagon-like peptide 1 and 2 concentrations in ileum resected short bowel patients with a preserved colon

BACKGROUND

The glucagon-like peptides (GLP) 1 and 2 are secreted postprandially from L cells located mainly in the ileum. Both hormones prolong intestinal transit and GLP-2 is intestinotrophic in rodents. Patients with a jejunostomy have poor adaptation, rapid gastric and intestinal transit, and impaired postprandial GLP-2 secretion. Ileum resected short bowel patients with a preserved colon show evidence of functional adaptation and have normal gastric emptying.

AIM

To investigate if GLP-1 and GLP-2 contribute to the positive effects of a preserved colon in short bowel patients by measuring circulating levels of GLP-1 and GLP-2 in seven ileum resected short bowel patients with a preserved colon and seven age and sex matched controls.

METHODS

GLP-1 and GLP-2 immunoreactivity was measured by specific radioimmunoassays in plasma collected at fasting and at regular intervals 180 minutes after a test meal.

RESULTS

Median (25-75%) fasting GLP-2 values were 72 (69-105) pmol/l versus 23 (19-27) pmol/l (p=0.001) and meal stimulated area under the curve was 21 078 (14 811-26 610) min x pmol/l versus 11 150 (7151-12 801) min x pmol/l (p=0.01) in short bowel patients with a preserved colon compared with control subjects. Fasting GLP-1 values were 10 (6-12) pmol/l versus 5 (3-5) pmol/l (p=0.01) and meal stimulated area under the curve was 3418 (2966-6850) min x pmol/l versus 2478 (1929-3199) min x pmol/l (p=0.04), respectively.

CONCLUSION

Ileum resected short bowel patients with a preserved colon had elevated fasting plasma concentrations of GLP-1 and GLP-2 and significantly larger meal stimulated areas under the curve compared with age and sex matched controls. Elevated GLP-1 and GLP-2 concentrations may contribute to the positive effects of a preserved colon on intestinal motility and functional adaptation in ileum resected short bowel patients.

Effect of high dose growth hormone with glutamine and no change in diet on intestinal absorption in short bowel patients: a randomised, double blind, crossover, placebo controlled study

BACKGROUND

High dose growth hormone, glutamine, and a high carbohydrate diet may improve intestinal function in short bowel patients.

AIMS

To investigate if growth hormone with glutamine and no change in diet improved intestinal function.

PATIENTS AND METHODS

Eight short bowel patients were randomised in a double blind crossover study between placebo and growth hormone (mean 0.12 mg/kg/day) with oral (mean 28 g/day) and parenteral glutamine (mean 5.2 g/day) for 28 days. Balance studies were performed at baseline and five days after placebo and treatment were terminated. Dietary energy, carbohydrate, and fat were maintained as usual.

RESULTS

Growth hormone with glutamine did not improve intestinal absorption of energy (baseline, placebo, treatment, mean: 46%, 48%, 46% of oral intake, respectively), carbohydrate (71%, 70%, 71%), fat (20%, 15%, 18%), nitrogen (27%, 18%, 19%), wet weight (37%, 39%, 31%), sodium (-16%, -16%, -36%), potassium (43%, 47%, 33%), calcium (-16%, -16%, -15%) or magnesium (-3%, 4%, 2%) compared with placebo or baseline (p>0.05) five days after treatment was terminated. All patients experienced adverse effects.

CONCLUSIONS

Combined high dose growth hormone and glutamine administered for four weeks did not improve intestinal absorption five days after treatment was terminated in short bowel patients on their usual diet.