The Neurovascular Unit in Dementia: An Opinion on Current Research and Future Directions

Essential New Complexity-Based Themes for Patient-Centered Diagnosis and Treatment of Dementia and Predementia in Older People: Multimorbidity and Multilevel Phenomenology

Dementia is a highly prevalent condition with devastating clinical and socioeconomic sequela. It is expected to triple in prevalence by 2050. No treatment is currently known to be effective. Symptomatic late-onset dementia and predementia (SLODP) affects 95% of patients with the syndrome. In contrast to trials of pharmacological prevention, no treatment is suggested to remediate or cure these symptomatic patients. SLODP but not young onset dementia is intensely associated with multimorbidity (MUM), including brain-perturbating conditions (BPCs). Recent studies showed that MUM/BPCs have a major role in the pathogenesis of SLODP. Fortunately, most MUM/BPCs are medically treatable, and thus, their treatment may modify and improve SLODP, relieving suffering and reducing its clinical and socioeconomic threats. Regrettably, the complex system features of SLODP impede the diagnosis and treatment of the potentially remediable conditions (PRCs) associated with them, mainly due to failure of pattern recognition and a flawed diagnostic workup. We suggest incorporating two SLODP-specific conceptual themes into the diagnostic workup: MUM/BPC and multilevel phenomenological themes. By doing so, we were able to improve the diagnostic accuracy of SLODP components and optimize detecting and favorably treating PRCs. These revolutionary concepts and their implications for remediability and other parameters are discussed in the paper.

Interaction Between Arteriosclerosis and Amyloid-β on Cognitive Function

BACKGROUND

Dementia is a multifactorial disease, with Alzheimer's disease (AD) and vascular pathology often co-occurring in many individuals with dementia. Yet, the interplay between AD and vascular pathology in cognitive decline is largely undetermined.

OBJECTIVE

The aim of the present study was to examine the joint effect of arteriosclerosis and AD pathology on cognition in the general population without dementia.

METHODS

We determined the interaction between blood-based AD biomarkers and CT-defined arteriosclerosis on cognition in 2,229 dementia-free participants of the population-based Rotterdam Study (mean age: 68.9 years, 52% women) cross-sectionally.

RESULTS

Amyloid-β (Aβ)42 and arterial calcification were associated with cognitive performance. After further adjustment for confounders in a model that combined all biomarkers, only arterial calcification remained independently associated with cognition. There was a significant interaction between arterial calcification and Aβ42 and between arterial calcification and the ratio of Aβ42/40. Yet, estimates attenuated, and interactions were no longer statistically significant after adjustment for cardio metabolic risk factors.

CONCLUSIONS

Arteriosclerosis and AD display additive interaction-effects on cognition in the general population, that are due in part to cardio metabolic risk factors. These findings suggest that joint assessment of arteriosclerosis and AD pathology is important for understanding of disease etiology in individuals with cognitive impairment.

Neurovascular glial unit: A target of phytotherapy for cognitive impairments

BACKGROUND

Neurovascular glial unit (NVGU) dysfunction has been reported to be an early and critical event in the pathophysiology of Alzheimer's disease (AD) and vascular dementia (VD). Although herbal medicines, with their favorable safety profiles and low adverse effects, have been suggested to be useful for the treatment of cognitive impairment, the potential role of the NVGU as the target of the effects of herbal medicines is still unclear.

PURPOSE

This review aimed to retrieve evidence from experimental studies of phytopharmaceuticals targeting the NVGU for the treatment of cognitive impairment in AD and VD, and discussed the potential of phytopharmaceuticals to improve cognitive impairment from the perspective of the NVGU.

STUDY DESIGN AND METHODS

We systematically searched PubMed, Google Scholar, Web of Science, and CNKI. The keywords used for searching information on the NVGU in the treatment of cognitive impairments included "Alzheimer's disease," "Vascular dementia," "Herbal medicines," "Natural products," "Neurovascular," "Adverse reaction," and "Toxicity, etc." We selected studies on the basis of predefined eligibility criteria.

RESULTS

NVGU mainly consists of endothelial cells, pericytes, astrocytes, microglia, oligodendrocytes, and neurons, and damage to these cells can induce cognitive impairment by impairing the blood-brain barrier (BBB) and cerebral blood flow (CBF) as well as neuronal function. The active components of herbal medicines, including Ginkgo biloba L., Ginseng Radix et Rhizoma, Epimedium Folium, Chuanxiong Rhizoma, Carthami flos, and Acorus tatarinowii Schott, as well as traditional Chinese medicine prescriptions have shown the potential to improve BBB function and increase CBF to prevent cognitive impairment by inhibiting astrocyte and microglia activation, protecting oligodendrocyte myelin function, reducing neuronal apoptosis, and promoting angiogenesis.

