Future scenarios for the prevention and delay of Alzheimer disease onset in high-risk groups. An ethical perspective

Apolipoprotein E in Cardiometabolic and Neurological Health and Diseases

A preponderance of evidence obtained from genetically modified mice and human population studies reveals the association of apolipoprotein E (apoE) deficiency and polymorphisms with pathogenesis of numerous chronic diseases, including atherosclerosis, obesity/diabetes, and Alzheimer’s disease. The human APOE gene is polymorphic with three major alleles, ε2, ε3 and ε4, encoding apoE2, apoE3, and apoE4, respectively. The APOE gene is expressed in many cell types, including hepatocytes, adipocytes, immune cells of the myeloid lineage, vascular smooth muscle cells, and in the brain. ApoE is present in subclasses of plasma lipoproteins, and it mediates the clearance of atherogenic lipoproteins from plasma circulation via its interaction with LDL receptor family proteins and heparan sulfate proteoglycans. Extracellular apoE also interacts with cell surface receptors and confers signaling events for cell regulation, while apoE expressed endogenously in various cell types regulates cell functions via autocrine and paracrine mechanisms. This review article focuses on lipoprotein transport-dependent and -independent mechanisms by which apoE deficiency or polymorphisms contribute to cardiovascular disease, metabolic disease, and neurological disorders.

Toward a road map for global -omics: a primer on -omic technologies

As highlighted in a recent editorial in the Journal (Am J Epidemiol. 2014;180(2):127-128), the research area of "-omics" includes genomics, proteomics, metabolomics, and nascent fields of scientific inquiry such as epigenomics and exposomics. These fields can be collectively referred to as "global -omics." Increasing efforts have been made over the past 2 decades to identify and modify environmental risk factors among persons who are susceptible to disease because of their genotype and to integrate genetic information and other biological variables with information about individual-level risk factors and group-level or societal factors related to the broader residential, behavioral, or cultural context. In genome-wide association studies, only a small proportion of heritability is explained by genetic variants identified to date, which has prompted researchers in bioinformatics and biostatistics to take into account nonlinear relationships due to gene-environment or gene-gene interactions. The exposome, which is dynamic and variable, consists of all of the internal and external exposures an individual incurs over a lifetime. Both the epigenome and exposome change with age. The prenatal and perinatal periods are thought to be important times for epigenetic marking. Once the human epigenome has been fully mapped, identification of the effects of all deleterious environmental exposures according to duration of exposure and time period will be a complex undertaking, requiring collaborative epidemiologic studies.

Do caregivers' experiences correspond with the concerns raised in the literature? Ethical issues relating to anti-dementia drugs

BACKGROUND

The use of Cholinesterase inhibitors (ChE-Is) has raised debate in the literature on the ethical issues of drug treatment in dementia patients. These issues concern the quality of life of dementia patients and the process of decision-making regarding the use of ChE-Is. We interviewed caregivers of patients with dementia, focussing on issues of quality of life and the process of decision-making regarding the use of anti-dementia drugs.

AIM

The aim of this article is to explore whether the ethical concerns raised in the literature are actually in line with experiences in the daily practice of dementia care.

METHODS

Qualitative data that have been collected by semi-structured interviews with 12 caregivers of patients who (had) used ChE-Is.

RESULTS

The results seem to indicate that theoretical considerations should be modified in the light of the reported experiences of caregivers. For example, problematic consequences of an early diagnosis and the creation of unreasonable hope did not appear in the study. Also problems concerning the rising awareness of cognitive decline were not found.

CONCLUSION

In the interest of an ongoing ethical debate on the development and use of anti-dementia drugs it is important to further specify theoretical issues and to conduct empirical research into the practice of decision making and to get more insight in the perspectives of the patients using anti-dementia medicines themselves.

