L-carnitine and aging -
In particular, the heart may be especially susceptible to mitochondrial dysfunction due to myocardial dependency on beta-oxidation of fatty acids for energy and the postmitotic nature of cardiac myocytes, which would allow for greater accumulation of mitochondrial mutations and deletions.
Thus, maintenance of mitochondrial function may be important to maintain overall myocardial function. Herein, we review the major age-related changes that occur to mitochondria in the aging heart and the evidence that two such supplements, acetyl-l-carnitine ALCAR and R -alpha-lipoic acid, may improve myocardial bioenergetics and lower the increased oxidative stress associated with aging.
We and others have shown that feeding old rats ALCAR reverses the age-related decline in carnitine levels and improves mitochondrial beta-oxidation in a number of tissues studied.
However, ALCAR supplementation does not appear to reverse the age-related decline in cardiac antioxidant status and thus may not substantially alter indices of oxidative stress. Lipoic acid, a potent thiol antioxidant and mitochondrial metabolite, appears to increase low molecular weight antioxidant status and thereby decreases age-associated oxidative insult.
Thus, ALCAR along with lipoic acid may be effective supplemental regimens to maintain myocardial function. Donate Today! Get Updates from the Institute. Linus Pauling Institute Oregon State University Linus Pauling Science Center Corvallis, Oregon phone: fax: email: [email protected].
For media contact information. Skip to main content. D Quantification of gstgfp expression in C. Images from 3 independent experiments were quantified using ImageJ and normalized to the value at time 0. elegans worms were prepared and treated as in C except that μM juglone final concentration was added to the NG medium.
Images from 2 independent experiments were quantified using ImageJ and normalized to the average at 12 hours. To further confirm the new finding that L-carnitine improves recovery from oxidative stress, we directly measured the ROS levels.
Animals raised with and without μM L-carnitine supplement from L1 stage to L4 stage were challenged with 1mM paraquat for 24 hours, then transferred to paraquat-free medium plate.
After 12, 24, 36 and 48 hours, animals were stained with Dihydroethidium DHE , a widely used ROS indicator [ 35 , 46 ]. The results showed that L-carnitine treatment robustly reduced the ROS levels in the intestine after 36 and 48 hours of recovery from paraquat Figure 2A , 2B. Figure 2.
L-carnitine promotes recovery from oxidative stress induced by paraquat and juglone. A L-carnitine facilitated the clearance of ROS. N2 wild-type C. The ROS generator paraquat was added to the medium to the final concentration of 1mM. After 24 hours, animals were transferred to new paraquat-free plate with and without L-carnitine for recovery.
After recovery for 12, 24, 48 hours, worms were stained with ROS dye dihydroethidium DHE and imaged with fluorescent microscope. Representative images at hour recovery were shown. B Quantification of DHE signal from at least 3 independent experiments in A by ImageJ and relative expression levels were plotted.
Worms were pick from agar plate to 1 mL M9 buffer in well plate and examined under dissecting microscope. Worms were moving left and right rapidly and the movement from one side to the other side then back to the original position was counted as 1 thrash.
D L-carnitine mitigated the toxicity of paraquat on mobility. Worms were treated with paraquat and L-carnitine as in A and recovered for 48 hours. Worms were then incubated in 50mM H 2 O 2 for 1 hour. Data were pooled from 2 independent experiments and survival rates under different treatment were compared.
Hatching were examined after 24 hours. Experiments were conducted 2 times with 5 replicates each time. Data were normalized to control group for comparison. Worms expressing human amyloid protein fragment Aβ in body wall muscle CL were treated with paraquat and L-carnitine as in A and recovered for 48 hours.
Worms were then homogenized in high-salt RAB buffer. Soluble and insoluble fraction were analyzed by western blot using anti-Aβ antibody.
Total lysate was analyzed by western using anti-actin antibody. Shown was representative results of 2 independent experiments. H L-carnitine mitigated Aβ -induced paralysis. Animals were raised at 25° C to young adult stage day-0 and examined every day thereafter for paralysis.
Log-rank test was performed P. Next, we tested multiple heath parameters related to oxidative stress. First, we examined if muscle strength could be improved by L-carnitine, by measuring the bending movement. When in liquid, the worms keep bending or thrashing Figure 2C , which has been used to indicate the muscle strength and mobility [ 47 ].
By treating the animals with paraquat and L-carnitine as mentioned above, we measured the thrashing speed after 48 hours of recovery. The results showed that the impaired mobility by paraquat treatment could be largely rescued by L-carnitine Figure 2D.
L-carnitine did not obviously improve mobility under normal conditions. Second, we tested if the faster recovery from oxidative stress could result in a better tolerance to oxidative damage by H 2 O 2.
Similarly, animals treated with paraquat and L-carnitine were collected 48 hours after recovery from paraquat and incubated with 50mM of H 2 O 2 for 1 hour. We found that paraquat-treated worms were sensitive to H 2 O 2 toxicity, which was largely rescued by L-carnitine Figure 2E.
