Endocrine Disorders and Cognitive Function in the Elderly

A direct link between cognition and endocrine function has been established at several levels, from preclinical models to large clinical surveys. In this regard, international guidelines suggest performing a screening test for thyroid function (circulating TSH level) in subjects with cognitive impairment in order to exclude a possible reversible cause of dementia [1]. Moreover, marked cognitive changes have been observed in patients with severe hypercortisolism [2]. Apart from the full-blown manifestations of hypothyroidism and hypercortisolism that may account for secondary causes of dementia, either subclinical thyroid dysfunction or mild adrenal hyper-function along with several other endocrine diseases including testosterone deficit, obesity and glucose metabolism alterations, have been observed in patients with neurodegenerative diseases, suggesting a potential role of these clinical entities on Alzheimer (AD) or Parkinson Disease (PD) development [3-8]. Moreover, we have to mention the possible link between cognition and neuro-endocrine alterations associated with cardiovascular dysfunction. In this regard, the adrenergic system seems to play a key role in the cognitive alterations observed in heart failure [9]. However, given that all these clinical conditions increase the cardiovascular risk and the consequent risk of vascular dementia, it is very difficult to distinguish their possible direct role on the neurodegenerative process from that consequent to chronic cerebrovascular disease. In any case, when analyzing the scientific literature regarding the association between mild endocrine or metabolic disorders and neurodegeneration, conflicting results are still present making the interpretation of reported results very complex. In fact, we have to consider different settings and different age ranges of the available studies along with the time of onset and the duration of the analyzed endocrine dysfunction. An increasing body of evidence suggests a possible concurrent effect of several endocrine disorders and the ageing process on the pathophysiology of neurodegenerative diseases and, in general, on cognitive function [3, 4-8, 10]. This thematic issue of the Journal “Recent Patents on Endocrine, Metabolic & Immune Drug Discovery” is aimed to explore these complex relationships and provide an updated review of the literature reporting also on most recent patents that may have an impact on the development and progress of neurodegenerative diseases