Platelet mitochondrial function and endogenous coenzyme Q10 levels are reduced in patients after COVID-19.

BACKGROUND: After an acute treatment for coronavirus disease (COVID-19), some symptoms may persist for several weeks, for example: fatigue, headaches, muscle and joint pain, cough, loss of taste and smell, sleep and memory disturbances, depression. Many viruses manipulate mitochondrial function, but the exact mechanisms of SARS-CoV-2 virus effect remain unclear. We tested the hypothesis that SARS-CoV-2 virus may affect mitochondrial energy production and endogenous biosynthesis of coenzyme Q10 (CoQ10). METHODS: Ten patients after COVID-19 and 15 healthy individuals were included in the study. Platelets isolated from peripheral blood were used as an accessible source of mitochondria. High-resolution respirometry for the evaluation of platelets mitochondrial function, and HPLC method for CoQ10 determination were used. Oxidative stress was evaluated by TBARS concentration in plasma. RESULTS: Platelet mitochondrial respiratory chain function, oxidative phosphorylation and endogenous CoQ10 level were reduced in the patients after COVID-19. CONCLUSION: We assume that a reduced concentration of endogenous CoQ10 may partially block electron transfer in the respiratory chain resulting in a reduced adenosine triphosphate (ATP) production in the patients after COVID-19. Targeted mitochondrial therapy with CoQ10 supplementation and spa rehabilitation may improve mitochondrial health and accelerate the recovery of the patients after COVID-19. Platelet mitochondrial function and CoQ10 content may be useful mitochondrial health biomarkers after SARS-CoV-2 infection (Tab. 3, Fig. 3, Ref. 46).

Is mitochondrial bioenergetics and coenzyme Q10 the target of a virus causing COVID-19?

COVID-19 ‒ a coronavirus disease, affected almost all countries in the world. It is a new virus disease, nobody has prior immunity to it, human population is prone to infections. In March 11 2020, WHO declared the pandemic status. The main symptoms include: fever, dry cough and fatigue. Virus proteins need mitochondrial energy for their own survival and replication. Upon viral infections, mitochondrial dynamics and metabolism can be modulated, which can influence the energy production in the host cells. Coenzyme Q10 is an integral component of mitochondrial respiratory chain and the key component of mitochondrial ATP production. The exact pathobiochemical mechanism of the disease is unknown. Modulated mitochondrial dynamics and metabolism with lower CoQ10 levels in viral infections leads us to the hypothesis that one of the main pathobiochemical effects of SARS-Cov-2 virus could be mitochondrial bioenergetics dysfunction with CoQ10 deficit leading to the reduction of its endogenous biosynthesis. The mechanism might be virus induced oxidative stress causing a mutation of one or more of the nine COQ genes, resulting in primary CoQ10 deficiency. New perspective for patients with COVID-19 may be supportive targeting therapy with coenzyme Q10 to increase the energy production, immunity and decrease oxidative stress (Fig. 1, Ref. 51). Keywords: COVID-19, virus, mitochondrial bioenergetics, coenzyme Q10, oxidative stress.

The importance of coenzyme Q10 and its ratio to cholesterol in the progress of chronic kidney diseases linked to non- -communicable diseases.

OBJECTIVES: The mortality of patients with chronic kidney diseases (CKD) increases with the decrease in glomerular filtration rate (eGFR). In the progress of CKD that is closely linked to non-communicable diseases (NCDs), the role of coenzyme Q10 (CoQ10) is not fully evaluated. We aimed to evaluate the importance of CoQ10, CoQ10/cholesterol ratio, and oxidative stress in the progress of CKD. PATIENTS AND METHODS: The control group was constituted of 19 healthy subjects who volunteered to enrol in the study, CKD group consisted of 58 patients with CKD, of whom 54 had CKD combined with hypertension, 22 had CKD combined with hypertension and diabetes type 2 , and 18 had CKD combined with hypertension and statin therapy. We observed age, BMI, creatinine, uric acid, eGFR, hemoglobin, CRP, glucose, lipids fraction, and liver enzymes. Coenzyme Q10-TOTAL (ubiquinol+ubiquinone) in platelets and plasma were determined using HPLC method with UV detection. Indexed of CoQ10/lipid fractions were evaluated. Oxidative stress was determined as thiobarbituric acid­reactive substances (TBARS). RESULTS: With increased stages of CKD, eGFR and CoQ10 as well as its ratio to lipids were significantly reduced while TBARS increased. CONCLUSION: We assume that lower endogenous CoQ10 level may be one of the reasons of kidney dysfunction. CoQ10/lipids ratio and increase in oxidative stress can predict the progression of CKD in patients with arterial hypertension, diabetes mellitus and dyslipidemia (Tab. 2, Fig. 4, Ref. 49).

