Shedding Light on the Effects of Blood Pressure on Cognitive Decline and Dementia Risk by Way of Neurobiological Evidence

Midlife cerebrovascular risk factors increase risk of late life cognitive impairment and dementia, while their presence in patients with dementia may lead to cognitive improvement or stabilization in late life. Defining the best measure of blood pressure (BP) to be associated with cognitive decline remains debatable, also due to possible bidirectionality. BP variability, pulse pressure, systolic and diastolic BP have been associated with cognitive status, dementia risk and Alzheimer's disease biomarkers. Proper BP control notwithstanding, BP variability increases risk for pathophysiological change in the Alzheimer's disease continuum, implying the need for selection of anti-hypertensive drugs with neurobiological evidence of benefits.

Pharmacogenetics of angiotensin modulators according to APOE-ϵ4 alleles and the ACE insertion/deletion polymorphism in Alzheimer's disease

OBJECTIVE

In Alzheimer's disease (AD), angiotensin II receptor blockers (ARBs) could reduce cerebrovascular dysfunction, while angiotensin-converting enzyme inhibitors (ACEis) might increase brain amyloid-β by suppressing effects of the angiotensin-converting enzyme 1, an amyloid-β-degrading enzyme. However, ACEis could benefit patients with AD by reducing the amyloidogenic processing of the amyloid precursor protein, by central cholinergic and anti-inflammatory mechanisms, and by peripheral modulation of glucose homeostasis. We aimed to investigate whether the ACE insertion/deletion polymorphism is associated with clinical changes in patients with AD, while considering apolipoprotein E (APOE)-ϵ4 carrier status and blood pressure response to angiotensin modulators.

METHODS

Consecutive outpatients with late-onset AD were screened with cognitive tests and anthropometric measurements, while their caregivers were queried for functional and caregiver burden scores. Prospective pharmacogenetic associations were estimated for 1 year, taking APOE-ϵ4 carrier status and genotypes of the ACE insertion/deletion polymorphism into account, along with treatment with ACEis or ARBs.

RESULTS

For 193 patients (67.4% women, 53.4% APOE-ϵ4 carriers), the ACE insertion/deletion polymorphism was in Hardy-Weinberg equilibrium (p = 0.281), while arterial hypertension was prevalent in 80.3% (n = 124 used an ACEi, n = 21 used an ARB). ARBs benefitted mostly APOE-ϵ4 carriers concerning caregiver burden variations, cognitive and functional decline. ACEis benefitted APOE-ϵ4 non-carriers concerning cognitive and functional decline due to improved blood pressure control in addition to possible central mechanisms. The ACE insertion/deletion polymorphism led to variable response to angiotensin modulators concerning neurological outcomes and blood pressure variations.

CONCLUSION

Angiotensin modulators may be disease-modifiers in AD, while genetic stratification of samples is recommended in clinical studies.

Pitfalls and biases in neuroepidemiological studies of COVID-19 and the nervous system: a critical appraisal of the current evidence and future directions

BACKGROUND

Neurological manifestations frequently occur in individuals with COVID-19, manifesting during the acute phase, persisting beyond the resolution of acute symptoms, and appearing days or weeks after the initial onset of COVID-19 symptoms. However, predicting the incidence, course, and outcome of these neurological manifestations at the individual patient level remains challenging. Biases in study design and limitations in data collection may contribute to the inconsistency and limited validity of the reported findings. Herein, we focused on critically appraising pitfalls and biases of prior reports and provide guidance for improving the quality and standardization of future research. Patients with COVID-19 exhibit diverse demographic features, sociocultural backgrounds, lifestyle habits, and comorbidities, all of which can influence the severity and progression of the infection and its impact on other organ systems. Overlooked or undocumented comorbidities and related treatments may contribute to neurological sequelae, which may not solely be attributable to COVID-19. It is crucial to consider the potential side effects of vaccines in relation to neurological manifestations.

CONCLUSION

To investigate neurological manifestations of COVID-19, it is essential to employ valid and reliable diagnostic criteria and standard definitions of the factors of interest. Although population-based studies are lacking, well-defined inception cohorts, including hospitalized individuals, outpatients, and community residents, can serve as valuable compromises. These cohorts should be evaluated for the presence of common comorbidities, alongside documenting the primary non-neurological manifestations of the infectious disease. Lastly, patients with COVID-19 should be followed beyond the acute phase to assess the persistence, duration, and severity of neurological symptoms, signs, or diseases.

Looking Behind the Curtain: Patient Stratification According to Genetic or Demographic Factors May Yield Unexpected Results in Studies of Neurodegenerative Diseases

Amyloid-PET studies of neurodegenerative diseases may yield inconclusive findings due to lacking stratification according to genetic or demographic variants. APOEɛ4 alleles are the major variants to increase disease susceptibility and cause earlier onset and more behavioral features in patients with late-onset Alzheimer's disease, but have no linear effects on cognitive or functional decline; thus, sample stratification according to APOEɛ4 carrier status may be the best option. Interactions among APOEɛ4 alleles, sex, and age on amyloid-β deposition may reveal even more innovative findings with sufficiently large samples, suggesting variable genomic effects of cognitive reserve, sex differences, and cerebrovascular risk on neurodegeneration.

