Recent research on the causes of Alzheimer's disease

ALWPs Improve Cognitive Function and Regulate Aβ Plaque and Tau Hyperphosphorylation in a Mouse Model of Alzheimer's Disease

Recently, we reported that ALWPs, which we developed by combining Liuwei Dihuang pills (LWPs) with antler, regulate the LPS-induced neuroinflammatory response and rescue LPS-induced short- and long-term memory impairment in wild-type (WT) mice. In the present study, we examined the effects of ALWPs on Alzheimer’s disease (AD) pathology and cognitive function in WT mice as well as 5x FAD mice (a mouse model of AD). We found that administration of ALWPs significantly reduced amyloid plaque levels in 5x FAD mice and significantly decreased amyloid β (Aβ) levels in amyloid precursor protein (APP)-overexpressing H4 cells. In addition, ALWPs administration significantly suppressed tau hyperphosphorylation in 5x FAD mice. Oral administration of ALWPs significantly improved long-term memory in scopolamine (SCO)-injected WT mice and 5x FAD mice by altering dendritic spine density. Importantly, ALWPs promoted spinogenesis in primary hippocampal neurons and WT mice and modulated the dendritic spine number in an extracellular signal-regulated kinase (ERK)-dependent manner. Taken together, our results suggest that ALWPs are a candidate therapeutic drug for AD that can modulate amyloid plaque load, tau phosphorylation, and synaptic/cognitive function.

Decade of the brain: neurological advances

In the last half century, neurological developments have been phenomenal and have escalated in this decade of the brain. Many infective disorders have been conquered, but AIDS has posed new challenges. Neuropharmacology has transformed the management of parkinsonism and epilepsy. New imaging techniques such as CT, NMR, PET and ultrasonic scanning have presented us with remarkable images of the nervous system in health and disease. Steroids control many autoimmune disorders; beta-interferon and other new drugs have begun to influence multiple sclerosis. Intensive care has saved many of those with head injury or acute neurological disorders, and we have greatly improved methods of rehabilitation. There are still many incurable neurological disorders but none are untreatable. Today's discovery in basic science brings tomorrow's improvement in patient care, as is clearly shown by molecular genetics. Some neurological and neuromuscular diseases in which the causal gene or genes have been located and characterised and in which the missing or abnormal gene product has been identified will be mentioned, as well as the prospects of carrier detection, antenatal diagnosis and gene therapy.

Alzheimer's disease and the aluminium connection: A literature review

This review explores the different areas of research that, over the past 35 years, have provided grounds for linking Alzheimer's disease and aluminium. However, in spite of the growing evidence, exposure to aluminium as a risk factor is yet to be confirmed. The evidence is discussed under four headings: evidence from brain aluminium studies; evidence from aluminium uptake studies; evidence from aluminium-related neurodegenerative conditions; and evidence from chronic aluminium exposure studies: aluminium in drinking water, and by occupational exposure.

Down's syndrome, dementia, and superoxide dismutase

Mental handicap includes specific behavioural phenotypes apparently caused by single enzyme errors or deletions, for example, compulsive self-mutilation and hypoxanthine-guanine phosphoribosyl transferase deficiency in the Lesch-Nyham syndrome. In Down's syndrome, the possession of additional genetic material is found to be linked to various physical abnormalities (premature cataract formation and hypothyroidism). These close associations between types of behaviour, illnesses, and known genetic abnormalities offer promising avenues for research. In this article we concentrate on the well known link between Down's syndrome and presenile dementia.

Substance P and neurodegenerative disorders. A speculative review

The causes of the neurodegenerative disorders of Parkinson's disease (PD), Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS) are unknown. It is proposed that all these disorders result primarily from a loss of trophic peptidergic neurotransmitter, possibly Substance P (SP). This loss in turn produces the classical neuronal degeneration seen in each of these diseases and occurs due to a combination of natural aging and chronic autoimmune destruction following a viral infection of the CNS, early in life. The loss is therefore slow and by the time of clinical presentation the inflammatory process is disappearing as the antigenic stimulus lessens with its removal. The implications of the theory in terms of future research and therapy are briefly discussed.

