Regulation of Diabetes: a Therapeutic Strategy for Alzheimer's Disease?

Accumulated evidence suggests that sporadic cases of Alzheimer's disease (AD) make up more than 95% of total AD patients, and diabetes has been implicated as a strong risk factor for the development of AD. Diabetes shares pathological features of AD, such as impaired insulin signaling, increased oxidative stress, increased amyloid-beta (Aß) production, tauopathy and cerebrovascular complication. Due to shared pathologies between the two diseases, anti-diabetic drugs may be a suitable therapeutic option for AD treatment. In this article, we will discuss the well-known pathologies of AD, including Aß plaques and tau tangles, as well as other mechanisms shared in AD and diabetes including reactive glia and the breakdown of blood brain barrier in order to evaluate the presence of any potential, indirect or direct links of pre-diabetic conditions to AD pathology. In addition, clinical evidence of high incidence of diabetic patients to the development of AD are described together with application of anti-diabetic medications to AD patients.

Radiation resistant PIDECα cell using photon intermediate direct energy conversion and a 210Po source.

Radiation damage is a significant concern with both alphavoltaic and betavoltaic cells because their performance degrades, especially with high-energy - (>200keV) beta and alpha particles. Indirect excitation methods, such as the Photon Intermediate Direct Energy Conversion (PIDEC) framework, can protect the transducer from radiation. A nuclear battery using a 90Sr beta source was constructed by the author's research group, which demonstrated the radiation resistance of a PIDEC cell driven by beta particles (PIDECß cell). Use of alpha sources to drive nuclear batteries would appear to be much more attractive than beta sources due to higher potential power density. However, they are also subject to higher rates of radiation damage. This paper describes the successful incorporation of alpha particles into the PIDEC framework using the alpha emitter 210Po to form a PIDECα cell. The PIDECα cell transducer was exposed to alpha particles for over one year without experiencing adverse effects from radiation damage.

Inhibition of p53 attenuates ischemic stress-induced activation of astrocytes.

In cerebral ischemia, studies of cell death have focused primarily on neurons, but recent work indicates that ischemia also causes damage to astrocytes. Activation of astrocytes is a typical brain response to stress stimuli and is evidenced by changes in cellular function and morphology, as well as upregulation of glial fibrillary acidic protein. The tumor-suppressor transcription factor p53 has recently been implicated as a mediator of ischemia-induced neuronal death, but very little is known about its role in the activation or the death of astrocytes. The present study investigated the role of p53 in astrocyte and neuronal toxicity using in-vitro and in-vivo ischemic stroke models. We showed that p53 is activated in ischemic brains and in oxygen-glucose deprivation (OGD)-induced cell death in neurons and astrocytes. Inhibition of p53 activity using either pifithrin-α or small interference RNA interference reduced OGD-induced cell death and pifithrin-α reversed OGD-induced impairment of glutamate uptake in astrocytes, suggesting that p53 might play a key role in mediating neurotoxicity and gliotoxicity in ischemic brain injury. This study shows that p53 is activated in astrocytes during ischemia and that inhibition of the activity of this molecule prevents not only OGD-induced neuronal and astrocytic death but also astrocyte activation and impaired glutamate uptake. These findings suggest that p53 may be a valuable therapeutic target in ischemic brain injury.

Expression of Alzheimer-Type Neurofibrillary Epitopes in Primary Rat Cortical Neurons Following Infection with Enterococcus faecalis.

The neurofibrillary tau pathology and amyloid deposits seen in Alzheimer's disease (AD) also have been seen in bacteria-infected brains. However, few studies have examined the role of these bacteria in the generation of tau pathology. One suggested link between infection and AD is edentulism, the complete loss of teeth. Edentulism can result from chronic periodontal disease due to infection by Enterococcus faecalis. The current study assessed the ability to generate early Alzheimer-like neurofibrillary epitopes in primary rat cortical neurons through bacterial infection by E. faecalis. Seven-day old cultured neurons were infected with E. faecalis for 24 and 48 h. An upward molecular weight shift in tau by Western blotting (WB) and increased appearance of tau reactivity in cell bodies and degenerating neurites was found in the 48 h infection group for the antibody CP13 (phospho-Serine 202). A substantial increase in reactivity of Alz-50 was seen at 24 and 48 h after infection. Furthermore, extensive microtubule-associated protein 2 (MAP2) reactivity also was seen at 24 and 48 h post-infection. Our preliminary findings suggest a potential link between E. faecalis infection and intracellular changes that may help facilitate early AD-like neurofibrillary pathology. HighlightsEnterococcus faecalis used in the generation of AD neurofibrillary epitopes in rat.Infection increases Alz-50, phospho-Serine 202 tau, and MAP2 expression.Infection by Enterococcus may play a role in early Alzheimer neurofibrillary changes.