Coenzyme q10 prevents apoptosis by inhibiting mitochondrial depolarization independently of its free radical scavenging property

Matrine induces cardiotoxicity by promoting ferroptosis through the Nrf2 antioxidant system in H9c2 cells

Matrine (MT) has shown promising efficacy in various cancers and chronic hepatitis; however, its clinical application is limited because of its side effects. Our previous studies have indicated that MT can induce severe hepatotoxicity and nephrotoxicity. The current study aimed to investigate its cardiotoxicity and potential underlying mechanisms in H9c2 cells. Our results showed that MT induced H9c2 cell death and disrupted the cellular membrane integrity. Moreover, MT decreased glutathione (GSH) and cysteine (Cys) levels, and increased Fe2+, lipid peroxidation, reactive oxygen species (ROS), and MDA levels, ultimately leading to ferroptosis. Interestingly, these phenomena were alleviated by the ferroptosis inhibitor Fer-1, whereas MT-induced ferroptosis was exacerbated by the ferroptosis agonist RSL3. In addition, MT significantly reduced FTH, Nrf2, xCT, GPX4, and FSP1 protein levels and inhibited the transcriptional activity of Nrf2 while increasing TFR1 protein levels. Supplementation with Nrf2 agonist (Dimethyl fumarate, DMF) or selenium (Sodium selenite, SS) and CoQ10 alleviated MT-induced cytotoxic effects in H9c2 cells. These results suggest that ferroptosis, which is mediated by an imbalance in the Nrf2 antioxidant system, is involved in MT-induced cardiac toxicity.

Involvement of Nrf2-PPAR-γ signaling in Coenzyme Q10 protecting effect against methotrexate-induced testicular oxidative damage

Studies have identified Coenzyme Q10 (CoQ10) as a promising agent in improving idiopathic male infertility; however, its role in chemically or environmentally induced testicular dysfunction is not well-established. We investigated the potential of CoQ10 to attenuate methotrexate (MTX)-induced testicular damage and to identify molecular targets of CoQ10 effects. Wistar rats received a single intraperitoneal dose of 20 mg/kg MTX on the fifth day of the 10-day experimental protocol. 100 mg/kg CoQ10 was given orally daily for ten days, alone or combined with MTX. The testes of MTX-treated animals showed thickened tunica albuginea, distortion of seminiferous tubules with a marked reduction of germinal lining, a few primary spermatocytes with no spermatozoa, apoptotic cells, congested sub-capsular and interstitial blood vessels, and interstitial edema. Reduction of reproductive hormones and increased oxidative, inflammatory, and apoptotic biomarkers levels were also seen in the MTX-treated rats. CoQ10 + MTX-treated rats were protected against MTX-induced testicular histological changes and showed improvement in testosterone, luteinizing-, and follicle-stimulating hormone serum levels compared to the MTX group. The testes of the CoQ10 + MTX-treated rats showed reduced malondialdehyde, myloperoxidase, tumor necrosis factor -α, interleukin-6 and -1β and Bax: Bcl2 ratio and enhanced glutathione, and catalase compared to MTX alone. CoQ10 enhanced MTX-induced downregulation of Nrf2 and PPAR-γ signaling and modulated its downstream targets, the inducible nitric oxide synthase, NF-κB, Bax, and Bcl2. In conclusion, CoQ10 targeted the Nrf2-PPAR-γ signaling loop and its downstream pathways, mitigating MTX-induced oxidative stress-related damages and alleviating the testicular dysfunction MTX caused. Our data suggest Nrf2-PPAR-γ signaling as a potential therapeutic target in testicular toxicity, where oxidative stress, inflammation, and apoptosis trigger damage.

Di (2-ethylhexyl) phthalate alters neurobehavioral responses and oxidative status, architecture, and GFAP and BDNF signaling in juvenile rat's brain: Protective role of Coenzyme10

Di-(2-ethylhexyl) phthalate (DEHP), a phthalate plasticizer, is widely spread in the environment, presenting hazards to human health and food safety. Hence, this study examined the probable preventive role of coenzyme10 (CQ10) (10 mg/kg.b.wt) against DEHP (500 mg/kg.wt) - induced neurotoxic and neurobehavioral impacts in juvenile (34 ± 1.01g and 3 weeks old) male Sprague Dawley rats in 35-days oral dosing trial. The results indicated that CQ10 significantly protected against DEHP-induced memory impairment, anxiety, depression, spatial learning disorders, and repetitive/stereotypic-like behavior. Besides, the DEHP-induced depletion in dopamine and gamma amino butyric acid levels was significantly restored by CQ10. Moreover, CQ10 significantly protected against the exhaustion of CAT, GPx, SOD, GSH, and GSH/GSSG ratio, as well as the increase in malondialdehyde, Caspas-3, interleukin-6, and tumor necrosis factor-alpha brain content accompanying with DEHP exposure. Furthermore, CQ10 significantly protected the brain from the DEHP-induced neurodegenerative alterations. Also, the increased immunoexpression of brain-derived neurotrophic factor, not glial fibrillary acidic protein, in the cerebral, hippocampal, and cerebellar brain tissues due to DEHP exposure was alleviated with CQ10. This study's findings provide conclusive evidence that CQ10 has the potential to be used as an efficient natural protective agent against the neurobehavioral and neurotoxic consequences of DEHP.

Trolox aids coenzyme Q10 in neuroprotection against NMDA induced damage via upregulation of VEGF in rat model of glutamate excitotoxicity

Glutamate induced damage to retinal ganglion cells (RGCs) requires tight physiological regulation of the N-methyl-D-aspartate (NMDA) receptors. Previously, studies have demonstrated the neuroprotective abilities of antioxidants like coenzyme Q10 (CoQ10) and vitamin E analogs like α-tocopherol against neuropathies resulting from NMDA insult, but have failed to shed light on the effect of CoQ10 and trolox, a hydrophilic analog of vitamin E, on glaucomatous neurodegeneration. In the current study, we wanted to investigate whether the combined effect of trolox with CoQ10 could alleviate NMDA-induced death of retinal cells while also trying to elucidate the underlying mechanism in relation to the yet unexplained role of vascular endothelial growth factor (VEGF) in NMDA-mediated excitotoxicity. After successful NMDA-induced degeneration, we followed it up with the treatment of combination of Trolox and CoQ10. The structural damage by NMDA was repaired significantly and retina retained structural integrity comparable to levels of control in the treatment group of Trolox and CoQ10. Detection of ROS generation after NMDA insult showed that together, Trolox and CoQ10 could significantly bring down the high levels of free radicals while also rescuing mitochondrial membrane potential (MMP). A significant increase in NMDA receptor Grin2A by CoQ10 alone as well as by CoQ10 and trolox was accompanied by a lowered Grin2B receptor expression, suggesting neuroprotective action of Trolox and CoQ10. Subsequently, lowered VEGFR1 and VEGFR2 receptor expression by NMDA treatment also recovered when subjected to combined treatment of Trolox and CoQ10. Western blot analyses also indicated the same whereby Trolox and CoQ10 could increase the diminished levels of phosphorylated VEGFR2. Immunofluorescence studies also indicated a positive correlation between recovered VEGFR2 and NMDAR2A levels and diminished levels of NMDAR2D, confirming the results obtained by RT-PCR analysis. This is the first report in our knowledge that demonstrates the efficacy of trolox in combination with CoQ10 highlighting the importance of maintaining VEGF levels that are lowered in ocular diseases due to NMDA-related toxicities.

Coenzyme Q10 attenuates neurodegeneration in the cerebellum induced by chronic exposure to tramadol

BACKGROUND

Chronic use of tramadol can cause neurotoxic effects and subsequently cause neurodegeneration in the cerebellum. The main damage mechanisms identified are oxidative stress and inflammation. Currently, we investigated the effects of coenzyme Q10 (CoQ10) in attenuates of neurodegeneration in the cerebellum induced by chronic exposure to tramadol.

