Reduced coenzyme Q10 supplementation decelerates senescence in SAMP1 mice

Dietary antioxidants and lifespan: Relevance of environmental conditions, diet, and genotype of experimental models

The rise of life expectancy in current societies is not accompanied, to date, by a similar increase in healthspan, which represents a great socio-economic problem. It has been suggested that aging can be manipulated and then, the onset of all age-associated chronic disorders can be delayed because these pathologies share age as primary underlying risk factor. One of the most extended ideas is that aging is consequence of the accumulation of molecular damage. According to the oxidative damage theory, antioxidants should slow down aging, extending lifespan and healthspan. The present review analyzes studies evaluating the effect of dietary antioxidants on lifespan of different aging models and discusses the evidence on favor of their antioxidant activity as anti-aging mechanisms. Moreover, possible causes for differences between the reported results are evaluated.

The Role of Antioxidants in the Interplay between Oxidative Stress and Senescence

Cellular senescence is an irreversible state of cell cycle arrest occurring in response to stressful stimuli, such as telomere attrition, DNA damage, reactive oxygen species, and oncogenic proteins. Although beneficial and protective in several physiological processes, an excessive senescent cell burden has been involved in various pathological conditions including aging, tissue dysfunction and chronic diseases. Oxidative stress (OS) can drive senescence due to a loss of balance between pro-oxidant stimuli and antioxidant defences. Therefore, the identification and characterization of antioxidant compounds capable of preventing or counteracting the senescent phenotype is of major interest. However, despite the considerable number of studies, a comprehensive overview of the main antioxidant molecules capable of counteracting OS-induced senescence is still lacking. Here, besides a brief description of the molecular mechanisms implicated in OS-mediated aging, we review and discuss the role of enzymes, mitochondria-targeting compounds, vitamins, carotenoids, organosulfur compounds, nitrogen non-protein molecules, minerals, flavonoids, and non-flavonoids as antioxidant compounds with an anti-aging potential, therefore offering insights into innovative lifespan-extending approaches.

CYP7A1, NPC1L1, ABCB1, and CD36 Polymorphisms Associated with Coenzyme Q10 Availability Affect the Subjective Quality of Life Score (SF-36) after Long-Term CoQ10 Supplementation in Women

The single nucleotide polymorphisms (SNPs) rs3808607, rs2072183, rs2032582, and rs1761667 are associated with coenzyme Q₁₀ (CoQ₁₀) bioavailability in women after long-term CoQ₁₀ supplementation. However, the beneficial aspects of the association between these SNPs and CoQ₁₀ supplementation remain unknown. We investigated their relationship using the subjective quality of life score SF-36 by reanalyzing previous data from 92 study participants who were receiving ubiquinol (a reduced form of CoQ₁₀) supplementation for 1 year. Two-way repeated-measures analysis of variance revealed a significant interaction between rs1761667 and the SF-36 scores of role physical (p = 0.016) and mental health (p = 0.017) in women. Subgrouping of participants based on the above four SNPs revealed significant interactions between these SNPs and the SF-36 scores of general health (p = 0.045), role emotional (p = 0.008), and mental health (p = 0.019) and increased serum CoQ₁₀ levels (p = 0.008), suggesting that the benefits of CoQ₁₀ supplementation, especially in terms of psychological parameters, are genotype-dependent in women. However, significant interactions were not observed in men. Therefore, inclusion of SNP subgrouping information in clinical trials of CoQ₁₀ supplementation may provide conclusive evidence supporting other beneficial health effects exerted by the association between these SNPs and CoQ₁₀ on women.

Increased glycolysis affects β-cell function and identity in aging and diabetes

OBJECTIVE

Age is a risk factor for type 2 diabetes (T2D). We aimed to elucidate whether β-cell glucose metabolism is altered with aging and contributes to T2D.

METHODS

We used senescence-accelerated mice (SAM), C57BL/6J (B6) mice, and ob/ob mice as aging models. As a diabetes model, we used db/db mice. The glucose responsiveness of insulin secretion and the [U-13C]-glucose metabolic flux were examined in isolated islets. We analyzed the expression of β-cell-specific genes in isolated islets and pancreatic sections as molecular signatures of β-cell identity. β cells defective in the malate-aspartate (MA) shuttle were previously generated from MIN6-K8 cells by the knockout of Got1, a component of the shuttle. We analyzed Got1 KO β cells as a model of increased glycolysis.