Platelet mitochondrial bioenergetic analysis in patients with nephropathies and non-communicable diseases: a new method.

OBJECTIVES: To test the hypothesis if mitochondrial bioenergetic function analyzed in circulating platelets may represent peripheral signature of mitochondrial dysfunction in nephropathy associated to non-communicable human diseases such as cardiovascular diseases, diabetes and with statins treatment. METHODS: High-resolution respirometry was used for analysis of mitochondrial bioenergetics in human platelets isolated from peripheral blood. This method is less-invasively compared to skeletal muscle biopsy. Patients with nephropathies and in combination with non-communicable diseases were included in the study. RESULTS: This pilot study showed platelet mitochondrial bioenergy dysfunction in patients with nephropathies and non-communicable diseases. Positive effect of treatment with 10 mg atorvastatin on platelet mitochondrial respiratory chain Complex I-linked respiration and ATP production in patients with nephropathies, diabetes and 80 mg atorvastatin in patient with nephropathy and dialysis was found. Positive effect of 80 mg fluvastatin treatment, and negative effect of thrombocytopenia and renal transplantation on platelet mitochondrial bioenergy was determined. CONCLUSION: High-resolution respirometry allowed detection of small changes in platelet mitochondrial function. This method could be used as a sensitive bioenergetic test of mitochondrial function for diagnosis and monitoring the therapy in patients with nephropathy (Tab. 1, Fig. 3, Ref. 39).

Cardioprotection induced by remote ischemic preconditioning preserves the mitochondrial respiratory function in acute diabetic myocardium.

A 2×2 factorial design was used to evaluate possible preservation of mitochondrial functions in two cardioprotective experimental models, remote ischemic preconditioning and streptozotocin-induced diabetes mellitus, and their interaction during ischemia/reperfusion injury (I/R) of the heart. Male Wistar rats were randomly allocated into four groups: control (C), streptozotocin-induced diabetic (DM), preconditioned (RPC) and preconditioned streptozotocin-induced diabetic (DM+RPC). RPC was conducted by 3 cycles of 5-min hind-limb ischemia and 5-min reperfusion. DM was induced by a single dose of 65 mg/kg streptozotocin. Isolated hearts were exposed to ischemia/reperfusion test according to Langendorff. Thereafter mitochondria were isolated and the mitochondrial respiration was measured. Additionally, the ATP synthase activity measurements on the same preparations were done. Animals of all groups subjected to I/R exhibited a decreased state 3 respiration with the least change noted in DM+RPC group associated with no significant changes in state 2 respiration. In RPC, DM and DM+RPC group, no significant changes in the activity of ATP synthase were observed after I/R injury. These results suggest that the endogenous protective mechanisms of RPC and DM do preserve the mitochondrial function in heart when they act in combination.

Remote ischemic preconditioning of the heart: protective responses in functional and biophysical properties of cardiac mitochondria.

UNLABELLED: Remote ischemic preconditioning (RIP)-induced protection of myocardial energetics was well documented on the level of tissue, but data concerning the involvement of mitochondria were missing. We aimed at the identification of changes in membrane properties and respiratory functions induced in rat heart mitochondria by RIP. Experiments were performed on 46 male Wistar rats divided into control and RIP-treated groups of 21 animals each. Blood flow in the occluded area was recorded by MRI angiography in four animals. RIP protocol comprised of three successive 5-min occlusions each followed by 5-min reperfusions of descending branches of the right hind limb femoral artery. The efficacy of RIP was evaluated as the extent of RIP-induced protection against damage to the functions of mitochondria isolated by differential centrifugation after 30-min global ischemia followed by 40-min reperfusion of the hearts in Langendorff mode. ASSESSMENTS: mitochondrial membrane fluidity with a fluorescent probe DPH, CoQ(9) and CoQ(10) with HPLC, mitochondrial respiration with the Oxygraph-2k (Oroboros). Results revealed that RIP was affecting the mitochondria. The immediate protection conferred by RIP involves beneficial and prognostically significant effects: a total elimination of ischemia/reperfusion-induced depression of mitochondrial membrane fluidity and a trend for better preservation of mitochondrial state 3 respiration.

