Gastroprotective and microbiome-modulating effects of ubiquinol in rats with radiation-induced enteropathy

Radiation enteritis is a frequently encountered issue for patients receiving radiotherapy and has a significant impact on cancer patients' quality of life. The gut microbiota plays a pivotal role in intestinal function, yet the impact of irradiation on gut microorganisms is not fully understood. This study explores the gastroprotective effect and gut microbiome-modulating potential of ubiquinol (Ubq), the reduced form of the powerful antioxidant CoQ-10. For this purpose, male albino rats were randomly assigned to four groups: Control, IRR (acute 7 Gy γ-radiation), Ubq_Post (Ubq for 7 days post-irradiation), and Ubq_Pre/Post (Ubq for 7 days pre and 7 days post-irradiation). The fecal microbiomes of all groups were profiled by 16S rRNA amplicon sequencing followed by bioinformatics and statistical analysis. Histopathological examination of intestinal tissue indicated severe damage in the irradiated group, which was mitigated by ubiquinol with enhanced regeneration, goblet cells, and intestinal alkaline phosphatase expression. Compared to the irradiated group, the Ubq-treated groups had a significant recovery of intestinal interleukin-1β, caspase-3, nitric oxide metabolites, and thio-barbituric reactive substances to near-healthy levels. Ubq_Pre/Post group displayed elevated peroxisome proliferator-activated receptor (PPAR-γ) level, suggesting heightened benefits. Serum insulin reduction in irradiated rats improved post-Ubq treatment, with a possible anti-inflammatory effect on the pancreatic tissue. Fecal microbiota profiling revealed a dysbiosis state with a reduction of bacterial diversity post-irradiation, which was re-modulated in the Ubq treated groups to profiles that are indistinguishable from the control group. These findings underscore Ubq's gastroprotective effects against radiation-induced enteritis and its potential in restoring the gut microbiota's diversity and balance.

Early microbial intervention reshapes phenotypes of newborn Bos taurus through metabolic regulations

BACKGROUND

The rumen of neonatal calves has limited functionality, and establishing intestinal microbiota may play a crucial role in their health and performance. Thus, we aim to explore the temporal colonization of the gut microbiome and the benefits of early microbial transplantation (MT) in newborn calves.

RESULTS

We followed 36 newborn calves for 2 months and found that the composition and ecological interactions of their gut microbiomes likely reached maturity 1 month after birth. Temporal changes in the gut microbiome of newborn calves are widely associated with changes in their physiological statuses, such as growth and fiber digestion. Importantly, we observed that MT reshapes the gut microbiome of newborns by altering the abundance and interaction of Bacteroides species, as well as amino acid pathways, such as arginine biosynthesis. Two-year follow-up of those calves further showed that MT improves their later milk production. Notably, MT improves fiber digestion and antioxidant capacity of newborns while reducing diarrhea. MT also contributes to significant changes in the metabolomic landscape, and with putative causal mediation analysis, we suggest that altered gut microbial composition in newborns may influence physiological status through microbial-derived metabolites.

CONCLUSIONS

Our study provides a metagenomic and metabolomic atlas of the temporal development of the gut microbiome in newborn calves. MT can alter the gut microbiome of newborns, leading to improved physiological status and later milk production. The data may help develop strategies to manipulate the gut microbiota during early life, which may be relevant to the health and production of newborn calves.

Coenzyme Q10 for Enhancing Physical Activity and Extending the Human Life Cycle

BACKGROUND

Coenzyme Q (CoQ) is an enzyme family that plays a crucial role in maintaining the electron transport chain and antioxidant defense. CoQ10 is the most common form of CoQ in humans. A deficiency of CoQ10 occurs naturally with aging and may contribute to the development or progression of many diseases. Besides, certain drugs, in particular, statins and bisphosphonates, interfere with the enzymes responsible for CoQ10 biosynthesis and, thus, lead to CoQ10 deficiency.

OBJECTIVES

This article aims to evaluate the cumulative studies and insights on the topic of CoQ10 functions in human health, focusing on a potential role in maintaining physical activity and extending the life cycle.

RESULTS

Although supplementation with CoQ10 offers many benefits to patients with cardiovascular disease, it appears to add little value to patients suffering from statin-associated muscular symptoms. This may be attributed to substantial heterogeneity in doses and treatment regimens used.

CONCLUSION

Therefore, there is a need for further studies involving a greater number of patients to clarify the benefits of adjuvant therapy with CoQ10 in a range of health conditions and diseases.