RESULTS

We identified hyperresponsiveness to glucose and compromised cellular identity as dysfunctional phenotypes shared in common between aged and diabetic mouse β cells. We also observed a metabolic commonality between aged and diabetic β cells: hyperactive glycolysis through the increased expression of nicotinamide mononucleotide adenylyl transferase 2 (Nmnat2), a cytosolic nicotinamide adenine dinucleotide (NAD)-synthesizing enzyme. Got1 KO β cells showed increased glycolysis, β-cell dysfunction, and impaired cellular identity, phenocopying aging and diabetes. Using Got1 KO β cells, we show that attenuation of glycolysis or Nmnat2 activity can restore β-cell function and identity.

CONCLUSIONS

Our study demonstrates that hyperactive glycolysis is a metabolic signature of aged and diabetic β cells, which may underlie age-related β-cell dysfunction and loss of cellular identity. We suggest Nmnat2 suppression as an approach to counteract age-related T2D.

Protective effects of coenzyme Q10 on cell damage induced by hydrogen peroxides in cultured skin fibroblasts

Cellular senescence is an intricate and multifactorial phenomenon, which is characterized by an irreversible cellular growth arrest, it is caused in response to irretrievably DNA damage, telomere shorting, activation of oncogene, and oxidative stress. Human diploid fibroblasts are a well-established experimental model for premature senescence-related studies, and exposure of fibroblasts to H₂O₂ is widely used as a SIPS model. Recently, it has been reported many studies of CoQ₁₀ as to anti-aging effects, however the effect of CoQ₁₀ on H₂O₂-induced SIPS model of human skin fibroblasts has not been understood. So that, we investigated that human skin fibroblasts were used to investigate the prevention effect of CoQ₁₀ against H₂O₂-induced SIPS model. We created SIPS model fibroblasts with treatment of 100 μM H₂O₂ for 2 h. In this study, CoQ₁₀ also increased cell viability and mRNA levels of type I, IV collagen and protein level of type I collagen. Moreover, it is shown that CoQ₁₀ suppressed oxidative stress, degradation of collagen by increasing MMP expression, and decreasing senescence-associated phenotypes (e.g. SA-βgal positive staining and SASP) for preventing skin aging via H₂O₂-induced SIPS model. These results suggested that CoQ₁₀ has possibility to be contributory for extension of healthy life expectancy in Japan.

CYP7A1, NPC1L1, ABCB1, and CD36 Polymorphisms Are Associated with Increased Serum Coenzyme Q10 after Long-Term Supplementation in Women

Coenzyme Q₁₀ (CoQ₁₀), an essential component for energy production that exhibits antioxidant activity, is considered a health-supporting and antiaging supplement. However, intervention-controlled studies have provided variable results on CoQ₁₀ supplementation benefits, which may be attributed to individual CoQ₁₀ bioavailability differences. This study aimed to investigate the relationship between genetic polymorphisms and CoQ₁₀ serum levels after long-term supplementation. CoQ₁₀ levels at baseline and after one year of supplementation (150 mg) were determined, and eight single nucleotide polymorphisms (SNPs) in cholesterol metabolism and CoQ₁₀ absorption, efflux, and cellular uptake related genes were assessed. Rs2032582 (ABCB1) and rs1761667 (CD36) were significantly associated with a higher increase in CoQ₁₀ levels in women. In addition, in women, rs3808607 (CYP7A1) and rs2072183 (NPC1L1) were significantly associated with a higher increase in CoQ₁₀ per total cholesterol levels. Subgroup analyses showed that these four SNPs were useful for classifying high- or low-responder to CoQ₁₀ bioavailability after long-term supplementation among women, but not in men. On the other hand, in men, no SNP was found to be significantly associated with increased serum CoQ₁₀. These results collectively provide novel evidence on the relationship between genetics and CoQ₁₀ bioavailability after long-term supplementation, which may help understand and assess CoQ₁₀ supplementation effects, at least in women.