MATERIAL AND METHODS

Seventy-two male mature albino rats were allocated into four equal groups, including; non-treated group, CoQ10 group (which received CoQ10 at 200 mg/kg/day orally for three weeks), tramadol group (which received tramadol hydrochloride at 50 mg/kg/day orally for three weeks), and tramadol+CoQ10 group (which received tramadol and CoQ10 at the same doses as the previous groups). Tissue samples were obtained for stereological, immunohistochemical, biochemical, and molecular evaluations. Also, functional tests were performed to evaluate behavioral properties.

RESULTS

We found a significant increase in stereological parameters, antioxidant factors (catalase, glutathione, and superoxide dismutase), and behavioral function scores in the tramadol+CoQ10 group compared to the tramadol group (p < 0.05). In addition, malondialdehyde levels, the density of apoptotic cells, as well as the expression of pro-inflammatory (tumor necrosis factor-alpha, interleukin 1 beta, and interleukin 6) and autophagy (lysosome-associated membrane protein 2, autophagy-related 5, beclin 1, and autophagy-related 12) genes were considerably reduced in the tramadol+CoQ10 group compared to the tramadol group (p < 0.05).

CONCLUSION

We conclude that the administration of CoQ10 has neuroprotective effects in the cerebellum of rats that have chronic exposure to tramadol.

Clinical and biochemical assessment of the effect of topical use of coenzyme Q10 versus topical corticosteroid in management of symptomatic oral lichen planus: randomized controlled clinical trial

BACKGROUND

Oral lichen planus (OLP) is a chronic mucocutaneous immunologically mediated condition that has a great adverse effect on oral functions. Corticosteroids are still the first drugs of choice used in the treatment of OLP; however, they have extensive medical side effects. The present study was carried out to assess the clinical therapeutic effect of the topical use of coenzyme Q10 (coQ10 or ubiquinol) versus topical corticosteroids in the management of symptomatic OLP and to determine whether the effect, if any, was due to the powerful antioxidant activity of coQ10.

SUBJECTS AND METHODS

We performed a randomized, double blinded controlled trial at the Faculty of Dentistry, Cairo University, Egypt. The study was conducted on 34 patients suffering from symptomatic OLP. Patients were randomly divided into two groups: intervention group (I),who received topical CoQ10 in the form of mucoadhesive tablets (40% CoQ10) 3 times daily for one month and control group (II),who received topical corticosteroid (kenacort in Orabase: triamcinolone acetonide 0.1% 5-g adhesive paste - dermapharm), 4 times daily for one month. Patients were evaluated at one-week intervals using the clinical parameters (score) of pain (VAS) and lesion size. Additionally, salivary levels of malondialdehyde (MDA) were detected in both groups before and after treatment using ELISA. All recorded data were analysed using independent t test, ANOVA followed by Bonferroni post hoc test for lesion size and salivary level of MDA data and Mann-Whitney U test and Friedman test for VAS data.

RESULTS

Both groups showed a significant reduction in pain and the size of the lesions (p ≤ 0.05) with no statistically significant difference between them (p > 0.05), and this clinical improvement was associated with a reduction in the salivary levels of MDA in both groups.

CONCLUSIONS

The topical use of CoQ10 mucoadhesive tablets was as effective as the topical use of triamcinolone acetonide, and its clinical effect was associated with a reduction in the salivary level of MDA.

TRIAL REGISTRATION

The study protocol was registered at www.

CLINICALTRIAL

gov (NCT04091698) and registration date: 17/9/2019.

Oxidative Stress in Obstructive Sleep Apnea Syndrome: Putative Pathways to Hearing System Impairment

INTRODUCTION

OSAS is a disease that affects 2% of men and 4% of women of middle age. It is a major health public problem because untreated OSAS could lead to cardiovascular, metabolic, and cerebrovascular complications. The more accepted theory relates to oxidative stress due to intermittent hypoxia, which leads, after an intense inflammatory response through multiple pathways, to endothelial damage. The objective of this study is to demonstrate a correlation between OSAS and hearing loss, the effect of the CPAP on hearing function, and if oxidative stress is also involved in the damaging of the hearing system.

METHODS

A review of the literature has been executed. Eight articles have been found, where seven were about the correlation between OSAS and the hearing system, and only one was about the CPAP effects. It is noted that two of the eight articles explored the theory of oxidative stress due to intermittent hypoxia.

RESULTS

All studies showed a significant correlation between OSAS and hearing function (p < 0.05).

CONCLUSIONS

Untreated OSAS affects the hearing system at multiple levels. Oxidative stress due to intermittent hypoxia is the main pathogenetic mechanism of damage. CPAP has no effects (positive or negative) on hearing function. More studies are needed, with the evaluation of extended high frequencies, the execution of vocal audiometry in noisy environments, and the evaluation of potential biomarkers due to oxidative stress.

Neuroprotective effects of coenzyme Q10 on neurological diseases: a review article

Neurological disorders affect the nervous system. Biochemical, structural, or electrical abnormalities in the spinal cord, brain, or other nerves lead to different symptoms, including muscle weakness, paralysis, poor coordination, seizures, loss of sensation, and pain. There are many recognized neurological diseases, like epilepsy, Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), stroke, autosomal recessive cerebellar ataxia 2 (ARCA2), Leber's hereditary optic neuropathy (LHON), and spinocerebellar ataxia autosomal recessive 9 (SCAR9). Different agents, such as coenzyme Q10 (CoQ10), exert neuroprotective effects against neuronal damage. Online databases, such as Scopus, Google Scholar, Web of Science, and PubMed/MEDLINE were systematically searched until December 2020 using keywords, including review, neurological disorders, and CoQ10. CoQ10 is endogenously produced in the body and also can be found in supplements or foods. CoQ10 has antioxidant and anti-inflammatory effects and plays a role in energy production and mitochondria stabilization, which are mechanisms, by which CoQ10 exerts its neuroprotective effects. Thus, in this review, we discussed the association between CoQ10 and neurological diseases, including AD, depression, MS, epilepsy, PD, LHON, ARCA2, SCAR9, and stroke. In addition, new therapeutic targets were introduced for the next drug discoveries.

Effectiveness of coenzyme Q10 on learning and memory and synaptic plasticity impairment in an aged Aβ-induced rat model of Alzheimer's disease: a behavioral, biochemical, and electrophysiological study

RATIONALE

Aging is the major risk factor for Alzheimer's disease (AD), and cognitive and memory impairments are common among the elderly. Interestingly, coenzyme Q10 (Q10) levels decline in the brain of aging animals. Q10 is a substantial antioxidant substance, which has an important role in the mitochondria.

OBJECTIVE

We assessed the possible effects of Q10 on learning and memory and synaptic plasticity in aged β-amyloid (Aβ)-induced AD rats.

METHODS

In this study, 40 Wistar rats (24-36 months old; 360-450 g) were randomly assigned to four groups (n = 10 rats/group)-group I: control, group II: Aβ, group III: Q10; 50 mg/kg, and group IV: Q10+Aβ. Q10 was administered orally by gavage daily for 4 weeks before the Aβ injection. The cognitive function and learning and memory of the rats were measured by the novel object recognition (NOR), Morris water maze (MWM), and passive avoidance learning (PAL) tests. Finally, malondialdehyde (MDA), total antioxidant capacity (TAC), total thiol group (TTG), and total oxidant status (TOS) were measured.

RESULTS

Q10 improved the Aβ-related decrease in the discrimination index in the NOR test, spatial learning and memory in the MWM test, passive avoidance learning and memory in the PAL test, and long-term potentiation (LTP) impairment in the hippocampal PP-DG pathway in aged rats. In addition, Aβ injection significantly increased serum MDA and TOS levels. Q10, however, significantly reversed these parameters and also increased TAC and TTG levels in the Aβ+Q10 group.

CONCLUSIONS

Our experimental findings suggest that Q10 supplementation can suppress the progression of neurodegeneration that otherwise impairs learning and memory and reduces synaptic plasticity in our experimental animals. Therefore, similar supplemental Q10 treatment given to humans with AD could possibly provide them a better quality of life.