Third, we examined the survival rate of progenies. Consistently, egg hatching was reduced by paraquat, but such reduction was significantly mitigated by L-carnitine Figure 2F. Fourth, we examined if human amyloid protein aggregation could be mitigated by supplementing L-carnitine in the medium.
Amyloid-beta Aβ has been known to aggregate upon oxidative stress or during aging [ 48 , 49 ]. By separating the soluble and insoluble fractions of the whole worm lysate and western blotting, we found that L-carnitine reduced the paraquat-induced Aβ aggregation Figure 2G.
Interestingly, despite the lack of effect of L-carnitine on Aβ aggregates under normal culturing conditions Figure 2G , the animals treated with L-carnitine slightly but significantly decreased amyloid-induced paralysis Figure 2H. Together, these functional assays confirmed that L-carnitine reduced oxidative stress damage in C.
Since ROS accumulates during aging, L-carnitine could also improve age-related oxidative damage. To test this, C. elegans were cultured from L1 stage on NG medium supplemented with or without μM L-carnitine and gstgfp expression was examined at L4, day-2, day-4 and day-6 of adulthoods. Interestingly, gstgfp was induced after reaching adulthood but gradually declined thereafter, consistent with a previous report [ 35 ].
Similar to that of paraquat treatment, aging-induced gstgfp expression was decreased by L-carnitine during the recovery stage but not the induction stage Figure 3A , 3B. Despite the decline in gstgfp expression after day-4, DHE-stained ROS continued to accumulate from day-2 to day Importantly, worms raised on L-carnitine appeared to have less ROS on day-6 and day of adulthood, suggesting a better recovery from oxidative stress during aging Figure 3C , 3D.
Figure 3. L-carnitine promotes oxidative stress recovery during aging and increased lifespan in C. A L-carnitine promoted recovery from oxidative stress during aging. elegans expressing the OSR marker gstgfp were synchronized at L1 larvae stage and raised on NG medium supplemented with or without 10 μM L-carnitine.
Representative images of 3 independent experiments were shown. B Quantification of images from experiment described in A. elegans during normal aging. Worms were treated as in A and stained with DHE dye at indicated time points, followed by imaging with fluorescent microscope.
Representative images from 3 experiments were shown. D Quantification of DHE-stained ROS levels described in C. Wild-type C. elegans were synchronized at L1 larvae stage and raised on NG medium supplemented with or without 10 μM L-carnitine.
Dead and viable worms were counted every 2 or 3 days starting from day of adulthood. F L-carnitine did not extend lifespan of C. elegans with skn-1 knockdown. Experiments were performed similar to E except RNAi bacteria was used. G L-carnitine did not extend lifespan of C.
elegans with daf knockdown. We also tested if aging was delayed in C. elegans by supplementing L-carnitine in the medium.
Animals were cultured under 20° C on NG medium containing various concentrations of L-carnitine throughout life. The results showed that L-carnitine extended lifespan of C. elegans at , and but not 50 μM Figure 3E and Supplementary Figure 1A.
At and μM, L-carnitine causes slight developmental delay in some worms Supplementary Figure 1B. We therefore chose μM for all experiments in this study. SKN-1 and DAF are transcription factors known to activate oxidative stress defensing programs and extend lifespan in C.
elegans [ 50 ]. Both RNAi knockdown prevented L-carnitine from extending lifespan, suggesting that SKN-1 and DAF are both needed for L-carnitine to extend lifespan in C. elegans Figure 3F , 3G. The requirement for DAF and SKN-1 for lifespan extension by L-carnitine prompted us to test the role of L-carnitine in long-lived mutants glp-1 and daf These animals, similar to carnitine-treated animals, require both DAF and SKN-1 for their long lifespan [ 36 , 51 ].
First, we asked if glp-1 e and daf-2 e mutants would recover from oxidative stress better than wild-type controls. As reported earlier [ 35 ], gstgfp expression was much higher in glp-1 mutant reaching adulthood Figure 4A. To evaluate the recovery, we normalized gstgfp expression levels at day-2 adulthood and examined the speed of decline in GFP intensity.
Indeed, glp-1 e showed a faster decline in gstgfp expression than controls Figure 4A , 4B. Similar results were obtained for daf-2 e mutants Figure 4B. We then asked if such improved recovery from OSR could lead to enhanced clearance of endogenous ROS levels.
Indeed, the experiments showed that both glp-1 e and daf-2 e mutant worms accumulated ROS slower than wild-type control Figure 4C , suggesting that the speed to recover from OSR plays an important role in aging. Figure 4. The long-lived mutants daf-2 and glp-1 recover from oxidative stress better than wild-type controls.
A glp-1 worms showed faster decrease in the expression of the OSR marker gstgfp. Age-matched, gstgfp -expressing WT and glp-1 mutant worms were raised from L1 to L4 at 25° C to deplete germ cells in glp-1 then maintained at 20° C throughout the experiment.
gstgfp expression were examined with fluorescent microscope at indicated time points. B Data from 2 independent experiments described in A were normalized to the average of day-2 adulthood.