The Paradox of Coenzyme Q10 in Aging

Coenzyme Q (CoQ) is an essential endogenously synthesized molecule that links different metabolic pathways to mitochondrial energy production thanks to its location in the mitochondrial inner membrane and its redox capacity, which also provide it with the capability to work as an antioxidant. Although defects in CoQ biosynthesis in human and mouse models cause CoQ deficiency syndrome, some animals models with particular defects in the CoQ biosynthetic pathway have shown an increase in life span, a fact that has been attributed to the concept of mitohormesis. Paradoxically, CoQ levels decline in some tissues in human and rodents during aging and coenzyme Q₁₀ (CoQ₁₀) supplementation has shown benefits as an anti-aging agent, especially under certain conditions associated with increased oxidative stress. Also, CoQ₁₀ has shown therapeutic benefits in aging-related disorders, particularly in cardiovascular and metabolic diseases. Thus, we discuss the paradox of health benefits due to a defect in the CoQ biosynthetic pathway or exogenous supplementation of CoQ₁₀.

Effects of lifelong intake of lemon polyphenols on aging and intestinal microbiome in the senescence-accelerated mouse prone 1 (SAMP1)

Polyphenols have been examined for their beneficial effects on health, particularly in rodents, but their lifelong effects are unclear. Lemons (Citrus limon), containing lemon polyphenols (LPP), are widely consumed but the effects of LPP on aging are unknown. Therefore, we examined the effects of LPP on aging such as aging-related scores, locomotor activity, cognitive functions, and intestinal microbiome using senescence-accelerated mouse prone 1 (SAMP1) and senescence-accelerated resistant mouse 1 (SAMR1). All mice had ad libitum access to water (P1_water group, SAMR1) or 0.1% LPP (P1_LPP group). In the P1_LPP group, LPP intake prolonged the lifespan by approximately 3 weeks and delayed increases in aging-related scores (e.g., periophthalmic lesions) and locomotor atrophy. The P1_water group showed large changes in the intestinal microbiome structure, while the R1 and P1_LPP groups did not. The phylum Bacteroidetes/Firmicutes, which is associated with obesity, in the P1_water group was significantly lower and higher than that in the P1_LPP and R1 groups, respectively. Although the relative abundance of Lactobacillus significantly increased in both P1 groups with aging, the P1_LPP group showed a significantly lower increase than the P1_water group. Thus, lifelong intake of LPP may have anti-aging effects on both phenotypes and the intestinal environment.

Polyamine Metabolism and Gene Methylation in Conjunction with One-Carbon Metabolism

Recent investigations have revealed that changes in DNA methylation status play an important role in aging-associated pathologies and lifespan. The methylation of DNA is regulated by DNA methyltransferases (DNMT1, DNMT3a, and DNMT3b) in the presence of S-adenosylmethionine (SAM), which serves as a methyl group donor. Increased availability of SAM enhances DNMT activity, while its metabolites, S-adenosyl-l-homocysteine (SAH) and decarboxylated S-adenosylmethionine (dcSAM), act to inhibit DNMT activity. SAH, which is converted from SAM by adding a methyl group to cytosine residues in DNA, is an intermediate precursor of homocysteine. dcSAM, converted from SAM by the enzymatic activity of adenosylmethionine decarboxylase, provides an aminopropyl group to synthesize the polyamines spermine and spermidine. Increased homocysteine levels are a significant risk factor for the development of a wide range of conditions, including cardiovascular diseases. However, successful homocysteine-lowering treatment by vitamins (B6, B12, and folate) failed to improve these conditions. Long-term increased polyamine intake elevated blood spermine levels and inhibited aging-associated pathologies in mice and humans. Spermine reversed changes (increased dcSAM, decreased DNMT activity, aberrant DNA methylation, and proinflammatory status) induced by the inhibition of ornithine decarboxylase. The relation between polyamine metabolism, one-carbon metabolism, DNA methylation, and the biological mechanism of spermine-induced lifespan extension is discussed.