The effect of dietary coenzyme Q10 supplementation on egg quality and liver histopathology of layer quails under cadmium challenge

The demand for quail eggs has been increased over the last decade due to its beneficial nutritional quality characteristics; however, different nutritional and environmental stressors adversely impact the quality of the produced eggs. This study was conducted to investigate whether dietary supplementation of coenzyme Q10 (CoQ10) could mitigate the negative impact of cadmium (Cd) administration on egg quality and liver histopathology. A total of 162 six-week-old laying Japanese quail (Coturnix japonica) were randomly allotted into three experimental groups. Treatments were as follows: (1) negative control (NC): feeding basal diet; (2) positive control (PC): feeding basal diet and Cd administration; and (3) CdQ10: feeding basal diet supplemented with CoQ10 (900 mg/kg diet) and Cd administration. Cadmium (10 mg/kg BW) was subcutaneously administrated at 10 and 11 weeks of age (woa). Feed conversion ratio (FCR), egg production, egg mass, mortality rate, Cd residue in egg, liver histopathology, and some internal and external egg quality indices were evaluated. Administration of Cd increased FCR in the PC group, but supplementation of CoQ10 partially ameliorated the impact of Cd on FCR (p < 0.05). Cadmium administration decreased both egg production and egg mass; however, CoQ10 supplementation partially mitigated these adverse effects of Cd injection in the CdQ10 compared to the PC group (p < 0.05). Cadmium decreased eggshell thickness and Haugh unit in PC quail compared to both NC and CdQ10 quail (p < 0.05). Moreover, egg yolk colour intensity was enhanced by CoQ10, where a* and b* indices were higher in CdQ10 compared to PC (p < 0.05). In conclusion, the current results demonstrate the beneficial effects of dietary CoQ10 supplementation on liver histopathology and some egg quality indices of Cd-challenged quail.

Antioxidant supplements relieve insulin resistance but do not improve lipid metabolism in women with polycystic ovary syndrome: a meta-analysis of randomized clinical trials

Objective: The effect of antioxidant supplements on glucose metabolism and lipid profiles in polycystic ovary syndrome (PCOS) remains controversial. This systematic review and meta-analysis aimed to evaluate whether antioxidant supplements improve glucose metabolism and lipid profiles in women with PCOS to provide optimal nutritional supplement advice in clinical practice. Methods: The search was conducted across multiple medical databases from inception to January 1, 2022 and performed following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A random effects model was used to calculate the overall effects. Results: Eighteen trials (1113 participants) were included. Antioxidant supplements significantly improved insulin resistance (95% CI, -0.62, -0.30; p < 0.00001; I² =48%), fasting insulin (95% CI, -0.80, -0.44; p < 0.00001; I² = 48%), and fasting plasma glucose (95% CI, -0.54, -0.21; p < 0.00001; I² = 38%) in patients with PCOS. However, antioxidant supplements were found to not improve most indices of lipid profiles in PCOS except triglyceride. Conclusions: Antioxidant supplements are an effective intervention for relieving insulin resistance but do not significantly improve lipid metabolism in women with PCOS.

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.

Plasma CoQ10 Status in Patients with Propionic Acidaemia and Possible Benefit of Treatment with Ubiquinol

Propionic acidaemia (PA) is an innate error of metabolism involving a deficiency in the enzyme propionyl-CoA carboxylase. Better control of acute decompensation episodes together with better treatment and monitoring have improved the prognosis of patients with this problem. However, long-term complications can arise in those in whom good metabolic control is achieved, the result of mitochondrial dysfunction caused by deficient anaplerosis, increased oxidative stress, and reduced antioxidative capacity. Coenzyme Q10 (CoQ10) is a nutritional supplement that has a notable antioxidative effect and has been shown to improve mitochondrial function. The present prospective, interventional study examines the plasma concentration of CoQ10 in patients with PA, their tolerance of such supplementation with ubiquinol, and its benefits. Seven patients with PA (aged 2.5 to 20 years, 4 males) received supplements of CoQ10 in the form of ubiquinol (10 mg/kg/day for 6 months). A total of 6/7 patients showed reduced plasma CoQ10 concentrations that normalized after supplementation with ubiquinol (p-value < 0.001), which was well tolerated. Urinary citrate levels markedly increased during the study (p-value: 0.001), together with elevation of citrate/methlycitrate ratio (p-value: 0.03). No other significant changes were seen in plasma or urine biomarkers of PA. PA patients showed a deficiency of plasma CoQ10, which supplementation with ubiquinol corrected. The urinary excretion of Krebs cycle intermediate citrate and the citrate/methylcitrate ratio significantly increased compared to the baseline, suggesting improvement in anaplerosis. This treatment was well tolerated and should be further investigated as a means of preventing the chronic complications associated with likely multifactorial mitochondrial dysfunction in PA.

Role of Oxidative Stress and Antioxidants in Acquired Inner Ear Disorders

Oxygen metabolism in the mitochondria is essential for biological activity, and reactive oxygen species (ROS) are produced simultaneously in the cell. Once an imbalance between ROS production and degradation (oxidative stress) occurs, cells are damaged. Sensory organs, especially those for hearing, are constantly exposed during daily life. Therefore, almost all mammalian species are liable to hearing loss depending on their environment. In the auditory pathway, hair cells, spiral ganglion cells, and the stria vascularis, where mitochondria are abundant, are the main targets of ROS. Excessive generation of ROS in auditory sensory organs is widely known to cause sensorineural hearing loss, and mitochondria-targeted antioxidants are candidates for treatment. This review focuses on the relationship between acquired hearing loss and antioxidant use to provide an overview of novel antioxidants, namely medicines, supplemental nutrients, and natural foods, based on clinical, animal, and cultured-cell studies.

Coenzyme Q10 in the eye isomerizes by sunlight irradiation

Photoisomerization of lipids has been well studied. As for the eyes, photoisomerization from 11-cis isomer to all-trans-retinal is well-known as the first step of the visual transduction in the photoreceptors. In addition to that, there would be other ocular lipids that undergo photoisomerization, which may be involved in ocular health and function. To explore any photoisomerizable lipids in the eyes, the nonirradiated and sunlight-irradiated eyeball extracts were subjected to liquid chromatography-mass spectrometry analysis, followed by the identification of the decreased lipid species in the irradiated extracts. Surprisingly, more than nine hundred lipid species were decreased in the irradiated extracts. Three lipid species, coenzyme Q10 (CoQ10), triglyceride(58:4), and coenzyme Q9, were decreased both significantly (p < 0.05) and by more than two-fold, where CoQ10 showed the most significant decrease. Later, photoisomerization was identified as the prominent cause underlying the decrease of CoQ10. Interestingly, CoQ10 in the sunlight-irradiated fresh eyeballs was also isomerized. Both the visible light and ultraviolet radiation were capable of producing CoQ10 isomer, while the latter showed rapid action. This study is believed to enhance our understanding of the biochemistry and photodamage of the eye and can potentially contribute to the advancement of opto-lipidomics.

UV Protection in the Cornea: Failure and Rescue

Simple Summary

The sun is a deadly laser, and its damaging rays harm exposed tissues such as our skin and eyes. The skin’s protection and repair mechanisms are well understood and utilized in therapeutic approaches while the eye lacks such complete understanding of its defenses and therefore often lacks therapeutic support in most cases. The aim here was to document the similarities and differences between the two tissues as well as understand where current research stands on ocular, particularly corneal, ultraviolet protection. The objective is to identify what mechanisms may be best suited for future investigation and valuable therapeutic approaches.

Abstract

Ultraviolet (UV) irradiation induces DNA lesions in all directly exposed tissues. In the human body, two tissues are chronically exposed to UV: the skin and the cornea. The most frequent UV-induced DNA lesions are cyclobutane pyrimidine dimers (CPDs) that can lead to apoptosis or induce tumorigenesis. Lacking the protective pigmentation of the skin, the transparent cornea is particularly dependent on nucleotide excision repair (NER) to remove UV-induced DNA lesions. The DNA damage response also triggers intracellular autophagy mechanisms to remove damaged material in the cornea; these mechanisms are poorly understood despite their noted involvement in UV-related diseases. Therapeutic solutions involving xenogenic DNA-repair enzymes such as T4 endonuclease V or photolyases exist and are widely distributed for dermatological use. The corneal field lacks a similar set of tools to address DNA-lesions in photovulnerable patients, such as those with genetic disorders or recently transplanted tissue.

