World Congress on Insulin Resistance, Diabetes, and Cardiovascular Disease: part 4

Insulin signaling: An opportunistic target to minify the risk of Alzheimer's disease

Alzheimer's disease (AD) is progressive neurodegenerative disorder characterized by accumulation of senile plaques, neurofibrillary tangles (NFT) and neurodegeneration. The diabetes mellitus (DM) is one of the risk factors for AD pathogenesis by impairment in insulin signaling and glucose metabolism in central as well as peripheral system. Insulin resistance, impaired glucose and lipid metabolism are leading to the Aβ (Aβ) aggregation, Tau phosphorylation, mitochondrial dysfunction, oxidative stress, protein misfolding, memory impairment and also mark over Aβ transport through central to peripheral and vice versa. Several pathways, like enzymatic degradation of Aβ, forkhead box protein O1 (FOXO) signaling, insulin signaling shared common pathological mechanism for both AD and DM. Recent evidence showed that hyperinsulinemia and hyperglycemia affect the onset and progression of AD differently. Some researchers have suggested that hyperglycemia influences vascular tone, while hyperinsulinemia may underlie mitochondrial deficit. The objective of this review is to determine whether existing evidence supports the concept that impairment in insulin signaling and glucose metabolism play an important role in pathogenesis of AD. In the first part of this review, we tried to explain the interconnecting link between AD and DM, whereas the second part includes more information on insulin resistance and its involvement in AD pathogenesis. In the final part of this review, we have focused more toward the AD treatment by targeting insulin signaling like anti-diabetic, antioxidant, nutraceuticals and dietary supplements. To date, more researches should be done in this field in order to explore the pathways in insulin signaling, which might ameliorate the treatment options and reduce the risk of AD due to DM.

THE PECULARITIES OF CORRELATION BETWEEN INSULIN RESISTANCE, CARBOHYDRATE AND LIPID METABOLISM INDICES IN PATIENTS WITH GRAVES’DISEASE

Aim. The number of patients with endocrine disorders in the world, in particular, Graves’ disease is continuously increasing. Recent studies have determined the fact of insulin resistance in thyroid disorders. On the one hand, numerous researches prove correlation of hypothyroidism with arterial hypertension, ischaemic heart disease and lipid metabolism disorder, on the other – carbohydrate metabolism disorder and hyper-sympathicotonia are closely associated with hyperthyroidism. The subject of the research was to study the correlation of insulin resistance, lipid and carbohydrate metabolism indices in patients with Graves’disease. Material and Methods. During the study 53 (37 female and 16 male) patients with Graves’ disease with noticed IR have been examined. At the beginning, after 3– and 6-months thyreostatic therapy with insulin sensitizers (metformin or pioglitazone) the following investigations have been performed: assessing thyroid-stimulating hormone levels, free thyroxine and triiodothyronine; assessing glycated haemoglobin, glucose, C-peptide and fasting insulin as primary IR markers; calculating НОМА-IR index for analysing tissue sensitivity to insulin; calculating НОМА-β index for evaluating the functional capacity of β-cells of islets of Langerhans; measuring Caro indices to monitor hyperinsulinemia, measuring total cholesterol level, low-density lipoproteins, very-low-density lipoproteins, high-density lipoproteins , triglycerides, for analysing IR in relation to lipid metabolism. Results. The research results found out that free thyroid hormones and thyroid-stimulating hormone are closely related to lipid metabolism. Thus, thyroid-stimulating hormone was characterized as having direct correlation with low-density lipoproteins, while the free thyroxine inversely correlated with total cholesterol, low-density lipoproteins, and high-density lipoproteins. The free triiodothyronine negatively correlated with high-density lipoproteins. The research has also determined the direct correlation between insulin and free thyroxine, as well as free triiodothyronine in patients with diffuse toxic goitre. Conclusions. The study proves the presence of insulin resistance in patients with Graves’ disease that generates interest to further study of the changes in insulin sensitivity, relation of insulin resistance to thyroid-stimulating hormone, thyroid hormones and looking for the ways to correct these disorders.