Differential associations of clinical features with cerebrospinal fluid biomarkers in dementia with Lewy bodies and Alzheimer's disease

AIM

To explore associations of cerebrospinal fluid biomarkers of neurodegeneration and amyloidosis with caregiver burden, cognition and functionality in dementia with Lewy bodies (DLB) paired with late-onset Alzheimer's disease (AD) and healthy older people.

METHODS

Consecutive outpatients with DLB were matched with outpatients with AD according to sex, cognitive scores and dementia stage, and with cognitively healthy controls according to age and sex to investigate associations of cerebrospinal fluid amyloid-β (Aβ₄₂,Aβ₄₀,Aβ₃₈), tau, phospho-tau Thr₁₈₁, ubiquitin, α-synuclein and neurofilament light with caregiver burden, functionality, reverse digit span, a clock drawing test, Mini-Mental State Examination (MMSE) and Severe MMSE, adjusted for sex, age, education, dementia duration and APOE-ε4 alleles.

RESULTS

Overall, 27 patients with DLB (78.98 ± 9.0 years-old; eleven APOE-ε4 +) were paired with 27 patients with AD (81.50 ± 5.8 years-old; twelve APOE-ε4 +) and 27 controls (78.98 ± 8.7 years-old; four APOE-ε4 +); two-thirds were women. In AD, Aβ₄₂/Aβ₃₈ and Aβ₄₂ were lower, while tau/Aβ₄₂ and phospho-tau Thr₁₈₁/Aβ₄₂ were higher; α-synuclein/Aβ₄₂ was lower in DLB and higher in AD. The following corrected associations remained significant: in DLB, instrumental functionality was inversely associated with tau/phospho-tau Thr₁₈₁ and tau/Aβ₄₂, and reverse digit span associated with α-synuclein; in AD, instrumental functionality was inversely associated with neurofilament light, clock drawing test scores inversely associated with phospho-tau Thr₁₈₁/Aβ₄₂ and α-synuclein/Aβ₄₂, and Severe MMSE inversely associated with tau/Aβ₄₂ and tau/phospho-tau Thr₁₈₁.

CONCLUSIONS

Cerebrospinal fluid phospho-tau Thr₁₈₁ in DLB was similar to AD, but not Aβ₄₂. In associations with test scores, biomarker ratios were superior to isolated biomarkers, while worse functionality was associated with axonal degeneration only in AD.

APOE ε4 Carrier Status as Mediator of Effects of Psychotropic Drugs on Clinical Changes in Patients With Alzheimer's Disease

OBJECTIVE

Neuropsychiatric syndromes have been associated with memory dysfunction and risk of and earlier onset of dementia, but how psychotropic drugs affect clinical changes in Alzheimer's disease is not entirely clear. This study aimed to assess the prospective effects of psychotropic drugs on cognitive and functional changes in Alzheimer's disease according to APOE ε4 carrier status.

METHODS

The study included consecutive outpatients with late-onset Alzheimer's disease (N=193) and examined score variations at 1 year on the following tests: Clinical Dementia Rating sum of boxes, Mini-Mental State Examination, Severe Mini-Mental State Examination (SMMSE), Brazilian version of the Zarit Caregiver Burden Interview, Index of Independence in Activities of Daily Living, and Lawton's Instrumental Activities of Daily Living Scale. Analyses of score variations accounted for the use of psychotropic drugs or the number of different medications in use, as well as APOE ε4 carrier status, with significance at p<0.05.

RESULTS

For APOE ε4 noncarriers (N=90), cholinesterase inhibitors were beneficial regarding caregiver burden (p=0.030) and basic functionality (p=0.046), memantine was harmful regarding SMMSE score changes (p=0.032), second-generation antipsychotics had nonsignificant harmful effects on SMMSE score changes (p=0.070), and antiepileptic therapy (p=0.001) and the number of different medications in use (p=0.006) were harmful in terms of basic functionality. APOE ε4 carriers (N=103) did not experience any effects of isolated psychotropic drugs on clinical changes, including antidepressants.

CONCLUSIONS

Results support the harmful prospective effects of second-generation antipsychotics and antiepileptic drugs on cognitive and functional changes in Alzheimer's disease, particularly for APOE ε4 noncarriers, whereas antidepressants may be safer options for behavioral enhancement.

Vascular cognitive impairment and dementia: An early career researcher perspective

The field of vascular contributions to cognitive impairment and dementia (VCID) is evolving rapidly. Research in VCID encompasses topics aiming to understand, prevent, and treat the detrimental effects of vascular disease burden in the human brain. In this perspective piece, early career researchers (ECRs) in the field provide an overview of VCID, discuss past and present efforts, and highlight priorities for future research. We emphasize the following critical points as the field progresses: (a) consolidate existing neuroimaging and fluid biomarkers, and establish their utility for pharmacological and non-pharmacological interventions; (b) develop new biomarkers, and new non-clinical models that better recapitulate vascular pathologies; (c) amplify access to emerging biomarker and imaging techniques; (d) validate findings from previous investigations in diverse populations, including those at higher risk of cognitive impairment (e.g., Black, Hispanic, and Indigenous populations); and (e) conduct randomized controlled trials within diverse populations with well-characterized vascular pathologies emphasizing clinically meaningful outcomes.