The Roles of Coenzyme Q in Disease: Direct and Indirect Involvement in Cellular Functions

Coenzyme Q (CoQ) is a key component of the respiratory chain of all eukaryotic cells. Its function is closely related to mitochondrial respiration, where it acts as an electron transporter. However, the cellular functions of coenzyme Q are multiple: it is present in all cell membranes, limiting the toxic effect of free radicals, it is a component of LDL, it is involved in the aging process, and its deficiency is linked to several diseases. Recently, it has been proposed that coenzyme Q contributes to suppressing ferroptosis, a type of iron-dependent programmed cell death characterized by lipid peroxidation. In this review, we report the latest hypotheses and theories analyzing the multiple functions of coenzyme Q. The complete knowledge of the various cellular CoQ functions is essential to provide a rational basis for its possible therapeutic use, not only in diseases characterized by primary CoQ deficiency, but also in large number of diseases in which its secondary deficiency has been found.

A Review of Potential Novel Glaucoma Therapeutic Options Independent of Intraocular Pressure

Glaucoma, a progressive optic neuropathy characterized by retinal ganglion cell degeneration and visual field loss, is the leading cause of irreversible blindness worldwide. Intraocular pressure (IOP) is presently the only modifiable risk factor demonstrated to slow or halt disease progression; however, glaucomatous damage persists in almost 50% of patients despite significant IOP reduction. Many studies have investigated the non-IOP-related risk factors that contribute to glaucoma progression as well as interventions that can prevent or delay glaucomatous neurodegeneration and preserve vision throughout life, independently of IOP. A vast number of experimental studies have reported effective neuroprotection in glaucoma, and clinical studies are ongoing attempting to provide strong evidence of effectiveness of these interventions. In this review, we look into the current understanding of the pathophysiology of glaucoma and explore the recent advances in non-IOP related strategies for neuroprotection and neuroregeneration in glaucoma.

Role of Oxidative Stress in Ocular Diseases Associated with Retinal Ganglion Cells Degeneration

Ocular diseases associated with retinal ganglion cell (RGC) degeneration is the most common neurodegenerative disorder that causes irreversible blindness worldwide. It is characterized by visual field defects and progressive optic nerve atrophy. The underlying pathophysiology and mechanisms of RGC degeneration in several ocular diseases remain largely unknown. RGCs are a population of central nervous system neurons, with their soma located in the retina and long axons that extend through the optic nerve to form distal terminals and connections in the brain. Because of this unique cytoarchitecture and highly compartmentalized energy demand, RGCs are highly mitochondrial-dependent for adenosine triphosphate (ATP) production. Recently, oxidative stress and mitochondrial dysfunction have been found to be the principal mechanisms in RGC degeneration as well as in other neurodegenerative disorders. Here, we review the role of oxidative stress in several ocular diseases associated with RGC degenerations, including glaucoma, hereditary optic atrophy, inflammatory optic neuritis, ischemic optic neuropathy, traumatic optic neuropathy, and drug toxicity. We also review experimental approaches using cell and animal models for research on the underlying mechanisms of RGC degeneration. Lastly, we discuss the application of antioxidants as a potential future therapy for the ocular diseases associated with RGC degenerations.

Effect of space flight on the behavior of human retinal pigment epithelial ARPE-19 cells and evaluation of coenzyme Q10 treatment

Astronauts on board the International Space Station (ISS) are exposed to the damaging effects of microgravity and cosmic radiation. One of the most critical and sensitive districts of an organism is the eye, particularly the retina, and > 50% of astronauts develop a complex of alterations designated as spaceflight-associated neuro-ocular syndrome. However, the pathogenesis of this condition is not clearly understood. In the current study, we aimed to explore the cellular and molecular effects induced in the human retinal pigment ARPE-19 cell line by their transfer to and 3-day stay on board the ISS in the context of an experiment funded by the Agenzia Spaziale Italiana. Treatment of cells on board the ISS with the well-known bioenergetic, antioxidant, and antiapoptotic coenzyme Q10 was also evaluated. In the ground control experiment, the cells were exposed to the same conditions as on the ISS, with the exception of microgravity and radiation. The transfer of ARPE-19 retinal cells to the ISS and their living on board for 3 days did not affect cell viability or apoptosis but induced cytoskeleton remodeling consisting of vimentin redistribution from the cellular boundaries to the perinuclear area, underlining the collapse of the network of intermediate vimentin filaments under unloading conditions. The morphological changes endured by ARPE-19 cells grown on board the ISS were associated with changes in the transcriptomic profile related to the cellular response to the space environment and were consistent with cell dysfunction adaptations. In addition, the results obtained from ARPE-19 cells treated with coenzyme Q10 indicated its potential to increase cell resistance to damage.

Mitochondrial Management of Reactive Oxygen Species

Mitochondria in aerobic eukaryotic cells are both the site of energy production and the formation of harmful species, such as radicals and other reactive oxygen species, known as ROS. They contain an efficient antioxidant system, including low-molecular-mass molecules and enzymes that specialize in removing various types of ROS or repairing the oxidative damage of biological molecules. Under normal conditions, ROS production is low, and mitochondria, which are their primary target, are slightly damaged in a similar way to other cellular compartments, since the ROS released by the mitochondria into the cytosol are negligible. As the mitochondrial generation of ROS increases, they can deactivate components of the respiratory chain and enzymes of the Krebs cycle, and mitochondria release a high amount of ROS that damage cellular structures. More recently, the feature of the mitochondrial antioxidant system, which does not specifically deal with intramitochondrial ROS, was discovered. Indeed, the mitochondrial antioxidant system detoxifies exogenous ROS species at the expense of reducing the equivalents generated in mitochondria. Thus, mitochondria are also a sink of ROS. These observations highlight the importance of the mitochondrial antioxidant system, which should be considered in our understanding of ROS-regulated processes. These processes include cell signaling and the progression of metabolic and neurodegenerative disease.

The Protective Effect of Ubiquinone against the Amyloid Peptide in Endothelial Cells Is Isoprenoid Chain Length-Dependent

Vascular brain pathology constitutes a common feature in neurodegenerative diseases that could underlie their development. Indeed, vascular dysfunction acts synergistically with neurodegenerative changes to exacerbate the cognitive impairment found in Alzheimer’s disease. Different injuries such as hypertension, high glucose, atherosclerosis associated with oxidized low-density lipoprotein or inflammation induce NADPH oxidase activation, overproduction of reactive oxygen species, and apoptosis in endothelial cells. Since it has been shown that pretreatment of cultured endothelial cells with the lipophilic antioxidant coenzyme Q10 (CoQ10) displays a protective effect against the deleterious injuries caused by different agents, this study explores the cytoprotective role of different CoQs homologues against Aβ_25–35-induced damage and demonstrates that only pretreatment with CoQ10 protects endothelial brain cells from Aβ_25–35-induced damage. Herein, we show that CoQ10 constitutes the most effective ubiquinone in preventing NADPH oxidase activity and reducing both reactive oxygen species generation and the increase in free cytosolic Ca²⁺ induced by Aβ_25–35, ultimately preventing apoptosis and necrosis. The specific cytoprotective effect of CoQ with a side chain of 10 isoprenoid units could be explained by the fact that CoQ10 is the only ubiquinone that significantly reduces the entry of Aβ_25–35 into the mitochondria.