The Effect of CoQ10 supplementation on ART treatment and oocyte quality in older women

A significant problem associated with assisted reproductive technologies (ART) is recurrent treatment failure which can be attributed to the age-associated decline in oocyte quality. Co-enzyme Q10 (CoQ10) is an antioxidant and essential component of the mitochondrial electron transport chain. It is reported that de novo CoQ10 production declines with ageing and coincides with age-related decline in fertility, leading to CoQ10 supplementation being advocated to enhance response to ovarian stimulation and improve oocyte quality. CoQ10 supplementation was found to improve fertilization rates, embryo maturation rates and embryo quality when used before and during in vitro fertilization (IVF) and in vitro maturation (IVM) treatment in women aged 31 and over. Regarding oocyte quality, CoQ10 was able to reduce high rates of chromosomal abnormalities and oocyte fragmentation, as well as improve mitochondrial function. Proposed mechanisms of CoQ10 function include restoration of reactive oxygen species imbalance, preventing DNA damage and oocyte apoptosis, as well as restoration of Krebs cycle downregulation from ageing. In this literature review, we provide an overview of the use of CoQ10 in improving the success of IVF and IVM in older women, and additionally assess the impact of CoQ10 on oocyte quality and discuss potential mechanisms of action by CoQ10 on the oocyte.

Mitochondrial fission drives neuronal metabolic burden to promote stress susceptibility in male mice

Neurons are particularly susceptible to energy fluctuations in response to stress. Mitochondrial fission is highly regulated to generate ATP via oxidative phosphorylation; however, the role of a regulator of mitochondrial fission in neuronal energy metabolism and synaptic efficacy under chronic stress remains elusive. Here, we show that chronic stress promotes mitochondrial fission in the medial prefrontal cortex via activating dynamin-related protein 1 (Drp1), resulting in mitochondrial dysfunction in male mice. Both pharmacological inhibition and genetic reduction of Drp1 ameliorates the deficit of excitatory synaptic transmission and stress-related depressive-like behavior. In addition, enhancing Drp1 fission promotes stress susceptibility, which is alleviated by coenzyme Q10, which potentiates mitochondrial ATP production. Together, our findings unmask the role of Drp1-dependent mitochondrial fission in the deficits of neuronal metabolic burden and depressive-like behavior and provides medication basis for metabolism-related emotional disorders.

The Cocrystal of Ubiquinol: Improved Stability and Bioavailability

Coenzyme Q10 (CoQ10) exists in two forms, an oxidized form and a reduced form. Ubiquinol is the fully reduced form of CoQ10. Compared to the oxidized form, ubiquinol has a much higher biological absorption and better therapeutic effect. However, ubiquinol has an important stability problem which hampers its storage and formulation. It can be easily transformed into its oxidized form-ubiquinone-even at low temperature. In this work, we designed, synthesized, and characterized a new cocrystal of ubiquinol with vitamin B3 nicotinamide (UQ-NC). Compared to the marketed ubiquinol form, the cocrystal exhibited an excellent stability, improved dissolution properties, and higher bioavailability. The cocrystal remained stable for a long period, even when stored under stressed conditions. In the dissolution experiments, the cocrystal generated 12.6 (in SIF) and 38.3 (in SGF) times greater maximum ubiquinol concentrations above that of the marketed form. In addition, in the PK studies, compared to the marketed form, the cocrystal exhibited a 2.2 times greater maximum total coenzyme Q10 concentration and a 4.5 times greater AUC than that of the marketed form.

An Overview of Analytical Methods for Quantitative Determination of Coenzyme Q10 in Foods

Food analysts have developed three primary techniques for coenzyme Q10 (CoQ10) production: isolation from animal or plant matrices, chemical synthesis, and microbial fermentation; this literature review is focused on the first method. Choosing the appropriate analytical method for determining CoQ10 in a particular food product is essential, as this analyte is a quality index for healthy foods; various associations of extraction and quantification techniques are available in the literature, each having advantages and disadvantages. Several factors must be considered when selecting an analytical method, such as specificity, linear range, detection limit, quantification limit, recovery rate, operation size, analysis time, equipment availability, and costs. In another train of thought, the food sector produces a significant amount of solid and liquid waste; therefore, waste-considered materials can be a valuable source of CoQ10 that can be recovered and used as a fortifying ingredient or dietary supplement. This review also pursues identifying the richest food sources of CoQ10, and has revealed them to be vegetable oils, fish oil, organs, and meat.

Dietary supplements could prevent cardiometabolic syndrome: Are they safe and reliable enough for disease prevention and health promotion?

Dietary supplements (DS) and their purchase is often based on a consumer's personal choice and advertisements. The associated DS regulations, particularly in manufacturing and marketing, are far more flexible and permissive than that of the well-regulated prescription pharmaceuticals. However, the adverse health effects associated with the inadvertent use of mega-doses of DS are not well understood. The demand for DS, nutraceuticals, and herbal remedies has experienced an upswing during the past two to three decades, and global product sales have thrived. More so, the prevention of cardiometabolic syndrome (CMS) and related disorders like diabetes mellitus, obesity, hypertension, and serum lipid abnormalities, as well as of other noncommunicable diseases (NCDs), is of highest health care priority globally, since these disorders impose very high economic burdens on health care systems and society. In this review, we argue why DS could prevent cardiometabolic syndrome, by providing the potential benefits and risks associated with them, especially self-medication considering their intake by the public at large. Good manufacturing practices and quality control are absolutely necessary for the manufacture of DS products, and proper labeling is needed regarding the optimal dose schedules of various DS and bioactive ingredients. Specific examples are used to underscore the indications and dosage recommendations made for the marketing and promotion of fish oil, coenzyme Q10, and Mg-containing products for the prevention of cardiometabolic syndrome.

