focus on protein metabolism

Transcription

1 Leipzig DGEM 2010 Glutamine and the gut: focus on protein metabolism P. Déchelotte, Rouen, France

2 Gut : a key organ for glutamine metabolism GLN and a target organ modulated by glutamine

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4 Clinical benefits of glutamine supplementation Cancer patients undergoing major GI surgery Complicated surgery ICU patients Trauma patients Severe burns Severe pancreatitis

5 Parenteral glutamine reduces mortality in critical illness Heyland et al,

6 Gln maintains physiological intestinal barrier Major GI surgery + (60) Gln (60) Severe burns de Souza Crit Care Med 2005

7 Mechanisms of glutamine beneficial effects supports gut metabolism preserves gut barrier function supports immunity (gut) reduces inflammatory response supports anti-oxidant defences (GSH, HSP) reduces insulin resistance... Coëffier & Déchelotte, Nutr Rev 2005

8 DNA synthesis Cytokines NO? IgA proliferation apoptosis GLUTAMINE proteolysis protein synthesis GSH HSP

9 Glutamine uptake and metabolism by enterocytes Apical basolateral Lenaerts, FEBS J 2005

10 Glutamine stimulates intestinal protein synthesis 1/ sur la synthèse protéique - in vitro : protein synthesis in enterocytes from septic rats Higashiguchi et al, JPEN 1993 and Clin Sci 1995 protein synthesis in the rat Van Acker et al, 1996 No effect in fed dogs or pigs

11 Glutamine preserves intestinal protein synthesis and TER LeBacquer, Am J Physiol 2003

12 Intestinal protein metabolism in humans Proteolysis Gln? free AA Protein synthesis ATP-ubiquitin dependent (proteasome) Ca 2+ activated (calpaines) lysosomal (cathepsins) mrna, RT-PCR WB Catalytic activities (stable) IV/IG isotope infusion GC-MS (FSR/ASR) proteomics

13 Glutamine and gut mucosal protein synthesis in hypercatabolic humans % / day * * 0 Group f-gln Group f-neq Group Tf-Gln Group Tf-Neq Values are means ± SE * p<0.05, phe vs leu 2H5-phenylalanine 13C-leucine Bouteloup, AJP, 2000;G

14 Enteral glutamine increases duodenal FSR in humans Coeffier, Am J Physiol 2003

15 and specifically inhibits ubiquitin mrna Ubiquitin mrna (%) * * 0 NaCl Glutamine 0 AA Glutamine Coeffier, Am J Physiol 2003

16 Influence of glutamine + maltodextrins and antioxidants (ONS) Short term enteral infusion of ONS increased FSR and reduced lysosomal proteolytic activity vs saline Coëffier, AJCN 2008

17 Mechanisms of glutamine beneficial effects preserves gut metabolism, preserves gut barrier function supports immunity (gut) reduces inflammatory response supports anti-oxidant defences (GSH, HSP) reduces insulin resistance...

18 GALT Neutrophils Eosinophils Monocytes Lymphocytes Mastocytes

19 Glutamine stimulates enterocyte proliferation - in vitro Kandil et al, AJP 1995 Rhoads et al, AJP 1997 Rhoads et al, Gastroenterology 2000 Murnin et al, J Gastrointest Surg in vivo Mandir et al, Gut 1999.

20 Glutamine reduces enterocyte apoptosis

21 activated caspase-3 Uehara et al, Crit Care Med 2005

22 Glutamine and intestinal proteome in inflammatory conditions Thébault S et al., Proteomics 2006

23 Glutamine effects under apoptotic conditions 28 modulated proteins expression : 20 down-and 8 up-regulated proteins Cell death regulator AVEN Caspase 3 (precursor) Stathmin Deniel S et al., Mol Cell Prot 2008

24 Transporters, enzymes Structural proteins : actin, occludin, claudins (1-17), Zonula Occludens (ZO-1)...

25 Contrôles stress 2h 22h post-stress ZO-1 Occludin Mazzon, Gut 2002

26 Enhanced trypsin-like activity during Irritable Bowel Syndrome Coëffier, Am J Gastroenterol, 2009

27 Increased degradation of occludin by proteasome in IBS A. occludin A. IκBα t (min) β-actin control IBS occludin / β-actin controls IBS B. C * Control IBS IκBα / β-actin Control IBS B. C. % relative inte ensity * t (min) % relative in ntensity * t (min) + MG132 Coëffier, Am J Gastroenterol, 2010

28 Glutamine preserves tight-junction proteins in vitro Li, Am J Physiol 2004

29 Mechanisms of glutamine beneficial effects preserves gut metabolism, preserves gut barrier function supports immunity (gut) reduces inflammatory response supports anti-oxidant defences (GSH, HSP) reduces insulin resistance...