Age-Related Loss in Bone Mineral Density of Rats Fed Lifelong on a Fish Oil-Based Diet Is Avoided by Coenzyme Q10 Addition

During aging, bone mass declines increasing osteoporosis and fracture risks. Oxidative stress has been related to this bone loss, making dietary compounds with antioxidant properties a promising weapon. Male Wistar rats were maintained for 6 or 24 months on diets with fish oil as unique fat source, supplemented or not with coenzyme Q10 (CoQ10), to evaluate the potential of adding this molecule to the n-3 polyunsaturated fatty acid (n-3 PUFA)-based diet for bone mineral density (BMD) preservation. BMD was evaluated in the femur. Serum osteocalcin, osteopontin, receptor activator of nuclear factor-κB ligand, ostroprotegerin, parathyroid hormone, urinary F₂-isoprostanes, and lymphocytes DNA strand breaks were also measured. BMD was lower in aged rats fed a diet without CoQ10 respect than their younger counterparts, whereas older animals receiving CoQ10 showed the highest BMD. F₂-isoprostanes and DNA strand breaks showed that oxidative stress was higher during aging. Supplementation with CoQ10 prevented oxidative damage to lipid and DNA, in young and old animals, respectively. Reduced oxidative stress associated to CoQ10 supplementation of this n-3 PUFA-rich diet might explain the higher BMD found in aged rats in this group of animals.

Ubisol-Q10 Prevents Glutamate-Induced Cell Death by Blocking Mitochondrial Fragmentation and Permeability Transition Pore Opening

Mitochondrial dysfunction and oxidative stress are the major events that lead to the formation of mitochondrial permeability transition pore (mPTP) during glutamate-induced cytotoxicity and cell death. Coenzyme Q10 (CoQ10) has widely been used for the treatment of mitochondrial disorders and neurodegenerative diseases. Comparing to traditional lipid-soluble CoQ10, water soluble CoQ10 (Ubisol-Q10) has high intracellular and intra-mitochondrial distribution. The aims of the present study are to determine the neuroprotective effects of Ubisol-Q10 on glutamate-induced cell death and to explore its functional mechanisms. HT22 neuronal cells were exposed to glutamate. Cell viability was measured and mitochondrial fragmentation was assessed by mitochondrial imaging. The mPTP opening was determined by mitochondrial membrane potential and calcium retention capacity. The results revealed that the anti-glutamate toxicity effects of Ubisol-Q10 was associated with its ability to block mitochondrial fragmentation, to maintain calcium retention capacity and mitochondrial membrane potential, and to prevent mPTP formation, AIF release, and DNA fragmentation. We concluded that Ubisol-Q10 protects cells from glutamate toxicity by preserving the integrity of mitochondrial structure and function. Therefore, adequate CoQ10 supplementation may be beneficial in preventing cerebral stroke and other disorders that involve mitochondrial dysfunction.

Coenzyme Q and Its Role in the Dietary Therapy against Aging

Coenzyme Q (CoQ) is a naturally occurring molecule located in the hydrophobic domain of the phospholipid bilayer of all biological membranes. Shortly after being discovered, it was recognized as an essential electron transport chain component in mitochondria where it is particularly abundant. Since then, more additional roles in cell physiology have been reported, including antioxidant, signaling, death prevention, and others. It is known that all cells are able to synthesize functionally sufficient amounts of CoQ under normal physiological conditions. However, CoQ is a molecule found in different dietary sources, which can be taken up and incorporated into biological membranes. It is known that mitochondria have a close relationship with the aging process. Additionally, delaying the aging process through diet has aroused the interest of scientists for many years. These observations have stimulated investigation of the anti-aging potential of CoQ and its possible use in dietary therapies to alleviate the effects of aging. In this context, the present review focus on the current knowledge and evidence the roles of CoQ cells, its relationship with aging, and possible implications of dietary CoQ in relation to aging, lifespan or age-related diseases.