Theoretical Investigation of Regiodivergent Addition of Anilines and Phenolates to p-Benzoquinone Ring

Two different products were obtained by the regiodivergent reaction of benzoquinone derivatives with phenolates and anilines: 3-aryloxybenzoquinone and 2-phenylamino-3-bromobenzoquinone. Calculated density functional theory free energies of reaction values corroborate the experimental observation of the formation of the substitution product in the reaction with phenolates in acetonitrile and the product of addition/oxidation for the reaction with aniline in water. Calculated charges and Fukui functions are similar for C2 and C3 atoms, indicating an equal possibility to suffer a nucleophilic attack. The calculated energy barriers for nucleophilic attack steps indicated that the first steps of the substitution with phenolates and addition/oxidation with anilines are faster, which justifies the formation of the respective products. The natural bond order analysis for the transition states revealed that there is a strong interaction between lone pairs of N and O atoms and the π_C2C3 ^* for the O → C2 and N → C3 attacks and a weak interaction for the O → C3 and N → C2 attacks, which also agrees with experimental observations.

Coenzyme Q10 in aging and disease

Coenzyme Q10 (CoQ10) is an essential component of the electron transport chain. It also acts as an antioxidant in cellular membranes. It can be endogenously produced in all cells by a specialized mitochondrial pathway. CoQ10 deficiency, which can result from aging or insufficient enzyme function, has been considered to increase oxidative stress. Some drugs, including statins and bisphosphonates, often used by older individuals, can interfere with enzymes responsible for endogenous CoQ10 synthesis. Oral supplementation with high doses of CoQ10 can increase both its circulating and intracellular levels and several clinical trials observed that its administration provided beneficial effects on different disorders such as cardiovascular disease and inflammation which have been associated with low CoQ10 levels and high oxidative stress. Moreover, CoQ10 has been suggested as a promising therapeutic agent to prevent and slow the progression of other diseases including metabolic syndrome and type 2 diabetes, neurodegenerative and male infertility. However, there is still a need for further studies and well-designed clinical trials involving a large number of participants undergoing longer treatments to assess the benefits of CoQ10 for these disorders.

Combined Supplementation of Coenzyme Q10 and Other Nutrients in Specific Medical Conditions

Coenzyme Q₁₀ (CoQ₁₀) is a compound with a crucial role in mitochondrial bioenergetics and membrane antioxidant protection. Despite the ubiquitous endogenous biosynthesis, specific medical conditions are associated with low circulating CoQ₁₀ levels. However, previous studies of oral CoQ₁₀ supplementation yielded inconsistent outcomes. In this article, we reviewed previous CoQ₁₀ trials, either single or in combination with other nutrients, and stratified the study participants according to their metabolic statuses and medical conditions. The CoQ₁₀ supplementation trials in elders reported many favorable outcomes. However, the single intervention was less promising when the host metabolic statuses were worsening with the likelihood of multiple nutrient insufficiencies, as in patients with an established diagnosis of metabolic or immune-related disorders. On the contrary, the mixed CoQ₁₀ supplementation with other interacting nutrients created more promising impacts in hosts with compromised nutrient reserves. Furthermore, the results of either single or combined intervention will be less promising in far-advanced conditions with established damage, such as neurodegenerative disorders or cancers. With the limited high-level evidence studies on each host metabolic category, we could only conclude that the considerations of whether to take supplementation varied by the individuals' metabolic status and their nutrient reserves. Further studies are warranted.

Effects of coenzyme Q10 supplementation on glycemic control: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND

Previous reviews reported that the effects of CoQ10 on glycemic control were inconsistent. There is no review exploring the optimal intake of CoQ10 for glycemic control. We aimed to investigate the efficacy of CoQ10 on glycemic control and evaluate the dose-response relationship via integrating the existing evidence from randomized control trials (RCTs).

METHODS

Databases (PubMed, Embase, and Cochrane Library) were searched to identify RCTs for investigating the efficacy of CoQ10 on fasting glucose, fasting insulin, HbA1c, and HOMA-IR up to March 12, 2022. We performed a meta-analysis on 40 RCTs of CoQ10. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated for net changes. Evidence certainty was assessed using GRADE. Dose-response relationships were evaluated using 1-stage restricted cubic spline regression model. The protocol was registered in PROSPERO (CRD42021252933).