30 Glutamine supports intestinal immune function - supports metabolism and proliferative response of intestinal immune cells Calder et al, AA supports Peyer s patches cellularity Manhart et al, Clin Nutr maintains/restores mucosal IgA secretion Kudsk et al, JPEN 2001

31 Mechanisms of glutamine beneficial effects preserves gut metabolism, preserves gut barrier function supports immunity (gut) reduces inflammatory response (gut) supports anti-oxidant defences (GSH, HSP) reduces insulin resistance...

32 Regulatory and signalling proteins TGFβ IL-7 SCF TECK IL-8 GRO-α,γ ENA-78 Eotaxins MEC RANTES MCP-1 Mig RANTES TECK I-TAC MEC, MDC MCP-3 IP-10 TGFα IL-1 IL-6 IL-10 IL-15 IL-18 GM-CSF MIP-3α IEL Neutrophils Eosinophils Monocytes Lymphocyts Dendritic cells

33 TNFα Uehara et al, Crit Care Med 2005

34 Uehara et al, Crit Care Med 2005

35 Glutamine reduces pro-inflammatory cytokines production Protein (% of control) p<0.05 p<0.05 p< IL-6 IL-8 IL-4 IL-10 Coëffier Clin Nutr 2003

36 Glutamine reduces IL-8 production via IkB-ubiquitinylation Hubert-Buron, J Nutr 2006

37 colonoscopy CDs patients 18h-culture * * * * * 1000 * * * Conditions (mm) 1 : Arg 0,1 / Gln 0,6 2 : Arg 2 / Gln 0,6 3 : Arg 0,1 / Gln 10 4 : Arg 2 / Gln 10 IL-8 (pg / mg tissue) TNFa (pg / mg tissue) Lecleire, J Nutr Arg low Arg high Arg low Arg low Arg high Arg Gln 1 2 low Glnlow Gln low high Glnlow Glnlow Gln3 4 high

38 Mechanisms of glutamine beneficial effects preserves gut metabolism, preserves gut barrier function supports immunity (gut) reduces inflammatory response (gut) supports anti-oxidant defences (GSH, HSP) reduces insulin resistance...

39 Depletion of mucosal GSH during intestinal nflammation GSH (nmol l/mg tissue) * controls healthy P<0,05 inflammed Crohn s colitis (Miralles-B et al Clin Nutr 1999)

40 Glutamine supports tissue glutathione in jejunal mucosa Cao 1999 Belmonte-Zalar 2007 in the liver Hong 1994 maintains GSH synthesis and GSH/GSSG Humbert 2001

41 Glutamine and heat-shock proteins Induction or stimulation of HSP by glutamine in vitro different cell types (Cai 1991, Zhou 1997) intestinal cell lines (Ehrenfield 1995, Wischmeyer1997, Chow 1998) in vivo (rat) intestine, heart, lung (Wischmeyer 2001, Hayashi 2002, Singleton 2005 & 2006) Intestinal protection HO-1 induction (rat) (Tamaki et al 1999, Uehara 2005)

42 Enteral glutamine increases HO-1 in humans Aa Gln Aa Gln Coëffier et al, J Nutr 2002

43 Gln and HSP modulation in humans Parenteral glutamine (high dose) increases serum Hsp70 in critically ill patients (Ziegler TR et al, Int Care Med 2005) Reduced length of hospital stay

44 Conclusion : gln and intestinal metabolism key issue for gut barrier function and immuno-inflammatory response involves multiple regulatory pathways and cellular interplay altered in different situations of stress, inflammation etc... metabolic and signalling effects supporting the benefits of gln supplementation

45 Join together in Nice for... Excellence in Science P Practice and Education in Nutrition 5-8th Sept 2010