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Anjom-Shoae J, Feinle-Bisset C, Horowitz M. Impacts of dietary animal and plant protein on weight and glycemic control in health, obesity and type 2 diabetes: friend or foe? Front Endocrinol (Lausanne) 2024; 15:1412182. [PMID: 39145315 PMCID: PMC11321983 DOI: 10.3389/fendo.2024.1412182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 07/17/2024] [Indexed: 08/16/2024] Open
Abstract
It is well established that high-protein diets (i.e. ~25-30% of energy intake from protein) provide benefits for achieving weight loss, and subsequent weight maintenance, in individuals with obesity, and improve glycemic control in type 2 diabetes (T2D). These effects may be attributable to the superior satiating property of protein, at least in part, through stimulation of both gastrointestinal (GI) mechanisms by protein, involving GI hormone release and slowing of gastric emptying, as well as post-absorptive mechanisms facilitated by circulating amino acids. In contrast, there is evidence that the beneficial effects of greater protein intake on body weight and glycemia may only be sustained for 6-12 months. While both suboptimal dietary compliance and metabolic adaptation, as well as substantial limitations in the design of longer-term studies are all likely to contribute to this contradiction, the source of dietary protein (i.e. animal vs. plant) has received inappropriately little attention. This issue has been highlighted by outcomes of recent epidemiological studies indicating that long-term consumption of animal-based protein may have adverse effects in relation to the development of obesity and T2D, while plant-based protein showed either protective or neutral effects. This review examines information relating to the effects of dietary protein on appetite, energy intake and postprandial glycemia, and the relevant GI functions, as reported in acute, intermediate- and long-term studies in humans. We also evaluate knowledge relating to the relevance of the dietary protein source, specifically animal or plant, to the prevention, and management, of obesity and T2D.
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Affiliation(s)
- Javad Anjom-Shoae
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
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Li RJW, Barros DR, Kuah R, Lim YM, Gao A, Beaudry JL, Zhang SY, Lam TKT. Small intestinal CaSR-dependent and CaSR-independent protein sensing regulates feeding and glucose tolerance in rats. Nat Metab 2024; 6:39-49. [PMID: 38167726 DOI: 10.1038/s42255-023-00942-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 11/08/2023] [Indexed: 01/05/2024]
Abstract
Proteins activate small intestinal calcium sensing receptor (CaSR) and/or peptide transporter 1 (PepT1) to increase hormone secretion1-8, but the effect of small intestinal protein sensing and the mechanistic potential of CaSR and/or PepT1 in feeding and glucose regulation remain inconclusive. Here we show that, in male rats, CaSR in the upper small intestine is required for casein infusion to increase glucose tolerance and GLP1 and GIP secretion, which was also dependent on PepT1 (ref. 9). PepT1, but not CaSR, is required for casein infusion to lower feeding. Upper small intestine casein sensing fails to regulate feeding, but not glucose tolerance, in high-fat-fed rats with decreased PepT1 but increased CaSR expression. In the ileum, a CaSR-dependent but PepT1-independent pathway is required for casein infusion to lower feeding and increase glucose tolerance in chow-fed rats, in parallel with increased PYY and GLP1 release, respectively. High fat decreases ileal CaSR expression and disrupts casein sensing on feeding but not on glucose control, suggesting an ileal CaSR-independent, glucose-regulatory pathway. In summary, we discover small intestinal CaSR- and PepT1-dependent and -independent protein sensing mechanisms that regulate gut hormone release, feeding and glucose tolerance. Our findings highlight the potential of targeting small intestinal CaSR and/or PepT1 to regulate feeding and glucose tolerance.
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Affiliation(s)
- Rosa J W Li
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Daniel R Barros
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Rachel Kuah
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Yu-Mi Lim
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
- Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Anna Gao
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Jacqueline L Beaudry
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Song-Yang Zhang
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Tony K T Lam
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada.
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
- Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada.
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Rezaie P, Bitarafan V, Rose BD, Lange K, Rehfeld JF, Horowitz M, Feinle-Bisset C. Quinine Effects on Gut and Pancreatic Hormones and Antropyloroduodenal Pressures in Humans-Role of Delivery Site and Sex. J Clin Endocrinol Metab 2022; 107:e2870-e2881. [PMID: 35325161 PMCID: PMC9250303 DOI: 10.1210/clinem/dgac182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Indexed: 02/07/2023]
Abstract
CONTEXT The bitter substance quinine modulates the release of a number of gut and gluco-regulatory hormones and upper gut motility. As the density of bitter receptors may be higher in the duodenum than the stomach, direct delivery to the duodenum may be more potent in stimulating these functions. The gastrointestinal responses to bitter compounds may also be modified by sex. BACKGROUND We have characterized the effects of intragastric (IG) versus intraduodenal (ID) administration of quinine hydrochloride (QHCl) on gut and pancreatic hormones and antropyloroduodenal pressures in healthy men and women. METHODS 14 men (26 ± 2 years, BMI: 22.2 ± 0.5 kg/m2) and 14 women (28 ± 2 years, BMI: 22.5 ± 0.5 kg/m2) received 600 mg QHCl on 2 separate occasions, IG or ID as a 10-mL bolus, in randomized, double-blind fashion. Plasma ghrelin, cholecystokinin, peptide YY, glucagon-like peptide-1 (GLP-1), insulin, glucagon, and glucose concentrations and antropyloroduodenal pressures were measured at baseline and for 120 minutes following QHCl. RESULTS Suppression of ghrelin (P = 0.006), stimulation of cholecystokinin (P = 0.030), peptide YY (P = 0.017), GLP-1 (P = 0.034), insulin (P = 0.024), glucagon (P = 0.030), and pyloric pressures (P = 0.050), and lowering of glucose (P = 0.001) were greater after ID-QHCl than IG-QHCl. Insulin stimulation (P = 0.021) and glucose reduction (P = 0.001) were greater in females than males, while no sex-associated effects were found for cholecystokinin, peptide YY, GLP-1, glucagon, or pyloric pressures. CONCLUSION ID quinine has greater effects on plasma gut and pancreatic hormones and pyloric pressures than IG quinine in healthy subjects, consistent with the concept that stimulation of small intestinal bitter receptors is critical to these responses. Both insulin stimulation and glucose lowering were sex-dependent.
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Affiliation(s)
- Peyman Rezaie
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide SA 5005, Australia
| | - Vida Bitarafan
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide SA 5005, Australia
| | - Braden D Rose
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide SA 5005, Australia
| | - Kylie Lange
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide SA 5005, Australia
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide SA 5005, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide SA 5005, Australia
| | - Christine Feinle-Bisset
- Correspondence: Prof Christine Feinle-Bisset, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Corner of North Tce and George St, Adelaide SA 5005, Australia.
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Role of dietary amino acids and microbial metabolites in the regulation of pig intestinal health. ANIMAL NUTRITION (ZHONGGUO XU MU SHOU YI XUE HUI) 2022; 9:1-6. [PMID: 35949980 PMCID: PMC9344294 DOI: 10.1016/j.aninu.2021.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/17/2021] [Accepted: 10/10/2021] [Indexed: 12/15/2022]
Abstract
With the rapid development of sequencing technology, research on pigs has focused on intestinal microbes. Accumulating evidence suggests that the metabolites of intestinal microbes are the key medium for interactions between microbes and the host. Amino acid metabolism is involved in the growth and immune processes of pigs. The gut microbes of pigs are heavily involved in the metabolism of amino acids in their hosts. Here, we review the latest relevant literature. Research findings show that microbial metabolites, such as indoles, short-chain fatty acids, and ammonia, play a key role in gut health. Moreover, we summarize the effects of amino acids on the structure of the gut microbial community and the metabolism of amino acids by pig gut microbes. Evidence shows that microbial amino acid metabolites act as signal molecules in the intestine and play an important role in the intestinal health of pigs.
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Lasta EL, da Silva Pereira Ronning E, Dekker RFH, da Cunha MAA. Encapsulation and dispersion of Lactobacillus acidophilus in a chocolate coating as a strategy for maintaining cell viability in cereal bars. Sci Rep 2021; 11:20550. [PMID: 34654845 PMCID: PMC8519969 DOI: 10.1038/s41598-021-00077-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/06/2021] [Indexed: 11/16/2022] Open
Abstract
Flour from Pereskia aculeata leaf and green banana were used as ingredients in the formulation of a cereal bar with added Lactobacillus acidophilus LA02-ID-1688. Encapsulation in a calcium-alginate hydrogel reinforced with magnesium hydroxide was used as a strategy to protect the probiotic cells under gastrointestinal conditions and to prolong shelf-life. The results are relevant especially for maintaining cell viability during shelf-life; a challenge for the food industry in relation to dry probiotic products. Encapsulation promoted the protection of probiotic cells in simulated gastric and intestinal conditions, allowing the maintenance of high viable cell counts (> 10 log CFU, colony forming unit). Encapsulation also contributed to cellular protection under extreme temperature conditions, with reductions of cell viability of < 1 logarithmic cycle when the capsules were subjected to 55ºC/10 min. Even at 75ºC/10 min, encapsulation protected the probiotic cells 3-times greater than the free-cells. The food bar proved to be rich in dietary fiber (19 g 100 g-1), lipids (12.63 g 100 g-1) and showed an appreciable protein content (5.44 g 100 g-1). A high viable probiotic cell count on storage over 120 days (12.54 log CFU) was observed, maintaining a probiotic survival rate > 90% and viability levels sufficient to promote health benefits.
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Affiliation(s)
- Everton Luiz Lasta
- Programa de Pós-Graduação em Tecnologia de Processos Químicos e Bioquímicos, Universidade Tecnológica Federal do Paraná, Via do Conhecimento Km 01, Pato Branco, Paraná, CEP 85503-390, Brazil
| | - Eduardo da Silva Pereira Ronning
- Departamento de Química, Universidade Tecnológica Federal do Paraná, Via do Conhecimento Km 01, Pato Branco, Paraná, CEP 85503-390, Brazil
- Grupo de Pesquisa em Tecnologia de Bioprocessos e Alimentos (GTBio), Universidade Tecnológica Federal do Paraná, Via do Conhecimento Km 01, Pato Branco, Paraná, CEP 85503-390, Brazil
| | - Robert F H Dekker
- Grupo de Pesquisa em Tecnologia de Bioprocessos e Alimentos (GTBio), Universidade Tecnológica Federal do Paraná, Via do Conhecimento Km 01, Pato Branco, Paraná, CEP 85503-390, Brazil
- Beta-Glucan Produtos Farmoquímicos EIRELI, Lote 24A, Bloco Zircônia, Universidade Tecnológica Federal do Paraná, Câmpus Londrina, Avenida João Miguel Caram 731, Londrina, Paraná, CEP 86036-700, Brazil
| | - Mário Antônio Alves da Cunha
- Departamento de Química, Universidade Tecnológica Federal do Paraná, Via do Conhecimento Km 01, Pato Branco, Paraná, CEP 85503-390, Brazil.
- Grupo de Pesquisa em Tecnologia de Bioprocessos e Alimentos (GTBio), Universidade Tecnológica Federal do Paraná, Via do Conhecimento Km 01, Pato Branco, Paraná, CEP 85503-390, Brazil.