FINDINGS

Forty studies (n = 2,424 participants) were included in this meta-analysis. CoQ10 significantly reduced fasting glucose (WMD: -5.22 [95% CI: -8.33, -2.11] mg/dl; P <0.001; I² =95.10%), fasting insulin (-1.32 [-2.06, -0.58] μIU/ml; P < 0.001; I² =78.86%), HbA_1c (-0.12% [-0.23, -0.01]; P =0.04; I² =49.10%), and HOMA-IR (-0.69 [-1.00, -0.38]; P <0.001; I² =88.80%). The effect of CoQ10 on outcomes was greater in diabetes with lower heterogeneity. A "U" shape dose-response relationship curve revealed that 100-200 mg/day of CoQ10 largely decreased fasting glucose (χ ² = 12.08, P _nonlinearity =0.002), fasting insulin (χ ² = 9.73, P _nonlinearity =0.008), HbA_1c (χ ² = 6.00, P _nonlinearity =0.049), HOMA-IR (χ ² = 25.89, P _nonlinearity <0.001).

INTERPRETATION

CoQ10 supplementation has beneficial effects on glycemic control, especially in diabetes, and 100-200 mg/day of CoQ10 could achieve the greatest benefit, which could provide a basis for the dietary guidelines of CoQ10 in patients with glycemic disorders.

FUNDING

This work was supported by the National Natural Science Foundation of China (No. 82030098, 81872617 and 81730090), Shenzhen Science, Technology, and Innovation Commission (No. JCYJ20180307153228190), CNS Research Fund for DRI, and National innovation and entrepreneurship training program for undergraduate student (No. 202210558161).

Bioavailability of Reduced Coenzyme Q10 (Ubiquinol-10) in Burn Patients

Mitochondrial dysfunction has been implicated in the pathogenesis of inflammation and multi-organ dysfunction in major trauma, including burn injury. Coenzyme Q10 (CoQ10) is a metabolite of the mevalonate pathway and an essential cofactor for the electron transport in the mitochondria. In addition, its reduced form (ubiquinol) functions as an antioxidant. Little is known as to whether oral CoQ10 supplementation effectively increases intracellular CoQ10 levels in humans. To study the bioavailability of CoQ10 supplementation, we conducted a randomized, double-blind, placebo-controlled study of reduced CoQ10 (ubiquinol-10) (1800 mg/day, t.i.d.) in burn patients at a single, tertiary-care hospital. Baseline plasma CoQ10 levels were significantly lower in burn patients than in healthy volunteers, although plasma CoQ10/cholesterol ratio did not differ between the groups. CoQ10 supplementation increased plasma concentrations of total and reduced CoQ10 and total CoQ10 content in peripheral blood mononuclear cells (PBMCs) in burn patients compared with the placebo group. CoQ10 supplementation did not significantly change circulating levels of mitochondrial DNA, inflammatory markers (e.g., interleukins, TNF-α, IFN-γ), or Sequential Organ Failure Assessment (SOFA) scores compared with the placebo group. This study showed that a relatively high dose of reduced CoQ10 supplementation increased the intracellular CoQ10 content in PBMCs as well as plasma concentrations in burn patients.

A knowledge graph of clinical trials ([Formula: see text])

Effective and successful clinical trials are essential in developing new drugs and advancing new treatments. However, clinical trials are very expensive and easy to fail. The high cost and low success rate of clinical trials motivate research on inferring knowledge from existing clinical trials in innovative ways for designing future clinical trials. In this manuscript, we present our efforts on constructing the first publicly available Clinical Trials Knowledge Graph, denoted as [Formula: see text]. [Formula: see text] includes nodes representing medical entities in clinical trials (e.g., studies, drugs and conditions), and edges representing the relations among these entities (e.g., drugs used in studies). Our embedding analysis demonstrates the potential utilities of [Formula: see text] in various applications such as drug repurposing and similarity search, among others.

Coenzyme Q10 supplementation - In ageing and disease

Coenzyme Q₁₀ (CoQ₁₀) is an essential component of the mitochondrial electron transport chain. It is also an antioxidant in cellular membranes and lipoproteins. All cells produce CoQ₁₀ by a specialized cytoplasmatic-mitochondrial pathway. CoQ₁₀ deficiency can result from genetic failure or ageing. Some drugs including statins, widely used by inter alia elderly, may inhibit endogenous CoQ₁₀ synthesis. There are also chronic diseases with lower levels of CoQ₁₀ in tissues and organs. High doses of CoQ₁₀ may increase both circulating and intracellular levels, but there are conflicting results regarding bioavailability. Here, we review the current knowledge of CoQ₁₀ biosynthesis and primary and acquired CoQ₁₀ deficiency, and results from clinical trials based on CoQ₁₀ supplementation. There are indications that supplementation positively affects mitochondrial deficiency syndrome and some of the symptoms of ageing. Cardiovascular disease and inflammation appear to be alleviated by the antioxidant effect of CoQ₁₀. There is a need for further studies and well-designed clinical trials, with CoQ₁₀ in a formulation of proven bioavailability, involving a greater number of participants undergoing longer treatments in order to assess the benefits of CoQ₁₀ treatment in neurodegenerative disorders, as well as in metabolic syndrome and its complications.