Pharmacogenetic Analyses of Therapeutic Effects of Lipophilic Statins on Cognitive and Functional Changes in Alzheimer’s Disease

Background: Pharmacogenetic effects of statins on clinical changes in Alzheimer’s disease (AD) could be mediated by epistatic interactions among relevant genetic variants involved in cholesterol metabolism. Objective: To investigate associations of HMGCR (rs3846662), NR1H2 (rs2695121), or CETP (rs5882&rs708272) with cognitive and functional changes in AD, with stratification according to APOE ɛ4 carrier status and lipid-lowering treatment with lipophilic statins. Methods: Consecutive outpatients with late-onset AD were screened with cognitive tests, while caregivers scored functionality and global ratings, with prospective neurotranslational associations documented for one year. Results: Considering n = 190:142 had hypercholesterolemia, 139 used lipophilic statins; minor allele frequencies were 0.379 (rs2695121-T:46.3% heterozygotes), 0.368 (rs5882-G:49.5% heterozygotes), and 0.371 (rs708272-A:53.2% heterozygotes), all in Hardy-Weinberg equilibrium. For APOE ɛ4 carriers: rs5882-GG protected from cognitive decline; rs5882-AA caused faster cognitive decline; carriers of rs2695121-CC or rs5882-AA were more susceptible to harmful cognitive effects of lipophilic statins; carriers of rs5882-GG or rs708272-AG had functional benefits when using lipophilic statins. APOE ɛ4 non-carriers resisted any cognitive or functional effects of lipophilic statins, while invariability of rs3846662 (all AA) prevented the assessment of HMGCR effects. When assessing CETP haplotypes only: rs5882-GG protected from cognitive and functional decline, regardless of lipophilic statin therapy; lipophilic statins usually caused cognitive and functional harm to carriers of rs5882-A and/or rs708272-A; lipophilic statins benefitted cognition and functionality of carriers of rs5882-G and/or rs708272-G. Conclusion: Reportedly protective variants of CETP and NR1H2 also slowed cognitive and functional decline particularly for APOE ɛ4 carriers, and regardless of cholesterol variations, while therapy with lipophilic statins might affect carriers of specific genetic variants.

Harmonizing neuropsychological assessment for mild neurocognitive disorders in Europe

INTRODUCTION

Harmonized neuropsychological assessment for neurocognitive disorders, an international priority for valid and reliable diagnostic procedures, has been achieved only in specific countries or research contexts.

METHODS

To harmonize the assessment of mild cognitive impairment in Europe, a workshop (Geneva, May 2018) convened stakeholders, methodologists, academic, and non-academic clinicians and experts from European, US, and Australian harmonization initiatives.

RESULTS

With formal presentations and thematic working-groups we defined a standard battery consistent with the U.S. Uniform DataSet, version 3, and homogeneous methodology to obtain consistent normative data across tests and languages. Adaptations consist of including two tests specific to typical Alzheimer's disease and behavioral variant frontotemporal dementia. The methodology for harmonized normative data includes consensus definition of cognitively normal controls, classification of confounding factors (age, sex, and education), and calculation of minimum sample sizes.

DISCUSSION

This expert consensus allows harmonizing the diagnosis of neurocognitive disorders across European countries and possibly beyond.

Behavioural effects of the ACE insertion/deletion polymorphism in Alzheimer's disease depend upon stratification according to APOE-ϵ4 carrier status

Introduction: The inherited risk of late-onset Alzheimer's disease (AD) is genetically determined. We aimed to examine associations of genetic variants of APOE and ACE with age at AD onset and with neuropsychiatric symptoms according to each dementia stage.Methods: Consecutive outpatients with AD were assessed for demographic features, Clinical Dementia Rating scores, and the 10-item Neuropsychiatric Inventory, and genotyped for rs7412 and rs429358 (APOE haplotypes, Real-Time Polymerase Chain Reactions), and the ACE insertion/deletion polymorphism (Polymerase Chain Reactions). Combined genetic variants of APOE and ACE were associated with age at dementia onset, and with neuropsychiatric symptoms in each dementia stage (adjusted for sex and age at dementia onset).Results: Over two-thirds of the 238 patients were women, whereas the mean age at dementia onset was 73.82 ± 6.2 years-old. APOE-ϵ4/ϵ4 carriers had earlier dementia onset (p<.001). The ACE insertion/deletion polymorphism was in Hardy-Weinberg equilibrium (p=.37) but was not associated with age at dementia onset, regardless of APOE-ϵ4 carrier status. The only results that survived corrections for false discovery rates were higher scores of dysphoria for APOE-ϵ4 carriers (n=122) who also carried ACE deletion/deletion (p=.031). No results survived corrections for false discovery rates for APOE-ϵ4 non-carriers (n=116).Conclusions: Though only the APOE-ϵ4/ϵ4 haplotype affected AD onset, effects of the ACE insertion/deletion polymorphism over behavioural features might differ according to APOE-ϵ4 carrier status in genetic associations.

Associations of Neuropsychiatric Features with Cerebrospinal Fluid Biomarkers of Amyloidogenesis and Neurodegeneration in Dementia with Lewy Bodies Compared with Alzheimer's Disease and Cognitively Healthy People

BACKGROUND

Behavioral features may reflect proteinopathies predicting pathophysiology in neurodegenerative diseases.

OBJECTIVE

We aimed to investigate associations of cerebrospinal fluid biomarkers of amyloidogenesis and neurodegeneration with neuropsychiatric features in dementia with Lewy bodies (DLB) compared with late-onset Alzheimer's disease (AD) and cognitively healthy people.