Age-matched worms expressing gstgfp were raised at 20° C. gstgfp expression was examined at indicated time points. Two independent experiments were performed. Age-matched wild-type or daf-2 worms were raised at 20° C throughout life with and without 10 μM L-carnitine supplement.
Dead and live worms were counted every 2 or 3 days starting from day of adulthood. Data from 2 experiments were pooled and analyzed by log-rank test Supplementary Table 2.
E L-carnitine did not further increase lifespan of glp-1 worms. Age-matched wild-type or glp-1 worms were raised at 25° C from L1 to L4 stage and then maintained at 20° C throughout life. Second, we tested if L-carnitine could further increase the lifespan of glp-1 and daf-2 mutants.
In several biological repeats, we found that L-carnitine could no longer increase lifespan of glp-1 e and daf-2 e mutant Figure 4D , 4E. These results suggest that the activation of DAF and SKN-1 in glp-1 and daf-2 mutants dominate the effect of L-carnitine, making these mutants no longer sensitive to L-carnitine.
Next, we investigated the mechanisms by taking advantage of the long-lived glp-1 and daf-2 mutants. We focused on genes that are upregulated by both mutants. One such genes, T08B1. Multiple sequence alignment of T08B1. We confirmed that T08B1. We tested if T08B1.
Animals were cultured in the presence of 10 μM L-carnitine with or without T08B1. By using the L-carnitine Assay Kit from Abcam, we showed that glp-1 and daf-2 mutants have higher carnitine content than WT controls after feeding L-carnitine for 48 hours from L1 stage Figure 5C.
L-carnitine levels were all reduced after T08B1. Figure 5. A potential carnitine transporter T08B1. A T08B1. Protein sequence of T08B1. Table shows blasting results of the top 2 matched sequences.
B T08B1. Age-matched glp-1 worms were raised at 25° C from L1 to L4 stage then changed to 20° C. Age-matched daf-2 worms were kept at 20° C.
mRNAs were extracted at day-1 of adulthood and RT-qPCR was performed. Age-synchronized L1 worms were raised on NG medium supplemented with10 μM L-carnitine until day-1 adulthood.
Worms were homogenized and relative L-carnitine content measured with L-carnitine Assay kit. Age-synchronized worms expressing gstgfp were raised on NG medium supplemented with10 μM L-carnitine until day-4 adulthood. Worms were imaged for GFP levels.
Shown are representative images from day-4 adulthood. E Quantification of day-2 and day-4 data from experiments shown in D. glp-1 worms were raised at 25° C from L1 to L4 stage and then changed to 20° C.
WT and daf-2 worms were kept at 20° C. G RNAi knocking down of T08B1. Age-matched N2 wild-type worms were kept at 20° C throughout life. We continued to ask if T08B1. To this aim, we fed age-matched L1 C. elegans expressing gstgfp with T08B1.
Consistent with previous results, L-carnitine significantly reduced the gstgfp expression, however, knocking down T08B1. Interestingly, T08B1. Consistently, T08B1.
In this study, we found that L-carnitine could facilitate the recovery from oxidative stress, but did not affect the induction of OSR. L-carnitine delayed ROS accumulation during aging, reduced amyloid protein aggregation and prolonged lifespan.
We also found that T08B1. Together, by using the genetically tractable model, we have gained significant insights into the functions of L-carnitine on aging.
The effect of L-carnitine on oxidative stress recovery is unprecedented. L-carnitine is derived from lysine and methionine and such special structure could directly scavenge free radicals [ 1 , 2 ]. Previous studies have shown that L-carnitine functions to reduce oxidative stress in mice, rat and humans [ 21 , 52 ].
Among many other proposed mechanisms such as PI3K, AKT, ERK pathways [ 53 , 54 ], the antioxidant effect of L-carnitine has been attributed to its role in activating Nrf2-dependent transcription [ 55 — 57 ].
L-Carnitine is an amino L-darnitine that is naturally adn by the L-cadnitine and helps L-carnktine fat into energy. L-carnktine only Pre-workout energy supplements it help Eating for fuel and performance weight loss but it also improves heart and brain function, sports performance, Organic pet supplements slows agimg. Here Hydration for outdoor activities fatty acids are oxidized burned to produce energy. Your body produces L-carnitine from the amino acids lysine and methionine which are found predominantly in animal proteins. However, research has shown that vegans or those suffering from certain genetic disorders may not be able to produce sufficient amounts, making L-carnitine a conditionally essential amino acid. It is an inactive form of L-carnitine and should be avoided as it may block other forms of L-carnitine within the body. This can cause symptoms that resemble L-carnitine deficiency.Video
Why CARNITINE COMPLEX Benefits All Age Groups L-Carnitine β-hydroxy-γ-N-trimethylaminobutyric Zging is a derivative of the amino acidHormone balance and aging Figure 1. It L-carntine first zging from meat L-carnitine and aging in Latin in L--carnitine the L- isomer of carnitine is biologically active 1. L-Carnitine appeared to act as a vitamin in the mealworm Tenebrio molitor and was therefore termed vitamin B T 2. Vitamin B Thowever, is a misnomer because humans and other higher organisms can synthesize L-carnitine see Metabolism and Bioavailability.
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