Animal Models of Coenzyme Q Deficiency: Mechanistic and Translational Learnings

Coenzyme Q (CoQ) is a vital lipophilic molecule that is endogenously synthesized in the mitochondria of each cell. The CoQ biosynthetic pathway is complex and not completely characterized, and it involves at least thirteen catalytic and regulatory proteins. Once it is synthesized, CoQ exerts a wide variety of mitochondrial and extramitochondrial functions thank to its redox capacity and its lipophilicity. Thus, low levels of CoQ cause diseases with heterogeneous clinical symptoms, which are not always understood. The decreased levels of CoQ may be primary caused by defects in the CoQ biosynthetic pathway or secondarily associated with other diseases. In both cases, the pathomechanisms are related to the CoQ functions, although further experimental evidence is required to establish this association. The conventional treatment for CoQ deficiencies is the high doses of oral CoQ₁₀ supplementation, but this therapy is not effective for some specific clinical presentations, especially in those involving the nervous system. To better understand the CoQ biosynthetic pathway, the biological functions linked to CoQ and the pathomechanisms of CoQ deficiencies, and to improve the therapeutic outcomes of this syndrome, a variety of animal models have been generated and characterized in the last decade. In this review, we show all the animal models available, remarking on the most important outcomes that each model has provided. Finally, we also comment some gaps and future research directions related to CoQ metabolism and how the current and novel animal models may help in the development of future research studies.

Targetable Pathways for Alleviating Mitochondrial Dysfunction in Neurodegeneration of Metabolic and Non-Metabolic Diseases

Many neurodegenerative and inherited metabolic diseases frequently compromise nervous system function, and mitochondrial dysfunction and oxidative stress have been implicated as key events leading to neurodegeneration. Mitochondria are essential for neuronal function; however, these organelles are major sources of endogenous reactive oxygen species and are vulnerable targets for oxidative stress-induced damage. The brain is very susceptible to oxidative damage due to its high metabolic demand and low antioxidant defence systems, therefore minimal imbalances in the redox state can result in an oxidative environment that favours tissue damage and activates neuroinflammatory processes. Mitochondrial-associated molecular pathways are often compromised in the pathophysiology of neurodegeneration, including the parkin/PINK1, Nrf2, PGC1α, and PPARγ pathways. Impairments to these signalling pathways consequently effect the removal of dysfunctional mitochondria, which has been suggested as contributing to the development of neurodegeneration. Mitochondrial dysfunction prevention has become an attractive therapeutic target, and there are several molecular pathways that can be pharmacologically targeted to remove damaged mitochondria by inducing mitochondrial biogenesis or mitophagy, as well as increasing the antioxidant capacity of the brain, in order to alleviate mitochondrial dysfunction and prevent the development and progression of neurodegeneration in these disorders. Compounds such as natural polyphenolic compounds, bioactive quinones, and Nrf2 activators have been reported in the literature as novel therapeutic candidates capable of targeting defective mitochondrial pathways in order to improve mitochondrial function and reduce the severity of neurodegeneration in these disorders.

Serum and tissue levels of coenzyme Q10 in pemphigus vulgaris

BACKGROUND

Pemphigus vulgaris (PV) is a debilitating autoimmune blistering disease of the skin and mucous membranes. It occurs due to the action of autoantibodies against various keratinocyte self-antigens. Anti-mitochondrial autoantibodies are detected in patients with PV. Coenzyme Q10 (CoQ10) is a member of the mitochondrial respiratory chain involved in cellular metabolism, including apoptosis. This study aimed to assess the serum and tissue levels of CoQ10 of patients with PV and healthy controls to determine its relevance to the disease pathogenesis.

METHODS

In this case-control study, 20 patients with PV and 20 healthy controls were included. Blood and skin samples were collected for the measurement of CoQ10 levels using ELISA.

RESULTS

CoQ10 was significantly lower in both serum and tissue of patients with PV compared with controls (p = 0.001). Similar results were found when gender subgroups were separately compared. A significant positive correlation was found between serum and tissue CoQ10 levels in controls (p = 0.019, r = 0.521), but not in patients with PV.

CONCLUSION

CoQ10 appears to be one of the parameters affected by the autoimmune response in PV, which may contribute to the tissue damage caused by autoantibodies. The absence of a significant correlation between CoQ10 level and disease severity or duration may be caused by the complex pathophysiological process in PV with multiple autoantibodies against different keratinocyte antigens.

Investigating the Effects of Coenzyme Q10 on Human Corneal Endothelial Cells

Purpose

To investigate the effects of Coenzyme Q10 (CoQ10) treatment on immortalised human corneal endothelial cells (HCEC-12).

Methods

HCEC-12 cells were cultured in different concentrations of CoQ10 (0.1%, 0.2%, 0.5%, and 1.0%) and analysed using live/dead staining assay to determine appropriate concentration for subsequent experiments. Cells were pretreated with CoQ10 before inducing apoptosis by ethanol (EtOH) treatment for 30 seconds which was followed by posttreatment with CoQ10. Viable, apoptotic, and dead cell proportions were analysed using Annexin V-FITC immunofluorescence staining. Mitochondrial intensity and respiratory functions were also investigated using MitoTracker staining and a Seahorse XFe24 analyser, respectively. Results were compared to a positive control for apoptosis. The experiments were carried out in triplicates. Graphpad prism software was used for statistical analysis where p < 0.05 was deemed statistically significant.

Results

CoQ10 treatment at 0.5% and 1% showed 92% and 30% viable cells compared with 0.1% and 0.2% that showed 96% and 94% viable cells, respectively (p=0.0562). 0.1% and 0.2% concentrations were, thus, used for subsequent experiments. Annexin V-FITC apoptotic analysis showed 2% at 0.1% and 3% at 0.2% of apoptotic cells (p=0.0824). Mitochondrial respiratory function and mitochondrial intensity increased in apoptotic cells following 0.1% CoQ10 treatment.

Conclusion

0.1% CoQ10 was found optimal for reducing apoptosis and increasing metabolic activity on human corneal endothelial cell line. These results support the need for further ex vivo studies to investigate the safety profile of CoQ10 as an antiapoptotic agent for human corneal endothelium.

An in vitro cytotoxicity of glufosfamide in HepG2 cells relative to its nonconjugated counterpart

BACKGROUND

Glufosfamide (β-D-glucosylisophosphoramide mustard, GLU) is an alkylating cytotoxic agent in which ifosforamide mustard (IPM) is glycosidically linked to the β-D-glucose molecule. GLU exerted its cytotoxic effect as a targeted chemotherapy. Although, its cytotoxic efficacy in a number of cell lines, there were no experimental or clinical data available on the oncolytic effect of oxazaphosphorine drugs in hepatocellular carcinoma. Therefore, the main objective of the current study is to assess the cytotoxic potential of GLU for the first time in the hepatocellular carcinoma HepG2 cell line model.

METHODS

Cytotoxicity was assayed by the MTT method, and half-maximal inhibitory concentration (IC₅₀) was calculated. Flow cytometric analysis of apoptosis frequencies was measured by using Annexin V/PI double stain, an immunocytochemical assay of caspase-9, visualization of caspase-3, and Bcl2 gene expression were undertaken as apoptotic markers. Mitochondrial membrane potential was measured using the potentiometric dye; JC-1, as a clue for early apoptosis as well as ATP production, was measured by the luciferase-chemiluminescence assay.

RESULTS

Glufosfamide induced cytotoxicity in HepG2 cells in a concentration- and time-dependent manner. The IC₅₀ values for glufosfamide were significantly lower compared to ifosfamide. The frequency of apoptosis was much higher for glufosfamide than that of ifosfamide. The contents of caspase-9 and caspase-3 were elevated following exposure to GLU more than IFO. The anti-apoptotic Bcl2 gene expression, the mitochondrial membrane potential, and the cellular ATP levels were significantly decreased than in case of ifosfamide.

CONCLUSIONS

The current study reported for the first time cytotoxicity activity of glufosfamide in HepG2 cells in vitro. The obtained results confirmed the higher oncolytic activity of glufosfamide than its aglycone ifosfamide. The generated data warrants further elucidations by in vivo study.

Mitochondrial Coenzyme Q10 Determination Via Isotope Dilution Liquid Chromatography -Tandem Mass Spectrometry

Coenzyme Q10 (CoQ₁₀) is an essential part of the mitochondrial respiratory chain . Here, we describe an accurate and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for determination of mitochondrial CoQ₁₀ in isolated mitochondria . In the assay, mitochondrial suspensions are spiked with CoQ₁₀-[²H₉] internal standard (IS), extracted with organic solvents and CoQ₁₀ quantified by LC-MS/MS using multiple reaction monitoring (MRM).