Solubilized ubiquinol for preserving corneal function

Defective cellular metabolism, impaired mitochondrial function, and increased cell death are major problems that adversely affect donor tissues during hypothermic preservation prior to transplantation. These problems are thought to arise from accumulated reactive oxygen species (ROS) inside cells. Oxidative stress acting on the cells of organs and tissues preserved in hypothermic conditions before surgery, as is the case for cornea transplantation, is thought to be a major reason behind cell death prior to surgery and decreased graft survival after transplantation. We have recently discovered that ubiquinol - the reduced and active form of coenzyme Q10 and a powerful antioxidant - significantly enhances mitochondrial function and reduces apoptosis in human donor corneal endothelial cells. However, ubiquinol is highly lipophilic, underscoring the need for an aqueous-based formulation of this molecule. Herein, we report a highly dispersible and stable formulation comprising a complex of ubiquinol and gamma cyclodextrin (γ-CD) for use in aqueous-phase ophthalmic products. Docking studies showed that γ-CD has the strongest binding affinity with ubiquinol compared to α- or β-CD. Complexed ubiquinol showed significantly higher stability compared to free ubiquinol in different aqueous ophthalmic products including Optisol-GS® corneal storage medium, balanced salt solution for intraocular irrigation, and topical Refresh® artificial tear eye drops. Greater ROS scavenging activity was noted in a cell model with high basal metabolism and ROS generation (A549) and in HCEC-B4G12 human corneal endothelial cells after treatment with ubiquinol/γ-CD compared to free ubiquinol. Furthermore, complexed ubiquinol was more effective at lowering ROS, and at far lower concentrations, compared to free ubiquinol. Complexed ubiquinol inhibited lipid peroxidation and protected HCEC-B4G12 cells against erastin-induced ferroptosis. No evidence of cellular toxicity was detected in HCEC-B4G12 cells after treatment with complexed ubiquinol. Using a vertical diffusion system, a topically applied inclusion complex of γ-CD and a lipophilic dye (coumarin-6) demonstrated transcorneal penetrance in porcine corneas and the capacity for the γ-CD vehicle to deliver drug to the corneal endothelium. Using the same model, topically applied ubiquinol/γ-CD complex penetrated the entire thickness of human donor corneas with markedly greater ubiquinol retention in the endothelium compared to free ubiquinol. Lastly, the penetrance of ubiquinol/γ-CD complex was assayed using human donor corneas preserved for 7 days in Optisol-GS® per standard industry practices, and demonstrated higher amounts of ubiquinol retained in the corneal endothelium compared to free ubiquinol. In summary, ubiquinol complexed with γ-CD is a highly stable composition that can be incorporated into a variety of aqueous-phase products for ophthalmic use including donor corneal storage media and topical eye drops to scavenge ROS and protect corneal endothelial cells against oxidative damage.

Stability of Reduced and Oxidized Coenzyme Q10 in Finished Products

The efficiency of coenzyme Q10 (CoQ10) supplements is closely associated with its content and stability in finished products. This study aimed to provide evidence-based information on the quality and stability of CoQ10 in dietary supplements and medicines. Therefore, ubiquinol, ubiquinone, and total CoQ10 contents were determined by a validated HPLC-UV method in 11 commercial products with defined or undefined CoQ10 form. Both forms were detected in almost all tested products, resulting in a total of CoQ10 content between 82% and 166% of the declared. Ubiquinol, ubiquinone, and total CoQ10 stability in these products were evaluated within three months of accelerated stability testing. Ubiquinol, which is recognized as the less stable form, was properly stabilized. Contrarily, ubiquinone degradation and/or reduction were observed during storage in almost all tested products. These reactions were also detected at ambient temperature within the products’ shelf-lives and confirmed in ubiquinone standard solutions. Ubiquinol, generated by ubiquinone reduction with vitamin C during soft-shell capsules’ storage, may lead to higher bioavailability and health outcomes. However, such conversion and inappropriate content in products, which specify ubiquinone, are unacceptable in terms of regulation. Therefore, proper CoQ10 stabilization through final formulations regardless of the used CoQ10 form is needed.