METHODS

Consecutive outpatients with DLB were paired with outpatients with AD according to sex, dementia stage, and cognitive scores, and with cognitively healthy controls according to sex and age to investigate associations of cerebrospinal fluid amyloid-β (Aβ)42, Aβ40, Aβ38, total tau, phospho-tau Thr181, α-synuclein, ubiquitin, and neurofilament light with neuropsychiatric features according to APOEɛ4 carrier status.

RESULTS

Overall, 27 patients with DLB (78.48±9.0 years old, eleven APOEɛ4 carriers) were paired with 27 patients with AD (81.00±5.8 years old, twelve APOEɛ4 carriers) and 27 controls (78.48±8.7 years old, four APOEɛ4 carriers); two thirds were women. Behavioral burden was more intense in DLB. Biomarker ratios reflecting amyloidogenesis and neurodegeneration in DLB were more similar to those in AD when patients carried APOEɛ4 alleles. After corrections for false discovery rates, the following associations remained significant: in DLB, dysphoria was associated with tauopathy and indirect measures of amyloidogenesis, while in AD, agitation, and night-time behavior disturbances were associated with tauopathy, and delusions were associated with tauopathy and indirect measures of amyloidogenesis.

CONCLUSION

Biomarker ratios were superior to Aβ and tau biomarkers predicting neuropsychiatric symptoms when associations with isolated biomarkers were not significant. At the end, APOEɛ4 carrier status influenced amyloidogenesis and tau pathology in DLB and in AD, and axonal degeneration only in DLB.

Swallowing in behavioral variant frontotemporal dementia

BACKGROUND

Swallowing and feeding problems may occur with the progression of behavioral variant frontotemporal dementia (bvFTD) and can impair the anticipatory and oral preparatory phases of swallowing.

OBJECTIVE

To characterize swallowing problems and the feeding situation of patients with bvFTD and to correlate the swallowing problems with functionality, executive functions, cognitive and behavioral features.

METHODS

Consecutive outpatients with bvFTD in mild, moderate and severe dementia stages were recruited along with their caregivers. Patients and caregivers were screened with the following scales: "Mini-Mental State Examination", "Severe Mini-Mental State Examination", "FTLD-modified Clinical Dementia Rating", "Neuropsychiatric Inventory", "Frontal Assessment Battery", "Index of Independence in Activities of Daily Living", "Swallowing Rating Scale" and "Assessment of Feeding and Swallowing Difficulties in Dementia".

RESULTS

Overall, thirty patients with bvFTD were included along with their caregivers. Patients with bvFTD showed feeding and swallowing difficulties such as: messy to eat, passivity, coughing and choking, difficulty with some food consistencies and with specific food. Swallowing problems in bvFTD correlated with impaired functionality (p<0.05) and cognition (p<0.05), executive dysfunction (p<0.01) and behavioral features (p<0.01). Caregivers had great difficulty in managing the feeding situation during mealtime, with different characteristics in each dementia stage.

CONCLUSION

Patients with bvFTD had inappropriate speed eating, passivity, coughing and choking starting in the mild dementia stage, and these problems worsen in the severe stage. Such difficulties affected caregiver performance during mealtime. The correlations indicated that swallowing difficulties tend to follow cognitive and behavioral decline in patients with bvFTD.

Dementia in Latin America: Paving the way toward a regional action plan

Across Latin American and Caribbean countries (LACs), the fight against dementia faces pressing challenges, such as heterogeneity, diversity, political instability, and socioeconomic disparities. These can be addressed more effectively in a collaborative setting that fosters open exchange of knowledge. In this work, the Latin American and Caribbean Consortium on Dementia (LAC-CD) proposes an agenda for integration to deliver a Knowledge to Action Framework (KtAF). First, we summarize evidence-based strategies (epidemiology, genetics, biomarkers, clinical trials, nonpharmacological interventions, networking, and translational research) and align them to current global strategies to translate regional knowledge into transformative actions. Then we characterize key sources of complexity (genetic isolates, admixture in populations, environmental factors, and barriers to effective interventions), map them to the above challenges, and provide the basic mosaics of knowledge toward a KtAF. Finally, we describe strategies supporting the knowledge creation stage that underpins the translational impact of KtAF.

The impact of SARS-CoV-2 in dementia across Latin America: A call for an urgent regional plan and coordinated response

The SARS-CoV-2 global pandemic will disproportionately impact countries with weak economies and vulnerable populations including people with dementia. Latin American and Caribbean countries (LACs) are burdened with unstable economic development, fragile health systems, massive economic disparities, and a high prevalence of dementia. Here, we underscore the selective impact of SARS-CoV-2 on dementia among LACs, the specific strain on health systems devoted to dementia, and the subsequent effect of increasing inequalities among those with dementia in the region. Implementation of best practices for mitigation and containment faces particularly steep challenges in LACs. Based upon our consideration of these issues, we urgently call for a coordinated action plan, including the development of inexpensive mass testing and multilevel regional coordination for dementia care and related actions. Brain health diplomacy should lead to a shared and escalated response across the region, coordinating leadership, and triangulation between governments and international multilateral networks.