Increased bioavailability of ubiquinol compared to that of ubiquinone is due to more efficient micellarization during digestion and greater GSH-dependent uptake and basolateral secretion by Caco-2 cells

The oral bioavailability of ubiquinol recently has been reported to be greater than that of ubiquinone in healthy adults. The basis for this influence of redox state of coenzyme Q (CoQ) on bioavailability has been investigated using the coupled in vitro digestion/Caco-2 cell model. Solubilized ubiquinol and ubiquinone were added to yogurt and subjected to simulated gastric and small intestinal digestion. Partitioning of CoQ in mixed micelles during small intestinal digestion was significantly greater during digestion of yogurt enriched with ubiquinol. Similarly, apical uptake from mixed micelles and transepithelial transport of CoQ by Caco-2 cells were significantly greater after digestion of the ubiquinol-rich yogurt compared to digested ubiquinone-rich yogurt. Reduction of cellular GSH significantly decreased cell uptake and basolateral secretion of both ubiquinol and ubiquinone, although the adverse impact was much greater for ubiquinol. These data suggest that the enhanced bioaccessibility and bioavailability of ubiquinol compared to ubiquinone results from reduced coenzyme being more efficiently incorporated into mixed micelles during digestion and its greater uptake and basolateral secretion in a glutathione-dependent mechanism.

Ubiquinol-10 supplementation activates mitochondria functions to decelerate senescence in senescence-accelerated mice

AIM

The present study was conducted to define the relationship between the anti-aging effect of ubiquinol-10 supplementation and mitochondrial activation in senescence-accelerated mouse prone 1 (SAMP1) mice.

RESULTS

Here, we report that dietary supplementation with ubiquinol-10 prevents age-related decreases in the expression of sirtuin gene family members, which results in the activation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a major factor that controls mitochondrial biogenesis and respiration, as well as superoxide dismutase 2 (SOD2) and isocitrate dehydrogenase 2 (IDH2), which are major mitochondrial antioxidant enzymes. Ubiquinol-10 supplementation can also increase mitochondrial complex I activity and decrease levels of oxidative stress markers, including protein carbonyls, apurinic/apyrimidinic sites, malondialdehydes, and increase the reduced glutathione/oxidized glutathione ratio. Furthermore, ubiquinol-10 may activate Sirt1 and PGC-1α by increasing cyclic adenosine monophosphate (cAMP) levels that, in turn, activate cAMP response element-binding protein (CREB) and AMP-activated protein kinase (AMPK).

INNOVATION AND CONCLUSION

These results show that ubiquinol-10 may enhance mitochondrial activity by increasing levels of SIRT1, PGC-1α, and SIRT3 that slow the rate of age-related hearing loss and protect against the progression of aging and symptoms of age-related diseases.

Long-term Effect of Ubiquinol on Exercise Capacity and the Oxidative Stress Regulation System in SAMP1 Mice

[Purpose] This study examined how exercise capacity and the oxidative stress regulation system are affected by different amounts of dietary Ubiquinol (reduced form of coenzyme Q10, H₂CoQ10: QH) over the long term. [Subjects and Methods] Twenty-three senescence-accelerated mouse P1 (SAMP1) mice were randomly divided into two groups: one consuming a relatively high amount of QH (300 mg/kg; Group A) and the other a relatively low amount (30 mg/kg, Group B). Food and tap water were provided ad libitum. Both groups were made to run on a treadmill until exhaustion, and total running duration was measured. For the oxidative stress regulation system, the d-ROM test value (degree of oxidative stress) and BAP test value (antioxidant potential) were measured in a resting state, and then the BAP/d-ROM ratio (B/R ratio) was calculated. The values of plasma QH and plasma ubiquinone (plasma oxidized form of CoQ10) were also measured, and the reduced ratio was calculated. Measurements were taken 3 times: at the start of the study when the animals were 39 weeks old (baseline), after consumption of QH for 7 months (7 mo), and after consumption of QH for 10 months (10 mo). [Results] The senescence score at 10 mo was significantly lower in Group A. Comparison of the mean percentage change in running time showed a difference of 15.1% between the 2 groups. At 10 mo, the d-ROM test value was significantly increased and the B/R ratio was significantly decreased in Group B. Significant increases in the plasma QH value and reduced ratio were seen in Group A. [Conclusion] Group A showed a greater decrease in the d-ROM test and increase in the reduced ratio than Group B. Thus, a dose-dependent effect of QH consumption was demonstrated.

