Radioprotection by α-Lipoic Acid Palladium Complex Formulation (POLY-MVA) in Mice

The radioprotective effects of alpha-lipoic acid on radiotherapy-induced toxicities: A systematic review

PURPOSE

Radiation therapy is one of the main cancer treatment modalities applied in 50-70% of cancer patients. Despite the many advantages of this treatment, such as non-invasiveness, organ-preservation, and spatiotemporal flexibility in tumor targeting, it can lead to complications in irradiated healthy cells/tissues. In this regard, the use of radio-protective agents can alleviate radiation-induced complications. This study aimed to review the potential role of alpha-lipoic acid in the prevention/reduction of radiation-induced toxicities on healthy cells/tissues.

METHODS

A systematic search was performed following PRISMA guidelines to identify relevant literature on the "role of alpha-lipoic acid in the treatment of radiotherapy-induced toxicity" in the electronic databases of Web of Science, Embase, PubMed, and Scopus up to January 2021. Based on the inclusion and exclusion criteria of the present study, 278 articles were screened. Finally, 29 articles were included in this systematic review.

RESULTS

The obtained results showed that in experimental in vivo models, the radiation-treated groups had decreased survival rate and body weight compared to the control groups. It was also found that radiation can induce mild to severe toxicities on gastrointestinal, circulatory, reproductive, central nervous, respiratory, endocrine, exocrine systems, etc. However, the use of alpha-lipoic acid could alleviate the radiation-induced toxicities in most cases. This radio-protective agent exerts its effects through mechanisms of anti-oxidant, anti-apoptosis, anti-inflammatory, and so on.

CONCLUSION

According to the obtained results, it can be mentioned that co-treatment of alpha-lipoic acid with radiotherapy ameliorates the radiation-induced toxicities in healthy cells/tissues.

Radio-protective potential of lipoic acid free and nano-capsule against 99mTc-MIBI induced injury in cardio vascular tissue

BACKGROUND

SPECT MPI (Single photon emission computed tomography myocardial perfusion imaging) is an essential tool for diagnosis of cardiovascular disease, but it also involves considerable exposure to ionizing radiation.

OBJECTIVE

To determine the radioprotective potential of lipoic acid free and nano-capsule against 99mTc-MIBI-induced injury in cardiovascular tissue.

METHODS

The radioprotective ability was assessed by blood count, histopathology and heart enzymes in different groups of mice. Hearts of mice from all groups were dissected and prepared for oxidative stress analysis of superoxide dismutase (SOD) and malondialdehyde (MDA). Furthermore, levels of DNA damage in heart and bone marrow cells were evaluated by alkaline comet assay technique. The same measurements were estimated after treating the mice with lipoic acid.

RESULTS

Comparing mice injected by radiopharmaceutics with control group showed a significant depression in the count of white blood cells (WBC) by about 40 % at 24 &72 hrs post-radiopharmaceutical administration. Moreover, platelets count was decreased by 27% at 72 hrs post-radiopharmaceutical administration. Radiation also dropped in super oxide dismutase (SOD) and increased in activity of heart enzymes and level of MDA (Malondialdehyde). Additionally, histopathological observation was characterized by focal necrosis of cardiac myocytes. 99mTc-MIBI induced DNA damage had significant increase. Nevertheless, pretreatment with free and lipoic acid nano-capsules (LANC's) prevented the reduction induced in WBCs and platelets, and improved their counts significantly. Conversely pre-treatment with lipoic acid free and nano-capsule significantly increased the activity of SOD and decreased the level of MDA and therefore protected the cardiovascular tissues and reduced DNA strand-break, consequently and enhanced the body weight of the mice.

CONCLUSIONS

These findings highlight the efficacy of lipoic acid free and nano-capsule as a radio protector.

Late Administration of a Palladium Lipoic Acid Complex (POLY-MVA) Modifies Cardiac Mitochondria but Not Functional or Structural Manifestations of Radiation-Induced Heart Disease in a Rat Model

Exposure of the heart to ionizing radiation can cause adverse myocardial remodeling. In small animal models, local heart irradiation causes persistent alterations in cardiac mitochondrial function and swelling. POLY-MVA is a dietary supplement that contains a palladium lipoic acid complex that targets mitochondrial complex I and has been demonstrated to have greater redox potential than lipoic acid alone. POLY-MVA improves mitochondrial function and anti-oxidant enzyme activity in the aged rat heart. In this study, we tested whether POLY-MVA can mitigate cardiac effects of ionizing radiation. Adult male rats were exposed to local heart X rays with a daily dose of 9 Gy for 5 consecutive days. Eighteen weeks after irradiation, POLY-MVA was administered orally at 1 ml/kg bodyweight per day during weekdays, for 6 weeks. Alterations in cardiac function as measured with echocardiography coincided with enhanced mitochondrial swelling, a reduction in mitochondrial expression of complex II, manifestations of adverse remodeling such as a reduction in myocardial microvessel density and an increase in collagen deposition and mast cell numbers. POLY-MVA enhanced left ventricular expression of superoxide dismutase 2, but only in sham-irradiated animals. In irradiated animals, POLY-MVA caused a reduction in markers of inflammatory infiltration, CD2 and CD68. Moreover, POLY-MVA mitigated the effects of radiation on mitochondria. Nonetheless, POLY-MVA did not mitigate adverse cardiac remodeling, suggesting that this tissue remodeling may not be alleviated by altering cardiac mitochondria alone. However, we cannot exclude the possibility that an earlier onset of POLY-MVA administration may have more profound effects on radiation-induced cardiac remodeling.