Agitation and impulsivity in mid and late life as possible risk markers for incident dementia

To identify knowledge gaps regarding new-onset agitation and impulsivity prior to onset of cognitive impairment or dementia the International Society to Advance Alzheimer's Research and Treatment Neuropsychiatric Syndromes (NPS) Professional Interest Area conducted a scoping review. Extending a series of reviews exploring the pre-dementia risk syndrome Mild Behavioral Impairment (MBI), we focused on late-onset agitation and impulsivity (the MBI impulse dyscontrol domain) and risk of incident cognitive decline and dementia. This scoping review of agitation and impulsivity pre-dementia syndromes summarizes the current biomedical literature in terms of epidemiology, diagnosis and measurement, neurobiology, neuroimaging, biomarkers, course and prognosis, treatment, and ongoing clinical trials. Validations for pre-dementia scales such as the MBI Checklist, and incorporation into longitudinal and intervention trials, are needed to better understand impulse dyscontrol as a risk factor for mild cognitive impairment and dementia.

Pharmacogenetic analyses of variations of measures of cardiovascular risk in Alzheimer's dementia

Background & objectives:

Neurodegeneration affects blood pressure variations, while renal function and cerebral perfusion are impaired by vascular risk factors. This study was aimed to estimate variations of measures of cardiovascular risk in Alzheimer's dementia by pharmacogenetic analyses of the effects of angiotensin-converting enzyme (ACE) inhibitors and statins.

Methods:

Consecutive patients were prospectively followed to study variations of creatinine clearance and blood pressure for one year, estimated by correlating the effects of ACE inhibitors with the ACE Alu I/D polymorphism and genotypes or haplotypes of rs1800764 or rs4291, and the effects of statins with LDLR (low-density lipoprotein receptor) genotypes or haplotypes of rs11669576 (exon 8) or rs5930 (exon 10), or genotypes of rs2695121 (liver X receptor β gene). Variations of the coronary heart disease (CHD) risk according to these cardiovascular measures were also explored.

Results:

All polymorphisms of the 193 patients were in Hardy-Weinberg equilibrium. Genetic determinants of cardiovascular effects affected the individual variability of the response to ACE inhibitors and statins. ACE inhibitors, but not statins, reduced blood pressure for all patients. ACE inhibitors protected carriers of alleles that supposedly decrease serum ACE levels (rs1800764-T, rs4291-A, Alu II) regarding creatinine clearance variations (P<0.005), but carriers of Alu DD (P<0.02), rs1800764-C (P<0.05), or rs4291-AT (P<0.04) showed better blood pressure lowering effects. The presence of rs2695121-T (P=0.007) or rs5930-A (P=0.039) was associated with systolic blood pressure lowering, whereas rs5930-AA was protective against decrease in creatinine clearance (P=0.019). Statins lowered creatinine clearance for carriers of rs2695121-CT (P=0.026).

Interpretation & conclusions:

Pharmacological response of blood pressure and creatinine clearance to ACE inhibitors and statins may be genetically mediated.

Lifetime Risk Factors for Functional and Cognitive Outcomes in Patients with Alzheimer's Disease

Lifetime risk factors for cognitive and functional decline in Alzheimer's disease (AD) are not fully understood, and were prospectively evaluated in patients with low mean schooling from São Paulo, Brazil. Consecutive outpatients with late-onset AD were assessed for APOE haplotypes and the following potential baseline predictors: gender, schooling, age at dementia onset, lifetime urban living and sanitary conditions, occupational complexity, cognitive and physical activities, cerebrovascular risk factors (obesity, lifetime alcohol use and smoking, length of arterial hypertension, diabetes mellitus, and a dyslipidemic profile), use of a pacemaker, creatinine clearance, body mass index, waist circumference, head traumas with unconsciousness, treated systemic bacterial infections, amount of surgical procedures under general anesthesia, and family history of AD. Participants were followed from October 2010 to May 2017 for baseline risk factor associations with time since dementia onset for Clinical Dementia Rating and Mini-Mental State Examination score changes. For 227 patients (154 women, 119 APOE ε 4 carriers), later AD onset (mean 73.60±6.4 years-old, earlier for APOE ε 4/ε 4 carriers, p < 0.001) was the only variable hastening all endpoints, baseline creatinine clearance and lifetime alcohol use were hazardous for earlier cognitive and functional endpoints, women had earlier cognitive endpoints only, and schooling had a cumulative protective effect over later cognitive endpoints, particularly for carriers of APOE ε 4. Exclusively for carriers of APOE ε 4, head traumas with unconsciousness were hazardous for earlier cognitive endpoints, while lifetime sanitary conditions were protective regarding later cognitive endpoints. Functional and cognitive outcomes in AD represent probable interactions between effects of brain reserve and cerebral perfusion over neurodegeneration.

Pharmacogenetics of Angiotensin-Converting Enzyme Inhibitors in Patients with Alzheimer's Disease Dementia

BACKGROUND

While the angiotensin-converting enzyme degrades amyloid-β, angiotensinconverting enzyme inhibitors (ACEis) may slow cognitive decline by way of cholinergic effects, by increasing brain substance P and boosting the activity of neprilysin, and by modulating glucose homeostasis and augmenting the secretion of adipokines to enhance insulin sensitivity in patients with Alzheimer's disease dementia (AD). We aimed to investigate whether ACE gene polymorphisms rs1800764 and rs4291 are associated with cognitive and functional change in patients with AD, while also taking APOE haplotypes and anti-hypertensive treatment with ACEis into account for stratification.

METHODS

Consecutive late-onset AD patients were screened with cognitive tests, while their caregivers were queried for functional and caregiver burden scores. Prospective pharmacogenetic correlations were estimated for one year, considering APOE and ACE genotypes and haplotypes, and treatment with ACEis.