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Zhou X, Chen J, Sun B, Wang Z, Zhu J, Yue Z, Zhang Y, Shan A, Ma Q, Wang J. Leucine, but not isoleucine or valine, affects serum lipid profiles and browning of WAT in mice. Food Funct 2021; 12:6712-6724. [PMID: 34160501 DOI: 10.1039/d1fo00341k] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Branched chain amino acids (BCAA), especially leucine (Leu), have been reported to decrease fat deposition. However, opposite effects of BCAA on lipid metabolism have been observed. To determine the role of BCAA in lipid metabolism, an amino acid-defined diet was formulated and C57BL/6J mice were assigned into the following groups: amino acid-defined control diet and control diet supplemented with Leu, isoleucine, or valine. Nitrogen was balanced by proportionally mixed amino acids except BCAA. Results showed that dietary Leu supplementation significantly increased the levels of serum triglycerides, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and urea nitrogen. Metabolomics showed that biosynthesis of unsaturated fatty acids was altered by Leu supplementation. Leu treatment up-regulated the expression of genes related to fat synthesis and down-regulated the expression of genes related to fatty acid synthesis. Furthermore, the genes and proteins of selective markers involved in browning of white adipose tissue (WAT) were up-regulated by dietary supplementation with Leu. This study indicated that dietary supplementation with Leu, but not isoleucine or valine, significantly affected lipid metabolism by regulating lipid metabolism-related genes and serum fatty acid concentration, providing a new tool in the management of obesity and metabolic disorders.
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Affiliation(s)
- Xinbo Zhou
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, 150030, China.
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Rose BD, Bitarafan V, Rezaie P, Fitzgerald PCE, Horowitz M, Feinle-Bisset C. Comparative Effects of Intragastric and Intraduodenal Administration of Quinine on the Plasma Glucose Response to a Mixed-Nutrient Drink in Healthy Men: Relations with Glucoregulatory Hormones and Gastric Emptying. J Nutr 2021; 151:1453-1461. [PMID: 33704459 DOI: 10.1093/jn/nxab020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/07/2020] [Accepted: 01/19/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND In preclinical studies, bitter compounds, including quinine, stimulate secretion of glucoregulatory hormones [e.g., glucagon-like peptide-1 (GLP-1)] and slow gastric emptying, both key determinants of postprandial glycemia. A greater density of bitter-taste receptors has been reported in the duodenum than the stomach. Thus, intraduodenal (ID) delivery may be more effective in stimulating GI functions to lower postprandial glucose. OBJECTIVE We compared effects of intragastric (IG) and ID quinine [as quinine hydrochloride (QHCl)] administration on the plasma glucose response to a mixed-nutrient drink and relations with gastric emptying, plasma C-peptide (reflecting insulin secretion), and GLP-1. METHODS Fourteen healthy men [mean ± SD age: 25 ± 3 y; BMI (in kg/m2): 22.5 ± 0.5] received, on 4 separate occasions, in double-blind, randomly assigned order, 600 mg QHCl or control, IG or ID, 60 min (IG conditions) or 30 min (IG conditions) before a mixed-nutrient drink. Plasma glucose (primary outcome) and hormones were measured before, and for 2 h following, the drink. Gastric emptying of the drink was measured using a 13C-acetate breath test. Data were analyzed using repeated-measures 2-way ANOVAs (factors: treatment and route of administration) to evaluate effects of QHCl alone and 3-way ANOVAs (factors: treatment, route-of-administration, and time) for responses to the drink. RESULTS After QHCl alone, there were effects of treatment, but not route of administration, on C-peptide, GLP-1, and glucose (P < 0.05); QHCl stimulated C-peptide and GLP-1 and lowered glucose concentrations (IG control: 4.5 ± 0.1; IG-QHCl: 3.9 ± 0.1; ID-control: 4.6 ± 0.1; ID-QHCl: 4.2 ± 0.1 mmol/L) compared with control. Postdrink, there were treatment × time interactions for glucose, C-peptide, and gastric emptying, and a treatment effect for GLP-1 (all P < 0.05), but no route-of-administration effects. QHCl stimulated C-peptide and GLP-1, slowed gastric emptying, and reduced glucose (IG control: 7.2 ± 0.3; IG-QHCl: 6.2 ± 0.3; ID-control: 7.2 ± 0.3; ID-QHCl: 6.4 ± 0.4 mmol/L) compared with control. CONCLUSIONS In healthy men, IG and ID quinine administration similarly lowered plasma glucose, increased plasma insulin and GLP-1, and slowed gastric emptying. These findings have potential implications for lowering blood glucose in type 2 diabetes. This study was registered as a clinical trial with the Australian New Zealand Clinical Trials at www.anzctr.org.au as ACTRN12619001269123.
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Affiliation(s)
- Braden D Rose
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Vida Bitarafan
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Peyman Rezaie
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Penelope C E Fitzgerald
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia 5000, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia 5000, Australia
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Elovaris RA, Bitarafan V, Agah S, Ullrich SS, Lange K, Horowitz M, Feinle-Bisset C. Comparative Effects of the Branched-Chain Amino Acids, Leucine, Isoleucine and Valine, on Gastric Emptying, Plasma Glucose, C-Peptide and Glucagon in Healthy Men. Nutrients 2021; 13:nu13051613. [PMID: 34064996 PMCID: PMC8150294 DOI: 10.3390/nu13051613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/22/2021] [Accepted: 04/29/2021] [Indexed: 02/04/2023] Open
Abstract
(1) Background: Whey protein lowers postprandial blood glucose in health and type 2 diabetes, by stimulating insulin and incretin hormone secretion and slowing gastric emptying. The branched-chain amino acids, leucine, isoleucine and valine, abundant in whey, may mediate the glucoregulatory effects of whey. We investigated the comparative effects of intragastric administration of leucine, isoleucine and valine on the plasma glucose, C-peptide and glucagon responses to and gastric emptying of a mixed-nutrient drink in healthy men. (2) Methods: 15 healthy men (27 ± 3 y) received, on four separate occasions, in double-blind, randomised fashion, either 10 g of leucine, 10 g of isoleucine, 10 g of valine or control, intragastrically, 30 min before a mixed-nutrient drink. Plasma glucose, C-peptide and glucagon concentrations were measured before, and for 2 h following, the drink. Gastric emptying of the drink was quantified using 13C-acetate breath-testing. (3) Results: Amino acids alone did not affect plasma glucose or C-peptide, while isoleucine and valine, but not leucine, stimulated glucagon (p < 0.05), compared with control. After the drink, isoleucine and leucine reduced peak plasma glucose compared with both control and valine (all p < 0.05). Neither amino acid affected early (t = 0–30 min) postprandial C-peptide or glucagon. While there was no effect on overall gastric emptying, plasma glucose at t = 30 min correlated with early gastric emptying (p < 0.05). (4) Conclusion: In healthy individuals, leucine and isoleucine lower postprandial blood glucose, at least in part by slowing gastric emptying, while valine does not appear to have an effect, possibly due to glucagon stimulation.
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Affiliation(s)
- Rachel A. Elovaris
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide 5005, Australia; (R.A.E.); (V.B.); (S.A.); (K.L.); (M.H.)
| | - Vida Bitarafan
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide 5005, Australia; (R.A.E.); (V.B.); (S.A.); (K.L.); (M.H.)
| | - Shahram Agah
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide 5005, Australia; (R.A.E.); (V.B.); (S.A.); (K.L.); (M.H.)
| | - Sina S. Ullrich
- Clinical Trials Unit, University Hospital Basel, 4031 Basel, Switzerland;
| | - Kylie Lange
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide 5005, Australia; (R.A.E.); (V.B.); (S.A.); (K.L.); (M.H.)
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide 5005, Australia; (R.A.E.); (V.B.); (S.A.); (K.L.); (M.H.)
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide 5005, Australia; (R.A.E.); (V.B.); (S.A.); (K.L.); (M.H.)
- Correspondence: ; Tel.: +61-8-8313-6053
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Wilbrink J, Masclee G, Klaassen T, van Avesaat M, Keszthelyi D, Masclee A. Review on the Regional Effects of Gastrointestinal Luminal Stimulation on Appetite and Energy Intake: (Pre)clinical Observations. Nutrients 2021; 13:nu13051601. [PMID: 34064724 PMCID: PMC8151500 DOI: 10.3390/nu13051601] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/22/2021] [Accepted: 05/05/2021] [Indexed: 02/06/2023] Open
Abstract
Macronutrients in the gastrointestinal (GI) lumen are able to activate “intestinal brakes”, feedback mechanisms on proximal GI motility and secretion including appetite and energy intake. In this review, we provide a detailed overview of the current evidence with respect to four questions: (1) are regional differences (duodenum, jejunum, ileum) present in the intestinal luminal nutrient modulation of appetite and energy intake? (2) is this “intestinal brake” effect macronutrient specific? (3) is this “intestinal brake” effect maintained during repetitive activation? (4) can the “intestinal brake” effect be activated via non-caloric tastants? Recent evidence indicates that: (1) regional differences exist in the intestinal modulation of appetite and energy intake with a proximal to distal gradient for inhibition of energy intake: ileum and jejunum > duodenum at low but not at high caloric infusion rates. (2) the “intestinal brake” effect on appetite and energy appears not to be macronutrient specific. At equi-caloric amounts, the inhibition on energy intake and appetite is in the same range for fat, protein and carbohydrate. (3) data on repetitive ileal brake activation are scarce because of the need for prolonged intestinal intubation. During repetitive activation of the ileal brake for up to 4 days, no adaptation was observed but overall the inhibitory effect on energy intake was small. (4) the concept of influencing energy intake by intra-intestinal delivery of non-caloric tastants is intriguing. Among tastants, the bitter compounds appear to be more effective in influencing energy intake. Energy intake decreases modestly after post-oral delivery of bitter tastants or a combination of tastants (bitter, sweet and umami). Intestinal brake activation provides an interesting concept for preventive and therapeutic approaches in weight management strategies.
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Affiliation(s)
- Jennifer Wilbrink
- Division of Gastroenterology-Hepatology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (J.W.); (G.M.); (T.K.); (M.v.A.); (D.K.)
| | - Gwen Masclee
- Division of Gastroenterology-Hepatology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (J.W.); (G.M.); (T.K.); (M.v.A.); (D.K.)
| | - Tim Klaassen
- Division of Gastroenterology-Hepatology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (J.W.); (G.M.); (T.K.); (M.v.A.); (D.K.)
| | - Mark van Avesaat
- Division of Gastroenterology-Hepatology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (J.W.); (G.M.); (T.K.); (M.v.A.); (D.K.)
| | - Daniel Keszthelyi
- Division of Gastroenterology-Hepatology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (J.W.); (G.M.); (T.K.); (M.v.A.); (D.K.)
- NUTRIM School of Nutrition and Translational Research in Metabolism, 6229 ER Maastricht, The Netherlands
| | - Adrian Masclee
- Division of Gastroenterology-Hepatology, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands; (J.W.); (G.M.); (T.K.); (M.v.A.); (D.K.)
