Collagen Tripeptide Cuts Oxidative Stress and Boosts Mitochondrial Function in Aging Mice
A 12-week collagen tripeptide supplement reduced oxidative damage, improved insulin sensitivity, and activated a key energy-sensing enzyme in aged mice.
Summary
Researchers at Kyungpook National University fed 58-week-old male C57BL/6J mice either collagen tripeptide (CTP), granulated CTP (gCTP), a Gly-Pro-Hyp tripeptide, or a control diet for 12 weeks. Both CTP and gCTP significantly reduced markers of oxidative stress—including TBARS and hydrogen peroxide—while boosting antioxidant enzyme activity (SOD and glutathione peroxidase). CTP also improved insulin sensitivity in liver and white adipose tissue by upregulating insulin receptor and glucose transporter expression. Critically, CTP and gCTP activated AMPKα, a master regulator of energy metabolism, suggesting a plausible mechanism for previously observed reductions in fatty liver and adiposity. The findings position CTP as a promising functional food ingredient for managing age-related metabolic disorders.
Detailed Summary
Aging is characterized by progressive oxidative stress that disrupts metabolic homeostasis, impairing insulin signaling, mitochondrial function, and the activity of AMPK—a master energy sensor. Prior work showed that collagen tripeptide (CTP) supplementation reduces fatty liver and lipid accumulation in aged mice, but the molecular mechanisms remained unknown. This study was designed to close that gap.
Thirty-eight male C57BL/6J mice aged 58 weeks were divided into four groups: an aging control (AC), a 0.03% Gly-Pro-Hyp (GPH) group, a 0.9% CTP group, and a 0.9% granulated CTP (gCTP) group. Eight young mice (6 weeks) served as a positive reference. All groups received AIN-93G–based diets for 12 weeks. Oxidative stress markers, antioxidant enzyme activities, insulin signaling proteins, and AMPKα phosphorylation were measured in plasma, liver, and white adipose tissue (WAT).
Both CTP and gCTP significantly reduced thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide levels compared with the aging control, indicating lower lipid peroxidation and overall oxidative burden. Concurrently, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were meaningfully elevated in CTP- and gCTP-treated animals, pointing to a restored antioxidant defense system. GPH showed more modest effects, suggesting that a full tripeptide mixture—rather than a single dominant tripeptide—is responsible for the broader benefits.
Insulin sensitivity improved in CTP-supplemented animals, evidenced by increased expression of insulin receptors and glucose transporters (notably GLUT4) in both liver and WAT. This improved signaling likely reduces ectopic lipid deposition. Most mechanistically significant was the finding that CTP and gCTP activated AMPKα—a kinase that declines with age and is suppressed by oxidative stress. AMPKα activation stimulates fatty acid oxidation, glucose uptake, and mitochondrial biogenesis, offering a unifying explanation for the previously reported reductions in fat mass and hepatic lipid accumulation.
These results suggest that reducing oxidative stress via CTP supplementation relieves the oxidative brake on AMPKα, thereby restoring energy homeostasis in aged tissue. While effects were observed in both liver and WAT, the study was conducted exclusively in male mice on a standard chow background, limiting direct extrapolation to humans or to diet-induced obesity models. Nevertheless, the data meaningfully extend the mechanistic understanding of CTP's metabolic benefits and support further clinical investigation.
Key Findings
- CTP and gCTP significantly reduced TBARS and H₂O₂ levels, lowering oxidative damage in aged mice.
- SOD and glutathione peroxidase activities were restored toward young-mouse levels by CTP and gCTP.
- CTP upregulated insulin receptor and GLUT4 expression in liver and white adipose tissue, improving insulin sensitivity.
- AMPKα activation was enhanced by CTP and gCTP, linking reduced oxidative stress to better mitochondrial energy metabolism.
- Granulated CTP (gCTP) showed effects comparable to standard CTP, supporting its use as a bioavailable formulation.
Methodology
Male C57BL/6J aged mice (58 weeks, n=38) were fed AIN-93G diets supplemented with 0.03% GPH, 0.9% CTP, or 0.9% gCTP for 12 weeks; young mice (n=8) served as a positive control. Outcomes included plasma and hepatic oxidative stress markers, antioxidant enzyme activities, and protein expression of insulin signaling and AMPKα pathways in liver and WAT.
Study Limitations
The study used only male mice on a standard diet, so findings may not generalize to females, humans, or high-fat diet models. The aging control lacked a positive pharmacological comparator (e.g., metformin), and no clinical bioavailability data for CTP peptides in aged subjects were provided.
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