Intravenous Administration of Coenzyme Q10 in Acute Period of Cerebral Ischemia Decreases Mortality by Reducing Brain Necrosis and Limiting Its Increase within 4 Days in Rat Stroke Model

Oxidative stress plays a key role in the pathogenesis of ischemic stroke. Coenzyme Q10 has a multi-targeting effect and may protect the brain against ischemic damage. The aim of our study was to evaluate the neuroprotective potential of ubiquinol by its intravenous administration. The study was performed on rats; a stroke was modeled by occlusion of the middle cerebral artery. On days 1 and 4 after ischemia, the neurological deficit and volume of the brain lesion were determined by MRI and TTC staining. Intravenous administration of coenzyme Q10 led to a decrease in rat mortality rate, improvement in neurological status, and decrease in the brain necrosis area in acute and delayed period after cerebral ischemia. A single intravenous administration of ubiquinol led to a limitation of the size of the brain damage for at least four days after ischemia. Thus, intravenous administration of coenzyme Q10 has a persistent neuroprotective potential. This finding suggests a possible therapeutic role of ubiquinol in acute ischemic conditions.

Succinate Dehydrogenase and Ribonucleic Acid Networks in Cancer and Other Diseases

Simple Summary

Although the dysfunction of the succinate dehydrogenase complex in mitochondria leads to cancer and other diseases due to aberrant metabolic reactions and signaling pathways, it is not well known how the succinate dehydrogenase complex is regulated. Our review highlights that non-coding ribonucleic acids (RNAs), RNA editing enzymes, and RNA modifying enzymes regulate expressions and functions of the succinate dehydrogenase complex. This research will provide new strategies for treating succinate dehydrogenase-relevant diseases in a clinic.

Abstract

Succinate dehydrogenase (SDH) complex connects both the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC) in the mitochondria. However, SDH mutation or dysfunction-induced succinate accumulation results in multiple cancers and non-cancer diseases. The mechanistic studies show that succinate activates hypoxia response and other signal pathways via binding to 2-oxoglutarate-dependent oxygenases and succinate receptors. Recently, the increasing knowledge of ribonucleic acid (RNA) networks, including non-coding RNAs, RNA editors, and RNA modifiers has expanded our understanding of the interplay between SDH and RNA networks in cancer and other diseases. Here, we summarize recent discoveries in the RNA networks and their connections to SDH. Additionally, we discuss current therapeutics targeting SDH in both pre-clinical and clinical trials. Thus, we propose a new model of SDH–RNA network interaction and bring promising RNA therapeutics against SDH-relevant cancer and other diseases.

Nanoparticles of Antroquinonol-Rich Extract from Solid-State-Cultured Antrodia cinnamomea Improve Reproductive Function in Diabetic Male Rats

Purpose

To characterize the nanoparticle of antroquinonol from A. cinnamomea and its ameliorative effects on the reproductive dysfunction in the diabetic male rat.

Material and Methods

The chitosan-silicate nanoparticle was used as the carrier for the delivery of antroquinonol from solid-state-cultured A. cinnamomea extract (AC). The rats were fed with a high-fat diet and intraperitoneally injected with streptozotocin to induce diabetes. The rats were daily oral gavage by water [Diabetes (DM) and Control groups], three different doses of chitosan-silicate nanoparticle of antroquinonol from solid-state-cultured A. cinnamomea (nano-SAC, NAC): (DM+NAC1x, 4 mg/kg of body weight; DM+NAC2x, 8 mg/kg; and DM+NAC5x, 20 mg/kg), solid-state-cultured AC (DM+AC5x, 20 mg/kg), or metformin (DM+Met, 200 mg/kg) for 7 weeks.

Results

The nano-SAC size was 37.68±5.91 nm, the zeta potential was 4.13±0.49 mV, encapsulation efficiency was 79.29±0.77%, and loading capacity was 32.45±0.02%. The nano-SAC can improve diabetes-induced reproductive dysfunction by regulating glucose, insulin, and oxidative enzyme and by increasing the level of testosterone, follicle-stimulating hormone, luteinizing hormone, and sperm count as well as sperm mobility. In testicular histopathology, the seminiferous tubules of A. cinnamomea-supplemented diabetic rats showed similar morphology with the control group.

Conclusion

The nanoparticle of antroquinonol from Antrodia cinnamomea can be used as an effective strategy to improve diabetes-induced testicular dysfunction.

Intrastriatal administration of coenzyme Q10 enhances neuroprotection in a Parkinson's disease rat model

Parkinson's disease is a neurodegenerative disorder, and no treatment has been yet established to prevent disease progression. Coenzyme Q10, an antioxidant, has been considered a promising neuroprotective agent; however, conventional oral administration provides limited efficacy due to its very low bioavailability. In this study, we hypothesised that continuous, intrastriatal administration of a low dose of Coenzyme Q10 could effectively prevent dopaminergic neuron degeneration. To this end, a Parkinson's disease rat model induced by 6-hydroxydopamine was established, and the treatment was applied a week before the full establishment of this disease model. Behavioural tests showed a dramatically decreased number of asymmetric rotations in the intrastriatal Coenzyme Q10 group compared with the no treatment group. Rats with intrastriatal Coenzyme Q10 exposure also exhibited a larger number of dopaminergic neurons, higher expression of neurogenetic and angiogenetic factors, and less inflammation, and the effects were more prominent than those of orally administered Coenzyme Q10, although the dose of intrastriatal Coenzyme Q10 was 17,000-times lower than that of orally-administered Coenzyme Q10. Therefore, continuous, intrastriatal delivery of Coenzyme Q10, especially when combined with implantable devices for convection-enhanced delivery or deep brain stimulation, can be an effective strategy to prevent neurodegeneration in Parkinson's disease.