RESULTS

For 193 patients, minor allele frequencies were 0.497 for rs1800764 - C (44.6% heterozygotes) and 0.345 for rs4291 - T (38.9% heterozygotes), both in Hardy-Weinberg equilibrium. Almost 94% of all patients used cholinesterase inhibitors, while 155 (80.3%) had arterial hypertension, and 124 used ACEis. No functional impacts were found regarding any genotypes or pharmacological treatment. Either for carriers of ACE haplotypes that included rs1800764 - T and rs4291 - A, or for APOE4- carriers of rs1800764 - T or rs4291 - T, ACEis slowed cognitive decline independently of blood pressure variations. APOE4+ carriers were not responsive to treatment with ACEis.

CONCLUSION

ACEis may slow cognitive decline for patients with AD, more remarkably for APOE4- carriers of specific ACE genotypes.

Associations of Blood Pressure with Functional and Cognitive Changes in Patients with Alzheimer's Disease

BACKGROUND

Midlife hypertension followed by late life hypotension resulting from neurodegeneration increases amyloidogenesis and tauopathy.

METHODS

Consecutive outpatients with late-onset Alzheimer's disease (AD) at various stages and their respective caregivers were assessed for score variations in 1 year of tests assessing caregiver burden, functionality and cognition according to blood pressure (BP) variations and APOE haplotypes, while also taking into account differential effects of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, calcium channel blockers, diuretics, or no antihypertensive medication on score changes. The diagnosis and treatment of arterial hypertension followed the JNC 7 report.

RESULTS

Variations in systolic BP (-11.76 ± 17.1 mm Hg), diastolic BP (-4.92 ± 10.3 mm Hg) and pulse pressure (-6.84 ± 12.6 mm Hg) were significant after 1 year (n = 191; x03C1; < 0.01). For APOE4+ carriers, rises in systolic or diastolic BP improved Clinical Dementia Rating Scale Sum of Boxes scores (x03C1; < 0.04), with marginally significant improvements in Mini-Mental State Examination scores resulting from risen systolic (x03C1; = 0.069) or diastolic BP (x03C1; = 0.079), and in basic independence only regarding risen diastolic BP (x03C1; = 0.055). APOE4- carriers resisted any functional or cognitive effects of BP variations. No differences were found regarding any antihypertensive class for variations in BP or any test scores, regardless of APOE haplotypes.

CONCLUSIONS

Targeting mild BP elevations brings better functional and cognitive results for APOE4+ carriers with AD.

Neurological impressions on the organization of language networks in the human brain

BACKGROUND

More than 95% of right-handed individuals, as well as almost 80% of left-handed individuals, have left hemisphere dominance for language. The perisylvian networks of the dominant hemisphere tend to be the most important language systems in human brains, usually connected by bidirectional fibres originated from the superior longitudinal fascicle/arcuate fascicle system and potentially modifiable by learning. Neuroplasticity mechanisms take place to preserve neural functions after brain injuries. Language is dependent on a hierarchical interlinkage of serial and parallel processing areas in distinct brain regions considered to be elementary processing units. Whereas aphasic syndromes typically result from injuries to the dominant hemisphere, the extent of the distribution of language functions seems to be variable for each individual.

METHOD

Review of the literature Results: Several theories try to explain the organization of language networks in the human brain from a point of view that involves either modular or distributed processing or sometimes both. The most important evidence for each approach is discussed under the light of modern theories of organization of neural networks.

CONCLUSIONS

Understanding the connectivity patterns of language networks may provide deeper insights into language functions, supporting evidence-based rehabilitation strategies that focus on the enhancement of language organization for patients with aphasic syndromes.

Pharmacogenetic effects of angiotensin-converting enzyme inhibitors over age-related urea and creatinine variations in patients with dementia due to Alzheimer disease

BACKGROUND

Renal function declines according to age and vascular risk factors, whereas few data are available regarding genetically-mediated effects of anti-hypertensives over renal function.

OBJECTIVE

To estimate urea and creatinine variations in dementia due to Alzheimer disease (AD) by way of a pharmacogenetic analysis of the anti-hypertensive effects of angiotensin-converting enzyme inhibitors (ACEis).

METHODS

Consecutive outpatients older than 60 years-old with AD and no history of kidney transplant or dialytic therapy were recruited for prospective correlations regarding variations in fasting blood levels of urea and creatinine in one year, considering ACE genotypes of rs1800764 and rs4291 and their respective haplotypes, and treatment with ACEis along with blood pressure variations.

RESULTS

For 190 patients, 152 had arterial hypertension, and 122 used ACEis. Minor allele frequencies were 0.492 for rs1800764-C and 0.337 for rs4291-T, both in Hardy-Weinberg equilibrium. There were no overall significant yearly variations in levels of urea and creatinine, but their concurrent variations were positively correlated (ρ <0.0001). Each A allele of rs4291 led to an yearly urea increase of 3,074 mg/dL, and an yearly creatinine increase of 0.044 mg/dL, while the use of ACEis was protective regarding creatinine variations. The use of ACEis was also protective for carriers of rs1800764-CT/rs4291-AA, while carriers of rs1800764-CT/rs4291-AT had steeper reductions in creatinine levels, particularly when they were treated with ACEis.

