Mexidol, Cytoflavin, and succinic acid derivatives as antihypoxic, anti-ischemic metabolic modulators, and ergogenic aids in athletes and consideration of their potential as performance enhancing drugs

Emoxypine (ethylmethylhydroxypyridine) is a synthetic derivative of vitamin B6 . Emoxypine succinate is a registered drug in Russia and Ukraine under various trade names including Mexidol, Mexicor, and Armadin Long. Mexidol demonstrates antihypoxic and anti-ischemic effects and also modulates metabolism. The use of Mexidol by Russian athletes has been confirmed in the past. Current use by athletes is unknown as this drug is not monitored or included in drug testing protocol. Metabotropic and antihypoxic effects of Mexidol were compared to the effects of meldonium or trimetazidine, both of which are included on the World Anti-Doping Agency (WADA) Prohibited List in category S4.4. Metabolic Modulators. The conjugation of emoxypine with succinate elevates the therapeutic effectiveness of the Mexidol formulation as succinic acid itself has important impacts to consider despite being a common food additive and drug excipient. Other succinic acid salts like ammonium succinate, found as dietary supplement, have been patented as performance enhancers. Available research on healthy subjects suggests that combinations of selected 3-substituted pyridine derivatives with succinate including Mexidol and a related drug Cytoflavin can enhance the performance of athletes. Cytoflavin is a multi-component formula containing meglumine sodium succinate, nicotinamide (vitamin B3 ), inosine (riboxin), and riboflavin. Other related succinate-based drugs include Remaxol, Reamberin, and Cogitum. Mexidol and Cytoflavin and related substances exhibit similar biological effects as drugs on the WADA Prohibited List, and if they are used for performance enhancement by athletes, they could be worthy of consideration as prohibited substances in sport.

[Evaluation of the results of sodium fumarate, furosemide, and mannitol on the initiation and outcome of renal warm ischemia in an experimental study]

While performing surgical treatment of the localized form of renal cell cancer by means of open or laparoscopic partial nephrectomy, renal warm ischemia is an important issue. Using renal warm ischemia allows to prevent parenchymal bleeding, to optimize conditions for resection of the tumor and to increase significantly the efficiency of hemostasis. However, an important problem is the probability of ischemic hypoxic damage of the remaining part of the kidney tissue during renal warm ischemia and renal functional impairment in the postoperative period.

AIM

To compare nephroprotective activity of sodium fumarate, mannitol and furosemide using experimental model of 30- and 60-minute renal warm ischemia in rabbits.

MATERIALS AND METHODS

The experiments were carried out on 360 conventional male-rabbits of the "Chinchilla" breed weighed 2,6+/-0,3 kg which were allocated into 10 groups. The control group No1 included intact animals, the control group No2 included the rabbits in which renal artery was not clamped. For the animals from the trial groups (No3-No10) the experimental model of 30- and 60-minute renal warm ischemia was used. In groups No3 and No4 no drugs were provided. Other rabbits undergone renal warm ischemia with a protection by sodium fumarate (groups No5 and No6 - 1,5 ml/kg IV), lasix (groups No7 and No8 - 3,0 mg/kg IV) and mannitol (No9 and No10 - 1,0 g/kg IV). The influence of renal warm ischemia on the renal tissue ultrastructure and the levels of NGAL, Cystatin-C and creatinine in blood and urine were studied.

RESULTS

During experimental pharmacologically uncorrected 30-minute renal warm ischemia in animals, edema of the terminal part of microvilli of the proximal tubules epithelium, an increase of lysosome number in the hyaloplasm of epithelial cells, appearance of flaky content of medium electronic density in the lumens of distal tubules and collecting tubules, as well as sharp peak-like increase of NGAL and cystatin-C in blood and urine were observed. Increasing the time of ischemia up to 60 minutes was accompanied by more severe disturbances. In groups where sodium fumarate, lasix and mannitol were used the observed ultrastructural disturbances were expressed to lesser extent, whereas sodium fumarate demonstrated the best nephroprotective activity. After using mannitol the severity of disturbances was less than in the groups where mannitol, lasix or sodium fumarate were not given. Lasix and sodium salt of fumaric acid showed a higher nephroprotective activity. The best results were received in the animals received sodium fumarate.