Atorvastatin-loaded solid lipid nanoparticles as eye drops: proposed treatment option for age-related macular degeneration (AMD)

Statins, widely prescribed for cardiovascular diseases, are also being eyed for management of age-related macular degeneration (AMD). Poor bioavailability and blood-aqueous barrier may however limit significant ocular concentration of statins following oral administration. We for the first time propose and investigate local application of atorvastatin (ATS; representative statin) loaded into solid lipid nanoparticles (SLNs), as self-administrable eye drops. Insolubility, instability, and high molecular weight > 500 of ATS, and ensuring that SLNs reach posterior eye were the challenges to be met. ATS-SLNs, developed (2339/DEL/2014) using suitable components, quality-by-design (QBD) approach, and scalable hot high-pressure homogenization, were characterized and evaluated comprehensively for ocular suitability. ATS-SLNs were 8 and 12 times more bioavailable (AUC) in aqueous and vitreous humor, respectively, than free ATS. Three-tier (in vitro, ex vivo, and in vivo) ocular safety, higher corneal flux (2.5-fold), and improved stability (13.62 times) including photostability of ATS on incorporation in ATS-SLNs were established. Autoclavability and aqueous nature are the other highlights of ATS-SLNs. Presence of intact fluorescein-labeled SLNs (F-SLNs) in internal eye tissues post–in vivo application as eye drops provides direct evidence of successful delivery. Perinuclear fluorescence in ARPE-19 cells confirms the effective uptake of F-SLNs. Prolonged residence, up to 7 h, was attributed to the mucus-penetrating nature of ATS-SLNs.

Secondary CoQ10 deficiency, bioenergetics unbalance in disease and aging

Coenzyme Q₁₀ (CoQ₁₀ ) deficiency is a rare disease characterized by a decreased accumulation of CoQ₁₀ in cell membranes. Considering that CoQ₁₀ synthesis and most of its functions are carried out in mitochondria, CoQ₁₀ deficiency cases are usually considered a mitochondrial disease. A relevant feature of CoQ₁₀ deficiency is that it is the only mitochondrial disease with a successful therapy available, the CoQ₁₀ supplementation. Defects in components of the synthesis machinery caused by mutations in COQ genes generate the primary deficiency of CoQ₁₀ . Mutations in genes that are not directly related to the synthesis machinery cause secondary deficiency. Cases of CoQ₁₀ deficiency without genetic origin are also considered a secondary deficiency. Both types of deficiency can lead to similar clinical manifestations, but the knowledge about primary deficiency is deeper than secondary. However, secondary deficiency cases may be underestimated since many of their clinical manifestations are shared with other pathologies. This review shows the current state of secondary CoQ₁₀ deficiency, which could be even more relevant than primary deficiency for clinical activity. The analysis covers the fundamental features of CoQ₁₀ deficiency, which are necessary to understand the biological and clinical differences between primary and secondary CoQ₁₀ deficiencies. Further, a more in-depth analysis of CoQ₁₀ secondary deficiency was undertaken to consider its origins, introduce a new way of classification, and include aging as a form of secondary deficiency.

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.

Primary Coenzyme Q deficiencies: A literature review and online platform of clinical features to uncover genotype-phenotype correlations

Primary Coenzyme Q (CoQ) deficiencies are clinically heterogeneous conditions and lack clear genotype-phenotype correlations, complicating diagnosis and prognostic assessment. Here we present a compilation of all the symptoms and patients with primary CoQ deficiency described in the literature so far and analyse the most common clinical manifestations associated with pathogenic variants identified in the different COQ genes. In addition, we identified new associations between the age of onset of symptoms and different pathogenic variants, which could help to a better diagnosis and guided treatment. To make these results useable for clinicians, we created an online platform (https://coenzymeQbiology.github.io/clinic-CoQ-deficiency) about clinical manifestations of primary CoQ deficiency that will be periodically updated to incorporate new information published in the literature. Since CoQ primary deficiency is a rare disease, the available data are still limited, but as new patients are added over time, this tool could become a key resource for a more efficient diagnosis of this pathology.

Dynamic Interplay between Copper Toxicity and Mitochondrial Dysfunction in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder, affecting millions of people worldwide, a number expected to exponentially increase in the future since no effective treatments are available so far. AD is characterized by severe cognitive dysfunctions associated with neuronal loss and connection disruption, mainly occurring in specific brain areas such as the hippocampus, cerebral cortex, and amygdala, compromising memory, language, reasoning, and social behavior. Proteomics and redox proteomics are powerful techniques used to identify altered proteins and pathways in AD, providing relevant insights on cellular pathways altered in the disease and defining novel targets exploitable for drug development. Here, we review the main results achieved by both -omics techniques, focusing on the changes occurring in AD mitochondria under oxidative stress and upon copper exposure. Relevant information arises by the comparative analysis of these results, evidencing alterations of common mitochondrial proteins, metabolic cycles, and cascades. Our analysis leads to three shared mitochondrial proteins, playing key roles in metabolism, ATP generation, oxidative stress, and apoptosis. Their potential as targets for development of innovative AD treatments is thus suggested. Despite the relevant efforts, no effective drugs against AD have been reported so far; nonetheless, various compounds targeting mitochondria have been proposed and investigated, reporting promising results.

Improvement of Oxidative Stress and Mitochondrial Dysfunction by β-Caryophyllene: A Focus on the Nervous System

Mitochondrial dysfunction results in a series of defective cellular events, including decreased adenosine triphosphate (ATP) production, enhanced reactive oxygen species (ROS) output, and altered proteastasis and cellular quality control. An enhanced output of ROS may damage mitochondrial components, such as mitochondrial DNA and elements of the electron transport chain, resulting in the loss of proper electrochemical gradient across the mitochondrial inner membrane and an ensuing shutdown of mitochondrial energy production. Neurons have an increased demand for ATP and oxygen, and thus are more prone to damage induced by mitochondrial dysfunction. Mitochondrial dysfunction, damaged electron transport chains, altered membrane permeability and Ca²⁺ homeostasis, and impaired mitochondrial defense systems induced by oxidative stress, are pathological changes involved in neurodegenerative disorders. A growing body of evidence suggests that the use of antioxidants could stabilize mitochondria and thus may be suitable for preventing neuronal loss. Numerous natural products exhibit the potential to counter oxidative stress and mitochondrial dysfunction; however, science is still looking for a breakthrough in the treatment of neurodegenerative disorders. β-caryophyllene is a bicyclic sesquiterpene, and an active principle of essential oils derived from a large number of spices and food plants. As a selective cannabinoid receptor 2 (CB2) agonist, several studies have reported it as possessing numerous pharmacological activities such as antibacterial (e.g., Helicobacter pylori), antioxidant, anti-inflammatory, analgesic (e.g., neuropathic pain), anti-neurodegenerative and anticancer properties. The present review mainly focuses on the potential of β-caryophyllene in reducing oxidative stress and mitochondrial dysfunction, and its possible links with neuroprotection.

The multiple roles of coenzyme Q in cellular homeostasis and their relevance for the pathogenesis of coenzyme Q deficiency

Coenzyme Q (CoQ) is a redox active lipid that plays a central role in cellular homeostasis. It was discovered more than 60 years ago because of its role as electron transporter in the mitochondrial respiratory chain. Since then it has become evident that CoQ has many other functions, not directly related to bioenergetics. It is a cofactor of several mitochondrial dehydrogenases involved in the metabolism of lipids, amino acids, and nucleotides, and in sulfide detoxification. It is a powerful antioxidant and it is involved in the control of programmed cell death by modulating both apoptosis and ferroptosis. CoQ deficiency is a clinically and genetically heterogeneous group of disorders characterized by the impairment of CoQ biosynthesis. CoQ deficient patients display defects in cellular bioenergetics, but also in the other pathways in which CoQ is involved. In this review we will focus on the functions of CoQ not directly related to the respiratory chain, and on how their impairment is relevant for the pathophysiology of CoQ deficiency. A better understanding of the complex set of events triggered by CoQ deficiency will allow to design novel approaches for the treatment of this condition.

