In recent time, many epidemiological studies have proved very close links existing between diabetes and Alzheimer´s disease. In fact, it has been stated that diabetes is a significant risk factor for suffering from Alzheimer and vascular dementia, the two main causes of dementia. This fact is at the origin in the proliferation of studies on this subject. At the University of Cadiz, several researchers led by Doctor Monica Garcia-Alloza, including Juan José Ramos-Rodríguez and María del Carmen Infante-García, have focused on analysing the different types of diabetes - mellitus type 1 and type 2 - and seeing to what extent these affect and/or worsen central nervous system situation by favouring development of dementia.
For this purpose, "we have created new models of animals generated in laboratory and we have typified them at different ages. These are the results out of crossing diabetes models with Alzheimer models in order to determine how both diseases advance in different stages" as the PhD student Ramos-Rodriguez explains. Out of these new and unique models at world level, "we have focused part of our work on analysing how diabetes type 1 - with very low insulin levels - as much as diabetes type 2 - in which there is an insulin resistance and high levels of insulin - negatively contribute to developing vascular dementia and significantly worsen development of Alzheimer, as they generate a major phosphorylation in tau protein leading to soluble and more toxic forms of amyloid beta. These are two of the typical neuropathological features of this disease". Thus, these researchers are clear that insulin has a window which must be perfectly monitored as "if you are not within those levels, the central nervous system starts having troubles".
Moreover, the creation of these new models has allowed studying the relationship between dementia and diabetes in different evolution stages, helping to complete a thorough study proving that "conversation between Alzheimer and diabetes goes back and forth. Suffering from Alzheimer worsen metabolic features and, at the same time, going through metabolic alterations has an impact on the central nervous system" in Monica Garcia-Alloza words.
In the School of Medicine of the University of Cadiz, they have managed to see a cerebral atrophy linked to the age of these models that so far it had been very difficult to observe. In fact, "we have been able to confirm that cerebral atrophy is partly due to the death of more neurons and the dendritic spines density is at risk".
All this work, which has been published in three different articles, one in the Molecular Neurobiology review journal and the other two in Psychoneuroendocrinology, is completed by a study focused on proving how "if we achieve to monitor one of the afore-mentioned aspects, we will also be able to stop the metabolic or central problem. In fact, nowadays, we are experimenting with different therapeutic alternatives to prove if we can interfere in some of the stages implied and, at least, draw out the negative effects of these diseases", a project which would be the core of the doctorate theses by Maria del Carmen Infante.