Glial cell loss in the hippocampus of alcoholics.

Alcohol abuse is often accompanied by cognitive impairment. Memory and concentration problems, especially, are described in neuropsychologically tested abstinent alcoholics. This impairment seems to be reversible, because a neuropsychological study has reported that after >5 years of abstinence, former alcoholics performed normally compared with a control group. The neuropathological correlate to the cognitive impairment associated with alcoholism is still under debate. Hippocampus is an area of the brain primarily involved in learning and memory, and the hippocampus is affected in several demential diseases. Over recent years, it has become evident that the glial cells in the brain, especially the astrocytes, play a central part in many activities that are critical to the normal functions of the brain. The total number of neuron and glial cells in the hippocampus was estimated in five severely affected alcoholics and five controls with an unbiased stereological technique: the optical fractionator. A statistically significant loss of 37% of the glial cells was found globally in the hippocampus of the alcoholics compared with controls. A reduction of astrocytes and oligodendrocytes and, to a lesser degree, microglial cells accounted for this loss. No loss of neurons was found in the hippocampus from alcoholics. The loss of glial cells and the potential for regeneration of these cells after cessation of alcohol abuse is discussed in the light of the results of clinical studies of former alcoholics.