Elevation in relative levels of brain membrane unsaturated fatty acids in Alzheimer's disease: high resolution proton spectroscopic studies of membrane lipid extracts

Unsaturation indices of cerebral cortex membrane phospholipids in Alzheimer's disease were determined utilizing high resolution proton nuclear magnetic resonance (NMR) spectroscopy of lipid extracts. The unsaturation index of Alzheimer's brain was found to be significantly higher (P less than 0.01) than that of age-matched controls. The study provides further support for the hypothesis that alteration in phospholipid metabolism, especially an elevation in unsaturated fatty acids, may play a role in the pathogenesis of Alzheimer's disease.

The brain and higher mental function

Critical evaluation of biological theories of psychiatric disorder requires an understanding of current concepts of higher mental function and its related biology. Both the nature of the topic and the rapidity of advances in the field make it difficult to obtain an updated synthesis. Part I of this paper attempts to provide that by reviewing current concepts of the mind/body relationship, emotion, arousal, attention, consciousness and motivation. Part II considers those concepts in relation to recent work on the structure and function of the reticular, limbic and anterior cerebral systems. It is concluded that the model of the limbic system as subserving emotional life could now perhaps be set aside in favour of the model of a core set of chemically identified neurons in the reticular system being necessary but not sufficient to subserve higher mental function whilst also subserving other integrating functions for which no mental terminology is required. The problem of developing an eclectic theory of higher mental function that will embrace these concepts is discussed.

The social psychiatry of later life

Throughout the two million years of human existence, it is without precedent that the elderly should now constitute such a large proportion of the world's population. Although it is already trite to emphasise this remarkable change in the global population structure, the increase is nothing less than an awesome imperative for public health as a socially responsible science. By the year 2025 AD, the United Kingdom will have 14 million persons aged over 60, which would be 26% of the population. Just under two million of them will be over 80 years old (United Nations, 1985). In Australia and New Zealand, 24.8% of the population will be aged 60 years or more. About one million Australians will be 80 years or over. West Germany will have 2.4 million aged over 80, the USA 7.7 million. The People's Republic of China will have 19.3% of its 1.5 billion people who will be aged over 60, and over 25 million will be over 80 years.

Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia

A randomized, double-blind, placebo-controlled, parallel-group clinical trial was carried out to compare 24-week periods of treatment with 1 g acetyl-l-carnitine twice daily and placebo in the treatment of patients with dementia of the Alzheimer type. A total of 36 patients entered the trial, of whom 20 patients (7 active, 13 placebo) completed the full 24 weeks. Whilst several of the efficacy indices showed little change in either group during the trial, there was an apparent trend for more improvement in the acetyl-l-carnitine group in relation to the Names Learning Test and a computerized Digit Recall Test, both related to aspects of short-term memory. Similarly, there was a trend for reaction time in the computerized classification test to show less deterioration in the active treatment group. Changes within groups, and changes between groups, failed to reach statistical significance, at least partially because of the small number of patients available for analysis. Two indices of overall therapeutic benefit showed a trend for less deterioration in the active-treatment group than in the placebo group. Nausea and/or vomiting occurred in 5 patients in the acetyl-l-carnitine group. Laboratory tests revealed no signs of drug toxicity. The results suggest that acetyl-l-carnitine may have a beneficial effect on some clinical features of Alzheimer-type dementia, particularly those related to short-term memory.

Binswanger's disease (Part II): Pathogenesis of subcortical arteriosclerotic encephalopathy and its relation to other dementing processes

Subcortical arteriosclerotic encephalopathy (SAE) is a common though infrequently recognized dementia of the elderly. The unique vascular anatomy of the subcortical white matter and central brain stem probably predisposes those regions to chronic ischemia and incomplete infarction in the presence of various cardiovascular and hemodynamic insults. Recent studies have begun to define the risk factors for SAE, and others have shown it to be a condition frequently comorbid with the dementias of Alzheimer's disease, the multi-infarct state, and normal pressure hydrocephalus. Recent research into the etiologies of these disorders suggest certain pathogenetic links between them, strongly implying that they are not neatly distinct disease entities, as is commonly believed, and accounting for some of the overlap between these dementing illnesses seen clinically.