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.

Long chain polyunsaturated fatty acids (LCPUFAs) and nordihydroguaiaretic acid (NDGA) modulate metabolic and inflammatory markers in a spontaneous type 2 diabetes mellitus model (Stillman Salgado rats).

BACKGROUND: Diabetes mellitus (DM) is a complex disease with alterations in metabolic and inflammatory markers. Stillman Salgado rats (eSS) spontaneously develop type 2 DM by middle age showing progressive impairment of glucose tolerance with hyperglycemia, hypertriglyceridemia and hyperinsulinemia. We analyzed the effects of supplementation of ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) with or without nordihydroguaiaretic acid (NDGA) added, an antioxidant and lipoxygenase inhibitor, on metabolic and inflammatory parameters in eSS rats to evaluate whether they can delay development and/or prevent progression of DM. METHODS: After weaning, eSS rats received, intraperitoneally, once a month ω-3 (EPA 35% and DHA 40%-6.25 mg/Kg) or ω-6 (90% arachidonic acid- 6. 25 mg/Kg) for twelve months. Two additional groups of rats received 1.9 mg/kg NDGA added to ω-3 and ω-6 fatty acids. Blood samples were collected at day 40, and at the end of the 6th month and 12th month of age to determine plasma triglycerides (TGs), total plasma fatty acids (FA), A1C hemoglobin (HbA1C), C-reactive protein (CRP), gamma glutamyl transpeptidase (GGT), lipo and hydro peroxides, nitrites and IL-6 (in plasma and liver, kidney, and pancreas) and underwent oral glucose tolerance test (OGTT) as well. Wistar and eSS rats that received saline solution were used as controls. RESULTS: Plasma lipids profile, TG, fasting and post-prandial blood glucose levels, and glycosylated HbA1C showed significant improvements in ω-3 and ω-3 + NDGA treated animals compared to eSS control group. ω-3 and ω-3 + NDGA groups showed an inverse correlation with fasting blood glucose and showed lower plasma levels of GGT, TG, and CRP. eSS rats treated with ω-3 LCPUFAs showed reduced level of inflammatory and oxidative indices in plasma and liver, kidney and pancreas tissues in comparison with eSS control (non-treated) and ω-6 treated groups. CONCLUSIONS: eSS rats are a useful model to study type 2 DM pathophysiology and related inflammatory indices. ω-3 + NDGA supplementation, at the doses tested, ameliorated inflammatory, metabolic and oxidative stress markers studied.

Efecto sinérgico de ácidos grasos poliinsaturados (PUFAS) y ácidos nordihidroguaiaretico (NDGA) sobre parámetros metabólicos, inflamatorios y de oxidación celular en el desarrollo de diabetes espontánea de un modelo experimental

La Diabetes Mellitus (DM) es una enfermedad compleja con progresivas alteraciones en los parámetros metabólicos incluyendo también un estado de inflamación crónica sistémica de bajo grado, entre otros. La actividad física y la planificación nutricional son herramientas efectivas para prevenir y tratar la enfermedad y disminuir otros factores de riesgo relacionados, como el sobrepeso y obesidad. El modelo animal de ratas Stillman Salgado (ratas eSS) se basa en el empleo experimental de una variedad de ratas Wistar las cuales desarrollan espontánea y progresivamente una forma de DM, habitualmente con repercusiones clínicas y de laboratorio de leves a moderadas. Con la evolución de la DM, los animales muestran progresiva intolerancia a la glucosa, con aumento de los niveles plasmáticos de insulina, triglicéridos y glucosa, entre otros parámetros alterados. Es ampliamente conocido que los perfiles lipídicos influyen y son influidos por diversas patologías, como por ejemplo enfermedad Cardiovascular, DM, obesidad, entre otras. La relación entre la ingesta de ácidos grasos poli insaturados (PUFAs) de la serie omega 6/omega 3 (ω-6/ ω-3) menor a 4:1 se relaciona con bajos índices inflamatorios y de oxidación celular, hallándose en la dieta denominada “occidental” un desbalanceado consumo de carnes rojas, un disbalance en la alimentación respecto a estos PUFAs, con porcentajes aún mayores a 10:1, inclusive llegando a 40:1. Ello colabora para que se produzca un aumento progresivo de moléculas inflamatorias (eicosanoides en general) a partir de ácido araquidónico (AA), PUFAs ω-6, constituyendo la denominación común en estas entidades el establecimiento de inflamación crónica sostenida de bajo grado (CLGI)...

Diabetes Mellitus (DM) is a complex disease with alterations inmetabolic and inflammatory indices. Stillman Salgado rats (eSS rats) spontaneouslydevelop DM once reached middle age showing progressive impairment of glucosetolerance along with hypertriglyceridemia, hyperglycemia, and hyperinsulinemia. Inthe present study, we analyzed the effects of ω-3 and ω-6 polyunsaturated fatty acids(PUFAs) supplementation with or without nordihydroguaiaretic acid (NDGA), astrong, natural antioxidant and Lipooxygenase inhibitor molecule, isolated from nativeflora plants, on metabolic and inflammatory parameters in eSS rats to search whetherwhich combination may delay the development of DM and/or prevent its progression.MATERIALS AND METHODS: eSS rats after 10th days stopping breastfeed weremonthly administered intraperitoneal (IP) with ω-3 commercial fish oil (EPA 35% andDHA 40% 6,25mg/Kg) and purchased ω-6 (90% arachidonic acid 6,25mg/Kg)throughout twelve months. Two additional groups of rats received IP 1.9mg/KgNDGA along with w-3 and w-6 fatty acids. Blood and tissue samples were collectedto determine plasma TGs (TG), total plasma fatty acids (FA), A1C hemoglobin, Creactiveprotein (CRP), Gamma glutamyl transpeptidase (GGTP), lipo and hydroperoxides, nitrites and IL-6 (in plasma and in different organs as liver, kidney andpancreas) and then underwent oral glucose tolerance test (OGTT) as well...

Is insulin resistance a disorder of the brain?

There is reasonable evidence to suggest that insulin resistance may have its origins in the hypothalamus. Insulin secretion is regulated by sympathetic and parasympathetic nervous systems and modulates the concentrations of hypothalamic neuropeptides and monoaminergic neurotransmitters, and, in return, hypothalamic monoamines regulate the secretion of insulin by pancreatic beta cells. A lesion of the ventromedial hypothalamus produces all the features of the metabolic syndrome including insulin resistance and hyperinsulinemia. These and other evidence suggest that insulin resistance may very well be a disease of the brain.

L-arginine, NO and asymmetrical dimethylarginine in hypertension and type 2 diabetes.

Both hypertension and type 2 diabetes mellitus are common and there are no reliable markers either to predict their development or complications. High fat diet and carbohydrate-rich diet enhance serum asymmetrical dimethylarginine (ADMA) levels, an endogenous inhibitor of nitric oxide synthesis. ADMA levels are elevated in patients with hypertension, poor control of hyperglycemia, diabetic microangiopathy and macroangiopathy and dyslipidemia. One of the earliest signs of vascular dysfunction and insulin resistance, which are present in hypertension and type 2 diabetes mellitus, is an elevation in serum ADMA levels. Displacing plasma ADMA by oral supplementation of L-arginine restores endothelial dysfunction by augmenting endothelial nitric oxide generation. Strict control of hyperglycemia decreases serum ADMA levels. These and other studies suggest that serum ADMA levels could be used to predict the development of hypertension and type 2 diabetes mellitus in those who are at high-risk to develop these diseases.