Diagnosis of vascular cognitive impairment and its main categories

Unraveling the role of brain renin angiotensin system in vascular dementia: mechanisms and therapeutic perspectives

Dementia is a heterogeneous syndrome characterized by the progressive deterioration of various brain functions, severely impacting cognitive, emotional, and social abilities. According to a World Health Organization (WHO) report, dementia represents a pressing global health concern, with the number of affected individuals projected to triple by 2050. Among its various subtypes, vascular dementia (VD) stands as the second most common form, following Alzheimer's disease (AD). Despite ongoing efforts in drug development, no pharmaceutical entity has yet received approval from the U.S. Food and Drug Administration (FDA) for the treatment of VD. Emerging evidence underscores the critical involvement of the brain's Renin-Angiotensin System (RAS) in the pathogenesis of multiple neurodegenerative disorders, including VD. The intricate roles of RAS components include regulating vascular tone, neuronal growth and survival, regulating cerebral blood flow and endothelial dysfunction, increasing neuroinflammation (by increasing release of IL-1, IL-6, TNF-α, microglial activation), oxidative stress and destruction of BBB integrity, mainly through Angiotensin II type 1 (AT1) and type 2 (AT2) receptors, are of significant interest in the pathophysiology of VD. However, disruptions in these signaling pathways are believed to contribute substantially to the progression of VD. This review addresses the limitations of current therapeutic approaches for VD while emphasizing the untapped potential of RAS-targeted interventions. We systematically explore the neurophysiological mechanisms of brain RAS, their role in promoting neuronal health, and the factors that compromise these pathways, ultimately leading to cognitive decline. By elucidating these mechanisms and challenges, the review offers novel insights into designing innovative RAS-based therapeutic strategies, paving the way for effective clinical management of VD. This work aspires to stimulate further research and development in this underexplored yet promising domain.

Bipolar Disorder and Manic-Like Symptoms in Alzheimer's, Vascular and Frontotemporal Dementia: A Systematic Review

BACKGROUND

An increased risk of manic episodes has been reported in patients with neurodegenerative disorders, but the clinical features of bipolar disorder (BD) in different subtypes of dementia have not been thoroughly investigated.

OBJECTIVES

The main aim of this study is to systematically review clinical and therapeutic evidence about manic syndromes in patients with Alzheimer's disease (AD), vascular dementia (VaD), and frontotemporal dementia (FTD). Since manic-mixed episodes have been associated to negative outcomes in patients with dementia and often require medical intervention, we also critically summarized selected studies with relevance for the treatment of mania in patients with cognitive decline.

METHODS

A systematic review of the literature was conducted according to PRISMA guidelines. PubMed, Scopus, and Web of Science databases were searched up to February 2022. Sixty-one articles on patients with AD, VaD, or FTD and BD or (hypo) mania have been included.

RESULTS

Manic symptoms seem to be associated to disease progression in AD, have a greatly variable temporal relationship with cognitive decline in VaD, and frequently coincide with or precede cognitive impairment in FTD. Overall, mood stabilizers, and electroconvulsive therapy may be the most effective treatments, while the benefits of short-term treatment with antipsychotic agents must be balanced with the associated risks. Importantly, low-dose lithium salts may exert neuroprotective activity in patients with AD.

CONCLUSION

Prevalence, course, and characteristics of manic syndromes in patients with dementia may be differentially affected by the nature of the underlying neurodegenerative conditions.