- NUTRIM School of Nutrition and Translational Research in Metabolism, 6229 ER Maastricht, The Netherlands
- Correspondence: ; Tel.: +31-43-3875021
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Duca FA, Waise TMZ, Peppler WT, Lam TKT. The metabolic impact of small intestinal nutrient sensing. Nat Commun 2021; 12:903. [PMID: 33568676 PMCID: PMC7876101 DOI: 10.1038/s41467-021-21235-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal tract maintains energy and glucose homeostasis, in part through nutrient-sensing and subsequent signaling to the brain and other tissues. In this review, we highlight the role of small intestinal nutrient-sensing in metabolic homeostasis, and link high-fat feeding, obesity, and diabetes with perturbations in these gut-brain signaling pathways. We identify how lipids, carbohydrates, and proteins, initiate gut peptide release from the enteroendocrine cells through small intestinal sensing pathways, and how these peptides regulate food intake, glucose tolerance, and hepatic glucose production. Lastly, we highlight how the gut microbiota impact small intestinal nutrient-sensing in normal physiology, and in disease, pharmacological and surgical settings. Emerging evidence indicates that the molecular mechanisms of small intestinal nutrient sensing in metabolic homeostasis have physiological and pathological impact as well as therapeutic potential in obesity and diabetes. The gastrointestinal tract participates in maintaining metabolic homeostasis in part through nutrient-sensing and subsequent gut-brain signalling. Here the authors review the role of small intestinal nutrient-sensing in regulation of energy intake and systemic glucose metabolism, and link high-fat diet, obesity and diabetes with perturbations in these pathways.
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Affiliation(s)
- Frank A Duca
- BIO5 Institute, University of Arizona, Tucson, AZ, USA. .,School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA.
| | - T M Zaved Waise
- Toronto General Hospital Research Institute, UHN, Toronto, Canada
| | - Willem T Peppler
- Toronto General Hospital Research Institute, UHN, Toronto, Canada
| | - Tony K T Lam
- Toronto General Hospital Research Institute, UHN, Toronto, Canada. .,Department of Physiology, University of Toronto, Toronto, Canada. .,Department of Medicine, University of Toronto, Toronto, Canada. .,Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada.
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Tuccinardi D, Perakakis N, Farr OM, Upadhyay J, Mantzoros CS. Branched-Chain Amino Acids in relation to food preferences and insulin resistance in obese subjects consuming walnuts: A cross-over, randomized, double-blind, placebo-controlled inpatient physiology study. Clin Nutr 2021; 40:3032-3036. [PMID: 33541836 DOI: 10.1016/j.clnu.2021.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/24/2020] [Accepted: 01/09/2021] [Indexed: 12/28/2022]
Abstract
BACKGROUND&AIMS To assess whether the concentrations of circulating Branched-Chain Amino Acids (BCAAs) change after walnut consumption and, whether these changes are associated with alterations in markers of insulin resistance and food preferences. METHODS In a crossover, randomized, double-blind, placebo-controlled study, ten subjects participated in two 5-day inpatient study admissions, during which they had a smoothie containing 48 g walnuts or a macronutrient-matched placebo smoothie without nuts every morning. Between the two phases there was a 1-month washout period. RESULTS Fasting valine and isoleucine levels were reduced (p = .047 and p < .001) and beta-hydroxybutyrate levels were increased after 5-days of walnut consumption compared to placebo (p = .023). Fasting valine and isoleucine correlated with HOMA-IR while on walnut (r = 0.709, p = .032 and r = 0.679, p = .044). The postprandial area under the curve (AUC) of leucine in response to the smoothie consumption on day 5 was higher after walnut vs placebo (p = .023) and correlated negatively with the percentage of Kcal from carbohydrate and protein consumed during an ad libitum buffet meal consumed the same day for lunch (r = -0.661, p = .037; r = -0.628, p = .05, respectively). CONCLUSION The fasting and postabsorptive profiles of BCAAs are differentially affected by walnut consumption. The reduction in fasting valine and isoleucine may contribute to the longer-term benefits of walnuts on insulin resistance, cardiovascular risk and mortality, whereas the increase in postabsorptive profiles with walnuts may influence food preference. TRIAL REGISTRATION CLINICALTRIALS.GOV: Number: NCT02673281, Website: https://clinicaltrials.gov/ct2/show/NCT02673281.
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Affiliation(s)
- Dario Tuccinardi
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center/Harvard Medical School, 330 Brookline Avenue, SL-419, Boston, MA, 02215, USA; Unit of Endocrinology and Diabetes, Department of Medicine, Campus Bio-Medico of Rome, 00128 Rome, Italy
| | - Nikolaos Perakakis
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center/Harvard Medical School, 330 Brookline Avenue, SL-419, Boston, MA, 02215, USA
| | - Olivia M Farr
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center/Harvard Medical School, 330 Brookline Avenue, SL-419, Boston, MA, 02215, USA
| | - Jagriti Upadhyay
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center/Harvard Medical School, 330 Brookline Avenue, SL-419, Boston, MA, 02215, USA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center/Harvard Medical School, 330 Brookline Avenue, SL-419, Boston, MA, 02215, USA.
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12
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Elovaris RA, Hajishafiee M, Ullrich SS, Fitzgerald PCE, Lange K, Horowitz M, Feinle-Bisset C. Intragastric administration of leucine and isoleucine does not reduce the glycaemic response to, or slow gastric emptying of, a carbohydrate-containing drink in type 2 diabetes. Diabetes Res Clin Pract 2021; 171:108618. [PMID: 33310174 DOI: 10.1016/j.diabres.2020.108618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/02/2020] [Accepted: 12/04/2020] [Indexed: 02/07/2023]
Abstract
AIMS In healthy individuals, intragastric administration of the branched-chain amino acids, leucine and isoleucine, diminishes the glycaemic response to a mixed-nutrient drink, apparently by stimulating insulin and slowing gastric emptying, respectively. This study aimed to evaluate the effects of leucine and isoleucine on postprandial glycaemia and gastric emptying in type-2 diabetes mellitus (T2D). METHODS 14 males with T2D received, on 3 separate occasions, in double-blind, randomised fashion, either 10 g leucine, 10 g isoleucine or control, intragastrically 30 min before a mixed-nutrient drink (500 kcal; 74 g carbohydrates, 18 g protein, 15 g fat). Plasma glucose, insulin and glucagon were measured from 30 min pre- until 120 min post-drink. Gastric emptying of the drink was also measured. RESULTS Leucine and isoleucine stimulated insulin, both before and after the drink (all P < 0.05; peak (mU/L): control: 70 ± 15; leucine: 88 ± 17; isoleucine: 74 ± 15). Isoleucine stimulated (P < 0.05), and leucine tended to stimulate (P = 0.078), glucagon before the drink, and isoleucine stimulated glucagon post-drink (P = 0.031; peak (pg/mL): control: 62 ± 5; leucine: 70 ± 9; isoleucine: 69 ± 6). Neither amino acid affected gastric emptying or plasma glucose (peak (mmol/L): control: 12.0 ± 0.5; leucine: 12.5 ± 0.7; isoleucine: 12.0 ± 0.6). CONCLUSIONS In contrast to health, in T2D, leucine and isoleucine, administered intragastrically in a dose of 10 g, do not lower the glycaemic response to a mixed-nutrient drink. This finding argues against a role for 'preloads' of either leucine or isoleucine in the management of T2D.
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Affiliation(s)
- Rachel A Elovaris
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Maryam Hajishafiee
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Sina S Ullrich
- Department of Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Penelope C E Fitzgerald
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Kylie Lange
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
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13
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Vieira CR, Grancieri M, Martino HSD, César DE, Barra RRS. A beverage containing ora-pro-nobis flour improves intestinal health, weight, and body composition: A double-blind randomized prospective study. Nutrition 2020; 78:110869. [DOI: 10.1016/j.nut.2020.110869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/15/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023]
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Fitzgerald PCE, Manoliu B, Herbillon B, Steinert RE, Horowitz M, Feinle-Bisset C. Effects of L-Phenylalanine on Energy Intake and Glycaemia-Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males. Nutrients 2020; 12:nu12061788. [PMID: 32560181 PMCID: PMC7353198 DOI: 10.3390/nu12061788] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 02/07/2023] Open
Abstract
In humans, phenylalanine stimulates plasma cholecystokinin (CCK) and pyloric pressures, both of which are important in the regulation of energy intake and gastric emptying. Gastric emptying is a key determinant of postprandial blood glucose. We evaluated the effects of intragastric phenylalanine on appetite perceptions and subsequent energy intake, and the glycaemic response to, and gastric emptying of, a mixed-nutrient drink. The study consisted of two parts, each including 16 healthy, lean males (age: 23 ± 1 years). In each part, participants received on three separate occasions, in randomised, double-blind fashion, 5 g (Phe-5 g) or 10g ('Phe-10 g) L-phenylalanine, or control, intragastrically, 30 min before a standardised buffet-meal (part A), or a standardised mixed-nutrient drink (part B). In part A, plasma CCK and peptide-YY (PYY), and appetite perceptions, were measured at baseline, after phenylalanine alone, and following the buffet-meal, from which energy intake was assessed. In part B, plasma glucose, glucagon-like peptide-1 (GLP-1), insulin and glucagon were measured at baseline, after phenylalanine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured by 13C-acetate breath-test. Phe-10 g, but not Phe-5 g, stimulated plasma CCK (p = 0.01) and suppressed energy intake (p = 0.012); energy intake was correlated with stimulation of CCK (r = -0.4, p = 0.027), and tended to be associated with stimulation of PYY (r = -0.31, p = 0.082). Both Phe-10 g and Phe-5 g stimulated insulin and glucagon (all p < 0.05), but not GLP-1. Phe-10 g, but not Phe-5 g, reduced overall plasma glucose (p = 0.043) and peak plasma glucose (p = 0.017) in response to the mixed-nutrient drink. Phenylalanine had no effect on gastric emptying of the drink. In conclusion, our observations indicate that the energy intake-suppressant effect of phenylalanine is related to the stimulation of CCK and PYY, while the glucoregulatory effect may be independent of stimulation of plasma GLP-1 or slowing of gastric emptying.
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Affiliation(s)
- Penelope C. E. Fitzgerald
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Benoit Manoliu
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Benjamin Herbillon
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Robert E. Steinert
- Department of Surgery, Division of Visceral and Transplantation Surgery, University Hospital Zürich, 8091 Zürich, Switzerland;
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
- Correspondence: ; Tel.: +61-8-8313-6053
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15
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McVeay C, Steinert RE, Fitzgerald PCE, Ullrich SS, Horowitz M, Feinle-Bisset C. Effects of intraduodenal coadministration of lauric acid and leucine on gut motility, plasma cholecystokinin, and energy intake in healthy men. Am J Physiol Regul Integr Comp Physiol 2020; 318:R790-R798. [PMID: 32160019 DOI: 10.1152/ajpregu.00352.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The fatty acid, lauric acid (C12), and the amino acid, leucine (Leu) stimulate gut hormones, including CCK, associated with suppression of energy intake. In our recent study, intraduodenal infusion of a combination of C12 and l-tryptophan, at loads that individually did not affect energy intake, reduced energy intake substantially, associated with much greater stimulation of CCK. We have now investigated whether combined administration of C12 and Leu would enhance the intake-suppressant effects of each nutrient, when given at loads that each suppress energy intake individually. Sixteen healthy, lean males (age: 23 ± 2 yr) received, in randomized, double-blind fashion, 90-min intraduodenal infusions of control (saline), C12 (0.4 kcal/min), Leu (0.45 kcal/min), or C12+Leu (0.85 kcal/min). Antropyloroduodenal pressures were measured continuously and plasma CCK at 15-min intervals, and energy intake from a standardized buffet-meal, consumed immediately postinfusion, was quantified. All nutrient infusions stimulated plasma CCK compared with control (P < 0.05). Moreover, C12 and C12+Leu stimulated CCK compared with Leu (P < 0.05) (mean concentration, pmol/L; control: 2.3 ± 0.3, C12: 3.8 ± 0.3, Leu: 2.7 ± 0.3, and C12+Leu: 4.0 ± 0.4). C12+Leu, but not C12 or Leu, stimulated pyloric pressures (P < 0.05). C12+Leu and C12 reduced energy intake (P < 0.05), and there was a trend for Leu to reduce (P = 0.06) energy intake compared with control, with no differences between the three nutrient treatments (kcal; control: 1398 ± 84, C12: 1226 ± 80, Leu: 1260 ± 92, and C12+Leu: 1208 ± 83). In conclusion, combination of C12 and Leu, at the loads given, did not reduce energy intake beyond their individual effects, possibly because maximal effects had been evoked.