Coenzyme Q homeostasis in aging: Response to non-genetic interventions

Coenzyme Q (CoQ) is a key component for many essential metabolic and antioxidant activities in cells in mitochondria and cell membranes. Mitochondrial dysfunction is one of the hallmarks of aging and age-related diseases. Deprivation of CoQ during aging can be the cause or the consequence of this mitochondrial dysfunction. In any case, it seems clear that aging-associated CoQ deprivation accelerates mitochondrial dysfunction in these diseases. Non-genetic prolongevity interventions, including CoQ dietary supplementation, can increase CoQ levels in mitochondria and cell membranes improving mitochondrial activity and delaying cell and tissue deterioration by oxidative damage. In this review, we discuss the importance of CoQ deprivation in aging and age-related diseases and the effect of prolongevity interventions on CoQ levels and synthesis and CoQ-dependent antioxidant activities.

Preventing Myocardial Injury Following Non-Cardiac Surgery: A Potential Role for Preoperative Antioxidant Therapy with Ubiquinone

Over 240 million non-cardiac operations occur each year and are associated with a 15-20% incidence of adverse perioperative cardiovascular events. Unfortunately, preoperative therapies that have been useful for chronic ischemic heart diseases, such as coronary artery revascularization, antiplatelet agents, and beta-blockers have failed to improve outcomes. In a pre-clinical swine model of ischemic heart disease, we showed that daily administration of ubiquinone (coenzyme Q₁₀, CoQ₁₀) enhances the antioxidant status of mitochondria within chronically ischemic heart tissue, potentially via a PGC1α-dependent mechanism. In a randomized controlled trial, among high-risk patients undergoing elective vascular surgery, we showed that NT Pro-BNP levels are an important means of risk-stratification during the perioperative period and can be lowered with administration of CoQ₁₀ (400 mg/day) for 3 days prior to surgery. The review provides background information for the role of oxidant stress and inflammation during high-risk operations and the potential novel application of ubiquinone as a preoperative antioxidant therapy that might reduce perioperative adverse cardiovascular outcomes.

Coenzyme Q10 Analogues: Benefits and Challenges for Therapeutics

Coenzyme Q₁₀ (CoQ₁₀ or ubiquinone) is a mobile proton and electron carrier of the mitochondrial respiratory chain with antioxidant properties widely used as an antiaging health supplement and to relieve the symptoms of many pathological conditions associated with mitochondrial dysfunction. Even though the hegemony of CoQ₁₀ in the context of antioxidant-based treatments is undeniable, the future primacy of this quinone is hindered by the promising features of its numerous analogues. Despite the unimpeachable performance of CoQ₁₀ therapies, problems associated with their administration and intraorganismal delivery has led clinicians and scientists to search for alternative derivative molecules. Over the past few years, a wide variety of CoQ₁₀ analogues with improved properties have been developed. These analogues conserve the antioxidant features of CoQ₁₀ but present upgraded characteristics such as water solubility or enhanced mitochondrial accumulation. Moreover, recent studies have proven that some of these analogues might even outperform CoQ₁₀ in the treatment of certain specific diseases. The aim of this review is to provide detailed information about these Coenzyme Q₁₀ analogues, as well as their functionality and medical applications.

Coenzyme Q10 enhances remyelination and regulate inflammation effects of cuprizone in corpus callosum of chronic model of multiple sclerosis

Multiple Sclerosis (MS) is a chronic, progressive demyelinating disease of the central nervous system that causes the most disability in young people, besides trauma. Coenzyme Q10 (CoQ10)-also known as ubiquinone-is an endogenous lipid-soluble antioxidant in the mitochondrial oxidative respiratory chain which can reduce oxidative stress and inflammation, the processes associated with demyelination in MS. Cuprizone (CPZ) intoxication is a well-established model of inducing MS, best for studying demyelination-remyelination. In this study, we examined for the first time the role of CoQ10 in preventing demyelination and induction of remyelination in the chronic CPZ model of MS. 40 male mice were divided into four groups. 3 group chewed CPZ-containing food for 12 weeks to induce MS. After 4 weeks, one group were treated with CoQ10 (150 mg/kg/day) by daily gavage until the end of the experiment, while CPZ poisoning continued. At the end of 12 weeks, tail suspension test (TST) and open field test (OFT) was taken and animals were sacrificed to assess myelin basic protein (MBP), oligodendrocyte transcription factor-1 (Olig1), tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) by real-time polymerase chain reaction (real-time PCR) and total antioxidant capacity (TAC) and superoxide dismutase (SOD) by Elisa test. Luxol fast blue (LFB) staining was used to evaluate histological changes. CoQ10 administration promoted remyelination in histological findings. MBP and Olig-1 expression were increased significantly in CoQ10 treated group compare to the CPZ-intoxicated group. CoQ10 treatment alleviated stress oxidative status induced by CPZ and dramatically suppress inflammatory biomarkers. CPZ ingestion made no significant difference between normal control group and the CPZ-intoxicated group in TST and OFT. CoQ10 can enhance remyelination in the CPZ model and potentially might have same effects in MS patients.

Sirtuin-3 activation by honokiol restores mitochondrial dysfunction in the hippocampus of the hepatic encephalopathy rat model of ammonia neurotoxicity

The neurotoxic level of ammonia in the brain during liver cirrhosis causes a nervous system disorder, hepatic encephalopathy (HE), by affecting mitochondrial functions. Sirtuin-3 (SIRT3) is emerging as a master regulator of mitochondrial integrity, which is currently being focused as a pathogenic hotspot for HE. This article describes SIRT3 level versus mitochondrial dysfunction markers in the hippocampus of the control, the moderate-grade hepatic encephalopathy (MoHE), developed in thioacetamide-induced (100 mg/kg bw ip for 10 days) liver cirrhotic rats, and the MoHE rats treated with an SIRT3 activator, honokiol (HKL; 10 mg/kg bw ip), for 7 days from 8th day of the thioacetamide schedule. As compared with the control group rats, hippocampus mitochondria of MoHE rats showed a significant decline in SIRT3 expression and its activity with concordant enhancement of ROS and declined membrane permeability transition and organelle viability scores. This was consistent with the declined mitochondrial thiol level and thiol-regenerating enzyme, isocitrate dehydrogenase 2. Also, significantly declined activities of electron transport chain complexes I, III, IV, and Q₁₀ , decreased NAD⁺ /NADH and ATP/AMP ratios, and enhanced number of the shrunken mitochondria were recorded in the hippocampus of those MoHE rats. However, all these mitochondrial aberrations were observed to regain their normal profiles/levels, concordant to the enhanced SIRT3 expression and its activity due to treatment with HKL. The findings suggest a role of SIRT3 in mitochondrial structure-function derangements associated with MoHE pathogenesis and SIRT3 activation by HKL as a relevant strategy to protect mitochondrial integrity during ammonia neurotoxicity.

The effects of CoQ10 supplement on matrix metalloproteinases, oxidative DNA damage and pro-inflammatory cytokines in testicular ischaemia/reperfusion injury in rats

We aimed to study the effect of coenzyme Q10 on pro-inflammatory cytokine, matrix metalloproteinase, oxidative DNA damage, caspase 3 and caspase 8 in ischaemia/reperfusion injury led to by testicular torsion/detorsion. Our research is a controlled experimental animal research using rats. This study was conducted with fifty-six adult male Albino Wistar rats. Interleucine-1β, 2, 6, 10, tumour necrosis factor-α, matrix metalloproteinase-2, 3, 9, 13, tissue inhibitor matrix metalloproteinase-1, 2, malondialdehyde and leucocyte 8-hydroxy-2-deoxy guanosine/10⁶ deoxyguanosine was detected in serum and tissue samples. In addition, immunohistochemical analysis of caspase 2 and caspase 8 was performed. In testicular I/R injury, especially 24 hr after detorsion, oxidative damage pro-inflammatory cytokines and matrix metalloproteinases were increased. At the coenzyme Q10 group, a meaningful decrease was observed in these parameters. In addition, a decrease in the expression of caspase3 and caspase 8 was viewed in coenzyme Q10-treated groups. The coenzyme Q10 has beneficial effects on oxidative damage, pro-inflammatory cytokine levels, remodelling of extracellular matrix and apoptosis in testicular I/R injury.