The quality control assessment of commercially available coenzyme q(10)-containing dietary and health supplements in Japan

Coenzyme Q₁₀ (CoQ₁₀) has been widely commercially available in Japan as a dietary and health supplement since 2001 and is used for the prevention of lifestyle-related diseases induced by free radicals and aging. We evaluated CoQ₁₀ supplements to ensure that these supplements can be used effectively and safely. Commercially available products were selected and assessed by the quality control tests specified in the Japanese Pharmacopoeia XV. When the disintegration time of CoQ₁₀ supplements was measured, a few tested supplements did not completely disintegrate even after incubation in water for an hour at 37°C. In the content test, many samples were well controlled. However, a few supplements showed low recovery rates of CoQ₁₀ as compared to manufacturer’s indicated contents. Among soft capsule and liquid supplements, the reduced form of CoQ₁₀ (H₂CoQ₁₀), as well as the oxidized form, was detected by HPLC with electrochemical detector. The results for experimental formulated CoQ₁₀ supplements demonstrated that H₂CoQ₁₀ was produced by the interaction of CoQ₁₀ with vitamins E and/or C. From these results, we concluded that quality varied considerably among the many supplement brands containing CoQ₁₀. Additionally, we also demonstrated that H₂CoQ₁₀ can be detected in some foods as well as in CoQ₁₀ supplements.

Effects of coenzyme Q10 on salivary secretion

OBJECTIVES

Dry mouth is a condition associated with reduced salivary secretion and is thought to be related to aging. This study was conducted to test whether reduced (ubiquinol) or oxidized (ubiquinone) forms of CoQ10 affect salivary secretion and salivary CoQ10 content before and after treatment.

DESIGN AND METHODS

Sixty-six patients were given either ubiquinol or ubiquinone orally at a dosage of 100 mg/day, or a placebo for 1 month, and salivary secretion and salivary CoQ10 content were analyzed before and after treatment.

RESULTS

Both parameters were significantly improved following treatment with either form of CoQ10, suggesting the effectiveness of CoQ10 in attenuating dry mouth symptoms.

CONCLUSION

CoQ10 was locally detected in salivary glands, suggesting that orally administered CoQ10 was transported to the salivary glands via the blood stream and exerted its activity, improving salivary secretion.

Mitochondrial reactive oxygen species generation by the SDHC V69E mutation causes low birth weight and neonatal growth retardation

We have previously demonstrated that excessive mitochondrial reactive oxygen species caused by mutations in the SDHC subunit of Complex II resulted in premature death in C. elegans and Drosophila, tumors in mouse cells and infertility in transgenic mice. We now report the generation and initial characterization of conditional transgenic mice (Tet-mev-1) using our uniquely developed Tet-On/Off system, which equilibrates transgene expression to endogenous levels. The mice experienced mitochondrial respiratory chain dysfunction that induced reactive oxygen species overproduction. The mitochondrial oxidative stress resulted in excessive apoptosis leading to low birth weight and growth retardation in the neonatal developmental phase in Tet-mev-1 mice.

Supplementation with the reduced form of Coenzyme Q10 decelerates phenotypic characteristics of senescence and induces a peroxisome proliferator-activated receptor-alpha gene expression signature in SAMP1 mice

Our present study reveals significant decelerating effects on senescence processes in middle-aged SAMP1 mice supplemented for 6 or 14 months with the reduced form (Q(10)H(2), 500 mg/kg BW/day) of coenzyme Q(10) (CoQ(10)). To unravel molecular mechanisms of these CoQ(10) effects, a genome-wide transcript profiling in liver, heart, brain and kidney of SAMP1 mice supplemented with the reduced (Q(10)H(2)) or oxidized form of CoQ(10) (Q(10)) was performed. Liver seems to be the main target tissue of CoQ(10) intervention, followed by kidney, heart and brain. Stringent evaluation of the resulting data revealed that Q(10)H(2) has a stronger impact on gene expression than Q(10), primarily due to differences in the bioavailability. Indeed, Q(10)H(2) supplementation was more effective than Q(10) to increase levels of CoQ(10) in the liver of SAMP1 mice. To identify functional and regulatory connections of the "top 50" (p<0.05) Q(10)H(2)-sensitive transcripts in liver, text mining analysis was used. Hereby, we identified Q(10)H(2)-sensitive genes which are regulated by peroxisome proliferator-activated receptor-alpha and are primarily involved in cholesterol synthesis (e.g. HMGCS1, HMGCL and HMGCR), fat assimilation (FABP5), lipoprotein metabolism (PLTP) and inflammation (STAT-1). These data may explain, at least in part, the decelerating effects on degenerative processes observed in Q(10)H(2)-supplemented SAMP1 mice.