Losartan improved respiratory function and coenzyme Q content in brain mitochondria of young spontaneously hypertensive rats.

Increased production of free radicals and impairment of mitochondrial function are important factors in the pathogenesis of hypertension. This study examined the impact of hypertension on mitochondrial respiratory chain function, coenzyme Q(9) (CoQ(9)), coenzyme Q(10) (CoQ(10)), and alpha-tocopherol content in brain mitochondria, and the effect of blockade of angiotensin II type 1 receptors (AT1R) in the prehypertensive period on these parameters. In addition, blood pressure, heart and brain weight to body weight ratios, and the geometry of the basilar artery supplying the brain were evaluated. In the 9th week blood pressure and heart weight/body weight ratio were significantly increased and brain weight/body weight ratio was significantly decreased in spontaneously hypertensive rats (SHR) when compared to Wistar rats (WR). The cross-sectional area of the basilar artery was increased in SHR. Glutamate-supported respiration, the rate of ATP production, and concentrations of CoQ(9), CoQ(10), and alpha-tocopherol were decreased in SHR. The succinate-supported function and cytochrome oxidase activity were not changed. The treatment of SHR with losartan (20 mg/kg/day) from 4th to 9th week of age exerted preventive effect against hypertension, heart and arterial wall hypertrophy, and brain weight/body weight decline. After the therapy, the rate of ATP production and the concentration of CoQ increased in comparison to untreated SHR. The impairment of energy production and decreased level of lipid-soluble antioxidants in brain mitochondria as well as structural alterations in the basilar artery may contribute to increased vulnerability of brain tissue in hypertension. Long-term treatment with AT1R blockers may prevent brain dysfunction in hypertension.

L-arginine fails to protect against myocardial remodelling in L-NAME-induced hypertension.

BACKGROUND: We investigated whether the substrate for nitric oxide synthesis L-arginine is able to modify hypertension and left ventricular hypertrophy development induced by chronic blockade of nitric oxide synthase activity by NG-nitro-L-arginine-methyl ester (L-NAME). MATERIAL AND METHODS: Four groups of rats were investigated: control, L-arginine 1.5 g kg-1, L-NAME 40 mg kg-1, and L-NAME +L-arginine in corresponding doses. Systolic blood pressure was measured by non-invasive tail-cuff plethysmography each week. After 4 weeks, the animals were sacrificed and hydroxyproline and coenzyme Q9 and Q10 concentrations in the left ventricle, and nitric oxide synthase activity in the left ventricle, kidney and brain were investigated. RESULTS: In the L-NAME group, nitric oxide synthase activity was decreased in the left ventricle, kidney and brain, and hypertension, left ventricular hypertrophy and fibrosis developed. Heart remodelling was associated with the decrease of coenzyme Q9 and Q10 concentrations in the left ventricle. Simultaneous treatment with L-NAME and L-arginine prevented nitric oxide synthase activity diminution in the left ventricle but not in the kidney and brain, and completely failed to prevent hypertension, left ventricular hypertrophy and fibrosis. Nevertheless, l-arginine prevented the diminution of coenzyme Q9 and Q10 concentrations in the left ventricle. CONCLUSIONS: We conclude that L-arginine failed to prevent hypertension, left ventricular hypertrophy and fibrosis development despite restoration of nitric oxide synthase activity in the left ventricle. However, L-arginine prevented the diminution of coenzyme Q levels in the left ventricle.

Regeneration of coenzyme Q9 redox state and inhibition of oxidative stress by Rooibos tea (Aspalathus linearis) administration in carbon tetrachloride liver damage.