CONCLUSIONS

The studied drugs provided a nephroprotective effect regarding ischemia of rabbit kidney. The effect of sodium fumarate was the most pronounced, followed by furosemide and, to a lesser extent, mannitol. Use of sodium fumarate allows to protect and stimulate the kidney tissue effectively during oxygen deprivation under ischemic state.

[Lesions of the cortical part of the auditory analyzer in explosive injury]

A survey of 48 victims aged 19-36 years with explosive trauma and combined damage to the auditory system was conducted to assess the level of damage to nerve structures by analyzing the bioelectric activity of the cerebral cortex. All patients underwent electroencephalography (EEG). It is established that akubarotrauma of explosive genesis almost always leads to lesions of the function of the cortical part of the auditory analyzer. Desynchronized activity on the EEG after acubarotrauma is a favorable prognostic sign, indicating only functional disorders of the cortical part of the auditory analyzer. On the contrary, EEG changes of an organic type of cortical or stem nature are an unfavorable prognostic factor, usually accompanied by sensorineural hearing loss with prolonged and incomplete hearing recovery. Promising drugs for the treatment of otoneurological disorders are antihypoxants, in particular, derivatives of triazine indole, which affect the molecular mechanisms of hypoxia development.

HIF-1α as a Target Molecule in the Use of Triazino-Indole Derivative on the Acoustic Trauma Model

The effect of triazino-indole derivative (Trisan) on hypoxia-inducible factor (HIF) expression level in the organ of Corti, when administering it for therapeutic and preventive purposes, was investigated using an acoustic trauma model in experimental animals (female F1 hybrids of CBA and C57BL/6 lines). Cytoflavin was used as a comparator product. Study product Trisan (1% solution) was injected intravenously, intramuscularly and intraperitoneally, in the dose of 5, 7 and 10 mg/kg 2 h after the acoustic trauma for therapeutic purposes and in the dose of 5, 7 and 10 mg/kg for 3 days before the acoustic trauma for preventive purposes. IHC methods were used to investigate the organ of Corti. Trisan was observed to increase HIF expression in hair cells and neurons of the spiral ganglion in case of acoustic trauma. Depending on the dose, the increased HIF-1 expression in hair cells and spiral ganglion occurred both after therapeutic and preventive use of Trisan. Maximum HIF expression in hair cells and ganglion was noted at the therapeutic and preventive drug dose of 10 mg/kg. Following experimental results, we conclude that the otoprotective effect of triazino-indole derivative is realized via its effect on HIF metabolism, which makes it a target molecule for the drug.

[Molecular mechanisms of hypoxia and adaptation to it. Part II]

Reprogramming of the mitochondrial electron transport chain (ETC) is the most important physiological mechanism that provides short- and long-term adaptation to hypoxia. The possibilities of additional pharmacological regulation of ETC activity are of considerable practical interest in correcting hypoxia-associated disorders. This review considers the main groups of antihypoxic compounds that exhibit their effect at the interface of ETC and the cycle of tricarboxylic acids, including succinate-containing and succinate-forming antihypoxants. The role of succinate during adaptation to hypoxia, the biological activity of the succinate, and its potentially adverse effects are currently not fully understood and require further clarification.

[Molecular mechanisms for hypoxia development and adaptation to it. Part I]

Hypoxia is a typical pathological process characterized by the occurrence of oxygen deficiency in tissues and cells and accompanied by the development of immediate and delayed compensatory and adaptive reactions. Reprogramming of the mitochondrial electron transport chain (ETC) function is one the most essential regulatory mechanisms that allow for immediate adaptation to hypoxia. Succinic acid, or succinate, is involved in this process not only as one of the intermediates of the tricarboxylic acid (TAC) cycle, but also as a signaling molecule. In this connection, the purpose of this review was to systematize the available data on the molecular mechanisms for the development of hypoxia and its adaptation at the ETC/TAC coupling site, as well as on the role of succinic acid in these processes.

