Rivastigmine for subcortical vascular dementia

Rivastigmine Regulates the HIF-1α/VEGF Signaling Pathway to Induce Angiogenesis and Improves the Survival of Random Flaps in Rats

Random skin flaps are frequently used to repair skin damage. However, the ischemic and hypoxic necrosis limits their wider application. Rivastigmine, a carbamate cholinesterase inhibitor (ChEI), has also been shown to reduce ischemia–reperfusion injury (IRI) and inflammation. This study was performed to examine the effect of rivastigmine on flap survival. Sixty male Sprague–Dawley rats with a modified McFarland flap were randomly divided into three groups: control group, 1 ml of solvent (10% DMSO + 90% corn oil); low-dose rivastigmine group (Riv-L), 1.0 mg/kg; and high-dose rivastigmine group (Riv-H), 2.0 mg/kg. All rats were treated once a day. On day 7, the skin flap survival area was measured. After staining with hematoxylin and eosin (H&E), the pathological changes and microvessel density (MVD) were examined. The expression of inflammatory factors IL-1β and IL-18, CD34, hypoxia-inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF) was examined by immunohistochemical staining. The malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were examined to determine the degree of oxidative stress. Lead oxide/gelatin angiography showed neovascularization and laser Doppler blood flowmetry showed the blood filling volume. Rivastigmine significantly increased the flap survival area and improved neovascularization. CD34, VEGF, and HIF-1α expression were increased, These changes were more pronounced in the Riv-H group. Treatment with rivastigmine reduced the level of MDA, improved SOD activity, and reduced expression of IL-1β and IL-18. Our results indicate that Rivastigmine can increase angiogenesis and significantly improve flap survival.

Rivastigmine: the advantages of dual inhibition of acetylcholinesterase and butyrylcholinesterase and its role in subcortical vascular dementia and Parkinson's disease dementia

Several studies have demonstrated clinical benefits of sustained cholinesterase inhibition with rivastigmine in Alzheimer's disease (AD) and Parkinson's disease dementia (PDD). Unlike donepezil and galantamine that selectively inhibit acetylcholinesterase (AChE; EC 3.1.1.7), rivastigmine is a unique cholinesterase inhibitor with both AChE and butyrylcholinesterase (BuChE; EC 3.1.1.8) inhibitory activity. Rivastigmine is also available as transdermal patch that has been approved by the US Food and Drug Administration for the treatment of mild, moderate, and severe AD as well as mild-to-moderate PDD. In this review, we explore the role of BuChE inhibition in addition to AChE inhibition with rivastigmine in the outcomes of cognition, global function, behavioral symptoms, and activities of daily living. Additionally, we review the evidence supporting the use of dual AChE-BuChE inhibitory activity of rivastigmine as a therapeutic strategy in the treatment of neurological disorders, with a focus on the role of rivastigmine in subcortical dementias such as vascular dementia (VaD) and PDD. Toward this objective, we performed a literature search in PubMed and Ovid with limits to articles published in the English language before June 2016. The available evidence from the literature suggests that the dual inhibition of AChE and BuChE may afford additional therapeutic potential of rivastigmine in subcortical dementias (subcortical VaD and PDD) with benefits on cognition and behavioral symptoms. Rivastigmine was found to specifically benefit executive dysfunction frequently observed in subcortical dementias; however, large randomized clinical studies are warranted to support these observations.

Synthesis and in vitro and in vivo evaluation of 18F-labeled positron emission tomography (PET) ligands for imaging the vesicular acetylcholine transporter

A new class of vesicular acetylcholine transporter inhibitor that incorporates a carbonyl group into the benzovesamicol structure was synthesized, and analogues were evaluated in vitro. (+/-)-trans-2-Hydroxy-3-(4-(4-[(18)F]fluorobenzoyl)piperidino)tetralin (9e) has K(i) values of 2.70 nM for VAChT, 191 nM for sigma(1), and 251 nM for sigma(2). The racemic precursor (9d) was resolved via chiral HPLC, and (+/-)-[(18)F]9e, (-)-[(18)F]9e, and (+)-[(18)F]9e were respectively radiolabeled via microwave irradiation of the appropriate precursors with [(18)F]/F(-) and Kryptofix/K(2)CO(3) in DMSO with radiochemical yields of approximately 50-60% and specific activities of >2000 mCi/micromol. (-)-[(18)F]9e uptake in rat brain was consistent with in vivo selectivity for the VAChT with an initial uptake of 0.911 %ID/g in rat striatum and a striatum/cerebellum ratio of 1.88 at 30 min postinjection (p.i.). MicroPET imaging of macaques demonstrated a 2.1 ratio of (-)-[(18)F]9e in putamen versus cerebellum at 2 h p.i. (-)-[(18)F]9e has potential to be a PET tracer for clinical imaging of the VAChT.