Quantification of reduced and oxidized coenzyme Q10 in supplements and medicines by HPLC-UV

Coenzyme Q10 (CoQ10) supplements are widely used because of their antioxidant and anti-inflammatory effects, especially in the management of cardiovascular diseases. The latest pharmaceutical approach to increase CoQ10 bioavailability and efficiency is the formulation of its reduced form. Regardless of the growing number and usage of CoQ10 preparations, their analytics and quality control is inadequate, neglecting interconversion between the two CoQ10 forms. Therefore, this study proposes a HPLC-UV method for the simultaneous quantification of both reduced and oxidized coenzyme Q10, as well as total CoQ10, as a sum of its individual forms. The suitability of the developed method was confirmed by two additional approaches for total CoQ10 determination - its total reduction and oxidation, differing from the proposed procedure only in the final stage of sample preparation. The results for total CoQ10 content were consistent between the three procedures and also with the official USP method for total CoQ10 determination. The proposed method was applied to 13 dietary supplements and medicines in the form of soft- and hard-shell capsules, revealing the co-existence of both CoQ10 forms in 85% of the tested preparations. CoQ10 forms that were undeclared accounted for up to 75% of the CoQ10 content, which is overlooked by current official methods that evaluate only the total CoQ10 content. This validated HPLC-UV method for the unequivocal quantification of reduced and oxidized CoQ10 is therefore appropriate for the routine analysis of CoQ10 preparations in quality control laboratories, as well as for stability studies, and is suggested to be adopted as an official method.

[Neuroprotective mechanisms of the ubiquinol action in experimental focal ischemia]

Ischemic stroke is one of the most socially important diseases characterized by impaired cerebral circulation with focal damage of the brain tissue and decreased functionality. Despite the successes of modern pharmacology, possibilities of pharmacotherapy for stroke remain limited, and the research for new drugs with neuroprotective effects that can prevent brain cell death is still relevant. In this study we have investigated the neuroprotective activity of ubiquinol as a part of an innovative form on a rat model of irreversible 24 h-cerebral ischemia with evaluation of the mechanisms of its neuroprotective effect. Ubiquinol (30 mg/kg), administered intravenously in the acute period of irreversible 24 h focal cerebral ischemia, had a direct neuroprotective effect, characterized by a decrease in the volume of brain tissue necrosis. The protective effect of ubiquinol is due to its ability to inhibit the development of oxidative stress by the direct anti-radical action, preventing the increase in the lipid hydroperoxide content in the brain tissue adjacent to the focus of necrosis, lowering the lipid oxidation rate in plasma against under conditions of increased total antioxidant activity in the brain and blood of experimental animals. In vitro experiments have shown the ability of ubiquinol to prevent cell death in primary culture of cerebral neurons of rat brain under 4 h oxygen/glucose deprivation followed by 20 h reoxygenation.

Bioavailability of Coenzyme Q10: An Overview of the Absorption Process and Subsequent Metabolism

A lack of understanding of the processes determining the absorption and subsequent metabolism of coenzyme Q₁₀ (CoQ₁₀) has resulted in some manufacturers’ making incorrect claims regarding the bioavailability of their CoQ₁₀ supplements, with potential consequences for the use of such products in clinical trials. The purpose of the present review article is, therefore, to describe the various stages of exogenous CoQ₁₀ metabolism, from its first ingestion, stomach transit, absorption from the small intestine into the lymphatic system, transport in blood, and access into cells. In particular, the importance of CoQ₁₀ crystal dispersion in the initial formulation is emphasised, the absence of which reduces bioavailability by 75%. In addition, evidence comparing the relative bioavailability and efficacy of ubiquinone and ubiquinol forms of CoQ₁₀ has been reviewed.

