Potential of Birds to Serve as Pathology-Free Models of Type 2 Diabetes, Part 2: Do High Levels of Carbonyl-Scavenging Amino Acids (e.g., Taurine) and Low Concentrations of Methylglyoxal Limit the Production of Advanced Glycation End-Products?

Abstract

In our previous publication, we reported on the advantages of using birds as a pathology-free model of type 2 diabetes mellitus (T2DM). Using this new perspective, we observed that birds are missing the RAGE gene, considered an important factor in the development of diabetic complications. In this article, we identify two additional Maillard reaction-related characteristics of birds that have the potential to account, in part, for avian ability to cope successfully with chronic hyperglycemia. First, compared to mammals, blood plasma of birds has significantly higher concentrations of taurine and other free amino acids that act as scavengers of reactive carbonyls. Second, there are also indications that avian blood plasma contains lower concentrations of methylglyoxal (MG) due, in part, to its decreased production by avian erythrocytes. Our deductions are based on relatively meager experimental data and are therefore speculative. One certain outcome of our study, however, is the idea that birds can be a useful model for the study of Maillard reactions and etiology of diabetic complications. We anticipate and hope that results of future studies will support the hypothesis identifying MG as a key intermediate in the etiology of diabetic complications. If this is indeed the case, then prevention and control of diabetic complications may become transformed into a more circumscribed, defined, and tractable problem whose goals will be to minimize the production of MG and to maximize its elimination by detoxification or scavenging.

Effect of Cysteine on Methylglyoxal-Induced Renal Damage in Mesangial Cells

“…From these results, we selected 500 µM concentration of MGO for further mechanism study. Similarly, Szwergold et al demonstrated a range of concentration (340-920 µM) of carbonyl-scavenging amino acids and low concentration of MGO in blood plasma of birds [31]. This study gave us an idea for the treatment concentration of l-Cysteine as we hypothesized that l-cysteine might interact with MGO to lower MGO-induced toxicity.…”

Taurine Supplementation for 48-Months Improved Glucose Tolerance and Changed ATP-Related Enzymes in Avians

“…An evolutionarily unconserved trait in avian muscle metabolism is unparalleled by an insistent energy system that is always in the “ on-state ” required for adaptive flight maneuvers. Notably, GLDH critically regulates amino acid metabolism and is present in high concentrations within liver, heart, muscle, and kidney mitochondria where it catalyzes the (i.e., reversible) oxidative deamination of l -glutamate to α -ketoglutarate [1, 7, 8, 11, 13], thereby providing energy via the citric acid cycle-dependent ATP. The GLDH activity is particularly important within pancreatic β - cells, which secretes insulin in an ATP:ADP ratio-dependent manner.…”

Effect of substitution of taurine for methionine and additional taurine supplementation on the performance and antioxidative capacity of laying hens

“…TAU is rich in the blood of layer-type chickens ( Takawaki et al., 2013 ) and in the liver and thigh muscle of broilers ( Huang et al., 2014 ). TAU level in blood is 6- to 11-fold higher in avian species than in humans ( Szwergold and Miller, 2014 ). Moreover, TAU is an essential nutrient against oxidative damage in mammal ( Brosnan and Brosnan, 2006 ) and in broilers ( Xu et al., 2020 ).…”