− この都医学研セミナーは終了しました。 −
Department of Oncology-Pathology, Karolinska Institutet, Sweden（Researcher）
Alcohol and drug addiction causes severe suffering for both the addict and relatives, and generates enormous costs for society. Unfortunately, the mechanisms behind addiction remain incompletely understood. One possible common pathway for addictive substances may be interference with hippocampal neurogenesis. Most animal studies report that alcohol impairs hippocampal neurogenesis. We studied this in the postmortem human brain using three different techniques; immunohistochemistry, stereology and retrospective neuronal age determination. The latter is based on the incorporation of nuclear-bomb-test-derived ¹⁴C into genomic DNA. We found that the numbers of proliferating cells (Ki67), stem/progenitor cells (SOX2) and immature neurons (DCX) in the dentate gyrus of hippocampus were reduced in subjects with an on-going alcohol abuse compared to controls. Using stereology with NeuN as a neuronal marker, we found a 50% loss of dentate gyrus granule cells in chronic alcoholics vs. controls. The third approach showed that chronic alcoholics had lower turnover rates of granule neurons than controls if the rates were corrected for a >30% cell loss in alcoholics. We also studied chronic cocaine users, who are not reported to show excessive granule cell loss, and their neuronal turnover rates were similar to controls. Even though the results might suggest that impaired neurogenesis is not a common feature to all forms of addiction, it may still be an important pathway for alcoholism.