CONCLUSIONS

Effects of ACEis over creatinine variations are genetically mediated and independent of blood pressure variations in older people with AD.

Pharmacogenetic effects of angiotensin-converting enzyme inhibitors over age-related urea and creatinine variations in patients with dementia due to Alzheimer disease

Background: Renal function declines according to age and vascular risk factors, whereas few data are available regarding genetically-mediated effects of anti-hypertensives over renal function. Objective: To estimate urea and creatinine variations in dementia due to Alzheimer disease (AD) by way of a pharmacogenetic analysis of the anti-hypertensive effects of angiotensin-converting enzyme inhibitors (ACEis). Methods: Consecutive outpatients older than 60 years-old with AD and no history of kidney transplant or dialytic therapy were recruited for prospective correlations regarding variations in fasting blood levels of urea and creatinine in one year, considering ACE genotypes of rs1800764 and rs4291 and their respective haplotypes, and treatment with ACEis along with blood pressure variations. Results: For 190 patients, 152 had arterial hypertension, and 122 used ACEis. Minor allele frequencies were 0.492 for rs1800764-C and 0.337 for rs4291-T, both in Hardy-Weinberg equilibrium. There were no overall significant yearly variations in levels of urea and creatinine, but their concurrent variations were positively correlated (ρ <0.0001). Each A allele of rs4291 led to an yearly urea increase of 3.074 mg/dL, and an yearly creatinine increase of 0.044 mg/dL, while the use of ACEis was protective regarding creatinine variations. The use of ACEis was also protective for carriers of rs1800764-CT/rs4291-AA, while carriers of rs1800764-CT/rs4291-AT had steeper reductions in creatinine levels, particularly when they were treated with ACEis. Conclusions: Effects of ACEis over creatinine variations are genetically mediated and independent of blood pressure variations in older people with AD.

Balance impairment does not necessarily coexist with gait apraxia in mild and moderate Alzheimer's disease

OBJECTIVES

To assess correlations among gait apraxia, balance impairment and cognitive performance in mild (AD1, n = 30) and moderate (AD2, n = 30) AD.

METHOD

The following evaluations were undertaken: gait apraxia (Assessment Walking Skills); balance performance (Berg Balance Scale); Clinical Dementia Rating and Mini-mental State Examination (MMSE).

RESULTS

While disregarding AD subgroups, Berg Balance Scale and the MMSE correlated significantly with Assessment Walking Skills and 23% of all subjects scored below its cut-off. After stratification, Berg Balance Scale correlated significantly with Assessment Walking Skills in both AD subgroups, and with the MMSE only in AD1.

CONCLUSIONS

Balance impairment does not necessarily coexist with gait apraxia. Gait apraxia is more prevalent in moderate AD when compared with mild AD.

Brain-penetrating angiotensin-converting enzyme inhibitors and cognitive change in patients with dementia due to Alzheimer's disease

Controversy over benefits of angiotensin-converting enzyme inhibitors (ACEIs) for treatment of dementia due to Alzheimer's disease (AD) led to this alternative investigational approach by the employment of pharmacogenetic methods, correlating the cognitive change of patients with late-onset AD with the presence of common ACE gene promoter polymorphisms, and stratifying the sample in groups of patients who responded or not to the brain-penetrating ACEIs Captopril or Perindopril. A trend was found for treatment with brain-penetrating ACEIs to slow cognitive decline in AD patients with the haplotype rs1800764 (CC): rs4291 (TT) (p = 0.024), and also non-significantly for independent carriers of rs1800764 or rs4291.

Risk factors for age at onset of dementia due to Alzheimer's disease in a sample of patients with low mean schooling from São Paulo, Brazil

OBJECTIVE

In view of the mild effects of pharmacological treatment for dementia due to Alzheimer's disease (AD), the search for modifiable risk factors is an important challenge. Although risk factors for AD are widely recognized, elements that influence the time of onset of the dementia syndrome have not been comprehensively reported. We aimed to investigate which risk factors might be associated with the age at onset of AD in a sample of patients with low mean schooling from São Paulo, Brazil.

METHODS

We included 210 consecutive patients with late-onset AD to investigate whether education, gender, nationality, urban living and sanitation, occupation, cognitive and physical inactivity, head trauma, depression, systemic infections, surgical interventions, cerebrovascular risk factors, family history of neurodegenerative diseases or cardiovascular diseases and apolipoprotein E gene (APOE) haplotypes might be related to the age at AD onset.

RESULTS

Each copy of APOE-ε4 led to onset of AD almost 2 years earlier, while depression, smoking, higher body mass index and family history of cardiovascular diseases were also highly significant. Protective factors included non-Brazilian nationality, use of a pacemaker and waist circumference. Cerebrovascular risk factors had a mild combined effect for earlier onset of AD.

CONCLUSION

APOE haplotypes, depression, nationality and cerebrovascular risk factors were the most important elements to influence the age at AD onset in this sample, whereas gender, education, occupation and physical activities had no isolated effects over the age at onset of this dementia syndrome.