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Affiliation(s)
- Christina McVeay
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Robert E Steinert
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Penelope C E Fitzgerald
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Sina S Ullrich
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
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16
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Abstract
AbstractKnowing the biological signals associated with appetite control is crucial for understanding the regulation of food intake. Biomarkers of appetite have been defined as physiological measures that relate to subjective appetite ratings, measured food intake, or both. Several metabolites including amino acids, lipids and glucose were proposed as key molecules associated with appetite control over 60 years ago, and along with bile acids are all among possible appetite biomarker candidates. Additional metabolites that have been associated with appetite include endocannabinoids, lactate, cortisol and β-hydroxybutyrate. However, although appetite is a complex integrative process, studies often investigated a limited number of markers in isolation. Metabolomics involves the study of small molecules or metabolites present in biological samples such as urine or blood, and may present a powerful approach to further the understanding of appetite control. Using multiple analytical techniques allows the characterisation of molecules, such as carbohydrates, lipids, amino acids, bile acids and fatty acids. Metabolomics has proven successful in identifying markers of consumption of certain foods and biomarkers implicated in several diseases. However, it has been underexploited in appetite control or obesity. The aim of the present narrative review is to: (1) provide an overview of existing metabolites that have been identified in human biofluids and associated with appetite control; and (2) discuss the potential of metabolomics to deepen understanding of appetite control in humans.
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17
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Bitarafan V, Fitzgerald PCE, Little TJ, Meyerhof W, Jones KL, Wu T, Horowitz M, Feinle-Bisset C. Intragastric administration of the bitter tastant quinine lowers the glycemic response to a nutrient drink without slowing gastric emptying in healthy men. Am J Physiol Regul Integr Comp Physiol 2020; 318:R263-R273. [PMID: 31774306 DOI: 10.1152/ajpregu.00294.2019] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The rate of gastric emptying and the release of gastrointestinal (GI) hormones are major determinants of postprandial blood-glucose concentrations and energy intake. Preclinical studies suggest that activation of GI bitter-taste receptors potently stimulates GI hormones, including glucagon-like peptide-1 (GLP-1), and thus may reduce postprandial glucose and energy intake. We evaluated the effects of intragastric quinine on the glycemic response to, and the gastric emptying of, a mixed-nutrient drink and the effects on subsequent energy intake in healthy men. The study consisted of 2 parts: part A included 15 lean men, and part B included 12 lean men (aged 26 ± 2 yr). In each part, participants received, on 3 separate occasions, in double-blind, randomized fashion, intragastric quinine (275 or 600 mg) or control, 30 min before a mixed-nutrient drink (part A) or before a buffet meal (part B). In part A, plasma glucose, insulin, glucagon, and GLP-1 concentrations were measured at baseline, after quinine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured. In part B, energy intake at the buffet meal was quantified. Quinine in 600 mg (Q600) and 275 mg (Q275) doses alone stimulated insulin modestly (P < 0.05). After the drink, Q600 and Q275 reduced plasma glucose and stimulated insulin (P < 0.05), Q275 stimulated GLP-1 (P < 0.05), and Q600 tended to stimulate GLP-1 (P = 0.066) and glucagon (P = 0.073) compared with control. Quinine did not affect gastric emptying of the drink or energy intake. In conclusion, in healthy men, intragastric quinine reduces postprandial blood glucose and stimulates insulin and GLP-1 but does not slow gastric emptying or reduce energy intake under our experimental conditions.
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Affiliation(s)
- Vida Bitarafan
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
| | - Penelope C E Fitzgerald
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
| | - Tanya J Little
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
| | - Wolfgang Meyerhof
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Karen L Jones
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Tongzhi Wu
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, SA, Australia
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18
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Tian M, Heng J, Song H, Zhang Y, Chen F, Guan W, Zhang S. Branched chain amino acids stimulate gut satiety hormone cholecystokinin secretion through activation of the umami taste receptor T1R1/T1R3 using an in vitro porcine jejunum model. Food Funct 2019; 10:3356-3367. [PMID: 31098606 DOI: 10.1039/c9fo00228f] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Branched chain amino acids (BCAAs) are essential amino acids involved in regulation of feed intake. The function of BCAAs on the central nervous system has been extensively studied, but effects of BCAAs on secretion of gut satiety hormones and their underlying mechanisms are largely unknown. In this study, we evaluated the distribution of gut hormones and amino acid receptors in the porcine GI tract and found cholecystokinin (CCK) and taste dimeric receptor type 1 member 1/3 (T1R1/T1R3) were predominantly expressed in the jejunum and functionally interrelated. We further evaluated the effects of l-leucine, l-isoleucine, l-valine, and BCAAs on CCK and T1R1/T1R3 expression in porcine jejunum tissue. Our data demonstrated that stimulation of porcine jejunum tissue with 10 mM l-leucine, l-isoleucine or BCAAs mix (l-leucine : l-isoleucine : l-valine = 1 : 0.51 : 0.63) for 2 hours significantly increased mRNA expression and protein abundance of T1R1/T1R3 and secretion of CCK (P < 0.05). However, the l-valine treatment only increased the mRNA and protein abundance of T1R1 and T1R3 (P < 0.05), but not CCK secretion (P > 0.10). l-Leucine-, l-isoleucine- or BCAAs mix-induced CCK secretion was significantly decreased after tissues were pretreated with lactisole, a T1R1/T1R3 inhibitor (P < 0.05). Furthermore, the increased mRNA and protein abundance of T1R1/T1R3 were also largely attenuated by blocking T1R1/T1R3 with lactisole (P < 0.05). l-Leucine, l-isoleucine and BCAAs mix appeared to induce the gut satiety hormone CCK secretion through jejunal T1R1/T1R3. These results indicate over-supplementation with BCAAs in the diet might decrease food intake in swine and humans through gastrointestinal feedback.
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Affiliation(s)
- Min Tian
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, People's Republic of China.
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Martin AM, Sun EW, Keating DJ. Mechanisms controlling hormone secretion in human gut and its relevance to metabolism. J Endocrinol 2019; 244:R1-R15. [PMID: 31751295 PMCID: PMC6892457 DOI: 10.1530/joe-19-0399] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/18/2019] [Indexed: 12/16/2022]
Abstract
The homoeostatic regulation of metabolism is highly complex and involves multiple inputs from both the nervous and endocrine systems. The gut is the largest endocrine organ in our body and synthesises and secretes over 20 different hormones from enteroendocrine cells that are dispersed throughout the gut epithelium. These hormones include GLP-1, PYY, GIP, serotonin, and CCK, each of whom play pivotal roles in maintaining energy balance and glucose homeostasis. Some are now the basis of several clinically used glucose-lowering and weight loss therapies. The environment in which these enteroendocrine cells exist is also complex, as they are exposed to numerous physiological inputs including ingested nutrients, circulating factors and metabolites produced from neighbouring gut microbiome. In this review, we examine the diverse means by which gut-derived hormones carry out their metabolic functions through their interactions with different metabolically important organs including the liver, pancreas, adipose tissue and brain. Furthermore, we discuss how nutrients and microbial metabolites affect gut hormone secretion and the mechanisms underlying these interactions.
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Affiliation(s)
- Alyce M Martin
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Emily W Sun
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Damien J Keating
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Correspondence should be addressed to D J Keating:
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Newmire DE, Rivas E, Deemer SE, Willoughby DS, Ben-Ezra V. The Impact of a Large Bolus Dose of l-leucine and l-isoleucine on Enteroendocrine and Pancreatic Hormones, and Glycemia in Healthy, Inactive Adults. Nutrients 2019; 11:nu11112650. [PMID: 31689951 PMCID: PMC6893504 DOI: 10.3390/nu11112650] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 10/15/2019] [Accepted: 10/31/2019] [Indexed: 12/19/2022] Open
Abstract
Background: The ingestion of whey protein and amino acids with carbohydrate (CHO) enhances the release of glucagon-like peptide-1 (GLP-1) and glucose-dependent-insulinotropic peptide (GIP) that promote insulin secretion. It is unknown if L-isoleucine (Ile) and L-leucine (Leu) have this same effect. The purpose of this study was to examine how Ile and Leu influence both GLP-1 and GIP, subsequent pancreatic hormones, and glycemia in healthy, inactive adults. Methods: Twelve adults (6F/6M; age 27.4 ± 2 years; BMI 26.3 ± 2 kg/m2; lean body mass 53.2 ± 5 kg; body fat 34.1 ± 3%) completed four conditions in a randomized, cross-over fashion. Treatments standardized (0.3 g/kg·LBM−1) (1) Leu, (2) Ile, (3) Equal (1:1 g) of Leu + Ile, and (4) placebo (Pla, 3.5 g inert stevia) ingested 30 min prior to an oral glucose tolerance test (OGTT). Samples of plasma glucose, insulin, glucagon, GIPTotal, and GLP-1Active were assessed. Results: A treatment (p = 0.01) effect comparing Ile vs. Leu (p = 0.02) in GIPTotal. Area under the curve showed an increase in GIPTotal from Ile compared to Leu and Pla (p = 0.03). No effect was found on GLP-1. The ingestion of Ile prior to CHO augmented GIP concentration greater than Leu or Pla. No correlation was found between GIP, insulin, and glucose between conditions. Conclusions: Ile impacts GIP concentration, which did not relate to either insulin or glucose concentrations. Neither Ile, nor Leu seem to have an effect on hyperglycemia ingested prior to a CHO drink.
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Affiliation(s)
- Daniel E Newmire
- Exercise Physiology and Biochemistry Lab, Department of Kinesiology, Texas A&M University-Corpus Christi, Corpus Christi, TX 78414, USA.
| | - Eric Rivas
- Exercise and Thermal Integrative Physiology Laboratory, Department of Kinesiology and Sports Management, Texas Tech University, Lubbock, TX 79409, USA.
| | - Sarah E Deemer
- Nutrition Obesity Research Center, University of Alabama-Birmingham, Birmingham, AL 35233, USA.
| | - Darryn S Willoughby
- Exercise and Biochemical Nutrition Laboratory, Department of Health, Human Performance, Recreation, Baylor University, Waco, TX 76707, USA.
| | - Victor Ben-Ezra
- Exercise Physiology and Biochemistry Lab, Department of Kinesiology, Texas Woman's University, Denton, TX 76204, USA.