[Modern approaches and prospective directions in treatment of acute sensorineural hearing loss following acoustic trauma]

The article presents a review of the literature on the treatment of acute sensorineural hearing loss, acoustic trauma in people exposed to impulse noise. Groups of the most used drugs for the pharmacological correction of hearing impairment in this pathology are present, such as glucocorticosteroids, antioxidants, nootropics, antihypoxants, and others, are covered. Particular attention is paid to use of drugs taking into account the main links of pathogenesis.

[The use of reamberin in antishock therapy in severely burned patients]

A 51-year-old severely burned woman had hospitalized at the Clinic of Thermal Injuries of the S.M. Kirov Military Medical Academy with a diagnosis: flame burn in a surface area of 40% (11%)/II-III b degrees of head, neck, trunk, limbs. Inhalation injury of moderate severity. The infusion drug of the combined action reamberin, which has a volemic and antihypoxic effect, had added to the complex antishock therapy. The presented clinical observation demonstrates the favorable course of burn shock: stopping of burn shock 28 hours after injury.

[Justification of a use of additional antioxidant therapy in experimental models of chronic bacterial prostatitis]

AIM

To study the changes of the main parameters of the oxidative status in prostate after standard antimicrobial monotherapy and to justify a use of additional antioxidant therapy in various experimental models of chronic bacterial prostatitis (CBP).

MATERIAL AND METHODS

A total of 60 outbred adult male healthy rats weighing 180-200 grams were used in the experiment. In a control group, 20 intact rats were included. Two experimental groups of 20 animals each were formed and in each group two subgroups (n=10) were distinguished. Two series of experiments were performed in the episodic and relapse models of CBP (based on the Nickel J.C. (1990) and Goto T. (1991)), respectively, with an evaluation of the efficiency of antimicrobial monotherapy (levofloxacin 12.5 mg/kg/day per os for 20 days) in each of the subgroups. In prostate homogenates the levels of CFUs, active forms of oxygen (ROS), diene conjugates and malonic dialdehyde, as well as an activity of superoxide dismutase (SOD) and succinate dehydrogenase (SDH)) were evaluated.

RESULTS

The microbiological efficiency of standard antimicrobial monotherapy in the episodic model of CBP was higher than in the recurrent model (90.0% vs 80.0, respectively, p<0.05). The degree of free radical aggression and a severity of lipid peroxidation in recurrent CBP were significantly higher, and the activity of SOD and SDH was significantly lower than in the episodic model of CBP (p<0.05). In both models, residual oxidative stress persisted in the prostate tissue after antimicrobial therapy, indicating an incompleteness (in the case of episodic model of CBP) or decompensation (in case of recurrent CBP) of the antioxidant defense system.

CONCLUSION

A persisting of residual oxidative stress after a course of etiotropic antimicrobial monotherapy in the prostate has justified a necessity of the additional administration of antioxidants (antihypoxants) for a combined pharmacotherapy of CBP.

[Experience with mexidol in neurological practice]

Antihypoxic, antioxidant and nootropic effects of mexidol contribute to the improvement of patients with cerebrovascular pathology. The results of clinical studies show that the sequential scheme of using mexidol (first i.v. or i.m., then per os) is effective in the complex therapy of ischemic diseases of the brain, vascular surgery, therapy and rehabilitation of patients with degenerative-dystrophic changes of the spine, treatment of neurodegenerative pathology (including multiple sclerosis, Parkinson's disease and diabetic polyneuropathy), infectious neuropathies (ARVI, herpes, tick-borne encephalitis), neuropsychological and autonomic disorders.