CONCLUSIONS

Herbal medicines demonstrate great potential to prevent cognitive impairment. Multiple components from herbal medicines may function through different signaling pathways to target the NVGU. Future studies using novel drug-carrier or delivery systems targeting the NVGU will certainly facilitate the development of phytopharmaceuticals for AD and VD.

Cerebral blood flow regulation is not acutely altered after a typical number of headers in women footballers

BACKGROUND

The repeated act of heading has been implicated in the link between football participation and risk of neurodegenerative disease, and acutely alters cerebrovascular outcomes in men. This study assessed whether exposure to a realistic number of headers acutely influences indices of cerebral blood flow regulation in female footballers.

METHODS

Nineteen female players completed a heading trial and seated control trial on two separate days. The heading trial involved six headers in 1 h (one every 10 min), with the ball traveling at 40 ± 5 km/h. Cerebrovascular reactivity to hypercapnia and hypocapnia was determined using serial breath holding and hyperventilation attempts. Dynamic cerebral autoregulation (dCA) was assessed by scrutinizing the relationship between cerebral blood flow and mean arterial blood pressure during 5 min of squat stand maneuvers at 0.05 Hz. Neurovascular coupling (NVC) was quantified as the posterior cerebral artery blood velocity response to a visual search task. These outcomes were assessed before and 1 h after the heading or control trial.

RESULTS

No significant time by trial interaction was present for the hypercapnic (P = 0.48,η p 2 = 0.05) and hypocapnic (P = 0.47,η p 2 = 0.06) challenge. Similarly, no significant interaction effect was present for any metric of dCA (P > 0.12,η p 2 < 0.16 for all) or NVC (P > 0.14,η p 2 < 0.15 for all).

CONCLUSION

The cerebral blood flow response to changes in carbon dioxide, blood pressure and a visual search task were not altered following six headers in female footballers. Further study is needed to observe whether changes are apparent after more prolonged exposure.

Postcovid Syndrome – The New Reality

The second year of the COVID-19 pandemic has demonstrated the need for detection and assessment of the long-term consequences SARS-CoV-2 infection, including adequate cognitive functioning. This review addresses our current understanding of the direct and indirect mechanisms of nervous system infection in COVID-19, paying special attention to cause-effect relationships between SARS-CoV-2 infection and long-term neuropsychological disorders. Understanding the pathogenesis of neurological impairments in COVID-19 is important for studies of the long-term sequelae of the disease and for identifying preventive and therapeutic possibilities in relation to brain damage. Further studies of nervous system lesions in COVID-19 are clearly needed to expand existing knowledge. Early initiation of therapeutic measures for emerging disorders will probably have decisive importance for improving quality of life for many COVID-19 survivors.

Protective Effect of Rivaroxaban Against Amyloid Pathology and Neuroinflammation Through Inhibiting PAR-1 and PAR-2 in Alzheimer's Disease Mice

BACKGROUND

Recent studies have revealed that atrial fibrillation (AF) patients have a high risk of developing cognitive impairment, vascular dementia, and Alzheimer's disease (AD). Some reports suggest that the application of oral anticoagulant with an appropriate dose may have a preventive effect on AD. However, which oral anticoagulant drug is more appropriate for preventing AD and the underlying mechanism(s) is still unknown.

OBJECTIVE

The aim of the present study was to assess the treatment effect of rivaroxaban administration as well as investigate the roles of PAR-1 and PAR-2 in the AD + CAA mice model.

METHODS

In the present study, we compared a traditional oral anticoagulant, warfarin, and a direct oral anticoagulant (DOAC), rivaroxaban, via long-term administration to an AD with cerebral amyloid angiopathy (CAA) mice model.

RESULTS

Rivaroxaban treatment attenuated neuroinflammation, blood-brain barrier dysfunction, memory deficits, and amyloid-β deposition through PAR-1/PAR-2 inhibition in the AD + CAA mice model compared with warfarin and no-treatment groups.

CONCLUSION

The present study demonstrates that rivaroxaban can attenuate AD progress and can be a potential choice to prevent AD.

[Postcovid syndrome - a new reality]

The second year of the COVID-19 (Coronavirus Disease 2019) pandemic has seen the need to identify and assess the long-term consequences of a SARS-CoV-2 (Severe acute respiratory syndrome coronavirus-2) infection on an individual's, including adequate cognitive functioning. This review is attempting to highlight the current understanding of the various direct and indirect mechanisms of nervous system damage, describing the causality of similar symptoms following SARS-CoV-2 infection. This understanding is essential to establish the long-term consequences from the disease (including the potential for increased risk of dementia in some cases) and to identify means of preventing or ameliorating the brain damage. There is urgent need for research to better understand the pathogenesis of neurological disturbances in COVID-19, some of which have probably been covert and the prevalence of which may be considerably underestimated. Neuropsychiatric monitoring follow-up of COVID-19 patients will be important in determining the extent and prevalence of long-term neurological and psychiatric consequences of COVID-19. Early intervention for emerging these problems will be critical for improving quality of life for many COVID-19 survivors.