Coenzyme Q and its role in glaucoma

Presently the management of glaucoma is limited to lowering of intra-ocular pressure (IOP). Since this modality does not appear to be successful in all cases there is increasing focus on non-IOP lowering medications. Coenzyme Q is a naturally occurring compound similar to vitamins. There are a few reports suggesting the neuroprotective efficacy of this agent in glaucoma models. The present systematic review was undertaken to study the pharmacology, physiology, metabolism and role of Coenzyme Q in glaucoma. An English-language search for relevant items was undertaken using PubMed, Google Scholar, Scopus and other databases. The present review found a positive outcome of Coenzyme Q as a neuroprotectant being reported in all studies. However, the review also found that the majority of studies on Coenzyme Q have been reported by a single group of researchers. In order to have a more wide-ranging impact regarding the efficacy of Coenzyme Q in glaucoma, it would be useful to undertake further multi- center trials.

Coenzyme Q10: Novel Formulations and Medical Trends

The aim of this review is to shed light over the most recent advances in Coenzyme Q10 (CoQ10) applications as well as to provide detailed information about the functions of this versatile molecule, which have proven to be of great interest in the medical field. Traditionally, CoQ10 clinical use was based on its antioxidant properties; however, a wide range of highly interesting alternative functions have recently been discovered. In this line, CoQ10 has shown pain-alleviating properties in fibromyalgia patients, a membrane-stabilizing function, immune system enhancing ability, or a fundamental role for insulin sensitivity, apart from potentially beneficial properties for familial hypercholesterolemia patients. In brief, it shows a remarkable amount of functions in addition to those yet to be discovered. Despite its multiple therapeutic applications, CoQ10 is not commonly prescribed as a drug because of its low oral bioavailability, which compromises its efficacy. Hence, several formulations have been developed to face such inconvenience. These were initially designed as lipid nanoparticles for CoQ10 encapsulation and distribution through biological membranes and eventually evolved towards chemical modifications of the molecule to decrease its hydrophobicity. Some of the most promising formulations will also be discussed in this review.

Natural Products: Evidence for Neuroprotection to Be Exploited in Glaucoma

Glaucoma, a leading cause of irreversible blindness worldwide, is an optic neuropathy characterized by the progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is recognized as the main risk factor. Despite effective IOP-lowering therapies, the disease progresses in a significant number of patients. Therefore, alternative IOP-independent strategies aiming at halting or delaying RGC degeneration is the current therapeutic challenge for glaucoma management. Here, we review the literature on the neuroprotective activities, and the underlying mechanisms, of natural compounds and dietary supplements in experimental and clinical glaucoma.

Coenzyme Q biosynthesis inhibition induces HIF-1α stabilization and metabolic switch toward glycolysis

Coenzyme Q₁₀ (CoQ, ubiquinone) is a redox-active lipid endogenously synthesized by the cells. The final stage of CoQ biosynthesis is performed at the mitochondrial level by the 'complex Q', where coq2 is responsible for the prenylation of the benzoquinone ring of the molecule. We report that the competitive coq2 inhibitor 4-nitrobenzoate (4-NB) decreased the cellular CoQ content and caused severe impairment of mitochondrial function in the T67 human glioma cell line. In parallel with the reduction in CoQ biosynthesis, the cholesterol level increased, leading to significant perturbation of the plasma membrane physicochemical properties. We show that 4-NB treatment did not significantly affect the cell viability, because of an adaptive metabolic rewiring toward glycolysis. Hypoxia-inducible factor 1α (HIF-1α) stabilization was detected in 4-NB-treated cells, possibly due to the contribution of both reduction in intracellular oxygen tension and ROS overproduction. Exogenous CoQ supplementation partially recovered cholesterol content, HIF-1α degradation, and ROS production, whereas only weakly improved the bioenergetic impairment induced by the CoQ depletion. Our data provide new insights on the effect of CoQ depletion and contribute to shed light on the pathogenic mechanisms of ubiquinone deficiency syndrome.

Coenzyme Q10 supplementation mitigates piroxicam-induced oxidative injury and apoptotic pathways in the stomach, liver, and kidney

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PM produced oxidative stress in gastric, liver, and kidney tissue.

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PM-induced toxicity was mediated by ROS and mitochondrial dysfunction.

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PM enhanced the activated caspase-3 expression.

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CoQ10 alleviates PM-induced gastropathy and hepato-renal damage.

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CoQ10 might be effective in COVID-19 treatment regimen.

Piroxicam (PM) is an oxicam-NSAID commonly recommended for various pain and associated inflammatory disorders. However, it is reported to have a gastric and hepato-renal toxic effect. Therefore, the current research was planned to investigate the possible mechanisms behind the mitigating action of the coenzyme (CoQ10), a natural, free radical scavenger, against PM tissue injury. Rats were assigned to five equal groups; Control, CoQ10 (10 mg/kg, orally), PM (7 mg/kg, i.p.), CoQ + PM L, and CoQ + PM H group. After 28 days, PM provoked severe gastric ulceration and marked liver and kidney damage indicated by an elevated gastric ulcer index and considerable alteration in liver and kidney biochemical tests. The toxic effects might be attributed to mitochondrial dysfunction and excess generation of reactive oxygen species (ROS), as indicated by enhanced malondialdehyde (MDA) levels along with decreased reduced-glutathione (GSH) levels and catalase (CAT) activity. Apoptotic cell death also was demonstrated by increased regulation of activated caspase-3 in the stomach, liver, and kidney tissues. Interestingly, external supplementation of CoQ10 attenuated the PM-inflicted deleterious oxidative harm and apoptosis. This ameliorative action was ascribed to the free radical scavenging activity of CoQ10.

Coenzyme Q10 ameliorates inflammation, oxidative stress, and testicular histopathology in rats exposed to heat stress

OBJECTIVES

Our work was aimed at investigating the impact and regulatory mechanism of coenzyme Q10 (CoQ10) on exogenous scrotal heat stress (HS)-induced testicular injuries in rats.

METHODS

The rats (n = 32) were assigned into four groups: control, HS control, HS+CoQ10, and CoQ10. To induce HS, rats' testicles were immersed in a water bath at 43°C for 20 min, every other day for 8 weeks. Moreover, treatment with CoQ10 (10 mg/kg) immediately started before inducing HS and continued for 8 weeks.

KEY FINDINGS

HS decreased the activity of the testicular antioxidant system, superoxide dismutase, glutathione peroxidase, and catalase, while the amount of lipid peroxidation (malondialdehyde) was increased. The index of apoptosis and mRNA expression of caspase 3 and Bax were increased, while the mRNA expression levels of Bcl-2, 3β-HSD, and 17β-HSD3 decreased after HS. Exposure to HS decreased the serum testosterone level but increased the activation of pro-inflammatory cytokines (interleukin 1 beta and tumor necrosis factor-alpha). Deleterious effects of HS on the mentioned parameters were reduced when the rats were treated with CoQ10.

CONCLUSIONS

CoQ10 could suppress the degenerative effects following testicular hyperthermia via its antiapoptotic, anti-inflammation, antioxidative, and androgen synthesis effects.

Current Medical Therapy and Future Trends in the Management of Glaucoma Treatment

Glaucoma is a neurodegenerative disease characterized by progressive loss of retinal ganglion cells and their axons. Lowering of intraocular pressure (IOP) is currently the only proven treatment strategy for glaucoma. However, some patients show progressive loss of visual field and quality of life despite controlled IOP which indicates that other factors are implicated in glaucoma. Therefore, approaches that could prevent or decrease the rate of progression and do not rely on IOP lowering have gained much attention. Effective neuroprotection has been reported in animal models of glaucoma, but till now, no neuroprotective agents have been clinically approved. The present update provides an overview of currently available IOP-lowering medications. Moreover, potential new treatment targets for IOP-lowering and neuroprotective therapy are discussed. Finally, future trends in glaucoma therapy are addressed, including sustained drug delivery systems and progress toward personalized medicine.