Cholinergic precursors in the treatment of cognitive impairment of vascular origin: ineffective approaches or need for re-evaluation?

Inhibition of endogenous acetylcholine degradation through cholinesterase inhibitors represents a milestone in symptomatic treatment of cognitive symptoms in mild to moderate stages of Alzheimer's disease. Cholinesterase inhibitors are also under investigation for treating cognitive dysfunction of cerebrovascular origin, but to date they do not have specific indication for vascular dementia or vascular cognitive impairment. This paper reviews the main clinical studies assessing the activity of cholinergic precursors in the treatment of adult-onset dementia disorders of vascular origin. The first cholinergic precursor used phosphatidylcholine (lecithin) did not show any clear clinical benefit on symptoms of dementia disorders. The same is not true for other phospholipids involved in choline biosynthetic pathways such as cytidine 5'-diphosphocholine (CDP-choline) and choline alphoscerate for which a modest improvement of cognitive dysfunction in dementia of neurodegenerative and vascular origin is documented. Positive results obtained with selected cholinergic precursors cannot be generalized due to the small numbers of patients studied in appropriate clinical trials. However, they probably would justify reconsideration of the most promising molecules in larger carefully controlled studies.

Use of antidementia agents in vascular dementia: beyond Alzheimer disease

Vascular dementia (VaD) is the second leading cause of dementia and is often underdiagnosed. Stroke is the leading cause of VaD, although it may also develop secondary to a variety of other cerebrovascular or cardiovascular conditions. Currently, no drugs are approved for the treatment of VaD. However, because cholinergic deficits have been found in patients with VaD, similar to those found in patients with Alzheimer disease (AD), it is believed that cholinesterase inhibitors, which are indicated for the treatment of mild to moderate AD, may also provide benefit for patients with VaD. Clinical trials of donepezil, galantamine, and rivastigmine have supported this idea, although as yet, large-scale, prospective studies in VaD have only been reported for donepezil. Donepezil was shown to provide benefits in cognition, global function, and activities of daily living compared with placebo. The N-methyl-D-aspartate receptor antagonist memantine may also provide some cognitive benefit in VaD, particularly in patients with more advanced disease. These data suggest that antidementia drugs currently used for treatment of AD should be considered for treatment of VaD as well.

Rehabilitation of the Older Adult with Stroke

Stroke is an increasing public health concern throughout the world as the leading cause of long-term disability. It is well known that there exist differences related to epidemiology, pathophysiology, comorbidity, and functional outcome of stroke patients with advanced age compared with the young. Factors that have been suggested to influence this disparity include age-related complications, availability of resources, lack of aggressive management, and possible diminished capacity for neuroplasticity. This article reviews the current medical and rehabilitative aspects of stroke and the possible disparities related to advanced age.

White matter hyperintensities and cortical acetylcholinesterase activity in parkinsonian dementia

OBJECTIVE

To investigate the relationship between the severity of white matter hyperintensities (WMH) and cortical acetylcholinesterase (AChE) activity in parkinsonian dementia (PDem).

METHODS

PDem (n = 11) and control subjects (n = 14) underwent [11C]methyl-4-piperidinyl propionate (11C-PMP) AChE brain positron emission tomography and magnetic resonance (MR) imaging. Presence of WMH on proton density and T2 MR images was scored using a modified version of the semi-quantitative rating scale by Scheltens et al. [J Neurol Sci114 (1993)].

RESULTS

Analysis demonstrated significantly lower mean cortical (11)C-PMP k3 hydrolysis rates in PDem (-19.9%) when compared with control subjects (P < 0.0001). PDem subjects had higher mean severity of WMH (+20.1%) when compared with control subjects (P < 0.05). When WMH severity was entered into the analysis of variance model, there was no significant co-variate effect on cortical AChE activity (F = 0.24, ns).

CONCLUSIONS

The concomitant presence of mild to moderate WMH in patients with PDem does not have a significant effect on cortical AChE activity.