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Elovaris RA, Hutchison AT, Lange K, Horowitz M, Feinle-Bisset C, Luscombe-Marsh ND. Plasma Free Amino Acid Responses to Whey Protein and Their Relationships with Gastric Emptying, Blood Glucose- and Appetite-Regulatory Hormones and Energy Intake in Lean Healthy Men. Nutrients 2019; 11:nu11102465. [PMID: 31618863 PMCID: PMC6835323 DOI: 10.3390/nu11102465] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/01/2019] [Accepted: 10/09/2019] [Indexed: 02/07/2023] Open
Abstract
This study determined the effects of increasing loads of whey protein on plasma amino acid (AA) concentrations, and their relationships with gastric emptying, blood glucose- and appetite-regulatory hormones, blood glucose and energy intake. Eighteen healthy lean men participated in a double-blinded study, in which they consumed, on 3 separate occasions, in randomised order, 450-mL drinks containing either 30 g (L) or 70 g (H) of pure whey protein isolate, or control with 0 g of protein (C). Gastric emptying, serum concentrations of AAs, ghrelin, cholecystokinin (CCK), glucagon-like-peptide 1 (GLP-1), insulin, glucagon and blood glucose were measured before and after the drinks over 180 min. Then energy intake was quantified. All AAs were increased, and 7/20 AAs were increased more by H than L. Incremental areas under the curve (iAUC0-180 min) for CCK, GLP-1, insulin and glucagon were correlated positively with iAUCs of 19/20 AAs (p < 0.05). The strongest correlations were with the branched-chain AAs as well as lysine, tyrosine, methionine, tryptophan, and aspartic acid (all R2 > 0.52, p < 0.05). Blood glucose did not correlate with any AA (all p > 0.05). Ghrelin and energy intake correlated inversely, but only weakly, with 15/20 AAs (all R2 < 0.34, p < 0.05). There is a strong relationship between gluco-regulatory hormones with a number of (predominantly essential) AAs. However, the factors mediating the effects of protein on blood glucose and energy intake are likely to be multifactorial.
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Affiliation(s)
- Rachel A Elovaris
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Amy T Hutchison
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
- Nutrition and Metabolism Theme, South Australian Health and Medical Research Institute, Adelaide 5000, Australia.
| | - Kylie Lange
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Michael Horowitz
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Christine Feinle-Bisset
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Natalie D Luscombe-Marsh
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Nutrition and Health Program, P.O. Box 10097, Adelaide 5000, Australia.
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22
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Bitarafan V, Fitzgerald PCE, Little TJ, Meyerhof W, Wu T, Horowitz M, Feinle-Bisset C. Effects of Intraduodenal Infusion of the Bitter Tastant, Quinine, on Antropyloroduodenal Motility, Plasma Cholecystokinin, and Energy Intake in Healthy Men. J Neurogastroenterol Motil 2019; 25:413-422. [PMID: 31177650 PMCID: PMC6657929 DOI: 10.5056/jnm19036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/22/2019] [Accepted: 04/07/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND/AIMS Nutrient-induced gut hormone release (eg, cholecystokinin [CCK]) and the modulation of gut motility (particularly pyloric stimulation) contribute to the regulation of acute energy intake. Non-caloric bitter compounds, including quinine, have recently been shown in cell-line and animal studies to stimulate the release of gastrointestinal hormones by activating bitter taste receptors expressed throughout the gastrointestinal tract, and thus, may potentially suppress energy intake without providing additional calories. This study aims to evaluate the effects of intraduodenally administered quinine on antropyloroduodenal pressures, plasma CCK and energy intake. METHODS Fourteen healthy, lean men (25 ± 5 years; BMI: 22.5 ± 2.0 kg/m2) received on 4 separate occasions, in randomized, double-blind fashion, 60-minute intraduodenal infusions of quinine hydrochloride at doses totaling 37.5 mg ("Q37.5"), 75 mg ("Q75") or 225 mg ("Q225"), or control (all 300 mOsmol). Antropyloroduodenal pressures (high-resolution manometry), plasma CCK (radioimmunoassay), and appetite perceptions/gastrointestinal symptoms (visual analog questionnaires) were measured. Ad libitum energy intake (buffet-meal) was quantified immediately post-infusion. Oral quinine taste-thresholds were assessed on a separate occasion using 3-alternative forced-choice procedure. RESULTS All participants detected quinine orally (detection-threshold: 0.19 ± 0.07 mmol/L). Intraduodenal quinine did not affect antral, pyloric or duodenal pressures, plasma CCK (pmol/L [peak]; control: 3.6 ± 0.4, Q37.5: 3.6 ± 0.4, Q75: 3.7 ± 0.3, Q225: 3.9 ± 0.4), appetite perceptions, gastrointestinal symptoms or energy intake (kcal; control: 1088 ± 90, Q37.5: 1057 ± 69, Q75: 1029 ±7 0, Q225: 1077 ± 88). CONCLUSIONS Quinine, administered intraduodenally over 60 minutes, even at moderately high doses, but low infusion rates, does not modulate appetite-related gastrointestinal functions or energy intake.
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Affiliation(s)
- Vida Bitarafan
- Adelaide Medical School and National Health and Medical Research Council of Australia (NHMRC) Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide,
Australia
| | - Penelope C E Fitzgerald
- Adelaide Medical School and National Health and Medical Research Council of Australia (NHMRC) Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide,
Australia
| | - Tanya J Little
- Adelaide Medical School and National Health and Medical Research Council of Australia (NHMRC) Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide,
Australia
| | - Wolfgang Meyerhof
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg,
Germany
| | - Tongzhi Wu
- Adelaide Medical School and National Health and Medical Research Council of Australia (NHMRC) Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide,
Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide,
Australia
| | - Michael Horowitz
- Adelaide Medical School and National Health and Medical Research Council of Australia (NHMRC) Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide,
Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide,
Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School and National Health and Medical Research Council of Australia (NHMRC) Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide,
Australia
- Correspondence: Christine Feinle-Bisset, PhD, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide SA 5005, Australia, Tel: +61-8-8313-6053, Fax: +61-8-8313-7794, E-mail:
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23
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Gastrointestinal Sensing of Meal-Related Signals in Humans, and Dysregulations in Eating-Related Disorders. Nutrients 2019; 11:nu11061298. [PMID: 31181734 PMCID: PMC6627312 DOI: 10.3390/nu11061298] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/29/2019] [Accepted: 06/05/2019] [Indexed: 12/13/2022] Open
Abstract
The upper gastrointestinal (GI) tract plays a critical role in sensing the arrival of a meal, including its volume as well as nutrient and non-nutrient contents. The presence of the meal in the stomach generates a mechanical distension signal, and, as gastric emptying progresses, nutrients increasingly interact with receptors on enteroendocrine cells, triggering the release of gut hormones, with lipid and protein being particularly potent. Collectively, these signals are transmitted to the brain to regulate appetite and energy intake, or in a feedback loop relayed back to the upper GI tract to further adjust GI functions, including gastric emptying. The research in this area to date has provided important insights into how sensing of intraluminal meal-related stimuli acutely regulates appetite and energy intake in humans. However, disturbances in the detection of these stimuli have been described in a number of eating-related disorders. This paper will review the GI sensing of meal-related stimuli and the relationship with appetite and energy intake, and examine changes in GI responses to luminal stimuli in obesity, functional dyspepsia and anorexia of ageing, as examples of eating-related disorders. A much better understanding of the mechanisms underlying these dysregulations is still required to assist in the development of effective management and treatment strategies in the future.
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24
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Kårlund A, Gómez-Gallego C, Turpeinen AM, Palo-Oja OM, El-Nezami H, Kolehmainen M. Protein Supplements and Their Relation with Nutrition, Microbiota Composition and Health: Is More Protein Always Better for Sportspeople? Nutrients 2019; 11:nu11040829. [PMID: 31013719 PMCID: PMC6521232 DOI: 10.3390/nu11040829] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/05/2019] [Accepted: 04/08/2019] [Indexed: 12/27/2022] Open
Abstract
Sports nutrition products are developed and targeted mainly for athletes to improve their nutrient intake, performance, and muscle growth. The fastest growing consumer groups for these products are recreational sportspeople and lifestyle users. Although athletes may have elevated physiological protein requirements and they may benefit from dietary supplements, the evidence regarding the role of dietary protein and supplements in the nutrition of recreational sportspeople and sedentary populations is somewhat complex and contradictory. In high-protein diets, more undigested protein-derived constituents end up in the large intestine compared to moderate or low-protein diets, and hence, more bacterial amino acid metabolism takes place in the colon, having both positive and negative systemic and metabolic effects on the host. The aim of the present review is to summarize the impact of the high-protein products and diets on nutrition and health, in sportspeople and in sedentary consumers. We are opening the debate about the current protein intake recommendations, with an emphasis on evidence-based effects on intestinal microbiota and personalized guidelines regarding protein and amino acid supplementation in sportspeople and lifestyle consumers.
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Affiliation(s)
- Anna Kårlund
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Carlos Gómez-Gallego
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | | | - Outi-Maaria Palo-Oja
- Business School, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Hani El-Nezami
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
- School of Biological Sciences, University of Hong Kong, Pok Fu Lam Road, Hong Kong SAR, China.
| | - Marjukka Kolehmainen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
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25
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Elovaris RA, Fitzgerald PCE, Bitarafan V, Ullrich SS, Horowitz M, Feinle-Bisset C. Intraduodenal Administration of L-Valine Has No Effect on Antropyloroduodenal Pressures, Plasma Cholecystokinin Concentrations or Energy Intake in Healthy, Lean Men. Nutrients 2019; 11:nu11010099. [PMID: 30621276 PMCID: PMC6356499 DOI: 10.3390/nu11010099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 02/07/2023] Open
Abstract
Whey protein is rich in the branched-chain amino acids, L-leucine, L-isoleucine and L-valine. Thus, branched-chain amino acids may, at least in part, mediate the effects of whey to reduce energy intake and/or blood glucose. Notably, 10 g of either L-leucine or L-isoleucine, administered intragastrically before a mixed-nutrient drink, lowered postprandial blood glucose, and intraduodenal infusion of L-leucine (at a rate of 0.45 kcal/min, total: 9.9 g) lowered fasting blood glucose and reduced energy intake from a subsequent meal. Whether L-valine affects energy intake, and the gastrointestinal functions involved in the regulation of energy intake, as well as blood glucose, in humans, is currently unknown. We investigated the effects of intraduodenally administered L-valine on antropyloroduodenal pressures, plasma cholecystokinin, blood glucose and energy intake. Twelve healthy lean men (age: 29 ± 2 years, BMI: 22.5 ± 0.7 kg/m²) were studied on 3 separate occasions in randomised, double-blind order. Antropyloroduodenal pressures, plasma cholecystokinin, blood glucose, appetite perceptions and gastrointestinal symptoms were measured during 90-min intraduodenal infusions of L-valine at 0.15 kcal/min (total: 3.3 g) or 0.45 kcal/min (total: 9.9 g), or 0.9% saline (control). Energy intake from a buffet-meal immediately after the infusions was quantified. L-valine did not affect antral, pyloric (mean number; control: 14 ± 5; L-Val-0.15: 21 ± 9; L-Val-0.45: 11 ± 4), or duodenal pressures, plasma cholecystokinin (mean concentration, pmol/L; control: 3.1 ± 0.3; L-Val-0.15: 3.2 ± 0.3; L-Val-0.45: 3.0 ± 0.3), blood glucose, appetite perceptions, symptoms or energy intake (kcal; control: 1040 ± 73; L-Val-0.15: 1040 ± 81; L-Val-0.45: 1056 ± 100), at either load (p > 0.05 for all). In conclusion, intraduodenal infusion of L-valine, at loads that are moderately (3.3 g) or substantially (9.9 g) above World Health Organization valine requirement recommendations, does not appear to have energy intake- or blood glucose-lowering effects.
