Early- and life-long intake of dietary advanced glycation end-products (dAGEs) leads to transient tissue accumulation, increased gut sensitivity to inflammation, and slight changes in gut microbial diversity, without causing overt disease.
Study Goal
The researchers aimed to examine the physiological effects of dietary advanced glycation end-products (dAGEs), particularly carboxymethyl-lysine (dCML), in Wild-Type and RAGE KO mice, and whether early-life exposure or dietary reversal influenced these effects.
Results Summary
The study found that chronic dCML consumption led to tissue accumulation but did not significantly increase inflammation, oxidative stress, or senescence markers. Age and RAGE knockout status had a greater impact on inflammation than diet, though an early dietary switch increased intestinal susceptibility to inflammation.
Population
Wild-Type and RAGE KO mice
Effective Dosage
Standard diet (20.8 ± 5.1 µg dCML/g) or dCML-enriched diet (255.2 ± 44.5 µg dCML/g)
Duration
Up to 70 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
dCML-enriched diet | no change | endogenous glycation, inflammation, oxidative stress or senescence parameters | Wild-Type (WT) and RAGE KO mice | no significative effect | had no significative effect | #1 |
dCML-enriched diet | increase | relative expression of TNFα, VCAM1, IL6, and P16 genes | WT animals | ∼2-fold | upregulated | #2 |
RAGE knockout | decrease | age-related renal expression of TNFα | RAGE KO mice | - | diminishing | #3 |
early age (6 weeks) diet switch (dCML→STD) | increase | TNFα expression in the intestinal tract | Switch group mice | ∼2-fold | significant increases were detectable | #4 |
dCML-enriched diet | increase | caecal microbiota composition at family level | mice | slight changes | minor fluctuations were observed | #5 |
chronic dCML consumption | increase | free CML levels in tissues | mice | higher | resulting in higher free CML levels | #6 |
chronic dCML consumption | no change | parameters related to inflammageing | mice | no substantial increases | there were no substantial increases | #7 |
dCML-enriched diet | increase | dCML in kidneys, ileum and colon | Wild-Type (WT) and RAGE KO mice | 3-fold, 17-fold and 20-fold increases compared with controls | significant RAGE-independent accumulation | #8 |
diet switching | decrease | tissue dCML concentrations | Switch group mice | baseline levels | returned tissue dCML concentrations to their baseline levels | #9 |
Dietary advanced glycation end-products (dAGEs) accumulate in organs and are thought to initiate chronic low-grade inflammation (CLGI), induce glycoxidative stress, drive immunosenescence, and influence gut microbiota. Part of the toxicological interest in glycation products such as dietary carboxymethyl-lysine (dCML) relies on their interaction with receptor for advanced glycation end-products (RAGE). It remains uncertain whether early or lifelong exposure to dAGEs contributes physiological changes and whether such effects are reversible or permanent. Our objective was to examine the physiological changes in Wild-Type (WT) and RAGE KO mice that were fed either a standard diet (STD - 20.8 ± 5.1 µg dCML/g) or a diet enriched with dCML (255.2 ± 44.5 µg dCML/g) from the perinatal period for up to 70 weeks. Additionally, an early age (6 weeks) diet switch (dCML→STD) was explored to determine whether potential harmful effects of dCML could be reversed. Previous dCML accumulation patterns described by our group were confirmed here, with significant RAGE-independent accumulation of dCML in kidneys, ileum and colon over the 70-week dietary intervention (respectively 3-fold, 17-fold and 20-fold increases compared with controls). Diet switching returned tissue dCML concentrations to their baseline levels. The dCML-enriched diet had no significative effect on endogenous glycation, inflammation, oxidative stress or senescence parameters. The relative expression of TNFα, VCAM1, IL6, and P16 genes were all upregulated (∼2-fold) in an age-dependent manner, most notably in the kidneys of WT animals. RAGE knockout seemed protective in this regard, diminishing age-related renal expression of TNFα. Significant increases in TNFα expression were detectable in the intestinal tract of the Switch group (∼2-fold), suggesting a higher sensitivity to inflammation perhaps related to the timing of the diet change. Minor fluctuations were observed at family level within the caecal microbiota, including Eggerthellaceae, Anaerovoracaceae and Marinifilaceae communities, indicating slight changes in composition. Despite chronic dCML consumption resulting in higher free CML levels in tissues, there were no substantial increases in parameters related to inflammageing. Age was a more important factor in inflammation status, notably in the kidneys, while the early-life dietary switch may have influenced intestinal susceptibility to inflammation. This study affirms the therapeutic potential of RAGE modulation and corroborates evidence for the disruptive effect of dietary changes occurring too early in life. Future research should prioritize the potential influence of dAGEs on disease aetiology and development, notably any exacerbating effects they may have upon existing health conditions.