The effect of rooibos tea (Aspalathus linearis) on liver antioxidant status and oxidative stress was investigated in rat model of carbon tetrachloride-induced liver damage. Synthetic antioxidant N-acetyl-L-cysteine (NAC) was used for comparison. Administration of carbon tetrachloride (CCl4) for 10 weeks decreased liver concentrations of reduced and oxidized forms of coenzyme Q9 (CoQ9H2 and CoQ9), reduced -tocopherol content and simultaneously increased the formation of malondialdehyde (MDA) as indicator of lipid peroxidation. Rooibos tea and NAC administered to CCl4-damaged rats restored liver concentrations of CoQ9H2 and alpha-tocopherol and inhibited the formation of MDA, all to the values comparable with healthy animals. Rooibos tea did not counteract the decrease in CoQ9, whereas NAC was able to do it. Improved regeneration of coenzyme Q9 redox state and inhibition of oxidative stress in CCl4-damaged livers may explain the beneficial effect of antioxidant therapy. Therefore, the consumption of rooibos tea as a rich source of natural antioxidants could be recommended as a market available, safe and effective hepatoprotector in patients with liver diseases.

Adaptive changes of antioxidant status in development of experimental diabetes.

BACKGROUND: In clinical and experimental research, attention is paid to the role of antioxidant defense systems in the prevention of diabetic complications. Little information is available about regulation of the endogenous level of antioxidants in the state of chronic oxidative stress in relation to the development of diabetes, and particularly about coenzyme Q as one of the most important endogenous antioxidants with an irreplaceable function in mitochondrial bioenergetics. PURPOSE: To examine changes in concentrations of two important lipophilic antioxidants, coenzyme Q9 and alpha-tocopherol, in rat tissues during the development of experimental diabetes. METHODS: Experimental diabetes in male Wistar rats, was induced by streptozotocin in the dose of 55 mg/kg intravenously. Coenzyme Q9 (CoQ9) and alpha-tocopherol (alpha-toc.) were determined in myocardial and skeletal muscles and in kidney tissue after 1, 6 and 8 months of diabetes duration by the method of high-performance liquid chromatography. RESULTS: Myocardial CoQ9 content increased progressively in the course of diabetes development by 14, 29 and 61%, while in skeletal muscles and kidney, the increases were not dependent on the duration of diabetes. The content of alpha-toc. increased in the myocardium after 8 months of diabetes duration, in kidney tissue and skeletal muscles, it did not change in comparison with control rats. CONCLUSIONS: An increased content of the lipophilic antioxidants coenzyme Q9 and alpha-tocopherol in tissues of diabetic rats is regarded as an adaptation of the antioxidant defense system to chronic oxidative stress. The exact mechanisms of accumulation of these antioxidants in diabetic tissues could be elucidated by studies investigating their relation to changes in lipid content and to the total of bioenergetic and antioxidant capacities. (Fig. 3, Ref. 25.)

[The effect of lysolecithin on rat liver microsome monooxygenase activity after induction by xenobiotics of the methylcholanthrene type]. / Vliianie lizoletsitina na monoksigenaznye aktivnosti mikrosom pecheni krys posle induktsii ksenobiotikami metilkholantrenovogo tipa.

Effects of exogenous gamma-myristoyl- and gamma-palmitoyllysolecithins on physico-chemical characteristics of rat liver microsomes, such as hydrophobicity and viscosity, as well as on oxidative NADPH-dependent O-deethylation of 7-ethoxycoumarin (7-EC), O-demethylation of p-nitroanisole (p-NA) and hydroxylation of 3.4-benz(a)pyrene (BP) induced by the mechylcholanthrene xenobiotics methylcholanthrene (MCh), beta-naphthoflavone (NF) and Sovol (SV) have been investigated. The specific inducible form of P-450c showed different affinity for the substrates. Lysolecithin decreased the hydrophobicity but only slightly increased membrane viscosity, whereas the monooxygenase substrates neutralized these effects. Lysolecithin (2-20 micrograms/mg of microsomal protein) inhibited the activity of deethylase 7-EC (maximally by 11%) in NF- and SV-induced microsomes, this inhibiting effect being more pronounced than that in MCh-induced microsomes. At higher concentrations lysolecithin inhibited the rate of 7-EC deethylation in MCh-induced microsomes more strongly; the maximal inhibition (23%) was observed at the protein concentration of 60 micrograms/mg. In case of NF- and SV-induced microsomes the inhibition was 18%. The inhibiting effect of lysolecithin on 7-EC dealkylation was expressed in a lesser degree than that on p-NA O-demethylation in induced (but not intact) microsomes. A significant positive correlation has been found between the changes in hydrophobicity and inhibition rates in the presence of lysolecithin, however only for 7-EC deethylation.