Coenzyme Q10: Clinical Applications in Cardiovascular Diseases

Coenzyme Q₁₀ (CoQ₁₀) is a ubiquitous factor present in cell membranes and mitochondria, both in its reduced (ubiquinol) and oxidized (ubiquinone) forms. Its levels are high in organs with high metabolism such as the heart, kidneys, and liver because it acts as an energy transfer molecule but could be reduced by aging, genetic factors, drugs (e.g., statins), cardiovascular (CV) diseases, degenerative muscle disorders, and neurodegenerative diseases. As CoQ₁₀ is endowed with significant antioxidant and anti-inflammatory features, useful to prevent free radical-induced damage and inflammatory signaling pathway activation, its depletion results in exacerbation of inflammatory processes. Therefore, exogenous CoQ₁₀ supplementation might be useful as an adjuvant in the treatment of cardiovascular diseases such as heart failure, atrial fibrillation, and myocardial infarction and in associated risk factors such as hypertension, insulin resistance, dyslipidemias, and obesity. This review aims to summarize the current evidences on the use of CoQ₁₀ supplementation as a therapeutic approach in cardiovascular diseases through the analysis of its clinical impact on patients' health and quality of life. A substantial reduction of inflammatory and oxidative stress markers has been observed in several randomized clinical trials (RCTs) focused on several of the abovementioned diseases, even if more RCTs, involving a larger number of patients, will be necessary to strengthen these interesting findings.

Comparative Bioavailability of Different Coenzyme Q10 Formulations in Healthy Elderly Individuals

Coenzyme Q10 (CoQ10) plays a central role in mitochondrial oxidative phosphorylation. Several studies have shown the beneficial effects of dietary CoQ10 supplementation, particularly in relation to cardiovascular health. CoQ10 biosynthesis decreases in the elderly, and consequently, the beneficial effects of dietary supplementation in this population are of greater significance. However, most pharmacokinetic studies have been conducted on younger populations. The aim of this study was to investigate the single-dose bioavailability of different formulations of CoQ10 in a healthy geriatric population. A randomized, three-period, crossover bioavailability study was conducted on 21 healthy older adults (aged 65–74). The treatment was a single dose with a one-week washout period. Three different formulations containing the equivalent of 100 mg of CoQ10 were used: Q10Vital^® water-soluble CoQ10 syrup (the investigational product—IP); ubiquinol capsules (the comparative product—CP); and ubiquinone capsules (the standard product—SP). Ubiquinone/ubiquinol was followed in the plasma for 48 h. An analysis of the ratio of the area under the baseline-corrected concentration curve (ΔAUC₄₈) for total CoQ10 and a comparison to SP yielded the following: The bioavailability of CoQ10 in the IP was 2.4-fold higher (95% CI: 1.3–4.5; p = 0.002), while the bioavailability of ubiquinol (CP) was not significantly increased (1.7-fold; 95% CI: 0.9–3.1, p = 0.129). No differences in the redox status of the absorbed coenzyme Q10 were observed between formulations, showing that CoQ10 appeared in the blood mostly as ubiquinol, even if consumed as ubiquinone.

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.

Hormetic and Mitochondria-Related Mechanisms of Antioxidant Action of Phytochemicals

Antioxidant action to afford a health benefit or increased well-being may not be directly exerted by quick reduction-oxidation (REDOX) reactions between the antioxidant and the pro-oxidant molecules in a living being. Furthermore, not all flavonoids or polyphenols derived from plants are beneficial. This paper aims at discussing the variety of mechanisms underlying the so-called "antioxidant" action. Apart from antioxidant direct mechanisms, indirect ones consisting of fueling and boosting innate detox routes should be considered. One of them, hormesis, involves upregulating enzymes that are needed in innate detox pathways and/or regulating the transcription of the so-called vitagenes. Moreover, there is evidence that some plant-derived compounds may have a direct role in events taking place in mitochondria, which is an organelle prone to oxidative stress if electron transport is faulty. Insights into the potential of molecules able to enter into the electron transport chain would require the determination of their reduction potential. Additionally, it is advisable to know both the oxidized and the reduced structures for each antioxidant candidate. These mechanisms and their related technical developments should help nutraceutical industry to select candidates that are efficacious in physiological conditions to prevent diseases or increase human health.

Electrochemical Methodology for Evaluating Skin Oxidative Stress Status (SOSS)

For the purpose of human disease prevention, several methods have been developed, and are still developing, to assess the oxidative stress status (OSS) of individuals. In the present paper, we describe an approach based on electrochemical detection able to evaluate skin oxidative stress status (SOSS) as a PAOT (Pouvoir AntiOxydant Total)-Skin Score^®. Normal reference values for the PAOT-Skin Score^® were: 0-62.94 (n = 263). Intra- and inter-assay coefficients of variation were, respectively, 12.47 ± 4.29% and 7.0 ± 2.5%. Our technology showed increased skin antioxidant activity following topical application of reduced coeznyme Q₁₀ cream or vitamin C intake as orange juice or supplements. Moreover, we found significant correlations between some blood oxidative stress biomarkers and the PAOT-Skin Score ^® (-tocopherol/α-tocopherol ratio (r = 0.43, p = 0.020); copper (r = -0.42, p = 0.022); copper/zinc ratio (r = -0.49, p = 0.006), and lipid peroxides (r = -0.43, p = 0.002)). In addition to being non-invasive, the present electrochemical methodology is also not expensive, fast, and easy to use.