EARLY IGF-1 GENE THERAPY ASSOCIATED WITH NANOTECHNOLOGY REVERSES COGNITIVE DEFICITS AND OXIDATIVE STRESS INDUCED BY TRAUMATIC BRAIN INJURY

MONTIVERO A; PONCE MF; PEREZ MF; GHERSI M; BECERRA M.C.; SILVERO MJ; HEREÑU C

Mar del Plata

Congreso; Congreso SAFE 2019; 2019

Sociedad Argentina de Investigación Clínica (SAIC), la Sociedad de Farmacología Experimental (SAFE), la Sociedad Argentina de Biología (SAB), la Sociedad Argentina de Protozoología (SAP), Asociación Argentina de Nanomedicinas (NANOMED-ar),

Traumatic brain injury (TBI) is a global public health concern (1). It is the leading cause of death in the population under forty years old (2) and after that, it remains as one of the main (3).TBI-related injuries are divided in 2 subcategories: primary injury, which occurs at the moment of trauma (4), and secondary injury, which occurs immediately after trauma and produces effects that may continue for a long period of time (5). The latter is attributable to further cellular damage from the effects of primary injuries and related to inflammatory mechanismsand oxidative stress (OS) and could by themselves have severe consequences. Secondary injuries may develop over a period of hours or days following the initial traumatic assault (6)and this delayed nature suggests that there is a window for therapeutic intervention to prevent progressive tissue damage and improve functional recovery after injury. Among survivors, neurological impairment may vary from subtle symptoms to severe long term sequelae, either physical as long as cognitive (7). To date, there is no treatment to target mechanisms of secondary injury and the therapeutic arsenal is limited to decrease intracranialpressure (8). Non-steroidal anti-inflammatory drugs and steroids are not effective in the treatment of TBI because of their limited access to central nervous system. A therapeutic alternative of increasing interest in the treatment of brain injuries, is the use of neurotropic factors such as Insulin-like growth factor 1 (IGF-1), since they are neuromodulators associatedwith neuroprotection and anti-inflammatory effects (9). Objective The aim of the present investigation is to evaluate the effectiveness of IGF-1 in the treatmentof TBI in both reversing OS as well as improving cognitive deficits.MethodsSelf-assembled magneto-adenoviral vectors were obtained as described by Pereyra et al. by a collaboration with Dr. Claudia Hereñu (10).To highlight the impact of TBI in early secondary pathophysiological mechanisms and their possible reversion by IGF-1 treatment, specific biomarkers were studied such as advanced oxidation protein products (AOPP)-to identify the protein oxidation damage and malondialdehyde (MDA) -as a final product of lipid peroxidation. Regarding to cognitive deficits, animals were evaluated in the Y-maze after IGF-1 treatment.We used an animal model of TBI, were rats (male Wistar 270-310 gr) were anesthetized and submitted to a drop weight model of trauma. Then, three groups were used to evaluate thetemporal course of OS (60 min, 24 hr and 7 days) and another group was submitted to Y-maze 7 days after TBI in order to evaluate working memory by spontaneous alternation. All groupswere compared to SHAM and IGF-1 treated individuals. Treatment consisted in theadministration of magnetic nanoparticles-adenoviral vectors complexes (RadIGF-1) designed toover-express IGF-1 after viral infection. Fifteen min after TBI, Rad-IGF1 /or viruses expressingthe red protein (Rad-DsRed) as controls in a dose of 1010 physical virus particles, via CisternaMagna and magnetically redirected to brain regions in the proximity of TBI, by using a magnetspecifically designed (10).Quantitative measures were analyzed using one-way ANOVA with a post-hoc Tukey?s multiplecomparisons test. Prisma version 6 was used to perform the analyses. A significance level of α< 0.05 was chosen to evaluate all statistical tests.ResultsThe results showed a significant increase of AOPP and MDA at 60 min, 24 hs and 7 days afterTBI in the motor cortex (MC), the prefrontal cortex (PFC), and hippocampus (HP) compared toSHAM (Fig 1). Spontaneous alternation in the Y-maze was decreased in TBI animals comparedto SHAM. IGF-1 gene therapy administrated early after TBI significantly reduced AOPP andMDA levels in the studied brain areas, leading to similar values of SHAM animals (Fig 2) andalso improved spontaneous alternation in the Y-maze (Fig 3). In all cases statistical results areshown in each figure. Number of animals used in each group is 5-6 for OS and 15-18 forbehavioral experiments.ConclusionsTBI is a complex and dynamic entity that induces OS right after the impact and last over aweek. It leads to cognitive deficits such as alteration of working memory which could reflectdysexecutive syndrome commonly seen in human individuals suffering of TBI. Early IGF-1 genetherapy showed to be effective not only in decreasing OS but also in reversing alterationsobserved in working memory assessed by the Y-maze. In the current clinical practice there isstill a suboptimal approach in the treatment of TBI patients, with no pharmacological therapyfocused on secondary injury mechanisms. Then, the use of neurotrophic factors, such as IGF-1,are a promising alternative in dealing with initial neuroinflammatory responses that underliebehavioral dysfunctions observed at late stages after TBI.