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Affiliation(s)
- Rachel A Elovaris
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Penelope C E Fitzgerald
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Vida Bitarafan
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Sina S Ullrich
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Michael Horowitz
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Christine Feinle-Bisset
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
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26
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Ullrich SS, Fitzgerald PCE, Giesbertz P, Steinert RE, Horowitz M, Feinle-Bisset C. Effects of Intragastric Administration of Tryptophan on the Blood Glucose Response to a Nutrient Drink and Energy Intake, in Lean and Obese Men. Nutrients 2018; 10:nu10040463. [PMID: 29642492 PMCID: PMC5946248 DOI: 10.3390/nu10040463] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 02/07/2023] Open
Abstract
Tryptophan stimulates plasma cholecystokinin and pyloric pressures, both of which slow gastric emptying. Gastric emptying regulates postprandial blood glucose. Tryptophan has been reported to decrease energy intake. We investigated the effects of intragastric tryptophan on the glycaemic response to, and gastric emptying of, a mixed-nutrient drink, and subsequent energy intake. Lean and obese participants (n = 16 each) received intragastric infusions of 1.5 g ("Trp-1.5g") or 3.0 g ("Trp-3.0g") tryptophan, or control, and 15 min later consumed a mixed-nutrient drink (56 g carbohydrates). Gastric emptying (13C-acetate breath-test), blood glucose, plasma C-peptide, glucagon, cholecystokinin and tryptophan concentrations were measured (t = 0-60 min). Energy intake was assessed between t = 60-90 min. In lean individuals, Trp-3.0g, but not Trp-1.5g, slowed gastric emptying, reduced C-peptideAUC and increased glucagonAUC (all P < 0.05), but did not significantly decrease the blood glucose response to the drink, stimulate cholecystokinin or reduce mean energy intake, compared with control. In obese individuals, Trp-3.0g, but not Trp-1.5g, tended to slow gastric emptying (P = 0.091), did not affect C-peptideAUC, increased glucagonAUC (P < 0.001) and lowered blood glucose at t = 30 min (P < 0.05), and did not affect cholecystokinin or mean energy intake. In obese individuals, intragastrically administered tryptophan may reduce postprandial blood glucose by slowing gastric emptying; the lack of effect on mean energy intake requires further investigation.
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Affiliation(s)
- Sina S Ullrich
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Penelope C E Fitzgerald
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Pieter Giesbertz
- Department of Nutritional Physiology, Technical University of Munich, Gregor-Mendel Strasse 2, 85354 Freising, Germany.
| | - Robert E Steinert
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
- Department of Surgery, Division of Visceral and Transplantation Surgery, University Hospital Zürich, Rämistrasse 100, 8091 Zürich, Switzerland.
| | - Michael Horowitz
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
| | - Christine Feinle-Bisset
- Adelaide Medical School and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia.
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27
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Martins CEC, Lima VBDS, Schoenfeld BJ, Tirapegui J. Effects of leucine supplementation and resistance training on myopathy of diabetic rats. Physiol Rep 2018; 5:e13273. [PMID: 28536139 PMCID: PMC5449559 DOI: 10.14814/phy2.13273] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 11/24/2022] Open
Abstract
Leucine supplementation and resistance training positively influence the protein translation process and the cell signaling mTOR (mammalian target of rapamycin) pathway that regulates muscle protein balance and muscle remodeling, and thus may be therapeutic to diabetic myopathy. However, the effect of a combined intervention has not been well studied. Forty male Wistar rats were divided into five groups, control (C), diabetic control (D), diabetic + trained (DT), diabetic + L-leucine (DL), diabetic + L-leucine + trained (DLT). The supplementation of 5% leucine in chow, and resistance training were conducted for 8 weeks postweaning of rats. The extensor digitorum longus was used to assess signaling proteins involved in muscle protein synthesis, and the gastrocnemius and soleus were used for determination of muscle weight. Blood samples were collected for biochemical assays. Strength and ambulation tests were employed to evaluate motor performance. Results showed that both leucine supplementation and resistance training elevated the activity of mTOR-p70S6K in diabetic rats (P < 0.05). Moreover, though leucine supplementation in combination with resistance training demonstrated synergistic effects on p70S6K (P < 0.05), both treatments were capable of recovering motor performance (P < 0.05). In conclusion, 5% leucine supplementation combined with resistance training has the potential to attenuate muscle loss and motor performance decrements in diabetic rats, at least in part through increased protein synthesis.
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Affiliation(s)
- Carlos Eduardo C Martins
- Department of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Vanessa B de S Lima
- Department of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | | | - Julio Tirapegui
- Department of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
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28
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Heeley N, Kirwan P, Darwish T, Arnaud M, Evans ML, Merkle FT, Reimann F, Gribble FM, Blouet C. Rapid sensing of l-leucine by human and murine hypothalamic neurons: Neurochemical and mechanistic insights. Mol Metab 2018; 10:14-27. [PMID: 29439854 PMCID: PMC5985239 DOI: 10.1016/j.molmet.2018.01.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 01/24/2018] [Accepted: 01/29/2018] [Indexed: 11/27/2022] Open
Abstract
Objective Dietary proteins are sensed by hypothalamic neurons and strongly influence multiple aspects of metabolic health, including appetite, weight gain, and adiposity. However, little is known about the mechanisms by which hypothalamic neural circuits controlling behavior and metabolism sense protein availability. The aim of this study is to characterize how neurons from the mediobasal hypothalamus respond to a signal of protein availability: the amino acid l-leucine. Methods We used primary cultures of post-weaning murine mediobasal hypothalamic neurons, hypothalamic neurons derived from human induced pluripotent stem cells, and calcium imaging to characterize rapid neuronal responses to physiological changes in extracellular l-Leucine concentration. Results A neurochemically diverse subset of both mouse and human hypothalamic neurons responded rapidly to l-leucine. Consistent with l-leucine's anorexigenic role, we found that 25% of mouse MBH POMC neurons were activated by l-leucine. 10% of MBH NPY neurons were inhibited by l-leucine, and leucine rapidly reduced AGRP secretion, providing a mechanism for the rapid leucine-induced inhibition of foraging behavior in rodents. Surprisingly, none of the candidate mechanisms previously implicated in hypothalamic leucine sensing (KATP channels, mTORC1 signaling, amino-acid decarboxylation) were involved in the acute activity changes produced by l-leucine. Instead, our data indicate that leucine-induced neuronal activation involves a plasma membrane Ca2+ channel, whereas leucine-induced neuronal inhibition is mediated by inhibition of a store-operated Ca2+ current. Conclusions A subset of neurons in the mediobasal hypothalamus rapidly respond to physiological changes in extracellular leucine concentration. Leucine can produce both increases and decreases in neuronal Ca2+ concentrations in a neurochemically-diverse group of neurons, including some POMC and NPY/AGRP neurons. Our data reveal that leucine can signal through novel mechanisms to rapidly affect neuronal activity. A neurochemically diverse group of mouse and human hypothalamic neurons rapidly sense and respond to l-leucine. Leucine can produce neuronal activation or neuronal inhibition via distinct and novel Ca2+ signaling mechanisms. Leucine activates 25% ARH POMC neurons. Leucine inhibits 10% ARH NPY/AGRP neurons and reduces AGRP secretion from fasted mediobasal hypothalamic slices.
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Affiliation(s)
- Nicholas Heeley
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Peter Kirwan
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Tamana Darwish
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Marion Arnaud
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Mark L Evans
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Florian T Merkle
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Frank Reimann
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Fiona M Gribble
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK
| | - Clemence Blouet
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 OQQ, UK.
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29
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Gribble FM, Meek CL, Reimann F. Targeted intestinal delivery of incretin secretagogues-towards new diabetes and obesity therapies. Peptides 2018; 100:68-74. [PMID: 29412834 PMCID: PMC5805852 DOI: 10.1016/j.peptides.2017.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 12/11/2022]
Abstract
A new strategy under development for the treatment of type 2 diabetes and obesity is to mimic some of the effects of bariatric surgery by delivering food-related stimuli to the distal gastrointestinal tract where they should enhance the release of gut hormones such as glucagon-like peptide-1 (GLP-1) and peptideYY (PYY). Methods include inhibition of food digestion and absorption in the upper GI tract, or oral delivery of stimuli in capsules or pelleted form to protect them against gastric degradation. A variety of agents have been tested in humans using capsules, microcapsules or pellets, delivering nutrients, bile acids, fatty acids and bitter compounds. This review examines the outcomes of these different approaches and supporting evidence from intestinal perfusion studies.
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Affiliation(s)
- Fiona M Gribble
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom.
| | - Claire L Meek
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Frank Reimann
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, United Kingdom.
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Myles JG, Manoli I, Venditti CP. Effects of medical food leucine content in the management of methylmalonic and propionic acidemias. Curr Opin Clin Nutr Metab Care 2018; 21:42-48. [PMID: 29035969 PMCID: PMC5815322 DOI: 10.1097/mco.0000000000000428] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW The current review highlights the varied effects of medical foods high in leucine (Leu) and devoid of valine (Val) and isoleucine (Ile) in the management of methylmalonic acidemia (MMA) and propionic acidemia and cobalamin C (cblC) deficiency, aiming to advance dietary practices. RECENT FINDINGS Leu is a key metabolic regulator with a multitude of effects on different organ systems. Recent observational studies have demonstrated that these effects can have unintended consequences in patients with MMA as a result of liberal use of medical foods. The combination of protein restriction and medical food use in MMA and propionic acidemia results in an imbalanced branched-chain amino acid (BCAA) dietary content with a high Leu-to-Val and/or Ile ratio. This leads to decreased plasma levels of Val and Ile and predicts impaired brain uptake of multiple essential amino acids. Decreased transport of methionine (Met) across the blood-brain barrier due to high circulating Leu levels is of particular concern in cblC deficiency in which endogenous Met synthesis is impaired. SUMMARY Investigations into the optimal composition of medical foods for MMA and propionic acidemia, and potential scenarios in which Leu supplementation may be beneficial are needed. Until then, MMA/propionic acidemia medical foods should be used judiciously in the dietary management of these patients and avoided altogether in cblC deficiency.
