Intraperitoneal injection of the pancreatic peptide amylin potently reduces behavioral impairment and brain amyloid pathology in murine models of Alzheimer's disease

Amylin, a pancreatic peptide, and amyloid-beta peptides (Aβ), a major component of Alzheimer's disease (AD) brain, share similar β-sheet secondary structures, but it is not known whether pancreatic amylin affects amyloid pathogenesis in the AD brain. Using AD mouse models, we investigated the effects of amylin and its clinical analog, pramlintide, on AD pathogenesis. Surprisingly, chronic intraperitoneal (i.p.) injection of AD animals with either amylin or pramlintide reduces the amyloid burden as well as lowers the concentrations of Aβ in the brain. These treatments significantly improve their learning and memory assessed by two behavioral tests, Y maze and Morris water maze. Both amylin and pramlintide treatments increase the concentrations of Aβ1-42 in cerebral spinal fluid (CSF). A single i.p. injection of either peptide also induces a surge of Aβ in the serum, the magnitude of which is proportionate to the amount of Aβ in brain tissue. One intracerebroventricular injection of amylin induces a more significant surge in serum Aβ than one i.p. injection of the peptide. In 330 human plasma samples, a positive association between amylin and Aβ1-42 as well as Aβ1-40 is found only in patients with AD or amnestic mild cognitive impairment. As amylin readily crosses the blood-brain barrier, our study demonstrates that peripheral amylin's action on the central nervous system results in translocation of Aβ from the brain into the CSF and blood that could be an explanation for a positive relationship between amylin and Aβ in blood. As naturally occurring amylin may play a role in regulating Aβ in brain, amylin class peptides may provide a new avenue for both treatment and diagnosis of AD.

Falls, poisonings, burns, and road traffic injuries in urban Peruvian children and adolescents: a community based study

OBJECTIVES

To identify individual and household characteristics associated with serious falls, poisonings, burns and road traffic injuries (RTIs) for children in Lima, Peru.

METHODS

5061 households consisting of 10,210 children were included in this community based, cross-sectional study in San Juan de Miraflores (SJM), a low income, urban district of Lima, Peru. Households were eligible if there was a consenting adult and at least one resident child aged < or =18 years. A door to door survey was conducted in SJM, collecting childhood injury, demographic, and socioeconomic data. Analysis was done at the individual and household level for injuries severe enough to have required medical consultation.

RESULTS

The greatest burden of injury was from falls and RTIs. For individuals, male gender and age were the most important predictors of injuries. Households in which multiple injuries were reported were more likely to be poor (odds ratio (OR) 1.66, 95% CI 1.24 to 2.22) and overcrowded (OR 1.88, 95% CI 1.20 to 2.94). The occurrence of serious falls, poisonings, burns, and pedestrian RTIs significantly increased the likelihood of a second serious injury in the home (adjusted ORs ranged between 1.88 and 2.99).

CONCLUSION

All children from households in which an unintentional injury has occurred appear to have an increased likelihood of future injury; such high risk households may be readily identifiable in the clinical setting. Interventions in this environment designed to prevent subsequent injuries merit further investigation.