Identification of two patterns of mitochondrial DNA-copy number variation in postcentral gyrus during aging, influenced by body mass index and type 2 diabetes.

AIMS: Mitochondrial (mt) DNA replication is strongly associated with oxidative stress, a condition triggered by aging and hyperglycemia, both of which contribute to mitophagy disruption and inflammation. This observational exploratory study evaluated mtDNA-copy number (mtDNA-CN) and expression of genes involved in mitochondriogenesis (PPARGC1A, TFAM, TFB1M, TFB2M), mitophagy (PINK1, PRKN), and inflammatory pathways triggered by hyperglycemia (TXNIP, NLRP3, NFKB1), in the postcentral gyrus of adults and older individuals with and without type 2 diabetes mellitus (T2D). MAIN METHODS: Quantitative real-time PCR was employed to evaluate mtDNA-CN and gene expression; tissue autofluorescence, a marker of aging and of cells with damaged organelles, was also quantified. KEY FINDINGS: No correlation was found between age and mtDNA-CN, but a direct correlation was observed for cases with mtDNA-CN >1000 (r = 0.41). The mtDNA-CN >1000 group had greater tissue autofluorescence and higher body mass index compared to the mtDNA-CN <1000 group (BMI; 25.7 vs 22.0 kg/m2, respectively). mtDNA-CN correlated with tissue autofluorescence in the overall sample (r = 0.55) and in the T2D group (r = 0.64). PINK and PRKN expressions were inversely correlated with age. Mitochondriogenesis genes and TXNIP expressions were higher in the T2D group, and correlations among the mitochondriogenesis genes were also stronger in this group, relative to the subgroup with mtDNA-CN >1000.

Diabetic encephalopathy: beneficial effects of supplementation with fatty acids ω3 and nordihydroguaiaretic acid in a spontaneous diabetes rat model.

BACKGROUND: Diabetic encephalopathy is a chronic complications of diabetes mellitus that affects the central nervous system. We evaluated the effect of ω3 and ω6 polyunsaturated fatty acids (PUFAs) supplementation plus the antioxidant agent nordihydroguaiaretic acid (NDGA) on the etiopathology of diabetic encephalopathy in eSS rats, a spontaneous model of type 2 diabetes. METHODS: One hundred twenty spontaneous diabetic eSS male rats and 38 non-diabetic Wistar, used as healthy control, received monthly by intraperitoneal route, ω3 or ω6 PUFA (6.25 mg/kg) alone or plus NDGA (1.19 mg/kg) for 12 months. Diabetic rats had a worse performance in behavioural Hole-Board test. Histopathological analysis confirmed lesions in diabetic rats brain tissues. We also detected low expression of synaptophysin, a protein linked to release of neurotransmitters, by immunohistochemically techniques in eSS rats brain. Biochemical and histopathological studies of brain were performed at 12th month. Biochemical analysis showed altered parameters related to metabolism. High levels of markers of oxidative stress and inflammation were detected in plasma and brain tissues. Data were analysed by ANOVA test and paired t test was used by comparison of measurements of the same parameter at different times. RESULTS: The data obtained in this work showed that behavioural, biochemical and morphological alterations observed in eSS rats are compatible with previously reported indices in diabetic encephalopathy and are associated with increased glucolipotoxicity, chronic low-grade inflammation and oxidative stress burden. Experimental treatments assayed modulated the values of studied parameters. CONCLUSIONS: The treatments tested with ω3 or ω3 plus NDGA showed improvement in the values of the studied parameters in eSS diabetic rats. These observations may form the basis to help in prevent and manage the diabetic encephalopathy.

Encefalopatia diabética e depressão: dano oxidativo no cérebro / Diabetic encephalopathy and depression: brain oxidative damage

O diabetes é um distúrbio complexo e heterogêneo caracterizado por hiperglicemia resultante de defeitos na secreção e ação da insulina. Tem sido reconhecido que, além do comprometimento de órgãos como rins, olhos, fígado e coração, o sistema nervoso central é suscetível aos efeitos deletérios da hiperglicemia em longo prazo. A encefalopatia diabética representa uma das complicações do diabetes, na qual os danos são caracterizados por alterações do funcionamento cognitivo, modificações estruturais e neurofisiológicas no cérebro. Existe uma associação bem reconhecida entre a depressão e o diabetes, uma vez que a prevalência de depressão é maior na população diabética comparada com a população geral. Porém, os mecanismos atribuídos a essa relação ainda estão em fase de investigação. O estresse oxidativo desempenha um papel importante nas complicações do diabetes e pode ser um mecanismo biológico envolvido na relação entre a depressão e o diabetes, relacionado à encefalopatia diabética. Neste artigo de revisão, apresentamos uma visão geral dos principais conceitos relacionados ao assunto, bem como dos dados clínicos e experimentais que suportam a relação entre o dano oxidativo no cérebro e a depressão relacionada com encefalopatia diabética...

Diabetes is a complex and heterogeneous disorder characterized by hyperglycemia resulting from defects in the secretion and action of insulin. It has been recognized that, in addition to the involvement of organs such as kidney, eye, liver, and heart, the central nervous system is susceptible to the deleterious effects of hyperglycemia in the long term. Diabetic encephalopathy is one of the complications of diabetes, in which the damage is characterized by changes in cognitive functioning, structural and neurophysiologic changes in the brain. There is a well-known association between depression and diabetes, since the prevalence of depression is higher in the diabetic population compared to the general population. However, the mechanisms assigned to this relationship are still under investigation. Oxidative stress plays an important role in the complications of diabetes and can be a biological mechanism involved in the relation between depression and diabetes related to diabetic encephalopathy. This review article is an overview of key concepts related to the subject, as well as of the clinical and experimental data supporting the relationship between oxidative damage in the brain and depression related to diabetic encephalopathy...

Diabetic encephalopathy-related depression: experimental evidence that insulin and clonazepam restore antioxidant status in rat brain.

There is increasing evidence suggesting that oxidative stress plays an important role in the development of many chronic and degenerative conditions such as diabetic encephalopathy and depression. Considering that diabetic rats and mice present higher depressive-like behaviour when submitted to the forced swimming test and that treatment with insulin and/or clonazepam is able to reverse the behavioural changes of the diabetic rats, the present work investigated the antioxidant status, specifically total antioxidant reactivity and antioxidant potential of insulin and clonazepam, as well as the effect of this drugs upon protein oxidative damage and reactive species formation in cortex, hippocampus and striatum from diabetic rats submitted to forced swimming test. It was verified that longer immobility time in diabetic rats and insulin plus clonazepam treatment reversed this depressive-like behaviour. Moreover, data obtained in this study allowed to demonstrate through different parameters such as protein carbonyl content, 2'7'-dichlorofluorescein oxidation, catalase, superoxide dismutase, glutathione peroxidase assay, total radical-trapping antioxidant potential and total antioxidant reactivity that there is oxidative stress in cortex, hippocampus and striatum from diabetic rats under depressive-like behaviour and highlight the insulin and/or clonazepam effect in these different brain areas, restoring antioxidant status and protein damage.

Cognitive and motor perturbations in elderly with longstanding diabetes mellitus.

Type 2 diabetes mellitus is a chronic disease characterized by insulin resistance; inflammation; oxidative stress; vascular damage; and dysfunction of glucose, protein, and lipid metabolisms. However, comparatively less attention has been paid to neurologic alterations seen in elderly individuals with type 2 diabetes. We review clinical, metabolic, and biochemical aspects of diabetic encephalopathy (DE) and propose that quality of dietary lipids is closely linked to DE. This implies that preventive nutritional interventions may be designed to improve DE.