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Affiliation(s)
| | - Irini Manoli
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Charles P Venditti
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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Steinert RE, Ullrich SS, Geary N, Asarian L, Bueter M, Horowitz M, Feinle-Bisset C. Comparative effects of intraduodenal amino acid infusions on food intake and gut hormone release in healthy males. Physiol Rep 2017; 5:e13492. [PMID: 29138359 PMCID: PMC5688783 DOI: 10.14814/phy2.13492] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/12/2017] [Indexed: 02/07/2023] Open
Abstract
In contrast to the many studies of the effects of individual amino acids (AAs) on eating, no studies have compared the effects of different AAs on eating and underlying preabsorptive gastrointestinal mechanisms. To compare the effects of intraduodenal infusions of l-tryptophan (TRP), l-leucine (LEU), l-phenylalanine (PHE) and l-glutamine (GLN) on appetite, gastrointestinal hormone responses (including ghrelin, cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 [GLP-1]), glycemia (glucagon, insulin and glucose) and test meal size in healthy males, we retrospectively analyzed data from four published independent, randomized, double-blind, placebo-controlled studies of 90-min intraduodenal infusions of the individual AAs. The designs of the studies were identical, except the dose of TRP (0.15 kcal/min) was lower than that of the other AAs (0.45 kcal/min) because higher doses of this AA were not well tolerated. TRP and LEU decreased intake more than PHE (reductions relative to control, ~219 ± 68, ~170 ± 48 and ~12 ± 57 kcal, respectively), and TRP decreased intake more than GLN (~31 ± 82 kcal). These effects of TRP and LEU versus GLN, but not versus PHE, were paralleled by greater decreases in plasma ghrelin, and increases in CCK, concentrations. TRP increased PYY more than GLN or LEU, but not PHE. LEU increased PYY less than PHE. No significant differences were detected for GLP-1. PHE increased glucagon more than TRP or LEU, and increased insulin more than TRP. Under our experimental conditions, intraduodenal TRP and LEU were more satiating than PHE and GLN. The greater satiating efficacy of LEU versus PHE was significantly dissociated from the effects of these AAs on PYY, while the greater satiating potency of TRP versus PHE was significantly dissociated from the effects of these AAs on insulin and glucagon. In contrast, ghrelin and CCK, and potentially other mechanisms, including central sensing of individual AAs, appear to be stronger candidate mechanisms for the relative satiating effects obtained.
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Affiliation(s)
- Robert E Steinert
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, South Australia, Australia
- Department of Surgery, Division of Visceral and Transplantation Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Sina S Ullrich
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, South Australia, Australia
| | - Nori Geary
- Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
| | - Lori Asarian
- Department of Medicine-Immunobiology, Robert Larner College of Medicine University of Vermont, Burlington, Vermont
| | - Marco Bueter
- Department of Surgery, Division of Visceral and Transplantation Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Michael Horowitz
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, South Australia, Australia
| | - Christine Feinle-Bisset
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, South Australia, Australia
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Bifari F, Ruocco C, Decimo I, Fumagalli G, Valerio A, Nisoli E. Amino acid supplements and metabolic health: a potential interplay between intestinal microbiota and systems control. GENES & NUTRITION 2017; 12:27. [PMID: 29043007 PMCID: PMC5628494 DOI: 10.1186/s12263-017-0582-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/17/2017] [Indexed: 01/12/2023]
Abstract
Dietary supplementation of essential amino acids (EAAs) has been shown to promote healthspan. EAAs regulate, in fact, glucose and lipid metabolism and energy balance, increase mitochondrial biogenesis, and maintain immune homeostasis. Basic science and epidemiological results indicate that dietary macronutrient composition affects healthspan through multiple and integrated mechanisms, and their effects are closely related to the metabolic status to which they act. In particular, EAA supplementation can trigger different and even opposite effects depending on the catabolic and anabolic states of the organisms. Among others, gut-associated microbial communities (referred to as gut microbiota) emerged as a major regulator of the host metabolism. Diet and host health influence gut microbiota, and composition of gut microbiota, in turn, controls many aspects of host health, including nutrient metabolism, resistance to infection, and immune signals. Altered communication between the innate immune system and the gut microbiota might contribute to complex diseases. Furthermore, gut microbiota and its impact to host health change largely during different life phases such as lactation, weaning, and aging. Here we will review the accumulating body of knowledge on the impact of dietary EAA supplementation on the host metabolic health and healthspan from a holistic perspective. Moreover, we will focus on the current efforts to establish causal relationships among dietary EAAs, gut microbiota, and health during human development.
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Affiliation(s)
- Francesco Bifari
- Laboratory of Cell Metabolism and Regenerative Medicine, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Chiara Ruocco
- Center for Study and Research on Obesity, Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
| | - Ilaria Decimo
- Section of Pharmacology, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Guido Fumagalli
- Section of Pharmacology, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Enzo Nisoli
- Center for Study and Research on Obesity, Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
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Bifari F, Nisoli E. Branched-chain amino acids differently modulate catabolic and anabolic states in mammals: a pharmacological point of view. Br J Pharmacol 2017; 174:1366-1377. [PMID: 27638647 PMCID: PMC5429325 DOI: 10.1111/bph.13624] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/28/2016] [Accepted: 08/03/2016] [Indexed: 12/21/2022] Open
Abstract
Substantial evidence has been accumulated suggesting that branched-chain amino acid (BCAA) supplementation or BCAA-rich diets have a positive effect on the regulation of body weight, muscle protein synthesis, glucose homeostasis, the ageing process and extend healthspan. Despite these beneficial effects, epidemiological studies have shown that BCAA plasma concentrations and BCAA metabolism are altered in several metabolic disorders, including type 2 diabetes mellitus and cardiovascular diseases. In this review article, we present an overview of the current literature on the different effects of BCAAs in health and disease. We also highlight the results showing the most promising therapeutic effects of dietary BCAA supplementation and discuss how BCAAs can trigger different and even opposite effects, depending on the catabolic and anabolic states of the organisms. Moreover, we consider the effects of BCAAs when metabolism is abnormal, in the presence of a mixture of different anabolic and catabolic signals. These unique pharmacodynamic properties may partially explain some of the markedly different effects found in BCAA supplementation studies. To predict accurately these effects, the overall catabolic/anabolic status of patients should be carefully considered. In wider terms, a correct modulation of metabolic disorders would make nutraceutical interventions with BCAAs more effective. LINKED ARTICLES This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.
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Affiliation(s)
- Francesco Bifari
- Laboratory of Cell Metabolism and Regenerative Medicine, Department of Medical Biotechnology and Translational MedicineUniversity of MilanMilanItaly
| | - Enzo Nisoli
- Center for Study and Research on Obesity, Department of Medical Biotechnology and Translational MedicineUniversity of MilanMilanItaly
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Trahair LG, Marathe CS, Standfield S, Rayner CK, Feinle-Bisset C, Horowitz M, Jones KL. Effects of small intestinal glucose on glycaemia, insulinaemia and incretin hormone release are load-dependent in obese subjects. Int J Obes (Lond) 2017; 41:225-232. [PMID: 27840416 DOI: 10.1038/ijo.2016.202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 08/10/2016] [Accepted: 09/30/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND/OBJECTIVES Studies concerning the glycaemic response to oral glucose, or meals in obesity have usually failed to account for gastric emptying. It has been suggested that the incretin effect may be diminished in obesity as a result of a reduction in glucagon-like peptide-1 (GLP-1) secretion. We sought to determine the effect of two different rates of intraduodenal glucose infusions on glycaemic, insulinaemic and incretin hormone responses in lean and obese subjects and compare the effects of oral and intraduodenal glucose in obese subjects. SUBJECTS/METHODS Eleven obese subjects (age 37.5±4.1 years, body mass index (BMI) 35.7±1.4 kg m-2) and 12 controls (age 34.7±4.0 years, BMI 23.9±0.7 kg m-2) received intraduodenal infusions of glucose at 1 or 3 kcal min-1, or saline for 60 min (t=0-60 min), followed by intraduodenal saline (t=60-120 min). In obese subjects, an oral glucose tolerance test was performed. Blood glucose, serum insulin, plasma total GLP-1 and total gastric inhibitory polypeptide (GIP) were measured. RESULTS In both the groups (P<0.001), the incremental areas under the curve (iAUC)0-60 min for glucose was greater with the 3 kcal min-1 than the 1 kcal min-1 infusion; the iAUC0-120 min for glucose during 3 kcal min-1 was greater (P<0.05), in the obese. Insulin responses to 1 kcal min-1 and, particularly, 3 kcal min-1 were greater (P<0.001) in the obese. Stimulation of GLP-1 and GIP were greater (P<0.001) in response to 3 kcal min-1, compared with 1 kcal min-1 and saline, without any difference between the groups. In the obese, glycaemic, insulinaemic and GIP, but not GLP-1, responses to oral and intraduodenal glucose were related (P<0.05). CONCLUSIONS The rate of duodenal glucose delivery is a major determinant of glycaemia, insulinaemia and incretin hormone release in obese subjects. Obesity is not apparently associated with impaired GLP-1 secretion.
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Affiliation(s)
- L G Trahair
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - C S Marathe
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - S Standfield
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - C K Rayner
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - C Feinle-Bisset
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - M Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - K L Jones
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
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Meyer-Gerspach AC, Häfliger S, Meili J, Doody A, Rehfeld JF, Drewe J, Beglinger C, Wölnerhanssen B. Effect of L-Tryptophan and L-Leucine on Gut Hormone Secretion, Appetite Feelings and Gastric Emptying Rates in Lean and Non-Diabetic Obese Participants: A Randomized, Double-Blind, Parallel-Group Trial. PLoS One 2016; 11:e0166758. [PMID: 27875537 PMCID: PMC5119776 DOI: 10.1371/journal.pone.0166758] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/01/2016] [Indexed: 12/13/2022] Open
Abstract
Background/Objectives Gut hormones such as cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) play a role as satiation factors. Strategies to enhance satiation peptide secretion could provide a therapeutic approach for obesity. Carbohydrates and lipids have been extensively investigated in relation to peptide release. In contrast, the role of proteins or amino acids is less clear. Our aim was to compare the effects of the amino acids L-tryptophan (L-trp) and L-leucine (L-leu) separately on gastric emptying and gut peptide secretion. Participants/Methods The study was conducted as a randomized (balanced), double-blind, parallel-group trial. A total of 10 lean and 10 non-diabetic obese participants were included. Participants received intragastric loads of L-trp (0.52 g and 1.56 g) and L-leu (1.56 g), dissolved in 300 mL tap water; 75 g glucose and 300 mL tap water served as control treatments. Results Results of the study are: i) L-trp at the higher dose stimulates CCK release (p = 0.0018), and induces a significant retardation in gastric emptying (p = 0.0033); ii) L-trp at the higher dose induced a small increase in GLP-1 secretion (p = 0.0257); iii) neither of the amino acids modulated subjective appetite feelings; and iv) the two amino acids did not alter insulin or glucose concentrations. Conclusions L-trp is a luminal regulator of CCK release with effects on gastric emptying, an effect that could be mediated by CCK. L-trp’s effect on GLP-1 secretion is only minor. At the doses given, the two amino acids did not affect subjective appetite feelings. Trial Registration ClinicalTrials.gov NCT02563847
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Affiliation(s)
- Anne Christin Meyer-Gerspach
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Department of Research, St. Claraspital, Basel, Switzerland
- * E-mail:
| | - Simon Häfliger
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Julian Meili
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Alison Doody
- Diabetes Complications Research Centre, Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jürgen Drewe
- Department of Clinical Pharmacology, University Hospital Basel, Basel, Switzerland
| | - Christoph Beglinger
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Department of Research, St. Claraspital, Basel, Switzerland
| | - Bettina Wölnerhanssen
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Department of Research, St. Claraspital, Basel, Switzerland
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Ullrich SS, Fitzgerald PC, Schober G, Steinert RE, Horowitz M, Feinle-Bisset C. Intragastric administration of leucine or isoleucine lowers the blood glucose response to a mixed-nutrient drink by different mechanisms in healthy, lean volunteers. Am J Clin Nutr 2016; 104:1274-1284. [PMID: 27655440 DOI: 10.3945/ajcn.116.140640] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 08/19/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The branched-chain amino acids leucine and isoleucine lower blood glucose after oral glucose ingestion, and the intraduodenal infusion of leucine decreases energy intake in healthy, lean men. OBJECTIVE We investigated the effects of the intragastric administration of leucine and isoleucine on the gastric emptying of, and blood glucose responses to, a physiologic mixed-macronutrient drink and subsequent energy intake. DESIGN In 2 separate studies, 12 healthy, lean subjects received on 3 separate occasions an intragastric infusion of 5 g leucine (leucine-5g) or an intragastric infusion of 10 g leucine (leucine-10g), an intragastric infusion of 5 g isoleucine (isoleucine-5g) or an intragastric infusion of 10 g isoleucine (isoleucine-10g), or a control. Fifteen minutes later, subjects consumed a mixed-nutrient drink (400 kcal, 56 g carbohydrates, 15 g protein, and 12 g fat), and gastric emptying (13C-acetate breath test) and blood glucose, plasma insulin, C-peptide, glucagon, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and cholecystokinin (leucine study only) were measured for 60 min. Immediately afterward, energy intake from a cold, buffet-style meal was assessed. RESULTS Compared with the control, leucine-10g decreased the blood glucose area under the curve (AUC) (P < 0.05) and tended to reduce peak blood glucose (P = 0.07), whereas effects of leucine-5g were NS. Leucine-10g, but not leucine-5g, increased plasma insulin and C-peptide AUCs (P < 0.01 for both), but neither dose affected glucagon, GLP-1, GIP, cholecystokinin, gastric emptying, or energy intake. Compared with the control, isoleucine-10g reduced the blood glucose AUC and peak blood glucose (P < 0.01), whereas effects of isoleucine-5g were NS. Neither load affected insulin, C-peptide, glucagon, GLP-1, or GIP. Isoleucine-10g, but not isoleucine-5g, slowed gastric emptying (P < 0.05), but gastric emptying was not correlated with the blood glucose AUC. Isoleucine did not affect energy intake. CONCLUSIONS In healthy subjects, both leucine and isoleucine reduced blood glucose in response to a mixed-nutrient drink but did not affect subsequent energy intake. The mechanisms underlying glucose lowering appear to differ; leucine stimulated insulin, whereas isoleucine acted insulin independently. These trials were registered at www.anzctr.org.au as 12613000899741 and 12614000837628.
