Alzheimer’s Factors in Ischemic Brain Injury

Aging nations are growing worldwide and now one in four of us may expect to experience an ischemic brain injury by the age 85. Stroke is the third most common cause of death and the second most common cause of dementia in industrialized societies with a mortality rate of circa 30% and an incidence of about 250–400 in 100,000. Stroke affects circa 700,000 people each year in the US alone, and about 50% of these individuals will experience lasting functional dysfunctions including sensory problems and cognitive deficits (Hillis 2006). It is estimated that ischemic stroke is responsible for approximately half of all patients hospitalized for acute neurological disorders. As outlined earlier, it can cause neurological dysfunctions in a number of neurological functions most commonly in the motor activity, cognitive decline, and dementia. Postischemic dementia is characterized by progressive cognitive deterioration including language, reasoning and memory. Of those individuals suffering from ischemic brain injury less than 50% will return to independent living during the following year. Even among those who regain functional independence, many stroke patients continue to manifest significant deficits, limitations and changes in their cognitive functioning and behavior. As such, stroke is one of the leading causes of disability and experiencing a stroke results in two-fold increase in risk for dementia. Other data showed that 1-in-10 developing dementia soon after first stroke, and over 1-in-3 being demented after recurrent stroke. The brain has limited responses to different kind of neuropathogens. Similar neuropathological features are observed in different cerebrovascular diseases and Alzheimer’s disease (Kalaria 2000; Pluta 2004a; Pluta 2004b; De la Torre 2005; Pluta 2006a; Benarroch 2007; Niedermeyer 2007; Pluta 2007c; Bell, Zlokovic 2009). Brain stroke is the leading cause of cognitive impairment worldwide. These data are supported by observations in clinical as well as in experimental studies, which suggest that ischemic brain injury is a major risk factor of dementia ranking only second to age (Gorelick 1997; Pluta 2006a; Pluta 2007c). Dementia, which is observed following different brain ischemic injuries, is associated with intellectual impairment and finally brain atrophy (Hossmann et al., 1987; Loeb et al., 1988; Tatemichi et al., 1990; Pluta 2002b; Kiryk et al., 2011). Amyloid plaques, which are the main pathological hallmarks of Alzheimer’s disease, account for about 90% of dementias including ischemic-type dementia (Jendroska et al., 1995; Wisniewski, Maslinska 1996; Shi et al., 1998; Pluta, 2007a; Qi et al., 2007). The relationship between brain ischemic injury dementia and Alzheimer’s disease type dementia is recently much debated. The mechanisms of the progressive cognitive decline after ischemic brain injury are not yet clear