Apolipoprotein E, cholesterol metabolism, diabetes, and the convergence of risk factors for Alzheimer's disease and cardiovascular disease

High fat diets and sedentary lifestyles are becoming major concerns for Western countries. They have led to a growing incidence of obesity, dyslipidemia, high blood pressure, and a condition known as the insulin-resistance syndrome or metabolic syndrome. These health conditions are well known to develop along with, or be precursors to atherosclerosis, cardiovascular disease, and diabetes. Recent studies have found that most of these disorders can also be linked to an increased risk of Alzheimer's disease (AD). To complicate matters, possession of one or more apolipoprotein E epsilon4 (APOE epsilon4) alleles further increases the risk or severity of many of these conditions, including AD. ApoE has roles in cholesterol metabolism and Abeta clearance, both of which are thought to be significant in AD pathogenesis. The apparent inadequacies of ApoE epsilon4 in these roles may explain the increased risk of AD in subjects carrying one or more APOE epsilon4 alleles. This review describes some of the physiological and biochemical changes that the above conditions cause, and how they are related to the risk of AD. A diversity of topics is covered, including cholesterol metabolism, glucose regulation, diabetes, insulin, ApoE function, amyloid precursor protein metabolism, and in particular their relevance to AD. It can be seen that abnormal lipid, cholesterol and glucose metabolism are consistently indicated as central in the pathophysiology, and possibly the pathogenesis of AD. As diagnosis of mild cognitive impairment and early AD are becoming more reliable, and as evidence is accumulating that health conditions such as diabetes, obesity, and coronary artery disease are risk factors for AD, appropriate changes to diets and lifestyles will likely reduce AD risk, and also improve the prognosis for people already suffering from such conditions.

Wirksam, indiziert - und dennoch ohne Nutzen?

Individual treatment decisions for patients with Alzheimer dementia are often characterized by uncertainty about the actual benefit that specific treatments or procedures may bring about. It often even remains unclear how the benefit of a treatment may be determined. In this paper, three criteria for determining the benefit of a treatment measure are developed: An intervention (1) must be effective and (2) able to achieve a clinically relevant goal, which is (3) desirable for the individual patient. By using example of anti-dementia drug treatment, it will by shown that even if standard goals of dementia care are achieved, the benefit for the patient may still be questionable. A cognitive improvement or a delay of cognitive decay may even harm the patient. Therefore it is not sufficient to focus on the efficacy of a drug and on general goals of care when making decisions about individual dementia treatments. Rather it is necessary to reflect and discuss explicitly the goals of the individual patient. As shown by various examples, this will facilitate coherent, patient-orientated treatment decisions.

Cognitive impairment in preclinical Alzheimer's disease: a meta-analysis

To determine the size of the impairment across different cognitive domains in preclinical Alzheimer's disease (AD), a meta-analysis based on 47 studies involving 9,097 controls and 1,207 preclinical AD cases was conducted. There were marked preclinical deficits in global cognitive ability, episodic memory, perceptual speed, and executive functioning; somewhat smaller deficits in verbal ability, visuospatial skill, and attention; and no preclinical impairment in primary memory. Younger age (< 75 years) and shorter follow-up intervals (< 3 years) were associated with larger effect sizes for both global cognitive ability and episodic memory. For global cognitive ability, studies that used population-based sampling yielded larger effect sizes; for episodic memory, larger differences were seen in studies that preidentified groups in terms of baseline cognitive impairment. Within episodic memory, delayed testing and recall-based assessment resulted in the largest effect sizes. The authors conclude that deficits in multiple cognitive domains are characteristic of AD several years before clinical diagnosis. The generalized nature of the deficit is consistent with recent observations that multiple brain structures and functions are affected long before the AD diagnosis.

Issues of clinical trial design and data interpretations in hypertension

There are many drug studies for the treatment of hypertension. Most studies compare one drug with another to determine if a drug or class of drugs have unique benefits. In evaluating drug trials, separation of hypertension as compared with atherosclerotic events is important. Trials that focus on prevention of hypertension, especially with new noninvasive markers, may have a bigger part in reducing morbidity and mortality due to elevated blood pressure.