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Affiliation(s)
- Sina S Ullrich
- Discipline of Medicine, University of Adelaide, Adelaide, Australia; and National Health and Medical Research Council of Australia Center of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia
| | - Penelope Ce Fitzgerald
- Discipline of Medicine, University of Adelaide, Adelaide, Australia; and National Health and Medical Research Council of Australia Center of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia
| | - Gudrun Schober
- Discipline of Medicine, University of Adelaide, Adelaide, Australia; and National Health and Medical Research Council of Australia Center of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia
| | - Robert E Steinert
- Discipline of Medicine, University of Adelaide, Adelaide, Australia; and National Health and Medical Research Council of Australia Center of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia
| | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, Australia; and National Health and Medical Research Council of Australia Center of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia
| | - Christine Feinle-Bisset
- Discipline of Medicine, University of Adelaide, Adelaide, Australia; and National Health and Medical Research Council of Australia Center of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia
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Zanchi D, Meyer-Gerspach AC, Suenderhauf C, Janach K, le Roux CW, Haller S, Drewe J, Beglinger C, Wölnerhanssen BK, Borgwardt S. Differential effects of L-tryptophan and L-leucine administration on brain resting state functional networks and plasma hormone levels. Sci Rep 2016; 6:35727. [PMID: 27760995 PMCID: PMC5071755 DOI: 10.1038/srep35727] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/04/2016] [Indexed: 12/28/2022] Open
Abstract
Depending on their protein content, single meals can rapidly influence the uptake of amino acids into the brain and thereby modify brain functions. The current study investigates the effects of two different amino acids on the human gut-brain system, using a multimodal approach, integrating physiological and neuroimaging data. In a randomized, placebo-controlled trial, L-tryptophan, L-leucine, glucose and water were administered directly into the gut of 20 healthy subjects. Functional MRI (fMRI) in a resting state paradigm (RS), combined with the assessment of insulin and glucose blood concentration, was performed before and after treatment. Independent component analysis with dual regression technique was applied to RS-fMRI data. Results were corrected for multiple comparisons. In comparison to glucose and water, L-tryptophan consistently modifies the connectivity of the cingulate cortex in the default mode network, of the insula in the saliency network and of the sensory cortex in the somatosensory network. L-leucine has lesser effects on these functional networks. L-tryptophan and L-leucine also modified plasma insulin concentration. Finally, significant correlations were found between brain modifications after L-tryptophan administration and insulin plasma levels. This study shows that acute L-tryptophan and L-leucine intake directly influence the brain networks underpinning the food-reward system and appetite regulation.
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Affiliation(s)
- Davide Zanchi
- Department of Psychiatry, University Hospital of Basel, CH-4012 Basel, Switzerland
| | | | - Claudia Suenderhauf
- Department of Psychiatry, University Hospital of Basel, CH-4012 Basel, Switzerland
| | - Katharina Janach
- Department of Biomedicine, University Hospital, CH-4031 Basel Switzerland
| | - Carel W le Roux
- Diabetes Complications Research Centre, Conway Institute University College Dublin, Dublin, Ireland
| | - Sven Haller
- Faculty of Medicine of the University of Geneva, Switzerland.,Affidea CDRC - Centre Diagnostique Radiologique de Carouge, Switzerland.,Department of Surgical Sciences, Radiology Uppsala University, Uppsala, Sweden.,Department of Neuroradiology, University Hospital Freiburg, Germany.,Faculty of Medicine of the University of Geneva, Switzerland
| | - Jürgen Drewe
- Department of Research, St. Claraspital, Switzerland
| | | | - Bettina K Wölnerhanssen
- Department of Biomedicine, University Hospital, CH-4031 Basel Switzerland.,Department of Research, St. Claraspital, Switzerland
| | - Stefan Borgwardt
- Department of Psychiatry, University Hospital of Basel, CH-4012 Basel, Switzerland
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Schober G, Lange K, Steinert RE, Hutchison AT, Luscombe-Marsh ND, Landrock MF, Horowitz M, Seimon RV, Feinle-Bisset C. Contributions of upper gut hormones and motility to the energy intake-suppressant effects of intraduodenal nutrients in healthy, lean men - a pooled-data analysis. Physiol Rep 2016; 4:e12943. [PMID: 27613824 PMCID: PMC5027351 DOI: 10.14814/phy2.12943] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 08/08/2016] [Indexed: 02/07/2023] Open
Abstract
We have previously identified pyloric pressures and plasma cholecystokinin (CCK) concentrations as independent determinants of energy intake following administration of intraduodenal lipid and intravenous CCK. We evaluated in healthy men whether these parameters also determine energy intake in response to intraduodenal protein, and whether, across the nutrients, any predominant gastrointestinal (GI) factors exist, or many factors make small contributions. Data from nine published studies, in which antropyloroduodenal pressures, GI hormones, and GI /appetite perceptions were measured during intraduodenal lipid or protein infusions, were pooled. In all studies energy intake was quantified immediately after the infusions. Specific variables for inclusion in a mixed-effects multivariable model for determination of independent predictors of energy intake were chosen following assessment for collinearity, and within-subject correlations between energy intake and these variables were determined using bivariate analyses adjusted for repeated measures. In models based on all studies, or lipid studies, there were significant effects for amplitude of antral pressure waves, premeal glucagon-like peptide-1 (GLP-1) and time-to-peak GLP-1 concentrations, GLP-1 AUC and bloating scores (P < 0.05), and trends for basal pyloric pressure (BPP), amplitude of duodenal pressure waves, peak CCK concentrations, and hunger and nausea scores (0.05 < P ≤ 0.094), to be independent determinants of subsequent energy intake. In the model including the protein studies, only BPP was identified as an independent determinant of energy intake (P < 0.05). No single parameter was identified across all models, and effects of the variables identified were relatively small. Taken together, while GI mechanisms contribute to the regulation of acute energy intake by lipid and protein, their contribution to the latter is much less. Moreover, the effects are likely to reflect small, cumulative contributions from a range of interrelated factors.
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Affiliation(s)
- Gudrun Schober
- University of Adelaide Discipline of Medicine, Adelaide, Australia
| | - Kylie Lange
- University of Adelaide Discipline of Medicine, Adelaide, Australia NHMRC Centre of Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, Australia
| | - Robert E Steinert
- University of Adelaide Discipline of Medicine, Adelaide, Australia NHMRC Centre of Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, Australia
| | - Amy T Hutchison
- University of Adelaide Discipline of Medicine, Adelaide, Australia NHMRC Centre of Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, Australia South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Natalie D Luscombe-Marsh
- NHMRC Centre of Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, Australia CSIRO Animal, Food and Health Sciences, Adelaide, Australia
| | - Maria F Landrock
- University of Adelaide Discipline of Medicine, Adelaide, Australia
| | - Michael Horowitz
- University of Adelaide Discipline of Medicine, Adelaide, Australia NHMRC Centre of Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, Australia
| | - Radhika V Seimon
- Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, University of Sydney, Sydney, Australia
| | - Christine Feinle-Bisset
- University of Adelaide Discipline of Medicine, Adelaide, Australia NHMRC Centre of Excellence in Translating Nutritional Science to Good Health University of Adelaide, Adelaide, Australia
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Moghei M, Tavajohi-Fini P, Beatty B, Adegoke OAJ. Ketoisocaproic acid, a metabolite of leucine, suppresses insulin-stimulated glucose transport in skeletal muscle cells in a BCAT2-dependent manner. Am J Physiol Cell Physiol 2016; 311:C518-27. [PMID: 27488662 DOI: 10.1152/ajpcell.00062.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/26/2016] [Indexed: 01/18/2023]
Abstract
Although leucine has many positive effects on metabolism in multiple tissues, elevated levels of this amino acid and the other branched-chain amino acids (BCAAs) and their metabolites are implicated in obesity and insulin resistance. While some controversies exist about the direct effect of leucine on insulin action in skeletal muscle, little is known about the direct effect of BCAA metabolites. Here, we first showed that the inhibitory effect of leucine on insulin-stimulated glucose transport in L6 myotubes was dampened when other amino acids were present, due in part to a 140% stimulation of basal glucose transport (P < 0.05). Importantly, we also showed that α-ketoisocaproic acid (KIC), an obligatory metabolite of leucine, stimulated mTORC1 signaling but suppressed insulin-stimulated glucose transport (-34%, P < 0.05) in an mTORC1-dependent manner. The effect of KIC on insulin-stimulated glucose transport was abrogated in cells depleted of branched-chain aminotransferase 2 (BCAT2), the enzyme that catalyzes the reversible transamination of KIC to leucine. We conclude that although KIC can modulate muscle glucose metabolism, this effect is likely a result of its transamination back to leucine. Therefore, limiting the availability of leucine, rather than those of its metabolites, to skeletal muscle may be more critical in the management of insulin resistance and its sequelae.
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Affiliation(s)
- Mahshid Moghei
- School of Kinesiology and Health Science and Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Pegah Tavajohi-Fini
- School of Kinesiology and Health Science and Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Brendan Beatty
- School of Kinesiology and Health Science and Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Olasunkanmi A J Adegoke
- School of Kinesiology and Health Science and Muscle Health Research Centre, York University, Toronto, Ontario, Canada
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