Diabetes mellitus tipo 3. ¿El renacer de la insulina inhalada?

Insulin Resistance, a Risk Factor for Alzheimer's Disease: Pathological Mechanisms and a New Proposal for a Preventive Therapeutic Approach

Peripheral insulin resistance (IR) is a well-documented, independent risk factor for the development of type 2 diabetes, cardiovascular disease, cancer and cellular senescence. Recently, the brain has also been identified as an insulin-responsive region, where insulin acts as regulator of the brain metabolism. Despite the clear link between IR and the brain, the exact mechanisms underlying this relationship remain unclear. Therapeutic intervention in patients showing symptoms of neurodegenerative diseases has produced little or no results. It has been demonstrated that insulin resistance plays a significant role in the pathogenesis of neurodegenerative diseases, particularly cognitive decline. Peripheral and brain IR may represent a modifiable state that could be used to prevent major brain disorders. In this review, we will analyse the scientific literature supporting IR as a risk factor for Alzheimer's disease and suggest some therapeutic strategies to provide a new proposal for the prevention of brain IR and its consequences.

[Type 3 c diabetes: Approach from the first level doctor]

DM3c is diabetes (DM) of the exocrine pancreas that must be suspected whenever there is a history of chronic pancreatitis (CP), acute pancreatitis (AP) or recurrence (80% of cases) or new-onset DM in individuals from over 50 years of age without any other justification (negative autoimmunity tests, Glutamic Acid Decarboxylase antibodies). It is an entity misdiagnosed as type 2 diabetes (DM2) (90%) and therefore, if it is not suspected, it can go unnoticed. For its diagnosis, abdominal ultrasound, determination of the CA 19.9 tumor antigen (carbohydrate antigen 19-9), nuclear magnetic resonance (NMR) or computerized axial tomography (CT) are useful. The treatment is the same as DM2, although certain specifications depend on the type of drugs and with the particularity that in dealing with «fragile diabetes» greater caution must be taken with hypoglycemia (monitoring). Likewise, as it is a disease of the exocrine pancreas, it will have to be specifically treated to avoid metabolic, malabsorptive and/or nutritional alterations.

A metabolic perspective of late onset Alzheimer's disease

After decades of research, the molecular neuropathology of Alzheimer's disease (AD) is still one of the hot topics in biomedical sciences. Some studies suggest that soluble amyloid β (Aβ) oligomers act as causative agents in the development of AD and could be initiators of its complex neurodegenerative cascade. On the other hand, there is also evidence pointing to Aβ oligomers as mere aggravators, with an arguable role in the origin of the disease. In this line of research, the relative contribution of soluble Aβ oligomers to neuronal damage associated with metabolic disorders such as Type 2 Diabetes Mellitus (T2DM) and obesity is being actively investigated. Some authors have proposed the endoplasmic reticulum (ER) stress and the induction of the unfolded protein response (UPR) as important mechanisms leading to an increase in Aβ production and the activation of neuroinflammatory processes. Following this line of thought, these mechanisms could also cause cognitive impairment. The present review summarizes the current understanding on the neuropathological role of Aβ associated with metabolic alterations induced by an obesogenic high fat diet (HFD) intake. It is believed that the combination of these two elements has a synergic effect, leading to the impairement of ER and mitochondrial functions, glial reactivity status alteration and inhibition of insulin receptor (IR) signalling. All these metabolic alterations would favour neuronal malfunction and, eventually, neuronal death by apoptosis, hence causing cognitive impairment and laying the foundations for late-onset AD (LOAD). Moreover, since drugs enhancing the activation of cerebral insulin pathway can constitute a suitable strategy for the prevention of AD, we also discuss the scope of therapeutic approaches such as intranasal administration of insulin in clinical trials with AD patients.