Glycation

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As glycation (also glycation ) is the reaction of proteins , lipids or nucleic acids with carbohydrates without the involvement of enzymes referred to. The enzymatic reaction, on the other hand, is called glycosylation . The glycation reaction product is also referred to as Advanced Glycation Endproduct ( AGE ). It can be exogenous or endogenous , i. H. outside or inside the body.

Exogenous glycation

Exogenous glycation usually occurs when proteins are cooked with sugars. Temperatures above 120 ° C favor this process. The glycation by dry cooking techniques with reducing sugars is called the Maillard reaction , some of the resulting colored reaction products belong to the melanoidins . AGEs are used in the food industry as flavor enhancers , colorings or to improve the appearance. Originally it was assumed that AGEs are harmless. However, recent research suggests that AGEs are at least involved in some diseases. Furthermore, glycation could also be involved in the formation of acrylamide . As a rule, however, the concentration of AGEs in unprepared foods is not a cause for concern. In particular, frequent consumption of fried and grilled foods can lead to concentrations that can no longer be neutralized by the body, similar to what is generally the case with advanced age.

Endogenous glycation

Endogenous glycation also occurs in the body, especially in the bloodstream . Essentially, fructose and galactose and, to a lesser extent, glucose react in an uncontrolled manner with the body's own proteins without the involvement of enzymes. As a result of the metabolism , reactive dicarbonyls such as 3-deoxyglucosone and methylglyoxal are formed . The problem here is the accumulation of the AGE over time, especially in the case of an increased blood sugar level , which can damage cells and tissue .

The glycation of hemoglobin produces HbA1c . The HbA1c proportion of hemoglobin can be measured to determine e.g. B. in diabetics to estimate the average blood sugar value of the last four to twelve weeks.

Health effects

The glycation is attributed to involvement in various age-related diseases, e.g. B. Diabetes mellitus type II and cardiovascular diseases . Higher concentrations of AGE arise e.g. B. in oxidative stress or hyperglycaemia . They are associated with arteriosclerosis , poor angiogenesis and impaired wound healing , among other things . Some AGEs promote inflammation , in part by binding to the cellular receptor Receptor for AGE ( RAGE ) on monocytes . The monocytes activated during AGE-induced inflammation secrete interleukin-1 , TNF-α , platelet-derived growth factor and insulin-like growth factor-1 . It also activates platelets , which can lead to increased blood clots . As a result of glycation, neurons can break down myelin and develop neuropathies , e.g. B. in diabetes mellitus type II and Alzheimer's disease . Participation in osteoporosis , glomerulosclerosis , food allergies , arthritis , respiratory failure and sepsis is also being investigated.

Individual evidence

  1. ^ M Peppa et al .: Glucose, Advanced Glycation End Products, and Diabetes Complications: What Is New and What Works . In: Clinical Diabetes , 21, 2003, pp. 186-187, doi: 10.2337 / diaclin.21.4.186 .
  2. ↑ H Vlassara: advanced glycation in Health and Disease: Role of the Modern Environment . In: Annals of the New York Academy of Science , 1043, 2005 pp. 452-460, doi: 10.1196 / annals.1333.051 .
  3. ↑ RH Stadler et al .: Acrylamide from Maillard reaction products . In: Nature , 419, 2002, pp. 449-50, PMID 12368845 .
  4. ↑ J Uribarri et al .: Circulating glycotoxins and dietary advanced glycation endproducts: two links to inflammatory response, oxidative stress, and aging . In: J Gerontol A Biol Sci Med Sci. , 62, 2007, pp. 427-433, PMID 17452738 .
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  7. ^ Theodore Koschinsky et al .: An environmental risk factor in diabetic nephropathy, An environmental risk factor in diabetic nephropathy. In: Proceedings of the National Academy of Sciences 94, 1997, pp. 6474-6479, PMC 21074 (free full text).
  8. ↑ S. Schiekofer et al .: Acute hyperglycemia causes intracellular formation of CML and activation of ras, p42 / 44 MAPK, and nuclear factor kappaB in PBMCs. In: Diabetes 52, 2003, pp. 621-633, PMID 12606501 .
  9. ↑ C. Ott, K. Jacobs, E. Haucke, A. Navarrete Santos, T. Grune, A. Simm: Role of advanced glycation end products in cellular signaling. Redox biology 2, 2014, pp. 411-429, doi: 10.1016 / j.redox.2013.12.016 , PMID 24624331 , PMC 3949097 (free full text).
  10. ↑ a b Y. K. Chuah et al .: Receptor for Advanced Glycation End Products and Its Involvement in Inflammatory Diseases . In: International journal of inflammation , 2013, 2013, p. 403460, doi: 10.1155 / 2013/403460 . PMID 24102034 . PMC 3786507 (free full text).
  11. ↑ VP Singh et al .: Advanced Glycation End Products and Diabetic Complications. In: Korean Journal of Physiology & Pharmacology , 18, 2014, pp. 1–14, doi: 10.4196 / kjpp.2014.18.1.1 . PMID 24634591 . PMC 3951818 (free full text).
  12. ↑ C. Angeloni, L. Zambonin, S. Hrelia: Role of Methylglyoxal in Alzheimer's Disease . In: BioMed research international , 2014, 2014, p. 238485, doi: 10.1155 / 2014/238485 . PMID 24734229 . PMC 3966409 (free full text).
  13. ^ R. Sanguineti et al .: Advanced Glycation End Products Play Adverse Proinflammatory Activities in Osteoporosis. Mediators of inflammation 2014, 2014, p. 975872, doi: 10.1155 / 2014/975872 . PMID 24771986 .
  14. ↑ EJ Lee, JH Park: Receptor for Advanced Glycation Endproducts (RAGE), Its Ligands, and Soluble RAGE: Potential Biomarkers for Diagnosis and Therapeutic Targets for Human Renal Diseases . In: Genomics & informatics , 11, 2013, pp. 224-229, doi: 10.5808 / GI.2013.11.4.224 . PMID 24465234 . PMC 3897850 (free full text).
  15. ↑ Roberto Berni Canani, Lorella Paparo, Rita Nocerino, Carmen Di Scala, Giusy Della Gatta: Good microbiome as Target for Innovative Strategies Against Food Allergy . In: Frontiers in Immunology . tape 10 , 2019, ISSN  1664-3224 , p. 191 , doi : 10.3389 / fimmu.2019.00191 , PMID 30828329 , PMC 6384262 (free full text).