Mouse model to study human A beta2M amyloidosis: generation of a transgenic mouse with excessive expression of human beta2-microglobulin

Patients on long-term hemodialysis can develop dialysis-related amyloidosis (DRA) due to deposition of beta(2)-microglobulin (beta(2)m) into amyloid fibrils (Abeta(2)M). Despite intensive biochemical studies, the pathogenesis of amyloid deposition in DRA patients remains poorly understood. To elucidate the mechanisms that underlie Abeta(2)M fibril formation in DRA, we generated transgenic mice that overexpress human beta(2)m protein in a mouse beta(2)m gene knockout background (hB2MTg(+/+) mB2m(+/+)). The hB2MTg(+/+)mB2m(-/-) mice express a high level of human beta(2)m protein in many tissues as well as a high plasma beta(2)m concentration (192.8 mg/L). This concentration is >100 times higher than that observed in healthy humans and >4 times higher than that detected in patients on dialysis. We examined spontaneous and amyloid fibril-induced amyloid deposition in these mice. Amyloid deposition of beta(2)m protein was not observed in aged or amyloid fibril injected animals. However, mouse senile apolipoprotein A-II amyloidosis (AApoAII) was detected, particularly in the joints of mice that were injected with AApoAII amyloid fibrils. This study demonstrates that this mouse model could be valuable in studying the components and conditions that promote DRA, and indicates that high plasma concentrations of hbeta(2)m as well as seeding with pre-existing amyloid fibrils may not be sufficient to induce Abeta(2)M.

Effects of ubiquinol-10 on microRNA-146a expression in vitro and in vivo

MicroRNAs (miRs) are involved in key biological processes via suppression of gene expression at posttranscriptional levels. According to their superior functions, subtle modulation of miR expression by certain compounds or nutrients is desirable under particular conditions. Bacterial lipopolysaccharide (LPS) induces a reactive oxygen species-/NF-kappaB-dependent pathway which increases the expression of the anti-inflammatory miR-146a. We hypothesized that this induction could be modulated by the antioxidant ubiquinol-10. Preincubation of human monocytic THP-1 cells with ubiquinol-10 reduced the LPS-induced expression level of miR-146a to 78.9 +/- 13.22%. In liver samples of mice injected with LPS, supplementation with ubiquinol-10 leads to a reduction of LPS-induced miR-146a expression to 78.12 +/- 21.25%. From these consistent in vitro and in vivo data, we conclude that ubiquinol-10 may fine-tune the inflammatory response via moderate reduction of miR-146a expression.

Life-long supplementation with a low dosage of coenzyme Q10 in the rat: effects on antioxidant status and DNA damage

Life-long low-dosage supplementation of coenzyme Q(10) (CoQ(10)) is studied in relation to the antioxidant status and DNA damage. Thirty-two male rats were assigned into two experimental groups differing in the supplementation or not with 0.7 mg/kg/day of CoQ(10). Eight rats per group were killed at 6 and 24 months. Plasma retinol, alpha-tocopherol, coenzyme Q, total antioxidant capacity and fatty acids were analysed. DNA strand breaks were studied in peripheral blood lymphocytes. Aging and supplementation led to significantly higher values for CoQ homologues, retinol and alpha-tocopherol. No difference in total antioxidant capacity was detected at 6 months but significantly lower values were found in aged control animals. Similar DNA strand breaks levels were found at 6 months. Aging led to significantly higher DNA strand breaks levels in both groups but animals supplemented with CoQ(10) led to a significantly lower increase in that marker. Aged rats showed significantly higher polyunsaturated fatty acids. This study demonstrates that lifelong intake of a low dosage of CoQ(10) enhances plasma levels of CoQ(9), CoQ(10), alpha-tocopherol and retinol. In addition, CoQ(10) supplementation attenuates the age-related fall in total antioxidant capacity of plasma and the increase in DNA damage in peripheral blood lymphocytes.