Communicating with the non-dominant hemisphere: Implications for neurological rehabilitation

Aphasic syndromes usually result from injuries to the dominant hemisphere of the brain. Despite the fact that localization of language functions shows little interindividual variability, several brain areas are simultaneously activated when language tasks are undertaken. Mechanisms of language recovery after brain injury to the dominant hemisphere seem to be relatively stereotyped, including activations of perilesional areas in the acute phase and of homologues of language areas in the non-dominant hemisphere in the subacute phase, later returning to dominant hemisphere activation in the chronic phase. Plasticity mechanisms reopen the critical period of language development, more specifically in what leads to disinhibition of the non-dominant hemisphere when brain lesions affect the dominant hemisphere. The non-dominant hemisphere plays an important role during recovery from aphasia, but currently available rehabilitation therapies have shown limited results for efficient language improvement. Large-scale randomized controlled trials that evaluate well-defined interventions in patients with aphasia are needed for stimulation of neuroplasticity mechanisms that enhance the role of the non-dominant hemisphere for language recovery. Ineffective treatment approaches should be replaced by more promising ones and the latter should be evaluated for proper application. The data generated by such studies could substantiate evidence-based rehabilitation strategies for patients with aphasia.

Educational bias in the assessment of severe dementia: Brazilian cutoffs for severe Mini-Mental State Examination

Cognitive assessment in advanced stages of Alzheimer’s disease (AD) is limited by the imprecision of most instruments. Objective: To determine objective cognitive responses in moderate and severe AD patients by way of the Severe Mini-Mental State Examination (SMMSE), and to correlate performances with Mini-Mental State Examination (MMSE) scores. Method: Consecutive outpatients in moderate and severe stages of AD (Clinical Dementia Rating 2.0 or 3.0) were evaluated and compared according to MMSE and SMMSE scores. Results: Overall 400 patients were included, 67.5% females, mean age 76.6±6.7 years-old. There was no significant impact of age or gender over MMSE or SMMSE scores. Mean schooling was 4.4±2.5 years, impacting SMMSE scores (p=0.008). Scores on MMSE and SMMSE were significantly correlated (F-ratio=690.6325, p<0.0001). Conclusion: The SMMSE is influenced by schooling, but not by age or gender, and is an accurate test for assessment of moderate and severe AD.

Pharmacological modulation of cognitive and behavioral symptoms in patients with dementia due to Alzheimer's disease

To evaluate correlations of pharmacological treatment with cognitive and behavioral symptoms in patients with dementia due to Alzheimer's disease with low schooling, subjects were assessed for demographic features, neuropsychiatric symptoms, cognitive decline, functionality, caregiver burden, APOE haplotypes and pharmacological treatment. Among 217 patients, use of cholinesterase inhibitors with or without Memantine was associated with less neuropsychiatric symptoms, while anti-psychotics and/or anti-epileptic drugs were associated with lower instrumental functionality. Anti-psychotics were also associated with more neuropsychiatric symptoms in moderately impaired patients, possibly reflecting the greater need for such treatment when behavioral symptoms are present. Patients receiving more medications were usually younger, obese, married, with higher schooling and more neuropsychiatric symptoms. APOE4+ haplotypes were correlated with earlier dementia onset, but not with pharmacological treatment. Higher caregiver burden was associated with more psychotropic drugs. A trend was found for treatment with cholinesterase inhibitors and Memantine to be associated with longer lengths of dementia for moderately impaired but not for severely impaired patients, regardless of APOE haplotypes, translating into a synergistic effect among such medications for slowing cognitive decline but not for prolonging survival. Further longitudinal studies may be required to assess dose-response relationships regarding treatment with psychotropics for patients with dementia.

A topographic study on the evaluation of speech and language in the acute phase of a first stroke

Evaluation of speech and language may help in localization of site and extension of brain lesions, particularly in the absence of other neurological signs or radiologically defined injuries. OBJECTIVE: To verify what language tasks are best correlated to which brain regions, in order to develop a test for neurologists in emergency settings. METHOD: Thirty-seven adult first-stroke patients were submitted to cognitive and language tests, and then paired with thirty-seven healthy controls. Patients underwent CT and/or MRI for topographic correlation with test results (p<0.05). RESULTS: All tests were able to distinguish patients from controls, but only word/sentence repetition, naming, ideomotor praxis and, non-significantly, comprehension and counting 1-20 predicted left hemisphere lesions. Repetition was related to perisylvian structures, comprehension to the posterior portion of the middle cerebral artery territory, and fluency to frontal lesions, while naming was accurate only for lesion side. CONCLUSION: Language and cognitive tasks can help in the localization of acute stroke lesions.

Global aphasia as a predictor of mortality in the acute phase of a first stroke

OBJECTIVE

To establish whether vascular aphasic syndromes can predict stroke outcomes.

METHOD

Thirty-seven adults were evaluated for speech and language within 72 hours after a single first-ever ischemic brain lesion, in blind association to CT and/or MR.

RESULTS

Speech or language disabilities were found in seven (87.5%) of the eight deceased patients and twenty-six (89.7%) of the twenty-nine survivors. Global aphasia was identified in eleven patients, all with left hemisphere lesions (nine mute; five deceased), consisting on a risk factor for death in the acute stroke phase (ρ=0.022). Age (z=1.65; ρ>0.09), thrombolysis (ρ=0.591), infarct size (ρ=0.076) and side (ρ=0.649) did not significantly influence survival. Absence of aphasia did not predict a better evolution, regardless of the affected hemisphere. Prevalence of cardiovascular risk factors was similar for all patient groups.

CONCLUSION

Global aphasia in acute stroke can adversely affect prognosis, translated into impairment of dominant perisylvian vascular territories, with mutism as an important semiological element.